skeletal muscle

Question 1

properties of muscle tissue

Answer 1

excitability

contractibility

extensibility- elasticity

Question 2

what type of contractions do smooth muscle have?

Answer 2

involuntary contraction

Question 3

what governs involuntary contraction of smooth and cardiac muscle?

Answer 3

autonomic nervous system

Question 4

smooth muscle appearance

Answer 4

non-striated

Question 5

what type of contractions does cardiac muscle perform?

Answer 5

involuntary

Question 6

cardiac muscle appearance

Answer 6

striated

Question 7

how do individual heart chambers contract as a unit?

Answer 7

fibers of cardiac muscle are interconnected for nerve impulses to cross multiple fibers

Question 8

what type of contractions does skeletal muscle have?

Answer 8

voluntary control

Question 9

skeletal muscle appearance

Answer 9

striated

Question 10

what does skeletal muscle do?

Answer 10

attach to the skeleton and produce joint movement

Question 11

functions of skeletal muscle

Answer 11

produce movement of skeleton

maintain posture and body position

stabilize joints

produce heat for temperature regulation

Question 12

what are skeletal muscle names determined by?

Answer 12

function
attachment sites
position/direction
shape
size

Question 13

what are skeletal muscle attachments called?

Answer 13

origin
insertion

Question 14

origin

Answer 14

proximal attachment site

can also be less mobile attachment site

Question 15

insertion

Answer 15

distal attachment site

can also be more mobile attachment site

Question 16

skeletal muscle architecture

Answer 16

muscle belly: comprised of groups of fascicles

fascicles: comprised of groups of muscle fibers

muscle fibers: comprised of groups of myofibrils

Question 17

what are the 3 concentric layers of connective tissue of muscle?

Answer 17

epimysium: surrounds entire muscle

perimysium: surrounds fascicle

endomysium: surrounds muscle fiber

Question 18

muscle histology:

a myofibril divides into repeating cell units called…

Answer 18

sarcomeres

Question 19

sarcomeres

Answer 19

the actual contractile unit that is made of bundles of myofilaments called actin and myosin

Question 20

actin and myosin

Answer 20

bundles of myofilaments

actin- thin
myosin- thick

Question 21

how many myofibrils does each muscle fiber contain?

Answer 21

100-1000

Question 22

mechanism of muscle contraction

Answer 22

nerve cell triggers release of calcium ions

enables myosin head to bind to actin filaments and pull them

shortens sarcomere through cycle of attachment, power stroke, and detachment

Question 23

sliding filament theory

Answer 23

ATP binds to myosin head allowing it to release from actin

ATPase activity on the myosin head hydrolyzes ATP

myosin head becomes cocked and energized, and swings over to weakly bind with a new actin molecule

power stroke occurs at release of phosphate from myosin molecule; myosin head rotates on its hinge pushing the actin filament past it

when ends of power stroke occurs the myosin head releases ADP and stays tightly bound

Question 24

muscle contraction summary

Answer 24

AChase is released and attaches to ACh receptors on sarcolemma

action potential occurs which is propapagnted along SR and t-tubules

causes release of calcium

Ca ions bind to troponin

tropomyosin alters its shape exposing the actin binding sites

myosin cross bridges attach to actin binding sites and pulls on actin filament

ATP binds to myosin and triggers release from actin

ATP breaks down, which provides energy for myosin cross bridge to return to cocked position

process repeats until muscle is fully contracted