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Epidermis Layers
- From surface to base:
- -Stratum Corneum (keratin)
- -Stratum Lucidum
- -Stratum Granulosum
- -Stratum Spinosum (spines = desmosomes)
- -Stratum Basale (stem cells)
"Californias Like Girls in String Bikinis"
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Epidermal Appendages
- Sebaceous Glands
- Eccrine Glands
- Apocrine Glands
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Sebaceous Glands
- -Holocrine (rupture of plasma membrane) secretion of sebum
- -Associated with hair follicle
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Eccrine Glands
- -Secrete sweat
- -found throughout the body
"Eccrine glands are Everywhere"
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Apocrine Glands
- -Secrete milky viscous fluid
- -Found in axillae, genitalia and areolae
- -Not functional until puberty
- -Malodorous because of bacterial action
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Epithelial Cell Junctions
-types
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Tight Junction
- "Zona Occludens"
- -apical surface of cells?
- Function:
- -prevents paracellular movement of solutes
- Structure:
- -claudins
- -occludins
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Adherens Junction
- "Zonula Adherens"
- -found below tight junctions
- Function:
- -forms "belt" connecting actin cytoskeletons of adjacent cells
- Structure:
- -CADherins (Ca2+ dependent adhesion proteins)
- Disease:
- -loss of E-cadherin promotes metastasis
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Desmosome
"Macula Adherens"
- Function:
- -structural support between cells
- Structure:
- -via keratin interactions
- Disease:
- -Pemphigus Vulgaris (autoantibodies)
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Gap Junction
- Function:
- -permit electrical and chemical communication between cells
- Structure:
- -connexins (channel proteins)
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Hemidesmosomes
- Function:
- -connect basal cells to underlying basement membrane
- Structure:
- -via keratin interactions
- Disease:
- -Bullous pemphigoid (autoantibodies)
- "hemidesmosomes are down bullow"
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Integrins
- -membrane proteins that maintain integrity of basement membrane
- -bind to laminin in basement mebrane
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Pudendal Nerve Block
"Saddle nerve block"
-relieve pain of delivery
Landmark = ischial spine
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Appendix Landmarks
2/3 of the way from the umbilicus to ASIS
McBurney's point
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Rotator Cuff Muscles
SItS ( small t for teres minor)
- Supraspinatus
- Infraspinatus
- Teres Minor
- Subscapularis
Innervated by C5-C6
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Supraspinatus
- Function:
- -abducts arm initially (before deltoid)
Most common rotator cuff injury
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Infraspinatus
- Function:
- -laterally rotates arm
Pitching injury
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Teres Minor
- Function:
- -adducts and laterally rotates arm
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Subscapularis
- Function:
- -medially rotates and adducts arm
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Wrist Bones
" Slide Left Tiny Pinky, Here Comes The Thumb"
- Scaphoid
- Lunate
- Triquetrium
- Pisiform
- Hamate
- Capitate
- Trapezoid
- Trapezium
- Scaphoid:
- -most commonly fractured carpal bone
- -prone to avascular necrosis due to retrograde blood supply
- Lunate:
- -dislocation may cause acute carpal tunnel syndrome
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Brachial Plexus
- "Randy Travis Drinks Cold Beer"
- -Roots
- -Trunks
- -Divisions
- -Cords
- -Branches
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Better Brachial Plexus Picture
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Brachial Plexus Nerves
-Long Thoracic Nerve
- -Dorsal Scapular Nerve
- -Suprascapular Nerve
-Lateral Pectoral
- -Upper Subscapular Nerve
- -Thoracodorsal Nerve
- -Lower Subscapular Nerve
- -Medial Pectoral
- -Medial Brachial Cutaneous
- -Medial Antebrachial Cutaneous
- -Musculocutaneous
- -Axillary
- -Median
- -Radial
- -Ulnar
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Long thoracic Nerve
- Innervates:
- -serratus anterior (abduction above horizontal position)
- Palsy:
- -scapular winging
- -can be injured during mastectomy (winging and ipsilateral lymphedema
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Dorsal Scapular Nerve
- Innervates:
- -Levator Scapulae
- -Rhomboids
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Suprascapular Nerve
- Innervates:
- -supraspinatus
- -infraspinatus
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Lateral Pectoral
- Innervates:
- -Pectoralis Major
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Upper Subscapular Nerve
- Innervates:
- -subscapularis
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Thoracodorsal Nerve
- Innervates:
- -Latissimus Dorsi
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Lower Subscapular Nerve
- Innervates:
- -Subscapularis
- -Teres Major
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Medial Pectoral Nerve
- Innervates:
- -Pectoralis Major
- -Pectoralis Minor
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Medial Brachial Cutaneous
- Innervates:
- -sensory to medial arm
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Medial Antebrachial Cutaneous
- Innervates:
- -sensory to medial forearm
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Upper Extremity Innervation
- -C7 root
- -Upper trunk
- -Axillary nerve
- -Radial nerve (spinal groove)
- -Median nerve
- -Ulnar nerve
- -Deep branch of radial nerve
- -Anterior Interosseus nerve
- -Recurrent branch of median nerve
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Musculocutaneous Nerve
- Nerve Roots:
- -C5-C7
- -terminal lateral cord
- Innervates:
- 1. MOTOR (flexion of arm at elbow):
- -Biceps
- -Brachialis
- -Coracobrachialis
- 2. SENSORY
- -Lateral forearm
- Typical Injury:
- -upper trunk compression
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Axillary
- Nerve Roots:
- -C5, C6
- -Posterior Cord
- Innervates:
- 1. MOTOR:
- -deltoid (abduction of arm at shoulder)
- Typical Injury:
- -fractured surgical neck of humerus
- Injury Sign:
- -atrophied deltoid
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Median Nerve
- Nerve Roots:
- -C5-C8, T1
- -Terminal lateral and medial cords
- Innervates:
- 1. MOTOR:
- -Thenar Muscles (opposition of thumb)
- -FDS, FDP 2 and 3, FPL (lateral finger flexion)
- -FCR (radial wrist flexion)
- -PT, PQ (forearm pronators)
- 2. SENSORY:
- -dorsal and plamar aspects of lateral 3.5 fingers
- -thenar eminence
- Typical Injury:
- -Proximal lesion: fracture of supracondylar humerus
- -Carpal tunnel syndrome
- -Superficial laceration of recurrent branch of median nerve
- Injury Sign:
- -Ape hand (loss of thumb opposition)
- -Pope's Blessing Hand
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Radial Nerve
- Nerve Roots:
- -C5-C8, T1
- -Terminal posterior cord
- Innervates:
- 1. MOTOR:
- -Brachioradialis
- -Extensors of wrist and fingers
- -Supinator
- -Triceps
- "BEST extensors"
- 2. SENSORY:
- -posterior arm
- -dorsoradial hand and thumb
- Typical Injury:
- -Fracture at midshaft of humerus (spiral groove)
- -"Saturday night palsy" (extended compression of axilla by chair or crutches)
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Ulnar Nerve
- Nerve Roots:
- -C8, T1
- -terminal medial cord
- Innervates:
- 1. MOTOR:
- -FCU (ulnar wrist flexion)
- -Ulnar FDP (medial finger flexion)
- -Intrinsic hand muscles
- 2. SENSORY:
- -Medial 1.5 fingers (dorsal and palmar)
- -hypothenar eminence
- Typical Injury:
- -Proximal lesion: fracture of medial epicondyle of humerus "funny bone"
- -Distal Lesion: trauma to heel of hand, fracture to hook of hamate
- Injury Signs:
- -radial deviation of wrist upon wrist flexion
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Cutaneous Innervation of Hand
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Dermatomes of Upper Limb/Hand
- C6: A-OK
- C7: flipping off

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Hand Muscles
-groups
- Thenar
- Hypothenar
- Dorsal Interosseous
- Palmar Interosseus
- Lumbricals
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Thenar Muscles
- Innervation:
- -median nerve
- Muscles:
- -Opponens pollicis
- -Abductor pollicis brevis
- -Flexor pollicis brevis
"OAF"
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Hypothenar Muscles
- Muscles:
- -Opponens digiti minimi
- -Abductor digiti minimi
- -Flexor digiti minimi
"OAF"
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Dorsal Interosseous Muscles
- Function:
- -abduct the fingers
DAB= Dorsals ABduct
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Palmar Interosseous Muscles
- Function:
- -adduct the fingers
PAD = Palmar ADduct
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Lumbricals
- Innervation:
- -Median Nerve (radial: first and second)
- -Ulnar nerve (ulnar: third and fourth)
- Function:
- -flex MCP joint
- -extend DIP and PIP joints
- "Queen's wave"
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Lower Extremity Nerves
- Obturator
- Femoral
- Common Peroneal
- Tibial
- Superior Gluteal
- Inferior Gluteal
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Obturator Nerve
- Innervates:
- 1. MOTOR
- -Thigh adductors (External obturator, Adductor lungs, Adductor brevis, Adductor Magnus, Gracilis)
- Typical Injury:
- -anterior hip dislocation
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Femoral Nerve
- Innervates:
- 1. MOTOR:
- -Quadraceps (Rectus femoris, Vastus lateralis, Vastus medialis, Vastus intermedius)
- -Function: Thigh Flexion and Leg extension
- 2. SENSORY:
- -anterior thigh
- -medial leg
- Typical Injury:
- -pelvic fracture
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Common Peroneal Nerve
- Innervates:
- 1. MOTOR
- -Anterior compartment of leg
- -Lateral compartment of leg
- -Foot eversion and dorsiflexion
- -toe extension
- 2. SENSORY:
- -Anterolateral leg and dorsal aspect of foot
- Typical Injury:
- -trauma or compression of lateral aspect of leg
- -fibula neck fracture
- Signs of Injury:
- -foot drop
- -foot slap
- -steppage gait
"PED = Peroneal Everts and Dorsiflexes; if injured foot dropPED"
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Tibial Nerve
- Innervates:
- 1. MOTOR
- -Posterior leg
- -foot inversion
- -foot plantarflexion
- -toe flexion
- Typical Injury:
- -knee trauma
TIP "Tibial Inverts and Plantarflexes, If injured can't stand on TIPtoes"
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Superior Gluteal
- Innervation:
- 1. MOTOR:
- -thigh abduction
- Typical Injury:
- -posterior hip dislocation
- -polio!
- Injury Sign:
- -positive Trendeleburg sign: contralateral hip drops when standing on leg ipsilateral to side of lesion
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Inferior Gluteal
- Typical Injury:
- -posterior hip dislocation
- Injury Signs:
- -can't jump, climb stairs, rise from seated position
- -can't push inferiorly (downward)
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Anterior Compartment of Thigh
- Muscles:
- -Rectus femoris
- -Vastus medialis
- -Vastus intermedius
- -Vastus lateralis
- -Sartorius
- Function:
- -extend the knee joint
- -flexion of the hip
- Blood Supply:
- -Femoral artery
- Innervation:
- -Femoral nerve
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Medial Compartment of the Thigh
- Muscles:
- -Gracilis
- -Adductor Magnus
- -Adductor Brevis
- -Adductor Longus
- Function:
- -adduction of the leg
- Blood Supply:
- -Obturator Artery
- Innervation:
- -Obturator nerve
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Posterior Compartment of the Thigh
- Muscles:
- -Biceps Femoris
- -Semitendinosus
- -Semimembranosus
- Function:
- -extension of the hip
- -rotation of the hip
- Blood Supply:
- -perforating arteries (from deep artery of the thigh)
- Innervation:
- -sciatic nerve
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Anterior Compartment of the Leg
- Muscles:
- -Tibialis anterior
- -Extensor digitorum longus
- -Extensor hallucis longus
- -Fibularis
- Function:
- -dorsiflexion
- -foot inversion
- Blood Supply:
- -anterior tibial artery
- Innervation:
- -deep fibular (peroneal) nerve
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Lateral Compartment of the Leg
- Muscles:
- -Fibularis longus
- -Fibularis brevis
- Blood Supply:
- -fibular artery
- Innervation:
- -superficial fibular nerve
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Superficial Posterior Compartment of the Leg
- Muscles:
- -Gastrocnemius
- -Soleus
- -Plantaris
- Blood Supply:
- -posterior tibial artery
- Innervation:
- -Tibial nerve
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Deep Posterior Compartment of the Leg
- Muscles:
- -Flexor digitorum longs
- -Flexor hallucis longus
- -Tibialis Posterior
- -Popliteus
- Function:
- -plantar flexion
- Blood Supply:
- -Posterior tibial artery
- Innervation:
- -Tibial nerve
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Skeletal Muscle Conduction to Contraction
1. AP depolarization opens presynaptic voltage gated Ca 2+ channels, inducing NT release
2. NT binds to postsynaptic membrane leading to muscle cell depolarization that the motor end plate
3. Depolarization travels along muscle cell and down the T tubule
 - 4. Depolarization of voltage-sensitive Dihydropyridine receptor results in opening of the ryanidine receptor on the sarcoplasmic reticulum (mechanically coupled or CICR).
- -induces Ca2+ release from sarcoplasmic reticulum
5. Released Ca 2+ binds troponin C causing a conformational change that moves tropomyosin out of the myosin-binding groove on actin filaments
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Sarcomere
- Z line:
- -forms the borders of the sarcomere
- -Z is the last letter of the alphabet, Z band is the last part of the sarcomere
- M line:
- -in the Middle of the sarcomere
- -within the H band
- A band:
- -entire length of a single thick filament
- -A band is Always the same length
- I band:
- -only actin (thin filament)
- -I is a thin letter
- H band:
- -only myosin (thick filament)
- -H is a thick letter
Contraction results in shortening of H and I bands and between the Z lines ( HIZ shrinkage)
A band remains the same length
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Type 1 Muscle Fibers
Slow Twitch, Red Fibers
Increased mitochondria and myoglobin concentration → ↑ oxidative phosphorylation
Allows for sustained contraction
"1 slow red ox"
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Type 2 Muscle Fibers
Fast Twitch, White Fibers
Decreased mitochondria and myglobin concentration → ↑ Anaerobic glycolysis
Weight training results in hypertrophy of fast twitch fibers
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Skeletal and Cardiac Muscle Contraction
 - 1. "Cocked State"
- -ATP hydrolysis cocks the myosin head (not attached to actin)
- 2. "Cross-Bridged State"
- -Ca2+ binds troponin C, causing conformational change
- -this displaces tropomyosin and allows the myosin head to bind actin
- 3. "Power Stroke State"
- -Pi is release changing myosin head conformation and causing the power stroke
- 4. "Released State"
- -ADP dissociates and ATP binds myosin head, causing release from actin filament
- -lack of ATP causes rigor mortis
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Smooth Muscle Contraction
1. AP depolarizes SM membrane
2. Voltage gated Ca 2+ channels open leading to increased Ca 2+ in the cytoplasm
3. Ca 2+ binds calmodulin and activates MLCK
4. MLCK phosphorylates actin leading to cross-bridge formation and muscle contraction
- Inhibition of Smooth Muscle contraction:
- -NO activates GC, activates cGMP which inhibits MLCK
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Endochondral Ossification
- Location:
- -bones of axial and appendicular skeleton
- -base of skull
1. Cartilaginous model of bone is made by chondrocytes
2. Osteoclasts and osteoblasts later replace with woven bone and then remodel to lamellar bone
- Woven bone:
- -haphazard arrangement of collagen fibers
- -weak
- -in adults occurs after fractures and in Paget's disease
- Lamellar bone:
- -collagen arranged in sheets
- -strong
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Membranous Ossification
- Location:
- -calvarium
- -facial bones
1. Woven bone formed directly without cartilage
2. Later remodeled to lamellar bone
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Osteoblasts
-function
-origin
- Function:
- -blasts build bone
- -secrete collagen and catalyze mineralization
- Origin:
- -differentiate from mesenchymal stem cells in periosteum
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Osteoclasts
-function
-origin
- Function:
- -multinucleated cells that dissolve bone by secreting acid and collagenases
- Origin:
- -differentiate from monocytes/macrophages
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Parathyroid Hormone
-low intermittent levels
-chronic high levels
- Low-Intermittent levels
- -anabolic effects (building bone) on osteoblasts and osteoclasts (indirect)
- Chronic high levels:
- -ie: primary hyperparathyroidism
- -catabolic effects (osteitis fibrosa cystica)
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Estrogen
-function
-deficiency
- Function:
- -inhibits apoptosis in bone-forming osteoblasts
- -induces apoptosis in bone-resorbing osteoclasts
- Estrogen Deficiency:
- -ie: surgical, postmenopausal
- -excess remodeling cycles and bone resorption lead to osteoporosis
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