MSK

Question 1

Type 1 muscle fibers

Answer 1

slow twitch
red, dark
increased mitochondria, myoglobin
oxidative phosphorylation
sustained contraction

ex: soleus m., planters m.

Question 2

Type 2 muscle fibers

Answer 2

fast twitch
less red
decreased mitochondria, myoglobin
anaerobic glycolysis - hypertrophy w/ weight lifting

ex: pectoralis major

Question 3

Myofibrils

Answer 3

make up myocytes

composed of repeating sections of sarcomeres

Question 4

Muscle conduction to contraction pathway

Answer 4

Each bind nAChR at NMJ
depolarize muscle down T tubules
AP hits dihydropyridine receptor which is mechanically attached to ryanodine receptor on the sarcoplasmic reticulum –> release of Ca2+

Ca2+ binds to troponin C on actin, causing conformational change in tropomyosin exposing myosin binding sites –> contraction

Question 5

label the sarcomere parts

Answer 5

page 87

Question 6

Extrafusal muscle fibers

Answer 6

functional unit of muscle

type 1 and type 2 muscle fibers

Question 7

Intrafusal muscle fibers

Answer 7

make up muscle spindle

proprioceptive - monitor length

stretch stimulates 1a afferent –> dorsal horn –> alpha motor neuron causing reflex muscle contraction to resist the stretch

tells you to lift harder for heavy things

Question 8

Golgi tendons

Answer 8

monitor tension - run perpendicular to intrafusal muscle fibers

provide inhibitory 1b afferent feedback - oppose contraction of muscle

tells you to drop something heavy

Question 9

Gamma loop

Answer 9

regulates sensitivity of the reflex arc

CNS –> gamma motor neuron –> contraction of intrafusal fiber (center part of spindle), increasing sensitivity of reflex arc

Question 10

Clinical reflexes

Answer 10

patellar L4
Achilles S1
Biceps C5
Brachioradialis C6
triceps C7

Question 11

Primitive reflexes

Answer 11

test health of neonates CNS

Rooting: stroke cheek - turn to find nipple
Sucking: touch roof mouth =sucking
Palmar reflex: touch palm –> grab
Plantar reflex: stroke sole of foot –> toes fan out, great toe dorsiflex (Babinski)
Galant reflex: hold on stomach, stroke side - flex to side
Moro: lift head/shoulders off table 1 inch, drop –> extend arms and flex in

Question 12

Muscles and nerves involved in shoulder abduction

Answer 12

0-15 degrees: supraspinatus m., supra scapular n.
15-90 degrees: deltoid m., axillary n.
90-180 degrees: Trapezius m, spinal accessory n; serrates anterior, long thoracic n.