Skeletal Muscle Contractions

Question 1

Epimysium

Answer 1

Connective tissue surrounding entire muscle

Question 2

Muscle

Answer 2

made up of multiple fascicles

Question 3

perimysium

Answer 3

connective tissue surrounding individual fascicle

Question 4

fascicle

Answer 4

a bundle of myofibers

Question 5

endomysium

Answer 5

delicate connective tissue around each myofiber

Question 6

sarcolemma (Plasmalemma)

Answer 6

cell membrane of muscle fiber (myofiber)

Question 7

myofiber (muscle cell)

Answer 7

individual multinucleated muscle cell

Question 8

Myofibril

Answer 8

a chain of sarcomeres within a myofiber

Question 9

myofilament

Answer 9

actin and myosin filaments that make up a sarcomere.

Question 10

T-tubules:

Answer 10

invaginations of sarcolemma, they lie close to cisternae of SR. they form triads with cisternae 2 t-tubules + 1 cisternae. Two per sarcomere.

Question 11

Z-disc

Answer 11

anchor actin filaments and are located at each end of a sarcomere

Question 12

I-Bands

Answer 12

composed entirely of actin, width changes during contraction

Question 13

A-Bands

Answer 13

composed of actin and myosin, width does not change during contraction.

Question 14

H-bands

Answer 14

Composed entirely of myosin, width changes during contraction.

Question 15

Dihydropyridine (DHP) receptors

Answer 15

voltage-sensitive L-Type calcium channels arranged in quadruplets. Located on the sarcolemma t-tubules. Cause conformational change in the ryanodine receptors. Allows in a minute amound of ca2+ into the cytosol

Question 16

Ryanodine receptors

Answer 16

located at the cisternae of the SR. Open in response to conformational change in DHP receptors. Allow calcium into the cytosol from the SR

Question 17

SERCA

Answer 17

Sarcoplasmic Reticulum Calcium ATPase, uses ATP to pump calcium back into the SR

Question 18

Calsequestrin in the SR maintains and optimum _____ _______ _________ to facilitate return of calcium to SR

Answer 18

calcium concentration gradient.