Chapter 13 Muscle Physiology

fibers

100

prime mover of any skeletal movement 

agonisitic muscle 

200

produce opposite action to agonists 

antagonisitic muscle 

300

plasma membrane of muscle fibers 

sacrolemma 

400

cytoplasm of muscle fibers 

sacroplasm 

500

E.R of muscle fibers ( stores Ca2+) 

sacroplasmic reticulum 

neurons

100

specialized region of sacrolemma at neuromuscular junctions (acetylcholine receptors) 

Motor end plate 

200

motor neuron and all innervated muscle fibers (1:100-1:2000)

motor unit 

300

subunits of muscle fibers (1um)

myofibrils 

400

even smaller structures within myofibrils 

myofilaments 

500

protein myosin- A band (dark under scope)

thick filaments 

filaments

100

protein actin (I band light under scope)

thin filaments 

200

light areas between stacks of thick filaments (myosin) (anchored by M lines) 

I bands 

300

stacks of thick filaments with overlapping thin (actin)

A bands 

400

sections of A bands without overlap

H bands 

500

hexagonal structures that connect sacromeres (myosin attaches via titin-recoil)

Z discs 

binding

100

extensions of myosin with "arms" and "heads" 

cross bridges 

200

ATP binding site & actin binding site on "head"

Myosin AtPase

300

force that pulls thin filament towards A band 

power stroke 

400

subunits of f-actin

G-actin

500

(inside helix) binds troponin complexes 

Tropomyosin

binds

100

thin filament 

F actin 

200

inhibits myosin binding 

troponin I

300

binds to tropomyosin 

troponin T 

400

binds Ca2+

Troponin C 

500

active transport of Ca2+ out to cytoplasmic reticul (terminal cisternae) (modified ERs that surround each myofibril) 

Muscle relaxation