PROSE PACK: Essay Q&A for Anatomy, Physiology, Biochemistry

PROSE PACK Detailed Essay Questions and Answers ANATOMY I PHYSIOLOGY I BIOCHEMISTRY OLABAYO ESAN P.R.O.S.E ESSAY COMPILATION SIMPMED PROSE PACK SIMPMED CONTENTS ABOUT BOOK ........................................................................................ 2 CHAPTER 1: ANATOMY........................................................................ 3 CHAPTER 2: BIOCHEMISTRY .............................................................. 41 CHAPTER 3: PHYSIOLOGY ................................................................ 67 1 PROSE PACK SIMPMED ABOUT BOOK SimpMed’s PROSE PACK for Part I Medical student is the first edition of its series, focusing primarily on the essay component of the Part I Professional Examinations It is a collection of high-yield and very recent essay questions on all Part I topics including: Anatomy, Physiology, and Biochemistry Each chapter contains detailed answers to recent and re-curing essay questions with rich-illustrations to help prepare you for the in-coming Professional examinations. 2 PROSE PACK SIMPMED ANATOMY HUMAN FORM AND DEVELOPMENT ................................................................... UPPER LIMB ................................................................................................................ THORAX ...................................................................................................................... LOWER LIMB .............................................................................................................. ABDOMEN .................................................................................................................. HEAD AND NECK ...................................................................................................... NEUROANATOMY .................................................................................................... ENDOCRINE ............................................................................................................... PELVIS & PERINEUM ................................................................................................. 3 PROSE PACK SIMPMED HUMAN FORM AND DEVELOPMENT 1. LIST THE THREE TYPES OF JOINTS AND GIVE AT LEAST AN EXAMPLE UNDER EACH a) Fibrous Joint (Synarthroses)  Sutures (joint in the skull)  Syndesmoses (Interosseous membrane) b) Cartilaginous joint  Primary cartilaginous joint (Synchondroses): Growth plate  Secondary cartilaginous joint (Symphysis): IV disc c) Synovial joint  Ball and socket: Hip joint  Hinge: Elbow joint  Condylar: Wrist joint  Saddle: Sternoclavicular joint 4 PROSE PACK SIMPMED 5 PROSE PACK 2. SIMPMED WRITE A SHORT NOTE ABOUT THE FOLLOWING STAGES OF EMBRYOGENESIS a) FERTILIZATION  Introduction • It is the fusion of the mature spermatozoa and ovum to form a Zygote (2n) • Occurs in the ampulla of the uterine tube  Phases • Phase 1  Sperm penetrates the CORONA RADIATA  Aided by the action of sperm and uterine tube mucosal enzymes. • Phase 2  Sperm binds and penetrates the ZONA PELLUCIDA  Binding occurs through interaction of sperm glycosyltransferases and ZP3 receptors located on the zona pellucida.  This triggers the ACROSOME REACTION resulting in the release of acrosomal enzymes and the penetration of the zona pellucida • Phase 3  Fusion of sperm and oocyte cell membrane  This occurs when the sperm membrane contacts cell membrane of a secondary oocyte  This triggers the CORTICAL REACTION resulting in the release of cortical granules rendering both the zona pellucida and oocyte membrane impermeable to other sperm.  The secondary oocyte completes meiosis II, forming a mature OVUM and second POLAR BODY.  Male and female then pronuclei fuses, forming a ZYGOTE b) CELL CLEAVAGE  Introduction • It is a series of mitotic divisions undergone by a newly formed zygote.  Process • Zygote cytoplasm is successively partitioned or cleaved to form a blastula • This consists of smaller blastomeres that increases evenly number after every mitotic division  2-cell stage  4-cell stage  8-cell stage  16-cell stage • 2 to 8 cell-stage blastomeres are considered TOTIPOTENT • 16 cell-stage blastomeres are referred to as a MORULA 6 PROSE PACK SIMPMED 7 PROSE PACK 3. SIMPMED MATCH THE CORRESPONDING EPITHELIAL LINING OF THE FOLLOWING ANATOMICAL STRUCTURES S/N 1. SYSTEM CARDIOVASCULAR 2. DIGESTIVE 3. RESPIRATORY ORGAN Blood vessels Heart (Pericardium) Heart (Endocardium Gingiva Tongue Hard-Palate Oesophagus Stomach Small Intestine Large Intestine Rectum Anus 5. URINARY REPRODUCTIVE (Male) Stratified squamous keratinized Stratified squamous keratinized Stratified squamous keratinized Stratified squamous non-keratinized Stratified columnar Stratified columnar Stratified columnar Stratified columnar Stratified squamous non-keratinized Stratified squamous keratinized Stratified squamous non-keratinized Stratified squamous non-keratinized Pseudostratified columnar ciliated Nose Pharynx Larynx Stratified squamous non-keratinized Pseudostratified columnar ciliated Pseudostratified columnar ciliated Pseudostratified columnar ciliated Trachea Bronchi Bronchioles (Terminal) Bronchioles (Respiratory) Alveoli 4. EPITHELIUM Simple Squamous Simple Squamous Simple Squamous Simple squamous Simple squamous Kidney (Glomerulus) Kidney (Proximal Convoluted Tubules) Kidney (Loop of Henley) Kidney (Distal Convoluted Tubules) Kidney (Collecting Duct) Renal Pelvis Ureter Urinary Bladder Urethra (Prostatic) Urethra (Membranous) Urethra (Spongy) Urethra Simple squamous Straight tubules Rete Testis Efferent ductulus Simple cuboidal Simple cuboidal Pseudostratified columnar 8 Simple cuboidal with microvilli Simple squamous Simple cuboidal without microvilli Simple cuboidal without microvilli Transitional Transitional Transitional Transitional Pseudostratified columnar non-ciliated Pseudostratified columnar non-ciliated PROSE PACK 6. SIMPMED REPRODUCTIVE (Female) 7. 8. 9. 10. ENDOCRINE LYMPHATIC NERVOUS SENSORY 11. INTEGUMENTARY Epididymis Vas deferens Ejaculatory duct Bulbourethral gland Seminal vesicle Pseudostratified columnar with stereocilia Pseudostratified columnar Simple columnar Simple columnar Pseudostratified columnar Ovaries Uterine tube Uterus Cervix Simple cuboidal Simple columnar ciliated Simple columnar ciliated Simple columnar non-ciliated Vagina Vulva Thyroid Lymph vessel Ependyma Cornea Ciliary body Iris Retina Olfactory Skin Sweat gland Sebaceous gland Stratified squamous non-keratinized Stratified squamous non-keratinized Stratified squamous non-keratinized Simple cuboidal Simple squamous Simple cuboidal Stratified squamous non-keratinized Simple columnar Simple squamous Simple cuboidal Pseudostratified columnar Stratified squamous keratinized Stratified cuboidal Simple cuboidal 9 PROSE PACK SIMPMED UPPER LIMB 1. DISCUSS THE TOPOGRAPHIC ANATOMY OF THE SHOULDER JOINT USING THE FOLLOWING HEADINGS a) Type of Joint  Ball and Socket Joint  Multi-axial Joint  Synovial Joint b) Articular surfaces  Glenoid cavity of the scapula  Head of the Humerus c) Ligaments  Glenohumeral ligament  Coracohumeral ligament  Coracoacromial ligament  Transvers humeral ligament d) Movement and Muscles  Flexion – Deltoid , Pectoralis major  Extension – Deltoid , Teres major  Abduction – Deltoid , Supraspinatus, Serratus anterior  Adduction - Pectoralis major , Teres major , Latissimus dorsi , Teres minor  Internal or Medial rotation - Pectoralis major , Teres major , Latissimus dorsi , Subscapularis  External or Lateral rotation - Teres minor , Infraspinatus e) Bursa  Sub-deltoid bursa  Sub-acromial bursa  Sub-tendinous bursa of scapularis  Synovial sheath f) Blood supply  Anterior circumflex humeral artery  Posterior circumflex humeral artery  Suprascapular artery g) Nerve  Axillary nerve (Hilton’s law) 10 PROSE PACK 2. SIMPMED NAME THE MUSCLE COMPARTMENTS OF THE ARM STRUCTURALLY AND FUNCTIONALLY a) STRUCTURALLY  Anterior compartment • Biceps • Brachialis • Coracobrachialis  Posterior compartment • Triceps b) FUNCTIONALLY  Flexor compartment • Biceps • Brachialis • Coracobrachialis  Extensor compartment • Triceps 11 PROSE PACK 3. SIMPMED LIST THE MUSCLES OF THE ARM STATING; THEIR ORIGIN, INSERTION AND INNERVATION a) Biceps  Origin • Short head – Tip of coracoid process of scapula • Long head – Supra-glenoid tubercle of scapula  Distal • Radial tuberosity  Innervation • Musculocutaneous nerve b) Brachialis  Origin • Distal half of anterior surface of Humerus  Insertion • Coronoid process • Ulna tuberosity  Innervation • Musculocutaneous nerve c) Coracobrachialis  Origin • Tip of coracoid process of scapula  Insertion • Middle third of medial surface of Humerus  Innervation • Musculocutaneous nerve d) Triceps  Origin • Long head - infra-glenoid tubercle of scapula • Medial head – posterior surface of Humerus, inferior to radial groove • Lateral head – posterior surface of Humerus, superior to radial groove  Insertion • Proximal end of olecranon of ulna and fascia of forearm  Innervation • Radial nerve e) Anconeus  Origin • Lateral epicondyle of Humerus  Insertion • Lateral surface of olecranon and superior part of posterior surface of the ulna  Innervation • Radial nerve 12 PROSE PACK SIMPMED 4. WHAT ARE THE BOUNDARIES OF THE CUBITAL FOSSA?  Superiorly: • Imaginary line between the medial and lateral epicondyles of the Humerus  Laterally: • Medial border of the brachioradialis  Medially: • Lateral border of the pronator teres  Roof: • Bicipital aponeurosis • Median cubital veins • Superficial fascia • Skin  Floor: • Brachialis 5. NAME THE CONTENT OF THE CUBITAL FOSSA  Median nerve  Brachial artery  Bicep’s tendon  Radial nerve  Cubital lymph nodes 13 PROSE PACK 6. SIMPMED USE THE FOLLOWING DIAGRAM TO ANSWER THE QUESTION BELOW a) b) c) Name this structure and identify A-F in the above diagram  Structure: RIGHT CLAVICLE  Landmarks • A – STERNAL END • B – IMPRESSION OF THE COSTOCLAVICULAR LIGAMENT • C – SUBCLAVIAN GROOVE • D – TRAPEZOID LINE • E – ACROMIAL END • F – CONOID TUBERCLE What surface of the structure is presented above?  INFERIOR SURFACE The concave surface represented by arc XY would in a normal subject face what direction  POSTERIOR 14 PROSE PACK SIMPMED THORAX 1. IN A TABULAR FORM STATE FOUR DIFFERENCES BETWEEN THE RIGHT AND LEFT LUNGS RIGHT LUNGS LEFT LUNGS LOBES Three lobes Two lobes MAIN BRONCHI Two bronchi One bronchus CARDIAC NOTCH Absent Present FISSURE Two fissures One fissure Horizontal fissure Oblique fissure Oblique fissure VOLUME Larger Smaller SIZE Shorter and wider Longer and narrower WEIGHT Heavier Lighter 2. LIST THE BOUNDARIES AND CONTENT OF THE SUPERIOR MEDIASTINUM a. Boundaries  Anteriorly:  Manubrium  Posteriorly:  Vertebral bodies of T1-T4  Superiorly:  Superior Thoracic Inlet  Inferiorly:  Imaginary line from sternal angle to T4/T5  Laterally:  Pleura & Apices of the Lungs b. Content  Thymus  Brachiocephalic veins, Internal Jugular and Subclavian  Brachiocephalic trunk, Left common carotid and Subclavian  Arch of Aorta  SVC  Phrenic nerve  Vagus nerve  Trachea  Esophagus  Thoracic duct 3. LIST THE BOUNDARIES AND CONTENT OF THE POSTERIOR MEDIASTINUM a. Boundaries  Anteriorly: ― Pericardium  Posteriorly: ― Vertebral bodies of T5-T12  Superiorly: ― Imaginary line from sternal angle  Inferiorly: ― Diaphragm  Laterally: ― Pleural and Lungs b. Content     Descending Thoracic Aorta and its branches Azygos venous system Thoracic duct, Thoracic Sympathetic trunk and Splanchnic nerves Esophagus and its plexus 15 PROSE PACK SIMPMED 16 PROSE PACK 4. SIMPMED WITH THE AID OF A WELL LABELLED DIAGRAM DESCRIBE THE PARTITIONING OF THE PRIMORDIAL ATRIUM a. Partitioning of the Primordial Atrium  A septum forms at the roof of the primitive atrium and grows toward the Endocardial (AV) cushion.  This is called the SEPTUM PRIMUM  A foramen is then created between the free edge of the septum primum and the AV cushions  This is called the FORAMEN PRIMUM  The septum primum eventually fuses with the AV cushions, obliterating the Foramen primum  A second foramen forms proximally at the center of the septum primum.  This is called FORAMEN SECUNDUM  Then a second septum forms to the right of the septum primum and also grows toward the Endocardial (AV) cushion.  This is called SEPTUM SECUNDUM  A third foramen is created between the upper limb of the septum primum and lower limbs of the septum secundum  This is called FORAMEN OVALE  During embryonic life, blood is shunted from the right atrium to the left atrium via the foramen ovale.  Later in life, the septum primum and septum secundum anatomically fuse to complete the formation of the atrial septum 17 PROSE PACK 5. SIMPMED IN A TABULAR FORM LIST THE MAJOR OPENINGS OF THE DIAPHRAGM, THEIR VERTEBRAL LEVEL AND STRUCTURES PASSING THROUGH MAJOR OPENINGS CAVAL OPENING VERTEBRAL LEVEL T8 ESOPHAGEAL HIATUS T10 AORTIC HIATUS T12 STRUCTURES IVC Right Phrenic nerve Esophagus Vagus nerve Aorta Thoracic duct Azygos vein 18 PROSE PACK SIMPMED LOWER LIMB 1. WRITE A SHORT NOTE ABOUT THE KNEE JOINT USING THE FOLLOWING HEADING a. Type of Joint i. Compound/ Modified Hinge Joint  Condylar part (Femoro-tibia)  Saddle part (Femoro-patella ii. Biaxial Joint iii. Synovial Joint b. Articular surfaces i. Lateral and Medial Condyles of the Femur ii. Lateral and Medial Condyles of the Tibia iii. Articular surface of the Patella iv. Patella surface of the Femur c. Ligaments i. Extracapsular ligament  Medial/Tibial collateral  Lateral/Fibular collateral  Oblique popliteal ligament  Arcuate popliteal ligament  Patella ligament ii. Intracapsular ligament  Anterior cruciate ligament  Posterior cruciate ligament  Medial meniscus  Lateral meniscus  Transverse Ligament d. Movement and Muscles i. Flexion – Hamstrings , Gracilis, Gastrocnemius, Plantaris, Popliteus ii. Extension – Quadriceps Femoris iii. Medial Rotation – Sartorius , Gracilis and Semitendinosus iv. Lateral Rotation – Biceps femoris and Popliteus e. Bursa i. Suprapatellar bursa ii. Prepatellar bursa iii. Infrapatellar bursa iv. Anserine Bursa f. Blood supply i. Genicular branches of Popliteal artery ii. Descending branch of the Lateral femoral circumflex artery iii. Anterior tibia recurrent artery g. Nerve supply i. Femoral nerve ii. Obturator nerve iii. Sciatic nerve iv. Common peroneal nerve v. Tibia nerve 19 PROSE PACK 2. SIMPMED WHAT ARE THE BOUNDARIES AND CONTENT OF THE FEMORAL TRIANGLE? a. Boundaries i. Superior:  Inguinal ligament ii. Lateral  Medial border of the Sartorius iii. Medially  Medial border of the Adductor longus iv. Roof  Fascia lata v. Floor  Adductor longus  Iliopsoas  Pectineus b. Content i. ii. iii. iv. v. vi. Femoral nerve Femoral branch of the Genitofemoral nerve Femoral artery Femoral vein Femoral canal Lymphatics 20 PROSE PACK 3. SIMPMED DESCRIBE THE ORIGIN, COURSE AND TERMINATION OF THE GREATER SAPHENOUS VEIN a. Origin i. Arises from the medial end of the Dorsal venous arch of the foot b. Course i. At the ankle it passes in front of the medial malleolus ii. In the leg it ascends along the medial aspect of the calf accompanied by the saphenous nerve iii. At the knee it passes behind the medial condyles of the femur and tibia iv. At the thigh it ascends along the medial aspect of the thigh c. Termination i. At the femoral triangle it pierces through cribriform fascia to assess the saphenous opening (fossa ovale) ii. Terminates by emptying into the femoral vein iii. Terminates by draining into the Axillary vein. 21 PROSE PACK SIMPMED ABDOMEN 1. A 25-YEAR-OLD FEMALE IS RUSHED INTO THE EMERGENCY ROOM WITH A GUNSHOT WOUND THAT PERFORATES THE ANTERIOR ABDOMINAL WALL. IN PREPARATION FOR SURGERY, YOU REVIEW THE ANATOMY OF THE ANTERIOR ABDOMINAL WALL. DISCUSS THE ORGANIZATION OF THE ANTERIOR ABDOMINAL WALL, AND INCLUDE MUSCLES, LIGAMENTS, FASCIA, NERVES, AND VASCULAR SUPPLY. a. Skin b. Camper’s fascia c. Scarpa’s fascia d. Anterolateral Abdominal Muscles  Anterior muscles  Rectus sheath  Rectus  Pyramidalis muscle  Lateral muscles  External oblique  Internal oblique  Transversus abdominis e. Transversalis fascia f. Retroperitoneal space and fat g. Parietal peritoneum 22 PROSE PACK 2. SIMPMED LIST THREE DIFFERENCES BETWEEN THE DIRECT AND INDIRECT INGUINAL HERNIA INDIRECT Children Congenital Presence of patent processus vaginalis Passes both the deep and superficial inguinal ring Found lateral to the inferior epigastric artery Content of the Hernia is found in the Scrotum DIRECT Elderly Acquired Weakness of the anterior abdominal wall Passes only superficial inguinal ring Found medial to the inferior epigastric artery Content is not found in the Scrotum 23 PROSE PACK 3. SIMPMED DIFFERENCES BETWEEN THE JEJUNUM AND ILEUM FEATURES JEJUNUM ILEUM WALL Thick and wide Thin and narrow LOCATION LUQ RLQ PROPORTION Left 2/5 Right 3/5 LENGTH 2.5m 3.5m VILLI More Less Larger Shorter Leaf like Finger like Present Present Fewer More AGGREGATED LYMPHOID or PAYERS PATCHES Absent Present MESENTERIC FAT Less More PERITONEAL WINDOWS Present Absent PLICA CIRCULARIS Prominent Sparse VASA RECTA Longer Shorter ARTERIAL ARCADES Less/Simple More/Complex SOLITARY LYMPHOID 24 PROSE PACK 4. SIMPMED IN A TABULATED FORM LIST 5 DIFFERENCES BETWEEN THE UPPER 2/3 AND LOWER 1/3 OF ANAL CANAL UPPER 2/3 LOWER 1/3 Simple Columnar Stratified Squamous Epithelium Hindgut/Anorectal canal Proctodeum Superior rectal vessels Middle and Inferior rectal vessels Inferior hypogastric nerves Inferior rectal nerve Internal Iliac Lymph nodes Superficial Inguinal Lymph nodes 25 PROSE PACK 5. SIMPMED IN A TABULATED FORM LIST 3 SITES OF PORTOSYSTEMIC ANASTOMOSIS, THE PORTAL AND SYSTEMIC VEINS INVOLVED IN EACH AND THE MOST COMMON PATHOLOGIC PRESENTATION SITE SYSTEM PORTAL PATHOLOGY ESOPHAGUS Esophageal branch of azygos vein Esophageal branch of left gastric vein Esophageal varices UMBILICUS or ANTERIOR ABDOMINAL WALL Superficial epigastric vein Paraumbilical vein Caput medusa ANAL CANAL or RECTUM Middle and Inferior rectal vein Superior rectal vein Hemorrhoids/ Rectal varices 26 PROSE PACK SIMPMED HEAD AND NECK 1. WITH THE AID OF DIAGRAM, WRITE A SHORT NOTE ABOUT THE LAYERS OF THE SCALP a. Skin  Outermost layer  Contains many hair follicles, sebaceous glands and sweat glands b. Connective tissue  Thick and dense superficial fascia  Highly vascularized and innervated c. Aponeurosis  Also called Epicranial or Galea aponeurosis  It is a broad, tough sheet of dense connective tissue covering the scalp  Serves as point of insertion for the occipital and frontal bellies of the occipitofrontalis muscle. d. Loose areolar tissue:  A sponge-like layer that is very loose and scanty  Contains a few small vessels and a potential space  Forms the DANGER AREA OF SCALP e. Peri-cranium:  Inner most layer  It is the periosteum of the outside of the skull  Made up of a dense layer of connective tissue that forms the external periosteum of the neurocranium. 27 PROSE PACK 2. SIMPMED LIST THE MUSCLES INVOLVED IN EXTRAOCULAR MUSCLES OF THE EYE-BALL, THEIR MOVEMENT AND NERVE SUPPLY EXTRAOCULAR MUSCLES SUPERIOR OBLIQUE SUPERIOR RECTUS INFERIOR RECTUS INFERIOR OBLIQUE MEDIAL RECTUS LATERAL RECTUS ACTION  Depression  Intortion  Abduction  Elevation  Intortion  Adduction  Depression  Extortion  Adduction  Elevation  Extortion  Abduction  Adduction  Abduction INNERVATION Trochlear (CN IV) SO4 Oculomotor (CN III) AR3 Abducens (CN VI) LR6 28 PROSE PACK 3. SIMPMED LIST THE BOUNDARIES OF THE POSTERIOR TRIANGLE a. Anteriorly:  Posterior border of SCM b. Posteriorly:  Anterior border of Trapezius c. Inferiorly:  Middle third of Clavicle d. Roof:  Investing cervical fascia e. Floor:  Pre-vertebral fascia and muscle 29 PROSE PACK 4. SIMPMED A LADY PRESENTED AT YOUR AIR-CONDITIONED CLINIC WITH PROTRUDING EYEBALLS, SIGNIFICANT SWEATING IN THE PALMS AND A MARKEDLY HOARSE VOICE. THEN YOU OBSERVED A SURGICAL SCAR IN FRONT OF THE ROOT OF THE NECK. a. What surgical procedure did this patient have?  SUB-TOTAL THYROIDECTOMY b. How do you explain the hoarseness?  Damage to the RECURRENT LARYNGEAL NERVE c. How do you explain the other symptoms?  Protruding eye ball  Occurs due to excessive production of extra-orbital fat seen in Graves’ disease  Excessive sweating  Hypersecretion T3 and T4 Thyroid Hormones from the remnant of the Thyroid gland  Excess Thyroid Hormones increases basal metabolic rate; hence raises the body temperature and causes excessive sweating 30 PROSE PACK SIMPMED NEUROANATOMY 1. WHICH VESSEL RUPTURE IS MOST LIKELY RESPONSIBLE FOR A SUB-DURAL HEMATOMA? a. BRIDGING VEINS connecting the SUPERIOR CEREBRAL VEINS to the SUPERIOR SAGITTAL VEINS 2. WHICH VESSEL RUPTURE IS MOST LIKELY RESPONSIBLE FOR AN EPIDURAL HEMATOMA? a. ANTERIOR BRANCH OF MIDDLE MENINGEAL ARTERY 3. WHICH VESSEL RUPTURE IS MOST LIKELY RESPONSIBLE FOR A SUB-ARACHNOID HEMORRHAGE? a. SACCULAR or BERRY ANEURSYM of the INTERNAL CAROTID ARTERY 31 PROSE PACK 4. SIMPMED WHICH VESSEL RUPTURE IS MOST LIKELY RESPONSIBLE FOR AN INTRACRANIAL HEMORRHAGE? a. LENTICULOSTRAITE ARTERY 32 PROSE PACK 5. SIMPMED KABIRU ASHAMU, A 59-YEAR-OLD CHAIRMAN OF NURTW AGBAKELE BRANCH SUDDENLY WOKE UP UNABLE TO LIFT HIS RIGHT LEG AND RIGHT ARM. A KNOWN HYPERTENSIVE AND DIABETIC, HE ALSO FOUND IT DIFFICULT TO SPEAK. HIS FACE SEEMED DEVIATED TO THE RIGHT SIDE WHEN HE TRIED TO BRUSH HIS TEETH WITH HIS LEFT HAND WHICH HE FOUND CLUMSY AS HE NATURALLY USES HIS RIGHT HAND. a. DISTINGUISH IN A TABULAR FORM BETWEEN UPPER AND LOWER MOTOR NEURON LESIONS b. FEATURES UPPER MOTOR NEURON LESION LOWER MOTOR NEURON LESION MUSCLE PARALYSIS Spastic paralysis Flaccid paralysis MUSCLE TONE Hypertonia Hypotonia DEEP TENDON REFLEX Hyperreflexia Hyporeflexia SUPERFICIAL REFLEX Absent Present BABINSKI SIGN Present Absent ATROPHY Disuse Atrophy/ None Severe Denervation Atrophy FASCICULATION Absent Present AT THE NEUROLOGY CLINIC, SARAH 63 YEARS COMPLAINED DIFFICULTY IN WALKING AND FEELS SHE IS WALKING ON AIR. PROFESSOR CHRISTIE CARRYING OUT TESTING AFTER DEMONSTRATION AND EXPLANATION ASKED HIM TO CLOSE HIS EYES AND TO TELL HER THE POSITION, SHE PLACES HER METACARPOPHALANGEAL JOINT. SHE FOUND IT DIFFICULT TO CORRECTLY IDENTIFY THE POSITION OF THIS JOINT IN PLANTAR OR DORSIFLEXION. YOU ARE ASKED TO IDENTIFY POSSIBLE PATHWAYS AFFECTED. LIST THE FEATURES SEEN IN HEMISECTION OF THE SPINAL CORD  Introduction  Lesion involving one lateral half of the spinal cord is called HEMISECTION OF THE SPINAL CORD  Also called BROWN SEQUARD SYNDROME  Clinical Features  At the Level of the Lesion • Ipsilateral Lower Motor Neuron Lesion (on the SAME SIDE)  Below the Level of the Lesion • Ipsilateral Upper Motor Neuron Lesion (on the SAME SIDE) • Ipsilateral loss of sensations of PROPIOCEPTION, VIBRATION, TACTILE TOUCH (on the SAME SIDE) • Contralateral loss of sensation of PAIN, TEMPRATURE, PRESSURE AND CRUDE TOUCH (on the OPPOSITE SIDE) 33 PROSE PACK 6. SIMPMED WHAT IS THE BRODMANN’S NUMBER FOR THE FOLLOWING AREAS OF THE CEREBRUM FUNCTIONAL AREAS OF THE CEREBRUM BRODMANN’S NUMBER Motor Area 4 Pre-Motor Area 6 Pre-Frontal Area 9, 10, 11 and 12 Frontal Eye Field 8 Primary Sensory/ Somatosensory Area 1 3,1,2 Sensory Association/ Somatosensory Area 2 5. 7 Primary Visual Area 17 Visual Association Area 18, 19 Auditory Area 41, 42 Broca’s area 44, 45 Wernicke’s area 22 34 PROSE PACK 7. SIMPMED WITH THE AID OF A DIAGRAM SHOW THE PATH OF THE CSF IN THE VENTRICULAR SYSTEM LATERAL VENTRICLES FORAMEN OF MONRO THIRD VENTRICLE CEREBRAL AQUEDUCT FOURTH VENTRICLE FOREAMEN OF LUSCHKA FORAMEN OF MAGENDIE SUBARACHNOID SPACE ARACHNOID VILLI or GRANULATIONS SUPERIOR SAGITTAL SINUS 35 PROSE PACK SIMPMED ENDOCRINE 1. NIGERIA HAS THE HIGHEST NUMBER OF PEOPLE LIVING WITH DIABETES MELLITUS IN AFRICA. THE PANCREATIC ISLET IS VERY IMPORTANTNT IN THE PATHOGENESIS AND MANAGEMENT OF DIABETES MELLITUS. USE A WELLLABELLED DIAGRAM TO DESCRIBE TO DESCRIBE THE CELL TYPE IN THE PANCREATIC ISLET CELLS, THEIR QUANTITY AND HORMONES SECRETED CELL TYPE Alpha cells Beta cells Delta cells Epsilon cells PP cells QUANTITY 20% 70% 5-10% <5% <1% HORMONE SECRETED Glucagon Insulin Somatostatin Ghrelin Pancreatic Peptide 36 PROSE PACK 2. SIMPMED PLEASE FILL IN THE MISSING SPACES ZONE STEROID PRODUCED PRINCIPAL PRODUCT REGULATION Zona Glomerulosa Mineralocorticoids Aldosterone RAAS Angiotensin II Zona Fasciculata Glucocorticoid Cortisol CRH ACTH Zona Reticularis Androgen Dehydroepiandrosterone ACTH Adrenal medulla Catecholamine Epinephrine Sympathetic Nervous System 37 PROSE PACK SIMPMED PELVIS & PERINEUM 1. IN A TABULAR FORM LIST THE EMBRYONIC STRUCTURES OF THE EXTERNAL REPRODUCTIVE ORGANS STATING THE MALE AND FEMALE HOMOLOGOUS STRUCTURES EMBRYONIC STRUCTURE LABIOSCROTAL SWELLING MALE Scrotum FEMALE Labia Majora GENITAL TUBERCLE Dorsal surface of Penis Clitoris UROGENITAL FOLDS Ventral surface of Penis Labia Minora UROGENITAL SINUS Bulbourethral gland Bartholin’s gland 2. LIST THE LAYERS OF THE SCROTUM FROM OUTSIDE TO INSIDE a. Skin b. Dartos fascia and muscle c. External spermatic fascia d. Cremasteric fascia and muscle e. Internal spermatic fascia f. Tunica vaginalis 3. HIGHLIGHT THE 4 MECHANISMS BY WHICH THE MALE REPRODUCTIVE SYSTEM REGULATES TEMPERATURE AT THE SITE OF THE TESTIS a. Pampiniform plexus b. Dartos muscle and changes in the scrotal skin c. Cremasteric muscle and reflex 38 PROSE PACK 4. SIMPMED ABOUT PREGNANCY AND THE PELVIS During pregnancy, the joints and ligaments in the pelvis relax, leading to increase in pelvic movements. The relaxation is caused by the increase in reproductive hormones and in particular the presence of the __RELAXIN____ hormone. The following changes take place: freer movement between the inferior parts of the vertebral column and the pelvis; greater rotation of the pelvis making the sacroiliac union less effective; increase in interpubic distance between the loosening of the interpubic disc; coccyx moves posteriorly during childbirth. The one diameter that remains unaffected is the _____TRUE/OBSTETRICAL DIAMETER______ between the posterior aspect of the __PUBIC SYMPHYSIS____ and the ___SACRAL PROMONTORY______ 39 PROSE PACK 5. SIMPMED LIST THE ARTERIES THAT ARISE FROM THE ANTERIOR AND POSTERIOR INTERNAL ILIAC ARTERIES a. Anterior Division  Umbilical artery  Obturator artery  Inferior vesical artery  Vaginal artery  Uterine artery  Middle Rectal artery  Internal Pudendal artery  Inferior Gluteal artery b. Posterior Division  Iliolumbar artery  Lateral sacral artery  Superior gluteal artery 40 PROSE PACK SIMPMED BIOCHEMISTRY M.C.M.B ....................................................................................................................... ACID & BASE ............................................................................................................. ENZYMOLOGY ......................................................................................................... CARBOHYDRATE METABOLISM ............................................................................. PROTEIN METABOLISM ........................................................................................... LIPID METABOLISM ................................................................................................... NUCLEIC ACID METABOLISM ................................................................................. HORMONES & VITAMINS ....................................................................................... GENE EXPRESSION & REGULATION .................................................................... MISCELLANEOUS ...................................................................................................... 41 PROSE PACK SIMPMED M.C.M.B 1 THE PATHWAYS OF MACROMOLECULES’ METABOLISM CAN BE LINKED TOGETHER. DUSCISS WITH SPECIFIC PATHWAYS AND ILLUSTRATIONS A Introduction  The pathways of macromolecule metabolism are interconnected, allowing for the flow of molecules and energy between different pathways.  These interconnections ensure that metabolic pathways are regulated and coordinated to meet the energy demands and cellular needs of an organism.  This interconnection enables the efficient utilization of resources and coordination of metabolic processes within cells. B Pathways     Glycolysis and gluconeogenesis: - Glycolysis is the pathway that breaks down glucose into pyruvate, producing ATP and NADH. On the other hand, gluconeogenesis is the reverse pathway that synthesizes glucose from noncarbohydrate precursors. These two pathways are interconnected and regulate blood glucose levels. - Pathway ♦ Glycolysis: glucose → pyruvate + ATP + NADH ↑ gluconeogenesis: pyruvate + ATP + NADH → glucose Citric acid cycle and fatty acid oxidation: - The citric acid cycle (also known as the Krebs cycle) is a central metabolic pathway that oxidizes acetyl-CoA, producing NADH, fadh2, and ATP. - Fatty acid oxidation breaks down fatty acids into acetyl-CoA, which can enter the citric acid cycle. - Pathway ♦ Citric acid cycle: acetyl-CoA + NAD+ + fad + ADP + PI + H2O → CO2 + NADH + FADH2 + GTP + CoA-SH ↑ ♦ Fatty acid oxidation: fatty acid + CoA + NAD+ + FAD → acetyl-CoA + NADH + FADH2 Glycolysis and pentose phosphate pathway: - The pentose phosphate pathway (PPP) is an alternative pathway to glycolysis that generates NADPH and ribose-5-phosphate. - It can operate concurrently with glycolysis and provides important intermediates for nucleotide synthesis and antioxidant defense. - Pathway ♦ Glycolysis: glucose → pyruvate + ATP + NADH ↑ pentose phosphate pathway: glucose-6-phosphate → ribose-5-phosphate + NADPH Glycolysis and glycogenesis/glycogenolysis: - Glycolysis is linked to glycogenesis (the synthesis of glycogen) and glycogenolysis (the breakdown of glycogen). - Glycogen serves as a storage form of glucose in animals and is crucial for maintaining blood glucose levels. - Pathway ♦ Glycolysis: glucose → pyruvate + ATP + NADH ↑ glycogenesis: glucose → glycogen ↑ glycogenolysis: glycogen → glucose 42 PROSE PACK SIMPMED ACID & BASE 1 WRITE CONCISELY ON THE BUFFER SYSTEMS IN HUMAN BODY FLUIDS. A Introduction  Buffer systems play a crucial role in maintaining the pH. balance of human body fluids.  These systems are composed of a weak acid and its corresponding conjugate base, or a weak base and its corresponding conjugate acid.  They work together to resist changes in pH. by accepting or donating protons (H+) in response to changes in acid or base concentrations.  The main buffer systems in human body fluids include the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system.  These buffer systems work together to maintain the pH. of various body fluids within a narrow range, ensuring optimal cellular function. They play a vital role in processes such as acid-base balance, respiration, and kidney function. Without efficient buffer systems, even slight changes in pH. could disrupt essential biochemical reactions and compromise physiological processes. B Types    Bicarbonate buffer system: - The bicarbonate buffer system is the primary buffer system in the extracellular fluid, including blood. - It involves the reversible reaction between carbonic acid (H2CO3) and bicarbonate ions (HCO3-). - When there is an increase in acid concentration, the excess h+ ions combine with bicarbonate ions to form carbonic acid, shifting the equation to the left. In contrast, when there is an increase in base concentration, carbonic acid dissociates into bicarbonate ions and H+ ions, shifting the equation to the right. Phosphate buffer system: - The phosphate buffer system operates in both intracellular and renal fluids. - It involves the reversible reaction between dihydrogen phosphate ions (H2PO4-) and monohydrogen phosphate ions (HOP4^2-). - Similar to the bicarbonate buffer system, when there is an increase in acid concentration, excess H+ ions combine with monohydrogen phosphate ions to form dihydrogen phosphate ions, shifting the equation to the left. - When there is an increase in base concentration, dihydrogen phosphate ions release H+ ions to form monohydrogen phosphate ions, shifting the equation to the right. Protein buffer system: - The protein buffer system operates within cells and plasma. - Proteins, especially those containing histidine residues, can act as buffers by accepting or donating protons. When there is an increase in H+ concentration, proteins bind with h+ ions, acting as a weak acid. - Conversely, when there is an increase in base concentration, proteins release H+ ions, acting as a weak base. 43 PROSE PACK SIMPMED ENZYMOLOGY 1 WRITE CONCISELY ON A ENZYME INHIBITION  Introduction - Enzyme inhibition refers to the process by which the activity of an enzyme is reduced or completely stopped by a molecule known as an inhibitor. Inhibitors interact with enzymes and disrupt their normal catalytic function, leading to a decrease in the rate of enzyme-catalyzed reactions.  Types - - Reversible Enzyme Inhibition ♦ In reversible inhibition, the inhibitor binds to the enzyme non-covalently and can be easily dissociated, allowing the enzyme to regain its activity. ♦ Reversible inhibition can be further classified into competitive, non-competitive, and uncompetitive inhibition, depending on the location and mode of inhibitor binding. ♦ Competitive inhibition  Occurs when the inhibitor competes with the substrate for binding at the active site of the enzyme.  This type of inhibition can be overcome by increasing the substrate concentration, as it outcompetes the inhibitor for binding to the enzyme. ♦ Non-competitive inhibition  Occurs when the inhibitor binds to a site on the enzyme distinct from the active site, causing a conformational change in the enzyme that affects its catalytic activity.  Increasing the substrate concentration does not reverse non-competitive inhibition, as the inhibitor and substrate can bind simultaneously to the enzyme. ♦ Uncompetitive inhibition  Occurs when the inhibitor binds to the enzyme-substrate complex, preventing the release of the product.  This type of inhibition requires both the substrate and the enzyme to be present for binding to occur. Irreversible inhibition, ♦ Involves the formation of a covalent bond between the inhibitor and the enzyme, rendering the enzyme permanently inactive. ♦ Irreversible inhibitors often contain reactive functional groups that react with specific amino acid residues in the active site, resulting in enzyme inactivation. 44 PROSE PACK B SIMPMED CLINICAL ENZYME  Introduction - Clinical enzymes, also known as diagnostic enzymes or biomarkers, are specific enzymes that are measured in clinical laboratory tests to aid in the diagnosis, monitoring, and management of various diseases and medical conditions. - These enzymes are found within cells or released into the bloodstream as a result of tissue damage, organ dysfunction, or other pathological processes.  Function - Used as markers of organ or tissue damage because their levels in the blood or other body fluids can indicate the extent and severity of certain conditions. - Changes in enzyme levels are often associated with specific diseases, and measuring these changes can provide valuable information for ♦ Screening ♦ Diagnosis ♦ Monitoring ♦ Prognosis  Examples - Alanine transaminase (ALT) and Aspartate transaminase (AST): ♦ These enzymes are found in liver cells and are released into the bloodstream when liver damage or disease occurs. ♦ Elevated levels of ALT and AST are indicative of liver injury, such as hepatitis or cirrhosis. - Creatine kinase (CK): ♦ CK is an enzyme found predominantly in muscle tissues. ♦ Increased levels of CK in the blood can indicate muscle damage or diseases like myocardial infarction (heart attack), muscular dystrophy, or rhabdomyolysis. - Amylase and lipase: ♦ These enzymes are produced by the pancreas and are involved in the digestion of carbohydrates and fats, respectively. ♦ Elevated levels of amylase and lipase can indicate pancreatic disorders such as pancreatitis. - Troponin: ♦ Troponin is a cardiac enzyme released into the bloodstream when heart muscle cells are damaged, typically during a heart attack. ♦ Measurement of troponin levels is crucial in diagnosing acute myocardial infarction. - Prostate-specific antigen (PSA): ♦ PSA is an enzyme produced by the prostate gland. ♦ Elevated levels of PSA can indicate prostate cancer, prostatitis or benign prostatic hyperplasia 45 PROSE PACK 2 SIMPMED BRIEFLY EXPLAIN THE DIAGNOSTIC USE OF THE FOLLOWING ENZYMES A Aldolase  Aldolase is an enzyme that plays a crucial role in carbohydrate metabolism. In clinical diagnostics, the measurement of aldolase levels is used to assess tissue damage, particularly muscle and liver damage.  Elevated levels of aldolase in blood samples can indicate conditions such as muscular dystrophy, myositis, or liver disease.  Aldolase is commonly used as a marker for muscle-specific damage, and its levels are monitored to evaluate disease progression or response to treatment. B Lipase    Lipase is an enzyme involved in the digestion and metabolism of dietary fats. In clinical diagnostics, lipase levels are measured primarily to evaluate pancreatic function. Elevated levels of lipase in blood samples are indicative of pancreatic disorders, such as acute pancreatitis or chronic pancreatitis. Lipase is considered a more specific marker for pancreatic injury compared to other enzymes, such as amylase. Monitoring lipase levels helps in the diagnosis, assessment of severity, and management of pancreatic disorders C Creatine phosphokinase  Creatine phosphokinase, also known as creatine kinase (ck), is an enzyme found predominantly in muscle tissues.  In clinical diagnostics, CPK levels are measured to assess muscle damage or diseases.  Elevated levels of CPK in blood samples can indicate conditions such as muscle trauma, muscle inflammation (myositis), or muscle diseases like muscular dystrophy.  CPK is also a valuable marker for diagnosing and monitoring myocardial infarction (heart attack), as its levels rise rapidly following heart muscle damage.  Monitoring CPK levels helps in assessing muscle and heart health and guiding appropriate medical interventions. D Lactate dehydrogenase  Lactate dehydrogenase is an enzyme that is involved in energy metabolism, specifically in the conversion of lactate to pyruvate.  In clinical diagnostics, LDH levels are measured to assess tissue damage and identify the source of injury.  Elevated levels of LDH in blood samples can indicate tissue injury or cell death in various organs, such as the heart, liver, kidneys, or lungs.  LDH is used as a general marker for tissue damage and is often measured alongside other specific enzymes to aid in the diagnosis and monitoring of specific diseases or conditions. 46 PROSE PACK SIMPMED CARBOHYDRATE METABOLISM 1 GIVE A LUCID ACCOUNT OF THE BIOCHEMICAL EVENTS INVOLVED IN THE GENERATION OF ATP IN THE MITOCHONDRIA. A Introduction  The generation of ATP (adenosine triphosphate) in the mitochondria involves a series of biochemical events that occur through the process of cellular respiration.  Cellular respiration consists of three main stages: - Glycolysis - Citric acid cycle (also known as the Krebs cycle or TCA cycle) - Electron Transport Chain / Oxidative phosphorylation. B Biochemical event on ATP generation in the mitochondrial  At the end of glycolysis, a net gain of two ATP and Pyruvate molecules are produced per glucose molecule.  After glycolysis, if oxygen is available, pyruvate enters the mitochondria and undergoes further processing in the citric acid cycle.:  Each pyruvate molecule is converted into acetyl-CoA, generating NADH and releasing carbon dioxide.  Acetyl-CoA combines with a four-carbon molecule called oxaloacetate to form citrate (also known as citric acid).  Citrate goes through a series of reactions, releasing carbon dioxide and producing NADH and FADH2 in each step.  At the end of the cycle, oxaloacetate is regenerated to combine with another acetyl-CoA molecule, restarting the cycle.  During the citric acid cycle, several high-energy electron carriers (NADH and FADH2) are generated, which will be used in the next stage for ATP synthesis.  The final stage of ATP generation takes place in the inner mitochondrial membrane through oxidative phosphorylation. Here's an overview of the key steps involved:  NADH and FADH2, produced in glycolysis and the citric acid cycle, donate their electrons to the electron transport chain (ETC) embedded in the inner mitochondrial membrane.  As the electrons move through the ETC, energy is released and used to pump protons (H+) from the mitochondrial matrix into the intermembrane space, creating an electrochemical gradient.  The buildup of protons in the intermembrane space drives the flow of protons back into the matrix through an enzyme called ATP synthase. This process is known as chemiosmosis.  The flow of protons through ATP synthase powers the synthesis of ATP from ADP (adenosine diphosphate) and inorganic phosphate (PI). This is called oxidative phosphorylation.  Oxygen serves as the final electron acceptor in the ETC, combining with protons to form water.  The ATP generated through oxidative phosphorylation is the most abundant source of cellular energy, and this process produces the majority of the ATP molecules in the body. 47 PROSE PACK 2 SIMPMED DESCRIBE THE KREB CYCLE WITH EMPHASIS ON THE POINTS OF NADH PRODUCTION AND THE STEPS OF ATP PRODUCTION IN ELECTRON TRANSPORT SYSTEM FOR ENERGY a Introduction  The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle, is a central metabolic pathway that occurs in the mitochondria of eukaryotic cells.  It plays a crucial role in the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, and it generates energy-rich molecules such as NADH and FADH2, which are utilized in the electron transport system (ETS) for ATP production. b Steps  Acetyl-CoA Formation: - The Krebs cycle begins when acetyl-CoA combines with a four-carbon molecule called oxaloacetate, forming a six-carbon molecule called citrate. - This reaction is catalyzed by the enzyme citrate synthase.  Citrate Isomerization: - Citrate is then isomerized to isocitrate through a dehydration-rehydration process. - The enzyme Aconitase catalyzes this conversion.  Isocitrate Oxidation: - Isocitrate is further oxidized to form alpha-ketoglutarate, releasing one molecule of carbon dioxide (CO2) and generating one molecule of NADH. - The enzyme Isocitrate dehydrogenase catalyzes this reaction.  Alpha-Ketoglutarate Decarboxylation: - Alpha-ketoglutarate is converted to succinyl-CoA through decarboxylation, releasing another molecule of CO2 and producing one molecule of NADH. - The enzyme alpha-ketoglutarate dehydrogenase catalyzes this reaction, similar to the pyruvate dehydrogenase complex in glycolysis.  Succinyl-CoA Formation: - Succinyl-CoA is converted to succinate, with the production of one molecule of GTP (which can be directly converted to ATP) through substrate-level phosphorylation. - The enzyme succinyl-CoA synthetase catalyzes this reaction.  Succinate Oxidation: - Succinate is oxidized to fumarate, and this step involves the generation of one molecule of FADH2. - The enzyme succinate dehydrogenase, which is embedded in the inner mitochondrial membrane and part of the electron transport system, catalyzes this reaction.  Fumarate Hydration: - Fumarate is hydrated to form malate through the action of the enzyme fumarase.  Malate Oxidation: - Malate is oxidized to oxaloacetate, producing one molecule of NADH in the process. - The enzyme malate dehydrogenase catalyzes this reaction, regenerating oxaloacetate and completing the cycle. c ATP production  The NADH molecules generated during the Krebs cycle carry high-energy electrons that are passed to the electron transport system, located in the inner mitochondrial membrane.  This transfer of electrons generates a proton gradient across the membrane, which drives ATP synthesis through oxidative phosphorylation.  The electrons from NADH are transferred through various protein complexes in the electron transport chain, ultimately reducing molecular oxygen (O2) to water (H2O) and creating a flow of protons (H+) across the membrane.  This proton flow drives the ATP synthase complex, which synthesizes ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi). 48 PROSE PACK SIMPMED 49 PROSE PACK SIMPMED PROTEIN METABOLISM 1 DESCRIBE ANY TWO INBORN ERRORS OF PROTEIN AND AMINOACID METABOLISM A Phenylketonuria DEFINITION EPIDERMIOLOGY TYPES Phenylketonuria (PKU) is inherited as an autosomal recessive trait characterized by the accumulation of phenylalanine 1 in 15,000 births Classic PKU Non-classic PKU CAUSES Classic PKU  Phenylalanine hydroxylase deficiency Non-classic PKU  Tetrahydrobiopterin deficiency BIOCHEMICAL BASIS Classic PKU Phenylalanine hydroxylase (PAH) deficiency Reduced conversion of phenylalanine to tyrosine Causes accumulation of excess phenylalanine Excess phenylalanine into transformed into phenylalanine metabolites like phenylpyruvate, phenylacetate  These metabolites are excreted in urine Non-classic PKU  Tetrahydrobiopterin (BH4) deficiency  Reduced conversion of phenylalanine to tyrosine  Causes accumulation of excess phenylalanine and deficiency in tyrosine, tryptophan and neurotransmitters  Excess phenylalanine into transformed into phenylalanine metabolites like phenylpyruvate, phenylacetate  These metabolites are excreted in urine Growth restriction Psychomotor delay Seizures Microcephaly Mental retardation Musty odor of urine     CLINICAL FEATURES DIAGNOSIS MANAGEMENT Newborn Screening  Serum Phenylalanine:- > 120mol/L or 2mg/dL Diagnostic  Urine test – Musty odor – Phenylketones in urine Dietary modification • Low phenylalanine diet • High tyrosine diet • BH4 supplementation • Avoid high protein diet • Give carbohydrate, fruits and vegetable rich diet 50 PROSE PACK B SIMPMED Alkaptonuria DEFINITION EPIDERMIOLOGY CAUSES BIOCHEMICAL BASIS CLINICAL FEATURES DIAGNOSIS MANAGEMENT Alkaptonuria is an inborn metabolic disease transmitted as an autosomal recessive gene resulting from impaired tyrosine and phenylalanine metabolism 1 in 250,000 births Deficiency of Homogentisate oxidase    Homogentisate oxidase deficiency Leads to impairment in the conversion of Homogentisate to 4-Maleylacetoacetate Causing accumulation of excess Homogentisate  Brownish Black discoloration of Urine  Ochronosis  Arthritis  Nephrolithiasis  Mitral valve sclerosis Blood  Elevated Homogentisate Urinalysis  Ferric chloride test – Urine turns black Dietary modification  Low phenylalanine and tyrosine diet Pharmacology  Give high dose Vitamin C 51 PROSE PACK 2 SIMPMED DISCUSS THE VARIOUS LEVELS OF STRUCTURAL ORGANIZATION OF A PROTEIN A Introduction  Proteins exhibit a hierarchical organization of structure, which can be categorized into four levels: - Primary structure - Secondary structure - Tertiary structure - Quaternary structure.  Each level contributes to the overall conformation and function of the protein.  The various levels of protein structure are intricately linked and influence each other.  Changes at one level can affect the higher-order structure and function of the protein B Organization  Primary structure: - The primary structure of a protein refers to the linear sequence of amino acids that make up the polypeptide chain. - The sequence is determined by the specific arrangement of codons in the corresponding gene. - The primary structure is critical because even a small change in the sequence can greatly impact the protein's structure and function.  Secondary structure: - The secondary structure describes the local folding patterns that occur within segments of the polypeptide chain. - The two most common secondary structures are alpha-helices and beta-sheets. Alpha-helices are formed by a coiled arrangement of the polypeptide chain, stabilized by hydrogen bonds between the amino acid residues. - Beta-sheets consist of multiple strands of the polypeptide chain aligned side-by-side, also held together by hydrogen bonds. - These secondary structures provide stability and contribute to the overall three-dimensional conformation of the protein.  Tertiary structure: - Tertiary structure refers to the overall three-dimensional conformation of the entire polypeptide chain. - It results from interactions between amino acid residues that are far apart in the primary sequence. - These interactions include hydrogen bonds, disulfide bridges, hydrophobic interactions, electrostatic interactions, and Van der Waals forces. - Tertiary structure is crucial for the protein's stability, folding, and function. - It determines the active site and binding properties of enzymes and the specific binding of other molecules, such as substrates or ligands.  Quaternary structure: - Quaternary structure refers to the arrangement and interaction of multiple polypeptide chains, or subunits, in a protein complex. - Some proteins consist of a single polypeptide chain (monomers), while others have multiple subunits (oligomers). - The subunits are held together by various forces, including hydrogen bonds, hydrophobic interactions, and disulfide bridges. - The quaternary structure contributes to the overall functionality of the protein complex, such as enzymatic activity or protein-protein interactions. 52 PROSE PACK SIMPMED 53 PROSE PACK SIMPMED LIPID METABOLISM 1 WRITE CONCISELY ON THE COMPLETE BETA OXIDATION OF FATTY ACIDS FOLLOWING A FATTY MEAL A Introduction  Following a fatty meal, the complete oxidation of fatty acids occurs through a series of biochemical reactions in the mitochondria of cells. B Process  Mobilization of fatty acids: - After a fatty meal, triglycerides stored in adipose tissue are broken down into fatty acids and glycerol through the process of lipolysis. - Fatty acids are then released into the bloodstream and transported to various tissues, including skeletal muscle and liver, for oxidation.  Activation of fatty acids: - Within the cytoplasm of cells, fatty acids are activated by attaching a molecule of coenzyme a (CoA) to their carboxyl end. - This reaction, catalyzed by an enzyme called fatty acyl-CoA synthetase, forms fatty acyl-CoA.  Entry into mitochondria: - Fatty acyl-CoA cannot directly enter the mitochondria for oxidation. Instead, it undergoes a series of reactions in the cytoplasm to form acylcarnitine, facilitated by the enzyme carnitine palmitoyltransferase I (CPT-I). - Acylcarnitine is then transported into the mitochondria through a carnitine-acylcarnitine translocase.  β-oxidation: - - Once inside the mitochondria, β-oxidation of fatty acids takes place. This process involves a repetitive series of four enzymatic steps: ♦ Oxidation:  The first step involves the oxidation of the fatty acyl-CoA by acyl-CoA dehydrogenase, producing a trans-2-enoyl-CoA. ♦ Hydration:  The trans-2-enoyl-CoA is then hydrated by enoyl-CoA hydratase, converting it into a β-hydroxyacyl-CoA. ♦ Oxidation:  The β-hydroxyacyl-CoA is further oxidized by β-hydroxyacyl-CoA dehydrogenase, forming a β-ketoacyl-CoA. ♦  Repeated β-oxidation steps: -   Cleavage:  Finally, thiolase catalyzes the cleavage of the β-ketoacyl-CoA, releasing a molecule of acetyl-CoA and shortening the fatty acyl-CoA chain by two carbon atoms. The β-oxidation steps are repeated until the entire fatty acyl-CoA chain is completely oxidized into multiple acetyl-CoA molecules. - The number of cycles depends on the length of the fatty acid chain. Generation of acetyl-CoA: - Acetyl-CoA produced from β-oxidation enters the citric acid cycle (also known as the Krebs cycle or TCA cycle) in the mitochondria. - In the citric acid cycle, acetyl-CoA is further oxidized to generate energy in the form of ATP. Electron transport chain and ATP production: - During the oxidation of acetyl-CoA in the citric acid cycle, reduced electron carriers (NADH and FADH2) are generated. - These electron carriers donate their electrons to the electron transport chain in the inner mitochondrial membrane, leading to the production of ATP through oxidative phosphorylation. 54 PROSE PACK SIMPMED 55 PROSE PACK 2 SIMPMED BRIEFLY DISCUSS THE GENERATION OF ENERGY USING ALTERNATIVE BODY FUELS IN THE ABSENCE OF DIETARY GLUCOSE. A Introduction  In the absence of dietary glucose, the body can utilize alternative fuels to generate energy through a process called gluconeogenesis and ketogenesis. B Gluconeogenesis:  Gluconeogenesis is the process by which the body synthesizes glucose from non-carbohydrate sources, primarily glycerol (from triglyceride breakdown).  It occurs mainly in the liver and to a lesser extent in the kidneys.  During gluconeogenesis, glycerol, derived from the breakdown of stored triglycerides, can also be converted into glucose.  Glycerol is first converted into dihydroxyacetone phosphate (DHAP), an intermediate in glycolysis, which can be converted further into glucose.  Gluconeogenesis helps maintain blood glucose levels during periods of fasting, prolonged exercise, or low carbohydrate intake, ensuring a steady supply of glucose for energy. C Ketogenesis:  Ketogenesis is the process of producing ketone bodies, specifically acetoacetate and βhydroxybutyrate, as alternative fuel sources when glucose availability is limited.  Ketone bodies are synthesized in the liver from fatty acids through a series of enzymatic reactions.  During periods of low glucose availability, such as fasting or a low-carbohydrate diet, the body relies on stored triglycerides in adipose tissue for energy.  Fatty acids are released from adipose tissue and transported to the liver, where they undergo βoxidation to generate acetyl-CoA.  Excess acetyl- CoA produced from fatty acid breakdown cannot directly enter the citric acid cycle due to the limited availability of oxaloacetate, a key intermediate.  Instead, acetyl- CoA is converted into ketone bodies through ketogenesis.  Ketone bodies can then be released into the bloodstream and transported to various tissues, such as the brain and muscles, to be utilized as an energy source.  The brain, in particular, can use ketone bodies as an alternative fuel during prolonged fasting or in individuals following a ketogenic diet, where carbohydrate intake is severely restricted. 56 PROSE PACK SIMPMED NUCLEIC ACID METABOLISM 1. ILLUSTRATE THE DE NOVO PATHWAY OF NUCLEOTIDE BIOSYNTHESIS A. Introduction  Nucleotide biosynthesis is the process by which nucleotides, the building blocks of DNA and RNA, are synthesized in cells.  There are two main pathways for nucleotide biosynthesis:  De novo pathway  Salvage pathway. B. De novo purine nucleotide biosynthesis:  Step 1:  The first step in de novo purine biosynthesis involves the synthesis of phosphoribosyl pyrophosphate (PRPP). PRPP is formed from ribose-5-phosphate, derived from the pentose phosphate pathway, and ATP.  The enzyme involved in this step is PRPP synthetase.  Ribose-5-phosphate + ATP → PRPP + PPI  Step 2:  PRPP reacts with glutamine to form 5-phosphoribosylamine.  This reaction is catalyzed by the enzyme amidophosphoribosyltransferase (also known as PRPP amidotransferase).  PRPP + glutamine → 5-phosphoribosylamine + PPI + glutamate  Step 3:  5-phosphoribosylamine is then transformed into inosine monophosphate (IMP) through a series of reactions.  The key intermediates in this pathway include 5-phosphoribosyl-1-amine (PRA), 5phosphoribosylglycinamide (PRGAR), and 5-phosphoribosylformylglycinamidine (FGAM).  Several enzymes are involved in these transformations.  In the end, imp is produced, which serves as a precursor for the synthesis of other purine nucleotides, such as adenosine monophosphate (amp) and guanosine monophosphate (GMP). C. De novo pyrimidine nucleotide biosynthesis:  Step 1:  The first step in de novo pyrimidine biosynthesis involves the synthesis of carbamoyl phosphate from glutamine and bicarbonate. The enzyme carbamoyl phosphate synthetase II (CPS II) catalyzes this reaction.  Glutamine + Bicarbonate + 2 ATP → Carbamoyl phosphate + 2 ADP + PI  Step 2:  Carbamoyl phosphate reacts with aspartate to form carbamoyl aspartate. This reaction is catalyzed by the enzyme aspartate transcarbomoylase.  Carbamoyl phosphate + Aspartate → Carbamoyl aspartate + PI  Step 3:  Carbamoyl aspartate is then converted into dihydroorotate by the enzyme dihydroorotase.  Carbamoyl aspartate → Dihydroorotate + H2O  Step 4:  Dihydroorotate is oxidized to orotate by the enzyme dihydroorotate dehydrogenase, utilizing a flavin mononucleotide (FMN) cofactor.  Dihydroorotate + FMN → Orotate + FMNH2  Step 5:  Orotate is phosphoribosylated by PRPP to form orotidine 5'-monophosphate (OMP). This reaction is catalyzed by the enzyme orotate phosphoribosyl transferase (OPRT).  Orotate + PRPP → OMP + PPI  Step 6:  OMP is decarboxylated to form uridine monophosphate (ump) by the enzyme orotidylate decarboxylase.  OMP → UMP + CO2  Ump is a precursor for the synthesis of other pyrimidine nucleotides, such as cytidine monophosphate (CMP) and thymidine monophosphate (TMP). 57 PROSE PACK SIMPMED 58 PROSE PACK 2. SIMPMED WRITE SHORT NOTES ON THE SALVAGE PATHWAY OF NUCLEOTIDE BIOSYNTHESIS A. Introduction  The salvage pathway of nucleotide biosynthesis is an essential cellular process that recycles preformed nucleotide bases and nucleosides to synthesize new nucleotides.  Unlike the de novo pathway, which involves the synthesis of nucleotides from simple precursors, the salvage pathway allows cells to conserve energy and reduce the demand for de novo synthesis by reusing existing nucleotide components. B. Pathway  Salvage of nucleosides:  In the salvage pathway, nucleosides are salvaged and converted back into nucleotides. Nucleosides are composed of a nitrogenous base (adenine, guanine, cytosine, thymine, or uracil) linked to a sugar (ribose or deoxyribose) but lack a phosphate group.  When nucleosides are released during the degradation of RNA and DNA or from other cellular processes, they can be recaptured and converted into nucleotides.  Phosphorylation of nucleosides:  In the salvage pathway, nucleosides are phosphorylated by specific enzymes to form nucleotides.  For example, adenosine (a nucleoside) can be phosphorylated to form adenosine monophosphate (amp) by the enzyme adenosine kinase.  Similarly, guanosine is converted to guanosine monophosphate (GMP) by guanylate kinase.  Recycling of nucleobases:  In addition to salvaging nucleosides, the salvage pathway can also recycle free nucleobases (the nitrogenous bases without the sugar).  For example, free adenine can be converted back into amp by the enzyme adenine phosphoribosyl transferase (APRT), and hypoxanthine can be recycled into IMP (Inosine monophosphate) by hypoxanthine-guanine phosphoribosyl transferase (HGPRT). C. Role  The salvage pathway plays a crucial role in maintaining an adequate pool of nucleotides in the cell.  Cells require a constant supply of nucleotides for DNA and RNA synthesis, energy metabolism (ATP and GTP), and various signaling pathways.  By recycling and reusing nucleotide bases and nucleosides, the salvage pathway helps meet these demands without the need for continuous de novo synthesis. 59 PROSE PACK SIMPMED HORMONES & VITAMINS 1. DISCUSS EXTENSIVELY ON THE ROLE OF THE FOLLOWING ON HUMAN NUTRITION AND HEALTH A. WATER SOLUBLE VITAMINS  Introduction  Water-soluble vitamins are a group of essential nutrients that dissolve in water and are not stored extensively in the body.  They play crucial roles in various biochemical processes and are vital for human nutrition and health.  The water-soluble vitamins include Vitamin B and Vitamin C.  Roles Water soluble vitamins Vitamin C (Ascorbic acid) Roles in Human nutrition and health  Plays a vital role in collagen synthesis, which is essential for skin, bones, and connective tissue health.  It enhances the absorption of iron from plant-based foods, supporting iron utilization in the body  Associated with a reduced risk of scurvy  It also supports the immune system, aids in wound healing, and may have anti-inflammatory effects. Vitamin B1(Thiamin)   Vitamin B2 (Riboflavin)  Plays a role in nerve function and muscle contraction. Associated with reduced risk of muscle weakness, nerve damage, and cardiovascular problems Plays a role in energy metabolism and serves as a precursor for coenzymes required in various cellular processes. Associated with a reduced risk of skin disorders, eye problems, and oral health issues, including cracked lips and a swollen tongue Plays a critical role in energy metabolism and cellular respiration. It is a precursor for coenzymes involved in redox reactions. Associated with a reduced risk of pellagra, a condition characterized by skin rashes, digestive issues, and neurological problems. Plays a role in energy metabolism as part of coenzyme A (CoA) and is essential for the synthesis of fatty acids, cholesterol, and steroid hormones. Associated with a reduced risk of symptoms like fatigue, numbness, and digestive disturbances. Plays a crucial role in protein metabolism, amino acid synthesis, and neurotransmitter synthesis. Associated with a reduced risk of neurological symptoms, such as depression and nerve damage. Plays an essential role in energy metabolism, fatty acid synthesis, and maintaining healthy skin, hair, and nails. Associated with a reduced risk of skin rashes, hair loss, and neurological symptoms. Plays a crucial role in DNA synthesis, cell division, and red blood cell production. Associated with a reduced risk of neural tube defects in the developing fetus and megaloblastic anemia. Plays a crucial role in DNA synthesis, nerve function, and the metabolism of amino acids and fatty acids. Associated with a reduced risk of pernicious anemia, leading to fatigue, weakness, and neurological symptoms.  Vitamin B3 (Niacin)    Vitamin B5 (Pantothenic acid)   Vitamin B6 (Pyridoxine)   Vitamin B7 (Biotin)   Vitamin B9 (Folic acid)   Vitamin B12 (Cyanocobalamin)   B. FAT SOLUBLE 60 PROSE PACK SIMPMED  Introduction  Fat-soluble vitamins are a group of vitamins that dissolve in fat and are stored in the body's fatty tissues and the liver.  They require fat for proper absorption and transport.  The fat-soluble vitamins include Vitamin A, Vitamin D, Vitamin E, and Vitamin K.  Roles Water soluble vitamins Vitamin A (Retinol) Vitamin D (Thiamin) Vitamin E (Tocopherol) Vitamin K Roles in Human nutrition and health  Plays a vital role in maintaining healthy vision, especially in lowlight conditions.  It also plays a role in immune function, skin health, and reproduction.  Associated with a reduced risk of night blindness, impaired immune function, and dry skin.  Adequate vitamin A intake supports eye health and immune system function.  Plays a crucial role in maintaining calcium and phosphorus levels in the body, supporting bone health and mineralization.  It also plays a role in immune function and cell growth regulation.  Associated with a reduced risk of rickets in children and osteomalacia in adults, causing weak and poorly mineralized bones.  Plays a crucial role as a potent antioxidant that protects cell membranes from oxidative damage.  It is involved in immune function and blood vessel health.  Associated with a reduced risk of neurological problems, muscle weakness, and impaired immune function.  Plays a role in blood clotting and bone health.  It is involved in the synthesis of clotting factors and bone proteins.  Associated with a reduced risk of bleeding disorders and impaired bone mineralization. 61 PROSE PACK SIMPMED GENE EXPRESSION & REGULATION 1. DESCRIBE AT LEAST THREE INBORN ERRORS ASSOCIATED WITH PURINE NUCLEOTIDE SYNTHESIS. A. Lesch-Nyhan syndrome:  Lesch-Nyhan syndrome is a rare x-linked recessive disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT).  HGPRT is involved in the purine salvage pathway, which recycles free purine bases (hypoxanthine and guanine) generated from the degradation of DNA and RNA.  In Lesch-Nyhan syndrome, mutations in the hprt1 gene result in deficient or absent HGPRT activity.  The lack of HGPRT activity leads to the accumulation of hypoxanthine and guanine, which are further metabolized to produce excessive amounts of uric acid.  This results in hyperuricemia, causing gout and other complications.  Additionally, the buildup of toxic metabolites, such as deoxyguanosine triphosphate (DGTP), in the brain is thought to be responsible for the severe neurological manifestations of Lesch-Nyhan syndrome, including intellectual disability, self-injurious behavior, and motor dysfunction. B. Adenosine deaminase (ADA) deficiency:  ADA deficiency is an autosomal recessive disorder caused by mutations in the ADA gene, resulting in a deficiency of the enzyme adenosine deaminase.  ADA is responsible for converting adenosine to inosine in the purine degradation pathway.  Without functional ADA, the degradation of adenosine is impaired, leading to the accumulation of toxic metabolites, particularly deoxyadenosine triphosphate (DATP).  The buildup of DATP is toxic to developing T and B Lymphocytes, which are crucial components of the immune system.  As a result, ADA deficiency leads to severe combined immunodeficiency (SCID), a condition characterized by a complete lack of functional immune cells, making affected individuals highly susceptible to infections. C. Xanthinuria:  Xanthinuria is a rare autosomal recessive disorder caused by the deficiency of the enzyme xanthine oxidase (XO).  XO is involved in the final steps of purine metabolism, converting hypoxanthine and xanthine to uric acid.  In individuals with xanthinuria, the lack of functional XO results in the accumulation of xanthine and hypoxanthine in the urine, leading to xanthine stones (Xanthinuria type I) or hypoxanthine stones (Xanthinuria type II).  These stones can cause kidney damage and recurrent kidney stones. 62 PROSE PACK 2. SIMPMED DESCRIBE THE ROLE OF THE FOLLOWING COMPONENTS IN THE TRANSLATIONAL PROCESS IN PROKARYOTES A. t-RNA  t-RNA plays a crucial role in the translation process in prokaryotes.  Each t-RNA molecule carries a specific amino acid, and its anticodon region is complementary to the codon on the m-RNA.  During translation, t-RNA molecules bring the appropriate amino acids to the ribosome, where they are added to the growing polypeptide chain.  The amino acid is attached to the t-RNA molecule through an ester bond at the 3' end. B. r-RNA     C. m-RNA     r-RNA is a major component of the ribosome, the cellular machinery responsible for protein synthesis. In prokaryotes, the small ribosomal subunit contains 16s r-RNA , while the large ribosomal subunit contains 23s and 5s r-RNA . These r-RNA molecules provide a scaffold for the ribosome and play a structural and catalytic role during translation. They help align the m-RNA and t-RNA in the ribosome and catalyze the formation of peptide bonds between amino acids during the elongation phase of translation m-RNA carries the genetic information from the DNA in the nucleus to the ribosomes in the cytoplasm, where protein synthesis occurs. It contains codons (triplets of nucleotides) that specify the sequence of amino acids in the polypeptide chain. During translation, the ribosome reads the m-RNA codons in a sequential manner and recruits the appropriate t-RNA molecules that carry the corresponding amino acids. This ensures that the correct sequence of amino acids is incorporated into the growing polypeptide chain. D. PEPTIDYLTRANSFERASE  Peptidyl-transferase is an enzyme that is a part of the large ribosomal subunit.  It catalyzes the formation of peptide bonds between adjacent amino acids in the growing polypeptide chain during translation.  The ribosome acts as a ribozyme, with the peptidyltransferase activity provided by the ribosomal RNA (r-RNA).  This process is fundamental for elongating the polypeptide chain and synthesizing a functional protein. E. PROTEIN FACTORS  Protein factors are additional proteins that assist in various stages of translation.  For example, initiation factors (IFS) help assemble the ribosome on the m-RNA and recruit the initiator t-RNA to start translation.  Elongation factors (EFS) assist in the movement of the ribosome along the m-RNA during the elongation phase.  Termination factors (RFS) recognize stop codons on the m-RNA, leading to the release of the newly synthesized protein from the ribosome. 63 PROSE PACK SIMPMED MISCELLANEOUS 1. EXPLAIN AND ILLUSTRATE THE BIOCHEMICAL EVENTS INVOLVED IN BLOOD CLOTTING. WHAT IS THE SIGNIFICANCE OF THIS PROCESS A. Introduction  Blood clotting, also known as coagulation, is a complex biochemical process that occurs in response to injury to prevent excessive bleeding and promote wound healing.  The process involves a series of sequential and tightly regulated biochemical events that ultimately lead to the formation of a stable blood clot. B. Biochemical events  Vasoconstriction:  When a blood vessel is injured, the first step in the clotting process is vasoconstriction.  The injured blood vessel contracts, reducing blood flow to the site of injury.  This constriction helps to limit the loss of blood and initiates the formation of a temporary platelet plug.  Platelet phase  Platelet adhesion ― When the blood vessel is damaged, exposed collagen and other components of the injured vessel wall attract platelets to the site. ― Platelet attach to the subendothelial structure of the vessels via Von Willebrand factor ― Platelets binds directly to Von-Willebrand factor via Gp Ib  Platelet activation: ― After binding to collagen platelet becomes activated ― This leads to a change in shape and release of mediators from its granules  Platelet aggregation ― Released mediators including ADP (adenosine diphosphate) and Thromboxane A2, helps to further recruit and activate more platelets. ― This process leads to the formation of a platelet plug, a temporary clot that helps seal the injured blood vessel.  Coagulation cascade:  Simultaneously, a series of biochemical reactions called the coagulation cascade is triggered.  The cascade involves a group of clotting factors, numbered from I to XIII, that interact in a stepwise manner to form fibrin, the main component of the blood clot.  The cascade occurs via the following pathway ― Intrinsic pathway:  The intrinsic pathway is initiated when factors XII, XI, IX, and VIII come into contact with exposed collagen at the site of injury.  This leads to the activation of factor X. ― Extrinsic pathway:  The extrinsic pathway is initiated by tissue factor (factor III) released from the damaged tissues.  Tissue factor forms a complex with factor VII, leading to the activation of factor X. 64 PROSE PACK SIMPMED ―  C. Common pathway:  Once activated, factor x combines with factor V and calcium ions to form the prothrombinase complex.  The prothrombinase complex converts prothrombin (factor II) to thrombin (factor IIa).  Thrombin then cleaves fibrinogen (factor I) into fibrin monomers.  Fibrin monomers spontaneously assemble into long, insoluble fibrin strands, which form the structural framework of the blood clot.  Factor XIII, also known as fibrin-stabilizing factor, crosslinks the fibrin strands, making the clot more stable and resistant to breakdown. Fibrinolysis:  Once the wound has healed, the clot is gradually dissolved through a process called fibrinolysis.  Plasmin, an enzyme derived from plasminogen, breaks down fibrin into soluble products, restoring blood flow and removing the clot. Significance:  the blood clotting process is of paramount importance in maintaining hemostasis, preventing excessive bleeding, and promoting wound healing.  Without effective blood clotting, even minor injuries could lead to life-threatening bleeding.  Additionally, the clotting process plays a vital role in controlling the spread of infections by trapping and isolating microorganisms at the site of injury.  However, the clotting process must be carefully regulated to avoid excessive clot formation, which can lead to thrombosis, a condition where clots form within blood vessels, obstructing blood flow and causing serious health complications such as heart attacks and strokes.  Proper regulation and balance of blood clotting are essential for maintaining the integrity of the circulatory system and ensuring overall health. 65 PROSE PACK 2. SIMPMED USING A DIAGRAM, BRIEFLY DESCRIBE THE NEUROTRANSMITTER RELEASE FROM THE SYNAPSE A. Action potential:  When an action potential reaches the presynaptic terminal, it depolarizes the membrane, causing voltage-gated calcium channels to open. B. Calcium influx:  Calcium ions (Ca2+) flow into the presynaptic terminal through the open calcium channels.  This influx of calcium triggers the fusion of neurotransmitter-containing vesicles with the presynaptic membrane. C. Exocytosis:  The fusion of neurotransmitter vesicles with the presynaptic membrane leads to exocytosis, a process where neurotransmitters are released into the synaptic cleft. D. Diffusion:  Neurotransmitters are released into the synaptic cleft and diffuse across the small gap between the presynaptic and postsynaptic neurons. E. Receptor binding:  Neurotransmitters bind to specific receptors located on the postsynaptic neuron's membrane. 66 PROSE PACK SIMPMED PHYSIOLOGY GENERAL PHYSIOLOGY ......................................................................................... BLOOD & BODY FLUIDS ......................................................................................... CARDIOVASCULAR PHYSIOLOGY ....................................................................... RESPIRATORY PHYSIOLOGY ................................................................................. GASTROINTESTINAL PHYSIOLOGY ..................................................................... RENAL PHYSIOLOGY ............................................................................................... NERVE & MUSCLE ..................................................................................................... NEUROPHYSIOLOGY .............................................................................................. ENDOCRINE PHYSIOLOGY .................................................................................... REPRODUCTIVE PHYSIOLOGY .............................................................................. 67 PROSE PACK SIMPMED GENERAL PHYSIOLOGY 1. WRITE AN ESSAY ON HISTORICAL PERSPECTIVE OF THE FEEDBACK MECHANISM A. Introduction  The term "homeostasis" was introduced by the American physiologist Walter Cannon in the early 20th century.  Cannon's work built upon the ideas of the French physiologist Claude Bernard, stating that the concept of feedback mechanisms is fundamental to understanding how living organisms maintain homeostasis and respond to changes in their internal and external environments.  The idea of feedback in physiological systems dates back centuries and has evolved through various scientific discoveries and contributions. B. 2. Historical perspective  Claude Bernard,  Referred to as the Father of Modern experimental physiology, was responsible for a major breakthrough in understanding the fundamental principles of organic life  He proposed the concept of the internal milieu, the idea that the body's internal environment must be kept constant despite changes in the external environment.  He explained that living body, though having need of the surrounding environment, is nevertheless relatively independent of it.  This independence which the organism has of its external environment, derives from the fact that in the living being the tissue are in fact withdrawn from direct external influences and are protected by a veritable internal environment which is constituted in particular by the fluid circulating in the body  Walter B Cannon  Expanded on the concept of Homeostasis by proposing that there are carefully coordinated physiological processes in the body through which homeostasis is maintained  These processes were referred to as the Control System or Feedback Mechanism LIST THE POSITIVE FEEDBACK MECHANISMS THAT YOU KNOW AND BRIEFLY DESCRIBE ANY ONE OF THEM A. POSITIVE FEEDBACK MECHANISM  Generation of nerve impulse  LH surge during ovulation  Hemostasis  Milk ejection  Parturition  Inflammatory responses B. MILK EJECTION  Introduction  This is achieved through a neuroendocrine reflex called Milk Ejection Reflex  Stimulus  The stimulus is suckling  Receptor  An infant suckling at the breast stimulates touch receptors on the nipples  Afferent or Input pathway  Impulses generated are relayed to the supraoptic and paraventricular nuclei of the hypothalamus  Integration center  At the Hypothalamus oxytocin is produced and stored in the posterior pituitary  Efferent or Output pathway  Released oxytocin is transported via blood towards the breast  Effector  At the breast, oxytocin causes contraction of the myoepithelial cells lining the duct walls, consequently milk is ejected from the alveoli through the nipple into the mouth of the waiting infant 68 PROSE PACK SIMPMED BLOOD & BODY FLUIDS 1. EXPLAIN 5 FUNCTIONS OF PLASMA PROTEINS A. Contribute to the immune system and the body’s defense  Immunoglobulins, also known as antibodies, are a specific group of plasma proteins produced by b lymphocytes.  They play a central role in the immune system by recognizing and neutralizing foreign antigens, such as bacteria, viruses, and other pathogens. Antibodies mark these invaders for destruction by other immune cells. B. Responsible for osmotic return of filtered fluid from interstitial fluid compartment  Plasma proteins, particularly albumin, contribute significantly to the maintenance of proper osmotic pressure in the blood vessels.  They help regulate the balance of water and solutes between the blood and tissues, preventing the excessive loss of fluid from the blood vessels. C. Blood buffers  Plasma proteins, especially albumin, act as buffering agents, contributing about 15% of blood buffering capacity  They help to maintain the pH balance of the blood.  They can accept or donate hydrogen ions (h+) to stabilize the blood pH and prevent drastic changes that could be harmful to the body's cells and enzymatic functions. D. Blood clotting  Several plasma proteins, including fibrinogen, prothrombin, and various clotting factors, are involved in the process of blood clotting.  When a blood vessel is injured, these proteins work together to form a stable blood clot, preventing excessive bleeding and promoting wound healing. E. Transport of Molecules  Plasma proteins act as carriers, facilitating the transport of various substances throughout the body.  For example, albumin, the most abundant plasma protein, transports hormones, fatty acids, and other molecules that are insoluble in water.  Globulins transport antibodies, lipoproteins carry lipids, and transferrin transports iron 2. USING A CHART, DESCRIBE THE BODY FLUID COMPARTMENT OF A 70KG ADULT MAN, PROVIDING THE RELATIVE PERCENTANGES AND THEIR VOLUMES IN LITERS 42L 60% in Males TOTAL BODY WATER TRANSCELLULAR FLUID <1% or 0.03mL INTRACELLULAR FLUID 40% or 28L PLASMA 5% or 3.5L INTRAVASCULAR 8% or 5L EXTRACELLULAR FLUID 20% or 14L INTERSTITIAL 12% or 9L 69 FORMED ELEMENTS 3% or 2.145L PROSE PACK 3. SIMPMED WRITE SHORT NOTE ON THE FOLLOWING A. STAGE OF RED BLOOD CELL PRODUCTION  Introduction  The process of formation of red blood cells is called Erythropoiesis  Stages HEMATOPOIETIC STEM CELLS MYELOID CELLS BFU-E LYMPHOID CELLS BFU-MK CFU-E Proerythroblast Basophilic Polychromatic Orthochromatic ERTHRYOCYTE 70 HPP CFC-1 PROSE PACK SIMPMED   Process  Stem cell stage ― Red blood cells are derived from of Pluripotential Hematopoietic Stem Cell which are uncommitted stem cells  BFU-E (Burst Forming Unit—Erythroid) ― Its EPO (erythropoietin) dependent stage ― Committed to erythroid cell formation  CFU-E (Colony Forming Unit—Erythroid) ― It is also EPO dependent stage ― Possess ABO Blood group antigen on its membrane  Proerythroblast cells stage. ― EPO & iron dependent stage. ― The stage between 3-4 is where Oestrogen stimulates RBC production ― Appears dark bluish on microscopy  Erythroblast stage. ― Iron dependent stage. ― It divided into;  Early Erythroblast stage: O involves ribosome synthesis.  Late Erythroblast stage: O Involves accumulation of haemoglobin.  Normoblast stage: O Involves the ejection of the nucleus.  Reticulocyte stage. ― Are immature erythrocytes ― Migrates from the bloodstream to the spleen ― Takes up to 48 to 72 hours in the spleen to maturate ― Maturation involves the removal in the spleen of fragment of nuclear material and left-over ribosomes  Mature red blood cells Duration  The whole process requires an average of 26 days (3 weeks) for the RBC maturation.  Stage 1 to stage 3 takes about 10 – 14 days.  Stage 3 to stage 5 takes about 5 – 7 days  Stage 6 to stage 7 takes about 1 -2 days. 71 PROSE PACK 4. SIMPMED WRITE A SHORT ESSAY ON ABO BLOOD GROUP AND DISCUSS ERYTHROBLASTOSIS FETALIS A. ABO BLOOD GROUP  Introduction  These are groups of antigens attached to oligosaccharide chain, protein and lipids on the red cell membrane  They are also called Agglutinogens, and are inherited character which give rise to antigen antibody reaction  Inheritance  Agglutinogen A & B are inherited according to Mendellian theory of inheritance  Blood group B may have inherited group B antigen from one of the parent and O antigen from the other parent  Thus an individual whose phenotype is B may have A genotype BB homozygous or genotype BO heterozygous  Types  There are four major blood groups according to the agglutinogen present on the red blood cells  These are Blood Group Discussion A Occurs in 40% of population RBC has only A antigen Plasma has Anti-B antibodies Can receive RBC from an A or O donor B Occurs in 10% of population RBC has only B antigen Plasma has Anti-A antibodies Can receive RBC from an B or O donor O Occurs in 45% of population RBC has only H antigen Plasma has both Anti-A and Anti-B antibodies Can receive RBC from A, B, O and AB donor It is a Universal recipient AB Occurs in 5% of population RBC has both A and B antigens Plasma has no antibodies Can donate RBC to A, B, O and AB recipient It is a Universal donor 72 PROSE PACK SIMPMED CARDIOVASCULAR PHYSIOLOGY 1. DESCRIBE THE AMPLITUDES AND INTERVALS OF A TYPICAL ECG WAVE. WHAT IS CONDUCTION BLOCK? A. AMPLITUDES AND INTERVALS OF A TYPICAL ECG WAVE  Amplitude  P wave ― The P wave represents atrial depolarization, which is the electrical activation of the atria. ― It is a small upward deflection and typically has an amplitude of 0.1-0.2 mv  R wave ― R wave represents ― It is a small upward deflection with an amplitude of 1 mv  Q wave ― Q wave represents ― It is a small downward deflection with an amplitude of about 0.1-0.3 mv  S wave ― S wave represents ― It is a small downward deflection with amplitude of about 0.3 mv in V₄-V₆ chest and limb leads.  T wave ― The T wave represents ventricular repolarization, which is the recovery of the ventricles after contraction. ― It is a dome-shaped waveform and typically has an amplitude of 0.3 mv.  QRS wave ― The QRS complex represents ventricular depolarization, which is the electrical activation of the ventricles. ― The total amplitude of the QRS complex is usually around 1.0 - 2.5mV  Intervals  PR interval ― The PR interval starts at the beginning of the P wave and ends at the beginning of the QRS complex. ― It represents the time taken for the electrical impulse to travel from the atria to the ventricles. ― The normal PR interval is about 0.18s  QT interval ― The QRS interval represents the time taken for ventricular depolarization. ― It starts at the beginning of the Q wave and ends at the end of the S wave. ― The normal QRS interval is usually about 0.40 s  QT interval ― The QT interval represents the total time for ventricular depolarization and repolarization. ― It starts at the beginning of the Q wave and ends at the end of the T wave. ― The duration of the QT interval varies with heart rate, and there are corrected formulas (e.g., QTc) to adjust for heart rate differences.is  ST interval ― ST interval is the period for ventricular repolarization. ― The normal ST interval is about 0.32 s. 73 PROSE PACK B. SIMPMED CONDUCTION BLOCK  Definition  Conduction block, also known as heart block, is a cardiac conduction disorder where the electrical signals that regulate the heart's rhythm are delayed or blocked as they pass through the heart's electrical conduction system. The conduction system consists of specialized cells that generate and transmit electrical impulses, coordinating the heart's contractions.  Types  First-degree heart block: in ― First-degree heart block, there is a delayed conduction of electrical impulses from the atria to the ventricles, leading to a prolonged pr interval on the ECG.  Second-degree heart block: ― Second-degree heart block; there is occasional dropped beats occur with or without a progressive PR interval change.  Third-degree heart block: ― Also known as complete heart block, in third-degree heart block, there is a complete blockage of electrical impulses between the atria and ventricles. ― As a result, the atria and ventricles contract independently, leading to a slow and potentially life-threatening heart rate. 74 PROSE PACK SIMPMED RESPIRATORY PHYSIOLOGY 1. WRITE AN ESSAY ON THE DIFFERENT FORMS OF CO2 TRANSPORT IN BLOOD A. Introduction  Carbon dioxide (CO2) is a waste product generated during cellular respiration and metabolism in the body.  Efficient removal of CO2 from tissues and its transport to the lungs for elimination is vital for maintaining acid-base balance and ensuring proper respiratory function.  CO2 is transported in the blood through three main forms: dissolved co2, bicarbonate ions (hco3-), and carbamino compounds. B. Forms  Dissolved CO2:  Dissolved CO2 refers to the physical dissolution of carbon dioxide in the plasma, where it exists as a simple gas in solution.  This form accounts for a small fraction of total CO2 transport in the blood.  The solubility of CO2 in plasma is relatively low, but it is essential for the immediate transport of CO2 from tissues to the lungs.  In the tissues, where cellular metabolism generates CO2, CO2 diffuses across cell membranes and enters the blood, where it dissolves in the plasma.  This dissolved CO2 is transported through the bloodstream and eventually reaches the lungs for elimination during exhalation.  Bicarbonate ions (HCO3-):  The majority of CO2 in the blood is transported in the form of bicarbonate ions.  This process involves a complex chemical reaction known as the bicarbonate buffer system.  It takes place primarily in red blood cells (erythrocytes) and is catalyzed by the enzyme carbonic anhydrase.  The bicarbonate buffer system can be summarized in the following steps: ― In the tissues, carbon dioxide diffuses into red blood cells. ― Inside the red blood cells, carbonic anhydrase catalyzes the combination of CO2 and water (H2O) to form carbonic acid (H2CO3). ― Carbonic acid then rapidly dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). ― The bicarbonate ions are transported out of the red blood cells and into the plasma in exchange for chloride ions (Cl-) through a transporter called the chloride shift. ― In the pulmonary capillaries, the reverse process occurs. Bicarbonate ions move back into the red blood cells, while chloride ions move back into the plasma. ― Carbonic anhydrase catalyzes the conversion of bicarbonate ions and hydrogen ions back into carbonic acid. ― Carbonic acid then breaks down into carbon dioxide and water, with the carbon dioxide diffusing out of the red blood cells and into the alveoli of the lungs for exhalation.  Carbamino compounds:  Carbamino compounds are formed by the combination of carbon dioxide with the amino groups of hemoglobin proteins in red blood cells.  This process is called carbamino formation and accounts for a small fraction of CO2 transport in the blood.  Hemoglobin has amino groups in its globin protein chains, and these groups can react with CO2 to form carbamino compounds.  This reaction is reversible, allowing CO2 to be released from hemoglobin in tissues with higher CO2 concentration and taken up in the lungs, where CO2 levels are lower.  Carbamino compounds play a minor role in CO2 transport but contribute to the overall regulation of CO2 levels in the blood. 75 PROSE PACK SIMPMED GASTROINTESTINAL PHYSIOLOGY 1. WRITE ON THE CONTROL OF GASTROINTESTINAL FUNCTION A. Introduction  The GI functions are regulated by signals from the neural, hormonal and paracrine mechanisms B. Control  Reflexes  Neural reflexes are the first mechanism involved in the control of GI function  There are two types of reflexes ― Long reflexes  Integrated within in the CNS  May originate in or outside of the GI tract  Feedforward & emotional reflexes are initiated and integrated entirely outside the GI tract  Also called cephalic reflexes ― Short reflexes  Integrated in the enteric nervous system  Initiated by changes in pH, distension, osmolarity, products of digestion  Submucosal plexus contains the sensory neurons  Afferent information to ganglia  Efferent information to submucosal and myenteric plexuses for control of secretion, motility and growth  GI peptide  Peptides released from the GI tract are also involved in regulating its functions  These peptides may either be ― Endocrine hormones, secreted into blood and acting on accessory organs, other part of the GI or in the brain ― Paracrine hormones, secreted into the lumen or extracellular fluid and acting on apical epithelial receptors or in the immediate vicinity of secretion  These peptide control GI functions by ― Altering GI secretion and motility ― Altering behavior related to eating  Some of these hormones includes gastrin, secretin, motilin, cholecystokinin  Autonomic/Enteric nervous system  Allows for the autonomous behavior of the digestive system  Structurally it is composed of ― Intrinsic neurons, similar to interneurons of CNS ― Extrinsic neurons, composed of autonomic neurons ― Glial support cells, similar to astrocytes in CNS ― Diffusion barrier formed by cells around capillaries in the ganglia are tight, just as the capillaries in the brain, forming the BBB  It releases Neurotransmitters and neuropeptide that act on non-adrenergic and noncholinergic receptors  It acts as its own integrating center, just as the CNS does 76 PROSE PACK SIMPMED RENAL PHYSIOLOGY 1. DISCUSS THE ROLE OF THE HAIRPIN COUNTER-CURRENT MECHANISM IN OSMOREGULATION A. Introduction  The hairpin counter-current mechanism is formed by the loop of Henle of the kidney and plays a critical role in osmoregulation.  Osmoregulation is the process by which organisms regulate the balance of water and solutes within their bodies to maintain proper internal fluid balance. B. Structure    The Loop of Henle is a U-shaped segment of the nephron, the functional unit of the kidney. It consists of a  Descending limb  A hairpin bend  Ascending limb. The hairpin counter-current mechanism involves the descending and ascending limbs of the loop of Henle and the surrounding medullary interstitium. C. Mechanism  Descending limb:  The descending limb is permeable to water but not to solutes like sodium and chloride ions.  As the ultrafiltrate moves down the descending limb, it encounters an increasing concentration of solutes in the medullary interstitium.  The high concentration of solutes in the interstitium creates an osmotic gradient, pulling water out of the descending limb by osmosis.  As a result, the fluid becomes more concentrated as it descends into the medulla.  At the thin segment of the loop of Henle there is passive diffusion of solutes but not water.  Hairpin bend:  At the hairpin bend, the ultrafiltrate reaches its highest concentration, known as the renal papillary osmolarity.  The hairpin bend is the deepest part of the nephron in the medulla.  Ascending limb:  The ascending limb of the loop of Henle is impermeable to water but actively transports solutes, such as sodium and chloride ions, out of the tubule and into the medullary interstitium.  As the ascending limb moves upward, the interstitial fluid becomes increasingly dilute. D. Role       The hairpin counter-current mechanism creates an osmotic gradient along the loop of Henle and the surrounding medullary interstitium. This gradient allows the kidney to concentrate urine effectively and conserve water. As the concentrated fluid moves down the descending limb, it loses water to the surrounding interstitium, leading to a concentrated fluid at the hairpin bend. Then, as the fluid moves up the ascending limb, solutes are actively transported out, further concentrating the interstitium. The combination of the descending limb's passive water reabsorption and the ascending limb's active solute transport establishes a countercurrent flow, where the fluid in the two limbs moves in opposite directions. This countercurrent exchange allows for the continuous concentration of solutes in the medullary interstitium, creating a favorable gradient for water reabsorption. Consequently, the kidney can produce concentrated urine, conserving water in the body and playing a vital role in osmoregulation to maintain proper fluid balance and regulate body fluid osmolality. 77

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