Muscle fiber anatomy

Question 1

the smallest contractile unit in a muscle

Answer 1

sarcomere

Question 2

Purpose of sarcoplasmic reticulum

Answer 2

Stores calcium ions and pumps them into sarcoplasm when muscle is stimulated

Question 3

Myoglobin

Answer 3

Molecule, made of proteins, that carries oxygen throughout sarcoplasm

Question 4

What is area does a sarcomere cover

Answer 4

From one z-line to the next z-line

Question 5

For full desired contractions to occur:

Answer 5

cross-bridges must be broken and repeated

Question 6

What prevents unwanted muscle contractions:

Answer 6

Tropomyosin and troponin block actin-binding sites

Question 7

Tropomyosin

Answer 7

Myofibril that blocks binding sites

Question 8

nebulin

Answer 8

actin binding protein strand

Question 9

Channels of sarcolemma:

Answer 9

Respond to neurotransmitter to allow sodium ions to enter the cell

Question 10

areas with no actin overlap are known as:

Answer 10

H-zone

Question 11

actin

Answer 11

“thin filament”

double, twisted strand of protein

Question 12

1) What organelle is especially abundant in sarcoplasm

2) Why?

Answer 12

1) Mitochondria

2) Creates ATP for the cell to use as energy

Question 13

Types of myofibrils (4 types)

Answer 13

1) actin
2) myosin
3) tropomyosin
4) troponin

Question 14

Cell membrane of muscle cells is called:

Answer 14

Sarcolemma

Question 15

Myosin name and purpose

Answer 15

“thick filament”

contains heads that temporarily bind to specific proteins along actin

Question 16

What action requires ATP

what action does not require ATP

Answer 16

1) breaking cross-bridges

2) formation of cross-bridges

Question 17

Strands of actin are attached to:

Answer 17

Z-lines

Question 18

Abundant, small fibers in sarcoplasm:

Answer 18

myofibrils

Question 19

Cross-bridge

Answer 19

Binding sites between myosin heads and actin

Question 20

z-line:

Answer 20

A skeletal fiber that attaches actin so that it anchors it in place

Question 21

Specialized endoplasmic reticulum in sarcoplasm:

Answer 21

Sarcoplasmic reticulum

Question 22

As contraction occurs:

Answer 22

the h-zone decreases in size and actin strands are brought closer to one another

Question 23

Troponin

Answer 23

Holds tropomyosin in place

Question 24

Proteins that bind the myosin heads known as:

Answer 24

Myosin binding sites

Question 25

Cytoplasm of muscle cells called:

Answer 25

Sarcoplasm