Corneum
Lucidum
22 sq ft
Granulosum
Stratified squamous
Spinosum
Basale
Sweat glands-3-4 million.1.ECCRINE(merocrine)-secretes sweat to cool
down ,directly into skin,functions after birth ,98%water,2%dissolved
salts/ urea .2.APOCRINE-emotional/secretes into hair follicle,functions at
puberty,more viscous=eccrine+lipids/protein
Skin’s Function:waterproof barrier,Protection against injury & infection; regulates body temperature(sweating,vasoconstriction/dilation-loseheat); sensory perception;regulates water loss;chemical synthesis;
excretion(ammonia,urea,salt)blood reservoir Sensory Receptors: every sqcm of skin has 14 pressure,200 pain,6cold,1 warmth receptors Free nerve endings: Dermis, cornea, tongue, joint capsules, visceral organs/
pain(nociceptor-somatic pain- in skin & sk muscle visceral-for internal homeostasis), temperature(thermoreceptor), TOUCH RECEPTORS-FINE TOUCH 1.Merkel’s Disc: S.basale/Epidermal-dermal junction,root of hair
plexus,mucosal membranes/fine touch low frequency vibrations(5-15 Hz) 2.Meissner's corpuscle: enclosed in a capsule of CT.Papillary dermis(fingertips,palms,soles,eyelids,external genitalia & lips)/Light touch,
vibrations below 50 Hz TOUCH RECEPTORS-PRESSURE SENSITIVE-1.Pacinian corpuscle:Dermis,subq tissue, pressure vibration changes deep in skin.onion shaped capsule-layers of schwann cells enclosed in CT.joint
capsule/stretch, vibration(250Hz)on-off pressure 2.Ruffini’s Corpuscle/Krause end bulb: encapsulated pressure sensors, Dermis, joint capsules/stretch,continuous pressure. THERMORECEPTORS:all over body -highest
concentration in face/nose/ears cold-starts below 95F,most stimulated when 77F,no longer stimulated when below 41F-skin is numb.hot-starts 86F,most stimulated 113F/beyond-pain receptors take over.Krause end bulb
- cold receptors - bulboid corpuscle. Found in eye, lip, tounge PROPRIOCEPTION:stretch receptors in joints,ligaments & tendons ,muscle tone Muscle Spindle: modified muscle fibers with sensory nerve endings wrapped
around the middle/ends/detect stretch & stimulate muscle contraction Tendon stretch Organ:Golgi Tendon Organ:In line with tendons/Stretch of tendons Burns: 1st-Red, painful, no blister, heals 5-10 days(hypo/hyper
pig),no TBSA 2nd-Red, painful, blister, swelling, superficial partial 2a:blanching, painful, heals 3 weeks no scarring full thickness 2b:no blanch, decreased sensation, heal 3-8 weeks, scar, needs hospital 3rd-Full
thickness:white, black, charred, leathery, dry no blanch, heals in > 8 weeks, scarring w/contracture SKIN PIGMENTS-melanin/carotene/hemoglobin. EUMELANIN-brown/black,protects skin from UV. PHEOMELANIN:reddish
Psoriasis:chronic, non infectious skin disease;skin=dry,scaly, often w/ pustules+many
/yellow,breaksvarieties;cycle
down with UV.skin cell production increases by 3-4x’s normal;stratum corneum=thick as dead cells accumulate;seems genetic component;triggered by trauma, infection,hormonal changes/stress
Vitiligo:autoimmune pigmentation disorder where melanocytes in epidermis destroyed. Boils(Furuncle):infections by Staphylococcus aureus bacteria. Staph infections form pockets in skin→pus filled fluid-contains bacteria, dead skin cells ,white blood cells.furuncle-hair follicle,
carbuncle-cluster of furuncles connectes subq/abscess-pus collection in skin. Impetigo:most common bacterial infection in children.Highly contagious infection superficial layers of epidermis caused by S aureus. Methicillin-resistant S aureus / gentamicin-resistant S aureus strains have
reported-cause impetigo.Impetigo classified as non bullous or bullous.Athlete's foot:fungus-Infect top layer-dead keratin, dermatophytes affect skin, hair shafts,& nails. Dermatophytes classified-three genera: Trichophyton, Microsporum,Epidermophyton.Basal Cell Carcinoma: least
malignant; 78% of all skin cancers; stratum basale can’t form keratin, lose boundary layer between epidermis/dermis; results in tissue erosion & ulceration; 99% are cured Squamous cell Carcinoma: 20% of all skin cancers; cancer of cell in stratum spinosum; from squamous cells in the
epidermis; induced by sun; cells grow rapidly & grow into the lymphatic tissues; hardened small red growth; spread rapidly if not removed; good chance of recovery if detected/treated early Malignant Melanoma: Cancer pigment cells=melanocytes;1% of skin cancers: deadly; poor
chance of cure once developed; begins with moles/neuus; spreads rapidly; early detection & treatment=key-survival Muscle Function: Stabilizing joints, maintaining posture, producing movement, moving substances within body, stabilizing body position+regulating organ volume,
producing heat(generates 85% of bh) Skeletal Muscle types:1.Parallel=Biceps brachii.2.Parallel-fusiform=Sartorius .3.Convergent= Pectoralis major.4.Circular=orbicularis oris/oculi.5.Pennate-Unipennate=Extensor Digitorum,Bipennate=Rectus Femoris , Multipennate=Deltoid Myoglobin
=protein in which muscle stores excess oxygen Muscle strength=directly related to the # of myofibrils in a sarcomere NMJ-all cell membranes have a membrane potential(-60-90 mV)achieved by controlling movement of ions through ion channels.ACTION POTENTIAL-electrical signal that
can travel along a cell membrane as a wave. SIGNALING-begins with neuron AP-travels down the axon to NMJ->axon terminal releases acetylcholine(by exocytosis)binds to receptors on motor end plate of sarcolemma->depolarize (membrane potential of the muscle fiber becomes
negative)-+ions move into muscle fiber->voltage gated Na channels open-Na enter muscle fiber->calcium released from sarcoplasmic reticulum & attaches to troponin->quickly repolarizes returning the negative membrane potential. CROSS BRIDGE FORMATION- in myosin
ATP->ATPase->ADP+Pi-both attach to Myosin->myosin attaches to actin->ATP attaches to myosin->pull-(power stroke)->detach -ADP=Pi. Phases of Contraction: LATENT PHASE: excitation contraction coupling=Propagation of AP along sarcolemma CONTRACTION PHASE: high Ca+ binds to
troponin RELAXATION PHASE: Ca+ transferred back to SR. Power stroke=Myosin pulls actin 10 nm toward M-line. Each thick filament has 300 myosin molecules ATP is also need to activate CA++ channels in the SR Twitch: Single action potential from a MN will=single contraction in the
muscle fiber of its Motion Unit isolated contraction. Can last few ms or 100ms.Muscle contractions STOP-signal from motor neuron ends or no ATP.Graded Muscle response: Input from nervous system, produces varying amount of force Muscle tension: frequency of nerve impulse:
number of MN transmitting the action potential (AP) Wave summation: If the fibers are stimulated while a previous twitch is occurring->second twitch is STRONGER. Tetanus: Incomplete-> Short relaxation Complete no relaxation TREPPE : When muscle tension increases in a graded
manner that looks like a set of stairs. Bottom of each wave = stimulus. Treppe = high Ca in sarcoplasmic but must be matched with adequate ATP. HYPOTONIA: low muscle tone (muscle atrophy) HYPERTONIA high muscle tone.HYPERTROPHY:structural proteins are added-increase size of
muscle. Skeletal Muscle Fiber: most Sk. Muscle contain all three type of fiber but in different proportion 1) SO (Slow Oxidative)-contract slowly, aerobic respirators Marathon runners, endurance exercise,postural muscle, red color as has myoglobin, large amount of mitochondria (lots of
ATP), small in diameter, do not produce large amount of tension,can function for long period without fatiguing, Stabilize bone/joints,maintain posture, Isometric : small movements that do not require large contracture, amount of energy 2) FO (Fast Oxidative)fast contraction, fatigue
easily, aerobic respiration , anaerobic respiration if needed. Intermediate fibrous, between SO/FG, low myoglobin(light color), produce ATP quickly> SO cam produce high amount of tension do not fatigue easily => used primarily for walking but not for sprinting.High mitochondria.3) FG
(Fast Glycolytic)Fast contraction, anaerobic glycolytic, fatigue more quickly. Anaerobic glycolytic as ATP source, large diameter,highest level of tension, high glycogen, low mitocondria, low myoglobin (white), fatigue quickly, used for short periods, rapid forceful contractions to make
quick powerful movements eg: resistance exercise,high power Poliomyelitis: viral infection of nerves=control skeletal muscle movement. Muscular Dystrophies: commonly caused mutation of gene for protein dystrophin helps in attaching+organizing filaments in sarcomere. Duchenne
Muscular Dystrophy & Becker muscular dystrophy =most common. The gene for dystrophin on the X chromosome=disorder is sex-linked. Muscle function is impaired. Myasthenia gravis: autoimmune disease affecting NMJ. smaller end plate potentials=antibodies being directed against
ACh receptors. Affects ability of impulse to cause muscle contraction. Administer inhibitor of acetylcholinesterase→restore contractibility. Tetanus: serious bacterial disease=affects nervous system,=painful muscle contractions, particularly of jaw+neck muscles. Tetanus can interfere
with ability to breathe->threaten your life. Tetanus is commonly known as "lockjaw".For a muscle to return to resting state:Oxygen reserves=replenished;Lactic acid=converted-pyruvic acid;Glycogen stores replaced ;ATP/creatine phosphate reserves must be resynthesized;Oxygen
debt–O2 needed to compensate for ATP produced w/o O2 during muscle contraction Atherosclerosis may block distal arteries, leading to intermittent claudication->causing severe pain in leg muscles/High intensity exercise for short duration produces strength, size & power gains in
muscles Low intensity exercise for long durations gives endurance benefits Trained muscles have better tone/state of readiness to respond Aging muscle: Sarcopenia, as muscle age muscle fiber die, replaced by connective & adipose tissue.low bone mass, low strength (posture mobility)
low FG fiber more SO fiber longer contractions low size of motor unit, low muscle tension. MYOSITIS: african/carribean,causes-bacteria(staph/strep),virus,parasite,toxin/drugs. 1.POLYMYOSITIS: gradual onset(wks-mths),endomysium,T cell mediated response. 2.DERMATO MYOSITIS :
cutaneous manifestation,common in females,perimysium,loss of hair,heliotrope rash(around eyes),gottron papules Skeletal functions: support; movement; protects internal organs; produces blood cells; stores & produces minerals & fat Ball & Socket - allows for complete range of
motion:shoulder, hip Pivot–one bone pivots in the arch of another:Axis/Atlas, proximal radioulnar joint Saddle – two directional movement between thumb & trapezium ,carpal & sternoclavicular Hinge-like door hinge – bending & extending:elbow, knee, finger joints Ellipsoid (Condyloid)
– side to side/ back & forth;radius end into carpal bones Plane or Gliding–least moveable – side to side only; intercarpal & intertarsal joints, between vertebrae.Characteristics of Cartilage Mostly water; no blood vessels or nerves Tough, resilient new cartilage forms from
chondroblasts,Heal poorly,Appositional Growth growth in diameter-adding to free surface of bone,occur at endo/periosteum Interstitial–growth in length. Occurs in hyaline cartilage of epiphyseal plate Hyaline Cartilages: fine collagen fiber matrix- most abundant type- found in articular
(movable joint)cartilages, costal cartilages (connect ribs to sternum), respiratory cartilages (in larynx & upper respiratory passageways) & nasal cartilages Elastic Cartilages: similar to hyaline cartilage, more elastic fibers (very flexible) – found in external ear & epiglottis (larynx covering)
Fibrocartilage: rows of chondrocytes with thick collagen fibers; highly compressible with great tensile strength- found in menisci of knee, intervertebral discs & pubic symphysis Axial=80 bones-22 skull/24 vertebrae/12 thoracic cage/7 head Appendicular=126 bones Scaphoid is most
commonly fractured carpal bone. Nutrients that support bone growth: Vit. D(calcium absorption), Vit. K (Bone mineralization), Magnesium, Fluoride, Calcium, Omega 3 Fatty acids INORGANIC SALTS IN BONE :Ca carbonate+Phosphate=hydroxyapatite (hardiness /strength), Magnesium
hydroxide,sulphur Hormones: Affects Osteoblast+Matrix: Growth Hormone=secreted by pituitary gland in brain, Thyroxine= thyroid gland, Calcitriol-active vit D(cholecalciferol),Sex hormones Affects Osteoclasts: PTH=parathyroid gland, Calcitonin=Thyroid BURSA: thin CT sac filled with
lubricating liquid. Subcutaneous Bursa, Submuscular Bursa, Subtendinous Bursa. Tendon Sheath: CT sac that surrounds a muscle tendon at places where the tendon crosses a joint. CARTILAGE: Hyaline)larynx, trachea, joints-articular;reduce friction, absorb shock Elastic)outer ear,
epiglottis, shape support Fibrous)intervertebral discs, pubic symphysis; rigidity, absorb shock. CELLS: Osteogenic=precursor to osteoblasts,growth factors,only cells that reproduce. Osteocytes=occupy lacunae,communicate with each other through canaliculi,,maintain bone,most
common cell. INTRAMEMBRANOUS (bones of face & clavicle)-1.mesenchymal cells in embryo differentiate into capillaries, osteogenic cells & osteoblasts-appear in a cluster called OSSIFICATION CENTER,secrete osteoid-uncalcified matrix 2.osteoid calcifies in a few days entrapping the
osteoblasts->cyte3.osteoid around capillaries->trabecular matrix,osteoblast on surface of the spongy bone->periosteum 4.trabecular bone near blood vessels->red marrow.last bone to ossify by IMO-facebones.ENDOCHONDRAL;1 mesenchymal-> Chondrocytes->cartilage template
-perichondrium forms3.capillaries penetrate cartilage,perichondrium->periosteum collar->PRIMARY OSSIFICATION.cartilage/chondrocyte-grow at ends- SECONDARY OSSIFICATION - cartilage remains at epiphyseal(growth plate)& at joint surface(articular cartilage).JOINT CLASSIFICATION
:Fibrous=sutures,syndesmoses (b/w long bones) ,& gomphosis(dentoalveolar)(synarthroses); Cartilaginous= fibrocartilaginous,& hyaline(amphiarthrosis); Primary cartilaginous:SYNCHONDROSIS-temporary/epiphyseal-sternocostal Secondary:SYMPHYSES-manubrium sternum,
intervertebral disc.Synovial= Nonaxial uniaxial,biaxial,multiaxial (diarthroses). Spinal Stenosis -narrowing of the spinal column Achondroplasia-Defect in cartilage formation at epiphysis long bones (dwarfing) Juvenile Rheumatoid Arthritis-chronic inflammatory diseases involving the
joints or other organs in children under 16 Ankylosing spondylitis-immobility of joint in spine Osteosarcoma-malignant sarcoma of bone Osteoporosis-Loss of bone mass that occurs throughout the skeleton. Predisposes people to fractures Disc Herniation-soft nucleus pushes out
through a tear in the annulus-disc-separates 2 vertebrae into spinal canal Scoliosis-a lateral curvature of the spine. Colles Fracture: Fall on an outstretched hand Bone Repair:fracture hematoma in 6-8 hrs,INTERNAL CALLUS-48hrs -fibrocartilaginous matrix EXTERNAL CALLUS-hyaline
cartilage +bone TRIVIA: Strongest force exerted:jaw muscle/975 lbs for 2 seconds Largest muscle:Latissimus Dorsi.Largest joint- knee.Teeth Enamel-hardest.17 muscles to smile 43 to frown.Strongest/largest bone:femur. More than half of the bones found in hands feet (106 bones: each
hand -27 bones, each foot- 26 ).Smallest muscles -inner ear(tensor tympani stapedius).Smallest bones:middle ear- stapes (lightest bone) . Muscles-40 %total body weight. Muscle movement -85% heat.An hour of reading, eyes make 10,000 coordinated movements. Babies have 300
bones- Adults-206 bones. Hyoid bone- no attachments/holds tongue in place. FUNNY BONE-ulnar nerve which runs on medial (inside) side of your elbow . Hitting it produces a tingling prickly pain sensation-hand-4th&5th finger
Membranes: Epithelial- Epithelial tissue & CT to which it is attached. Mucous Membranes-line the body cavities that open to outside.EX: GI, resp,excretory,
reproductive tracts. Serous Membranes-line body cavities that do not open directly to the outside, cover organs.have 2 layers,serous fluid lubricates/ reduces
friction/abrasion when organs in the thoracic(pleura)or abdominopelvic cavity(peritoneum) move.Connective Tissue Membranes- Connective tissue
membranes contain only connective tissue.EX:Synovial & meninges (CT covering of brain/spinal cord.)
EXERCISE- Acute - ↑synovial fluid ↓viscosity,↑nutrients,↑uptake of mineral,
↑bone density Chronic -increase in density,size,weight & resistant to injury.
TRIANGULAR FIBROCARTILAGE COMPLEX in wristS- separated /sliding growth
plate L-below-thorough-erasure/rammed AUTOGRAFT: same person-one
Calcitonin
PTH
Calcitriol
point to another.ALLOGRAFT:graft from donor of same species but not
Osteoblast Act.
Increase
Decreases
Decreases
genetically identical. ISOGRAFT:graft from one to another individual of the
same genetic constitution- EX:identical twins.XENOGRAFT: different
Increase
Increase
Decreases
Osteoclast Act.
species,EX: animal to man.PH of sweat is slightly acidic-4.5-7- lower
PH=acidic.Desmosomes:intercellular junctions provide strong adhesion
Increase
Decreases
Ca++ absorption
between cells.MAST CELLS-release histamine.SPF 15-blocks 93%,
Increase
30-97%,50-98%,100-99%
Dermis