Chapter 12 Muscle Physiology

Question 1

What is the Neuromuscular Junction

Answer 1

Place where the nerve synapses with the muscle

Question 2

What is released at the neuromuscular junction

Answer 2

Acetylcholine

Question 3

What is stimulated by ACh at neuromuscular junction

Answer 3

nicotinic receptors

Question 4

What is a Single Motor Unit

Answer 4

All muscle fibers that are stimulated by 1 neuron

Question 5

What is a large motor unit

Answer 5

Produces more force when stimulated 1:100 ratio, found in large muscles like hamstrings or calf

Question 6

What is a small motor unit

Answer 6

Produces less force when stimulated almost 1:1 ratio, more fine control of muscles like palms or fingers

Question 7

Is myosin thick or thin

Answer 7

thick

Question 8

Is actin thick or thin

Answer 8

thin

Question 9

What is an I band

Answer 9

Light striations in 1 sarcomere, just actin

Question 10

What is an A band

Answer 10

Dark striations in 1 sarcomere, overlapping myosin and actin

Question 11

What is an H band

Answer 11

Thick filament in the sarcomere, just myosin

Question 12

What are Z discs

Answer 12

Anchoring points for actin, beginning and end of each sarcomere

Question 13

What is the M line

Answer 13

Keeps the thick filament together

Question 14

What is Titin

Answer 14

Largest protein in the body, connects thick filament (myosin) to z-disc

Question 15

What is tropomyosin

Answer 15

Protein that blocks myosin from binding to actin

Question 16

What is the role of Calcium in muscle contraction

Answer 16

Calcium binds to troponin complex causing tropomyosin to shift around the actin exposing binding sites

Question 17

What is the sarcoplasmic reticulum

Answer 17

Modified endoplasmic reticulum that spans the muscle and regulates contractions

Question 18

What is the function of the Sarcoplasmic Reticulum (SR)

Answer 18

Pumps calcium into the lumen and is regulated by motor neurons