Chapter 12: The Muscular System

Question 1

What are all muscles?

Answer 1

Excitable, contactable, extensible, and elastic.

Question 2

What are the functions of the skeletal muscles?

Answer 2

Support body, move parts of the body, maintain body temperature, promote movement in veins and lymph vessels, and protection (internal organs and stabilizing joints).

Question 3

Tendons

Answer 3

Attaches muscle to bone

Question 4

Origin of Muscle

Answer 4

The end that does not move on a stationary bone

Question 5

Insertion of Muscle

Answer 5

The end of the bone that moves

Question 6

Biceps Brachii

Answer 6

Bends the forearm at elbow

Question 7

Quadricieps Femoris

Answer 7

Straightens leg at knee; raises thigh

Question 8

Trapezius

Answer 8

Rasies scaputa, as when shrugging shoulders; pulls head backwards

Question 9

Glutemus Maximus

Answer 9

Extends thigh back

Question 10

What are muscles made of?

Answer 10

Many bundles off muscle fibers (proteins)

Question 11

Myofibrils

Answer 11

Muscle threads of bundles of myofilaments

Question 12

Myofiliaments

Answer 12

Long strands of protein, two kinds (Myosin and Actin)

Question 13

Sarcomere

Answer 13

Smallest contractable unit, myosin filaments on the inside, actin filaments on either side, Z-lines are bands of protein at edge where actin attached

Question 14

Actin Filaments

Answer 14

Thinner, like two strands of beads twisted together

Question 15

Myosin Filaments

Answer 15

Thicker, bundles, each strand has a double “golf club” head

Question 16

Motor Unit

Answer 16

Number of cells stimulated by one neuron, size varies, strength of contraction depends on the number involved

Question 17

Actylcholine

Answer 17

Released from neuron at neuromuscular junction, binds to receptor proteins in muscle cell membrane and starts electical signal inside cell, causes release.

Question 18

Troponin-Tropomyosin Complex

Answer 18

Attached to actin filiaments, blocking binding sites, calcium binds to troponin, twists tropomyosin to reveal binding sites for myosin.

Question 19

Sliding Filament Model

Answer 19

Resting sarcomere, cross-bridge attachment, pivoting of myosin head, cross-bridge detachment, myosin reactivation.

Question 20

What do muscle contractions require?

Answer 20

ATP: free supply in muscle cells

Question 21

Muscle Cell Type: Slow Twitch

Answer 21

Endurance, lots of equipment for cellular respiration

Question 22

Muscle Cell Type: Fast Twitch

Answer 22

Rapid Power, more filaments, faster enzyme form (ATP split myosin)

Question 23

Spasms

Answer 23

Involuntary contractions (cramps)

Question 24

Strain

Answer 24

Stretching or tearing of muscle

Question 25

Sprain

Answer 25

Twisting of joint, injures muscles, ligaments, tendons, blood vessels, and nerves.

Question 26

Tendinitis

Answer 26

Inflamed tendons, only after strain of joint

Question 27

Myalgia

Answer 27

Pain in muscles, may be overuse, infections, or immune disorders.

Question 28

Muscular Dystrophy

Answer 28

Group of disorders with progressive muscle loss, fat and connective tissue replace as muscle cells die

Question 29

ALS (Amyotrophic lateral sclerosis)

Answer 29

Loss of muscle function as motor neurons degenerate, progressive loss of vountary muscle control, death from loss of swallowing and/or breathing.