Muscular system: Microscopic anatomy of skeletal muscle

Question 1

Cylindrical and multinucleated cells

Answer 1

Muscle fibers

Question 2

long, cylindrical,
multinucleated cells

Answer 2

Muscle Fiber

Question 3

Two types of muscle fiber

Answer 3

Sarcolemma
Sacroplasm

Question 4

It is the plasma membrane of the muscle fibers

Answer 4

Sarcolemma

Question 5

cytoplasm, which contains organelles, glycogen (for energy), and myoglobin (oxygen
storage)

Answer 5

Sacroplasm

Question 6

the term for energy

Answer 6

glycogen

Question 7

the term for oxygen storage

Answer 7

myoglobin

Question 8

cylindrical organelles running the length of the muscle fiber,
responsible for contraction

Answer 8

Myofibrils

Question 9

structural and functional
unit of a myofibril; the site of
contraction.

Answer 9

sacromere

Question 10

protein
filaments anchored to the Z-line; involved in contraction.

Answer 10

Actin (thin filaments)

Question 11

protein
filaments with heads that bind to
actin and pull during contraction.

Answer 11

Myosin (thick filaments)

Question 12

defines the boundaries of a
sarcomere and anchors actin.

Answer 12

Z-line

Question 13

center of the sarcomere,
anchors myosin.

Answer 13

M-line

Question 14

light region containing only
actin filaments.

Answer 14

I-band

Question 15

dark region containing the
full length of myosin filaments,
overlapping with actin.

Answer 15

A-band

Question 16

the central part of the A-
band with only myosin (disappears
during contraction)

Answer 16

H-zone

Question 17

projections at the
end of thick filaments

Answer 17

Myosin heads

Question 18

attachment of a myosin head to an active site of actin in the thin filament

Answer 18

Cross bridges

Question 19

elastic filaments that run through the core of the thick filament

Answer 19

Titin

Question 20

Specialized smooth endoplasmic reticulum that surrounds myofibrils. Stores and releases calcium ions (Ca²⁺), which are crucial for muscle contraction

Answer 20

Sacroplasmic reticulum