02 Microscopic Anatomy of Skeletal Muscle

Question 1

plasma membrane in muscle fibers

Answer 1

Sarcolemma

Question 2

cytoplasm of the cell

Answer 2

Sarcoplasm

Question 3

“the fibers in muscle”
- long ribbon-like organelles which nearly fill the
cytoplasm

Answer 3

Myofibrils

Question 4

contractile protein in the thin filaments that binds into the myosin heads

Answer 4

Actin

Question 5

thick filaments

Answer 5

Myosin Filaments

Question 6

KEEP IN MIND!!
myo = muscle

Question 7

• give the muscle fiber its striated (banded) appearance

Answer 7

Light (I) bands and Dark (A) bands

Question 8

Compose of Z line
-there is a zigzag line where thin filaments are attached (lighter order)

Answer 8

I band

Question 9

Has H zone that is composed of M line
- dark band

Answer 9

A band

Question 10

midline interruption in the light I band

Answer 10

Z disc

Question 11

lighter central area of the dark band (a band)

Answer 11

H zone

Question 12

contains tiny protein rods that hold adjacent thick filaments together

Answer 12

M line

Question 13

are anchored to the Z disc, and do not extend into
the middle of a relaxed sarcomere

Answer 13

Thin filaments

Question 14

its interconnecting tubules and sacs surround every myofibril, and stores calcium and to release it on demand when the muscle fiber is stimulated to contract

Answer 14

Sarcoplasmic Reticulum

Question 15

structural and functional units of skeletal muscle

Answer 15

Sarcomeres

Question 16

myofilaments that extend the entire length of the dark A band, and are made mostly of bundled
molecules of the protein myosin

Answer 16

Thick filaments

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