Muscle Info

Question 1

Cardiac muscle tissue

Answer 1

heart

Question 2

Smooth muscle tissue

Answer 2

located in the walls of the hollow visceral organs and blood vessels

Question 3

Skeletal muscle tissue

Answer 3

located in the muscle of the skeleton. Skeletal muscles are under the control of the will; hence they are called voluntary muscles.

Question 4

Skeletal muscle tissue is composed of

Answer 4

skeletal muscle cells

Question 5

It wraps around the entire muscle

Answer 5

epimysium

Question 6

around groups of muscle cells within the muscle

Answer 6

perimysium

Question 7

around each individual muscle cell

Answer 7

endomysium

Question 8

tendons

Answer 8

attach the muscle to the bone.

Question 9

Extensibility

Answer 9

the muscle can be stretched like an elastic band.

Question 10

Elasticity

Answer 10

after the muscle is stretched it can return to its normal resting length when the stretch force is removed.

Question 11

Contractility

Answer 11

the average muscle can shorten to approximately 1/2 its resting length.

Question 12

FYI

Answer 12

The movement a contracting muscle produces is determined by the type of joint the muscle spans and the relation of the muscle’s line of pull to the joint. Example = a muscle crossing anterior to the elbow will contract and shorten and will cause flexion of the elbow whereas a muscle crossing posterior to the elbow joint will cause extension. Keeping this in mind, a muscle located on the lateral surface of the shoulder will shorten and lift the arm up into abduction.

Question 13

Isotonic Contraction

Answer 13

tension remains constant as the muscle shortens or lengthens. There are two types of isotonic contractions: concentric or shortening and eccentric or lengthening contractions.

Question 14

Concentric or shortening Contraction

Answer 14

tension created overcomes the resistance and moves one attachment of the muscle toward the other.

Question 15

Eccentric or lengthening Contraction

Answer 15

muscle slowly lengthens as it gives in to an external force which is greater than the force it is exerting. The muscle gradually returns to its normal resting length.

Question 16

Isometric or Static Contraction

Answer 16

muscle remains contracted with no change in its length. This occurs when the muscles which are working against each other counterbalance one another. Example: attempting to lift something which is too heavy to move or pushing against a wall.

Question 17

Agonist

Answer 17

a muscle which is directly responsible for effecting a movement, also called the prime mover.

Question 18

Antagonist

Answer 18

a muscle whose contraction produces a movement exactly opposite from that of the agonist.

Question 19

Synergist

Answer 19

muscles which contract at the same time as the prime mover. Generally speaking synergistic action of muscles is thought to be a team effort to produce a more efficient movement. However synergistic action may occur in normal or pathological situations.

Question 20

Stabilizer

Answer 20

Located proximal to the moving part