19.4 Microscopic Structure and Metabolism of Cardiac Muscle

Question 1

Composition

Answer 1

striated, relatively shor, branched cells housing 1 or 2 central nuclei

Question 2

Endomysium

Answer 2

areolar connective tissue supporting cells

Question 3

Intercalated disc

Answer 3

link muscle cells together electrically and mechanically so that the heart beats in unison

Question 4

z-disc

Answer 4

fibers that can corss each other to allow muscles to contract

Question 5

desosomes

Answer 5

proteins filaments that physically links one cardiac cell to another

Question 6

gap junctions

Answer 6

provide a pathway of little resistance between closely connected cells for ions to travel through + allow one action potential to stimulate a whole heart chamber

Question 7

striations

Answer 7

alternating thick and thin filaments

Question 8

sarcolemma

Answer 8

plasma membranesa

Question 9

rcoplasmic reticulum

Answer 9

where calcium is sotred and allows a proton pump

Question 10

sarcomere

Answer 10

one unit within a myofibril + goes from z-disc to z-disc

Question 11

myofibril

Answer 11

bundles of muscle fibers

Question 12

myofilament

Answer 12

individual muscle fibers

Question 13

t-tubulues

Answer 13

extension of the sarcolemma so the excitation of the muscle cell can reach the inside of the cell