MSK Anatomy and Physiology Flashcards
Layers of Epidermis
Statum Corneum, Lucidum, Granulosum, Spinosum (spine=desmosomes), Basale (stem cell site) [Californians Like Girls in String Bikinis]
Tight Junction
Zonula Ocludens; no paracellular transport; found apically; composed of claudins and occludins
Adherens junction
Zonula adherens: Below tight junction, belt with actin cytoskeletons with CADherins (Ca2+ dependent adhesion proteins).
Loss of what protein promotes metastasis
E-cadherin
Desmosome
Macula adherens: structural support via keratin interactions. Pemphigus vulgaris has autoantibodies. Desmoplakin between the cells.
Hemidesmosome
Connects keratin in basal cells to underlying basement membrane. Bullous pemphigoid
Integrins function
Maintain integrity of basolateral membrane by binding to collagen and laminin in basement membrane
McMurray test
Pain on external rotation is medial meniscus tear
Pain on internal rotation is lateral meniscus tear
Unhappy triad of Knee Injuries
ACL, MCL, and medial meniscus. Lateral meniscus injury is more common.
Where is pudendal nerve block given
Ischial spine
Innervation of rotator cuff
C5-C6
Suprascapular nerve: supraspinatus, infraspinatus, subscapularis
Axillary nerve: Teres minor (lies below the infraspinatus)
Pitching injury
Infraspinatus
fact: infraspinatus is below the scapular spine (so teres minor is below the infraspinatus)
.
Name the carpal bones
Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, captiate, Trapezoid, Trapezium
Carpal bone mnemonic
Some Lovers Try Posititions That They Can’t Handle
What carpal articulates with the thumb
Trapezium
Winged scapule nerve
Long Thoracic Nerve
Erb’s palsy trunk
Upper trunk (C5-C6) [Erb-er]
Klumpke palsy trunk
Lower trunk (C8-T1)
Klumpke palsy presentation
Intrinsic hand muscles: lumbicals, interossei, thenar, hypothenar. CLAW HAND
Thoracic outlet syndrome
Compression of lower trunk and subclavian vessels, same as klumpke with symptoms of vascular compression (ischemic signs)
Wrist drop injury
Posterior cord of brachial plexus
Deltoid paralysis injury
Axillary nerve
Saturday night palsy
Radial nerve
Difficulty flexing elbow, variable sensory loss injury
Musculocutaneous
Decreased thumb function, “Pope’s blessing” injury
Median nerve
Intrinsic muscles of hand, claw hand
Ulnar nerve
Hypothenar and Thenar eminence movements
Oppose, Abduct, and Flex (OAF)
Skeletal Muscle contraction steps
- Action potential depolarizes presynaptic membrane opening up voltage gated Ca2+ channels leading to ACh release.
- ACh binds NAChR on muscle leading to depolarization which spreads down the T tubules.
- Depolarization of voltage-sensitive dihydropyridine receptor mechanically coupled to the ryanodine receptor on SR results in Ca2+ release.
- Ca2+ binds troponin C, moving tropomyosin out of the myosin binding groove on actin filaments.
- ATP cocks the myosin head which then binds actin, the power stroke doesn’t use ATP hydrolysis.
- Shortening of H and I bands and Z lines (HIZ shrinkage), but A band is always same length
How does the power stroke work?
Actin increases the myosin ATPase activity, that’s why myosin doesn’t burn off ATP otherwise.
ATP binding is what pulls myosin off of actin.
Smooth muscle contraction
L-type voltage gated Ca2+ channel activates Ca2+-calmodulin complex leading to Myosin-light-chain kinase activity for contraction.
Two types of bone formation
Endochondral ossification and Membranous ossification
Endochondral ossification
Axial, appendicular, and base of skull. Cartilage first, then woven bone, then lamellar bone.
What is lamellar bone?
In layers (lamella) and is mechanically stronger than woven bone.
What happens in fracturse and Paget’s
Woven bone grows in
Membranous ossification
Bones of calvarium and facial bones. Woven bone formed directly without cartilage, later remodeled to lamellar bone.
Osteoblasts function
secrete collagen and catalyze mineralization. Mesenchymcal stem cells in periosteum
osteoclasts function
Multinucleated cells that dissolve bone with acid and collagenases. From monocytes/macrophages
PTH on bone
low, intermittent levels is anabolic on bone. High PTH levels chroncially is catabolic (osteitis fibrosa cystica)
Estrogen and bone
Inhibits apoptosis of osteoblasts and induces apoptosis of osteoclasts.