Musculoskeletal System

Question 1

muscle

Answer 1

specific tissue w/i body that generates mechanical force in response to NS motor output; afferent message to brain to effect message that stimulates muscles for motor output

Question 2

3 types of muscle in vert

Answer 2

skeletal, smooth, cardiac

Question 3

skeletal muscle

Answer 3

responsible for movements of skeleton; muscles attached to bones via tendons; tough cords made of connective tissue

Question 4

muscle fiber

Answer 4

long, cylindrical multinucleated cell; several cels fused together to create fiber in dev; T-tubules, sarcoplasmic reticulum, characterized by myofibrils

Question 5

T-tubules

Answer 5

infoldings of pm

Question 6

sarcoplasmic reticulum (SR)

Answer 6

specific ER in muscle fibers

Question 7

myofibrils

Answer 7

long fiber w/i muscle fibers, run lenthwise; 2 types of filaments: thin and thick

Question 8

thin filament

Answer 8

2 strands of actin; contractile protein w myosin binding sites; regulatory proteins: tropomyosin, troponin

Question 9

thick filament

Answer 9

about 350 myosin contractile protein molecules; each w head (stick out from molecule) and tail (associate w each other, thickness)

Question 10

actin + myosin

Answer 10

found in many cells but only highly organized in muscle cells; filament arrangement in muscle cells give “striped” appearance;; skeletal muscle = striated

Question 11

sarcomere

Answer 11

basic unit of contraction w/i myofibrial; repeated unit of overlapping thin/thick filaments; lots of sarcomeres lined up end to end = myofibril = lots of muscle; made of z-lines and m-lines

Question 12

z-lines

Answer 12

location where thin actin filaments are attached; join adjacent sarcomeres together @ their ends

Question 13

m-lines

Answer 13

location of thick myosine filaments; anchored in middle

Question 14

during muscle contraction

Answer 14

think actin + thick myosin filaments slide past one another need connections to each other: some old connections break, some new connections form; overall result = sarcomere gets shorter: distance btwn z lines going to shorten, length of filaments does not change only amnt of over changes

Question 15

muscle fiber @ rest

Answer 15

trophomyosin covers myosin binding site along the thin actin filament

Question 16

muscle contraction steps

Answer 16

see notebk/textbk

Question 17

myosin head

Answer 17

low E: ATP attached, relaxed; high E: ATP hydrolyzed to ADP+Pi, wound up, cocked, contract

Question 18

cardiac muscle

Answer 18

wallks of heart; striated; branched muscle fibers; different area of heart contract simultaneously via intercalated discas; juctions allow ions to pass btwn cells; APs move quickly; can conract on their own bc alway want heart beating; high permeable to Na+ ions lots of depolarization lots of sponataneous APs

Question 19

smooth muscle

Answer 19

walls of DT, bladder, uterus, BVs; NOT attached to bones, striated NOT highly organized; no T-tubules + no well dev SR; less eff sys for delivering messages; slow, sustained long involuntary contraction

Question 20

3 function of skeleton

Answer 20

support, protection, movement

Question 21

hydrostatic skeleton

Answer 21

fluid-filled skeletons bc closed compartment doesn’t let fluid out, under pressure; peristalsis = movement via rhythmic muscle contraction; ex: soft bodied inverts, cnidarians, nematodas, annelids, hydra = 2 layers of antagonistic contractile cells (inner = cicular = thinner/taller, outer = longitudinal = shorten/widen)

Question 22

exoskeleton

Answer 22

external; comprised of nonliving tissue; producted by epidermal cells; no growth; molting via ecdysis; ex: arthoropods w chitin exo skeleton for protection and transmitting force, moluscs w CaCO3 exoskeleton secreted by mantle give proteins