A&P Lecture Exam 4

Question 1

Myo, Mys, Sarco

Answer 1

prefixes meaning muscles.

Question 2

Skeletal muscle

Answer 2

Attached to bones, has striations, voluntary (doesn’t contract till brain tells it to). Responsible for body motility, adapts to environment and tires out quickly.

Question 3

Cardiac muscle

Answer 3

Walls of the heart, has striations, involuntary (contracts all the time, heart beats on its own without nervous system stimulating it. Beats faster when under serious exercise and slows down normal when resting.

Question 4

Smooth muscle

Answer 4

Walls of the hollow organs, no striations, involuntary (lungs breathe on their own, digest itself). Visceral

Question 5

Excitability

Answer 5

Responsiveness. Ability for cell to receive and respond to stimulus by changing the membrane potential (usually stimulus from nervous system)

Question 6

Contractility

Answer 6

Contract/getting shorter. Ability to shorten when stimulated, sets muscle apart from other tissue types.

Question 7

Extensibility

Answer 7

Extends and stretches (gets larger). Muscle cells shorten when contracted, and can be stretched when relaxed.

Question 8

Elasticity

Answer 8

Recoil and resume its resting length after stretching.

Question 9

What are the 5 functions of muscles.

Answer 9

1. Movement
2. Maintain posture
3. Stabilizes joints
4. Generate heat: when contracting, plays a role in maintaining normal body temp.
   5.Protect organs, form valves, control pupil size, cause “goose bumps.”

Question 10

What are skeletal muscles served by?

Answer 10

Served by one artery, one nerve, and one more veins. This is how blood gets to muscle to heal, notorious, waste products out, oxygen to muscle to form ATP.

Question 11

What are the 3 connective tissue sheaths?

Answer 11

1. Epimysium
2. Perimysium
3. Endomysium

Question 12

Epimysium

Answer 12

Fascicles wrapped together to make one muscle. The most superficial layer, surrounds the whole muscle.

Question 13

Perimysium

Answer 13

each skeletal muscle is grouped into fascicles (bundles). Perimysium surrounds these bundles as a layer of dense irregular connective tissue, around the muscles.

Question 14

Endomysium

Answer 14

Sheath of connective tissue surrounding each muscle fiber (1 each). Consists of areolar connective tissue.

Question 15

Insertion

Answer 15

Muscle attaches to moveable bone in joint. Distal

Question 16

Origin

Answer 16

Site where bone and muscles attach, bu do not move. Proximal

Question 17

Direct attachment

Answer 17

Epimysium of muscle fused to periosteum of bone. (don’t need tendon to connect

Question 18

Indirect attachment

Answer 18

muscles connective tissue wrap extends beyond muscle as tendon. Tendon anchors the muscle to connective tissue of bone to fascicles of muscle.

Question 19

Sarcolemma

Answer 19

muscle fibers plasma membrane, able to conduct electrical impulses.

Question 20

Sarcoplasm

Answer 20

Calcium is released here. “cytoplasm” of muscle fibers. Contains large amounts of glycosomes and myoglobin.

Question 21

Myofibrils

Answer 21

single muscle fibers stuffed with these, made of proteins arranged in specific patterns. Makes up 80% volume of muscle fibers, it’s what exhibits striations.

Question 22

Sarcoplasmic reticulum

Answer 22

draped around myofibrils (endoplasmic reticulum- but in muscle fibers) releases calcium.

Question 23

Sarcomeres

Answer 23

Pattern that myofibril are arranged in and how proteins line up (myosin and actin).

Question 24

H Zone

Answer 24

thick filaments only, middle of sarcomere

Question 25

M Line

Answer 25

thick filaments linked by accessory proteins (myosin)

Question 26

Z Discs

Question 27

A Band

Answer 27

contains actin and myosin, (thick and thin filaments overlap)

Question 28

I Band

Answer 28

only actin protein present (thin filaments)