11.2 – Skeletal muscle cells

Question 1

which stem cells fuse to form a muscle fiber?

Answer 1

myoblasts

Question 2

when a muscle is injured, cells called ___ cells can multiply and help repair the damage

Answer 2

satellite

Question 3

which membranous structures conduct impulses thru the sarcoplasm to stimulate the release of calcium?

Answer 3

T-tubules

Question 4

in a myofibril, a thick filament is composed of pairs of ___ molecules intertwined together

Answer 4

myosin

Question 5

which unspecialized cells are located b/n a muscle fiber and the endomysium?

Answer 5

satellite cells

Question 6

what is found in thin filaments?

Answer 6

fibrous (F) actin
globular (G) actin
tropomyosin
troponin

Question 7

which cells help regenerate damaged skeletal muscle?

Answer 7

satellite cells

Question 8

in a myofibril, the ___ filaments stabilize the thick filaments and prevent over-stretching

Answer 8

elastic

Question 9

what is the function of T-tubules?

Answer 9

to stimulate the terminal cisternae to release calcium

Question 10

what is found in thin filaments but is not a regulatory protein?

Answer 10

actin

Question 11

infoldings of the sarcolemma, called transverse tubules, as associated w/ 2 terminal cistern, forming a unit called a ___

Answer 11

triad

Question 12

what happens when calcium ions bind to troponin?

Answer 12

tropomyosin moves off the active site on actin

Question 13

which protein makes up the thick filaments of a myofibril?

Answer 13

myosin

Question 14

what causes skeletal muscle cells to be striated?

Answer 14

the alternating light and dark regions of the sarcomeres

Question 15

thin filaments are primarily composed of which protein?

Answer 15

F actin

Question 16

in a sarcomere, the thick filaments attach to the ___ line, found in the middle of the H band.

Answer 16

M

Question 17

elastic filaments in a myofibril are made of which protein?

Answer 17

titin

Question 18

in a thin filament, each tropomyosin molecule has a small calcium-binding protein called ___ bound to it

Answer 18

troponin

Question 19

which is true of the light bands in skeletal muscle?

Answer 19

they are called I bands and are bisected by a Z disc

“I” in “light”

Question 20

what are 2 contractile proteins found in a myofibil?

Answer 20

actin
myosin

Question 21

w/in skeletal muscle cells, what extends from one Z disc to the next and constitutes one contractile unit?

Answer 21

sarcomere

Question 22

under the microscope, muscle that has alternating light and dark regions is said to be which of the following?

Answer 22

striated

Question 23

the dark bands in the striations of skeletal muscle are called ___ bands and they represent the ___

Answer 23

A
overlap of actin and myosin

Question 24

in a myofibril, the ___ filaments stabilize the thick filaments and prevent over-stretching

Answer 24

elastic

Question 25

w/in a sarcomere, the region within the A band that lacks thin filaments is called the ___ band

Answer 25

H

Question 26

the portion of a myofibril from one Z disc to the next is called a(n) ___

Answer 26

sarcomere

Question 27

in a sarcomere, the thick filaments attach to the ___ line, found in the middle of the H band

Answer 27

M