SKIN AND BODY MEMBRANES
Epithelial Membranes
• The cutaneous membrane is the:
• Mucous membranes
• Mucosae
•
• Serous Membranes
• Paired membranes that line:
• Parietal layer • Visceral layer –
• Serous Membranes are named based on their location:
•Parietal and visceral pleura surround:
•Parietal and visceral pericardium surround:
•Parietal and visceral peritoneum surround:
(e.g., digestive and respiratory tracts)
Skin (Integument)
•
Consists of three major regions
1.
2.
3.
Epidermis—
Dermis—
Hypodermis (superficial fascia)—
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Epidermis
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Cells of epidermis
• Keratinocytes—
• Melanocytes
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Layers of the Epidermis: Stratum Basale
•
• Also called stratum germinativum:
• Cells travel from basal layer to surface
• Takes 25–45 days
Layers of the Epidermis: Stratum Spinosum
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Layers of the Epidermis: Stratum Granulosum
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Layers of the Epidermis: Stratum Lucidum
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Layers of the Epidermis: Stratum Corneum
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• Functions
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Dermis
• Made up of Two layers:
• Papillary layer
• Reticular layer
Layers of the Dermis: Papillary Layer
• Papillary layer
• Composed of:
• Contains dermal papillae which may have:
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Layers of the Dermis: Reticular Layer
• Reticular layer
•Composed of:
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Skin Color
• Three pigments contribute to skin color:
1. Melanin
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2. Carotene
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3. Hemoglobin
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Appendages of the Skin
• Derived from the epidermis
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Sweat Glands
• Two main types of sweat (sudoriferous) glands
1. Eccrine sweat glands— abundant on palms, soles, and forehead
• Sweat:
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2. Apocrine sweat glands—confined to:
• Sebum:
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Sebaceous (Oil) Glands
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• Sebum
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Hair
• Functions
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• Consists of:
Hair Follicle
• Two-layered wall consisting of:
• Hair bulb:
• Hair follicle receptor (root hair plexus):
3
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• Arrector pili
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Structure of a Nail
•
•Structures of the nail:
Functions of the Integumentary System
1.Protection—
• Chemical
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• Physical/mechanical barriers
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• Biological barriers
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2.Body temperature regulation
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3.Cutaneous sensations
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4.Metabolic functions
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5.Blood reservoir—
6.Excretion—
Skin Cancer
• Three major types:
• Basal cell carcinoma
• Squamous cell carcinoma
• Melanoma
Basal Cell Carcinoma
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•Appearance:
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Squamous Cell Carcinoma
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• Appearance:
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Melanoma
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• Appearance:
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Melanoma
• Characteristics (ABCDE rule)
A: AsymmetryB: BorderC: ColorD: DiameterE: EvolutionPartial-Thickness Burns
• First degree
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• Second degree
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Full-Thickness Burns
• Third degree
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THE CARDIOVASCULAR SYSTEM
Heart Anatomy
• Approximately the size of a fist
• Location
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Enclosed in pericardium, a double-walled sac
Pericardium
• Superficial fibrous pericardium
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• Deep two-layered serous pericardium
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Parietal layer lines:
Visceral layer (epicardium) is on :
Separated by fluid-filled pericardial cavity (decreases friction)
Layers of the Heart Wall
1.Epicardium =
2.Myocardium
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3.Endocardium

Chambers
• Four chambers
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Two atria
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• Separated internally by:
• Two ventricles
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Separated internally by:
Major Blood Vessels of the Heart
• Vessels entering right atrium
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• Vessels entering left atrium
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• Vessel leaving the right ventricle
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• Vessel leaving the left ventricle
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Pathway of Blood Through the Heart
• The heart is two side-by-side pumps
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Right side is the pump for the pulmonary circuit
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Left side is the pump for the systemic circuit
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• Right atrium  tricuspid valve  right ventricle
Right ventricle  pulmonary semilunar valve  pulmonary trunk  pulmonary arteries  lungs
Lungs  pulmonary veins  left atrium
Left atrium  bicuspid valve  left ventricle
Left ventricle  aortic semilunar valve  aorta
Aorta  systemic circulation
• Anatomy of the ventricles reflects differences in pulmonary and systemic circuits
Coronary Circulation
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• Arteries
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• Veins
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Homeostatic Imbalances
• Angina pectoris
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• Myocardial infarction (heart attack)
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Heart Valves
• Ensure unidirectional blood flow through the heart
• Atrioventricular (AV) valves
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Chordae tendineae anchor AV valve cusps to papillary muscles
• Semilunar (SL) valves
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Microscopic Anatomy of Cardiac Muscle
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• Intercalated discs: junctions between cells anchor cardiac cells
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Desmosomes prevent :
Gap junctions allow :
• Heart muscle behaves as a functional syncytium
Heart Physiology: Electrical Events
• Intrinsic cardiac conduction system
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Defined:
Autorhythmic Cells
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Heart Physiology: Sequence of Excitation
1.Sinoatrial (SA) node (pacemaker)
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2.Atrioventricular (AV) node
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3.Atrioventricular (AV) bundle (bundle of His)
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4.Right and left bundle branches
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5.Purkinje fibers
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Homeostatic Imbalances
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Defects in the intrinsic conduction system may result in
1. Arrhythmias:
2. Fibrillation: rapid, irregular contractions; useless for pumping blood
• Defective AV node may result in
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Extrinsic Innervation of the Heart
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• Cardiac centers are located in the medulla oblongata
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Cardioacceleratory center innervates:
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Cardioinhibitory center inhibits:
Electrocardiography
• Electrocardiogram (ECG or EKG): a composite of all the action potentials generated by nodal and contractile cells at a
given time
• Three waves
1. P wave:
2. QRS complex:
3. T wave:
Mechanical Events: The Cardiac Cycle
• Cardiac cycle: all events associated with blood flow through the heart during one complete heartbeat
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Systole—
Diastole—
Cardiac Output (CO)
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• CO = heart rate (HR) x stroke volume (SV)
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HR =
SV =
Cardiac Output (CO)
• At rest
• CO (ml/min) = HR (75 beats/min)  SV (70 ml/beat)
= 5.25 L/min
• Maximal CO is 4–5 times resting CO in nonathletic people
• Maximal CO may reach 35 L/min in trained athletes
Homeostatic Imbalances
• Tachycardia: abnormally fast heart rate (>100 bpm)
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• Bradycardia: heart rate slower than 60 bpm
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Developmental Aspects of the Heart
• Fetal heart structures that bypass pulmonary circulation
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BLOOD VESSEL PHISIOLOGY
Blood Vessels
 Arteries:

Capillaries:

Veins:
Structure of Blood Vessel Walls
 Arteries and veins
o Tunica intima –
o Tunica media o Tunica externa -

Lumen

Capillaries
o
o
o Functions:
Capillary Exchange of Respiratory Gases and Nutrients
 Diffusion of
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Hydrostatic Pressures
 Capillary hydrostatic pressure (HPc) (capillary blood pressure)
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Osmotic Pressures
 Capillary oncotic pressure (OP c)
o Created by:
o
Arteries to Know:
 Aorta
 Coronary arteries
 Subclavian arteries (what is the difference btwn. Left and right subclavian arteries in terms of how they branch)
 Brachiocephalic trunk
 Axillary artery
 Brachial artery
 Radial and ulnar artery
 Palmar arch and digital arteries
 Celiac trunk (foregut)
o Common hepatic
o Left gastric
o splenic
 Superior mesenteric artery (midgut)
 Inferior mesenteric artery (hindgut)
 Hepatic portal system
o Splenic vein and superior mesenteric vein are final tributaries to the hepatic portal vein
o Blood is drained from liver via hepatic veins into inferior vena cava to right atrium of heart
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