Test 5 Chap. 10 &11

Question 2

What is a muscle fiber?

Answer 2

A muscle fiber is a single muscle cell specialized for contraction.

Question 3

Define sarcomere.

Answer 3

The functional contractile unit of a muscle, composed of myofilaments.

Question 4

What are myofibrils?

Answer 4

Cylindrical structures containing actin and myosin filaments, responsible for contraction.

Question 5

What are actin and myosin?

Answer 5

Proteins involved in muscle contraction; actin forms thin filaments, myosin forms thick filaments.

Question 6

What is the sarcoplasmic reticulum (SR)?

Answer 6

Stores calcium ions required for contraction.

Question 7

What is sarcoplasm?

Answer 7

Cytoplasm of a muscle fiber, containing ATP and other organelles.

Question 8

What defines the boundaries of a sarcomere?

Answer 8

Z-line.

Question 9

What is the M-line?

Answer 9

Center of the sarcomere, where myosin filaments attach.

Question 10

What does the I-band contain?

Answer 10

Contains only thin filaments, appears light under a microscope.

Question 11

What is found in the A-band?

Answer 11

Contains overlapping thick and thin filaments, appears dark.

Question 12

What is the H-zone?

Answer 12

Region within the A-band containing only thick filaments.

Question 13

What is a neuromuscular junction?

Answer 13

Site where a neuron stimulates a muscle cell.

Question 14

What is the motor end plate?

Answer 14

Region on the muscle cell receiving the signal.

Question 15

What neurotransmitter is released to trigger muscle contraction?

Answer 15

Acetylcholine (ACh).

Question 16

Fill in the blank: The sliding filament model describes how _______ slide past myosin filaments.

Answer 16

actin

Question 17

What happens during muscle relaxation?

Answer 17

ACh is broken down by acetylcholinesterase, calcium is reabsorbed into the SR, and myosin releases actin.

Question 18

What are fast-twitch fibers?

Answer 18

Contract quickly, fatigue rapidly, rely on anaerobic metabolism.

Question 19

What are slow-twitch fibers?

Answer 19

Contract slowly, fatigue-resistant, rich in myoglobin and mitochondria.

Question 20

What characterizes intermediate fibers?

Answer 20

Combination of fast and slow-twitch characteristics.

Question 21

What does glycolysis produce?

Answer 21

2 ATP per glucose.

Question 22

What type of respiration occurs in the mitochondria?

Answer 22

Aerobic respiration.

Question 23

What is produced as a byproduct of anaerobic respiration?

Answer 23

Lactic acid.

Question 24

What is the role of myoglobin in muscles?

Answer 24

Stores oxygen in muscle cells for aerobic respiration.

Question 25

What is flexion?

Answer 25

Bending a joint.

Question 26

What is extension?

Answer 26

Straightening a joint.

Question 27

What do agonist muscles do?

Answer 27

Primary muscle causing movement.

Question 28

What is the role of antagonist muscles?

Answer 28

Opposes the agonist.

Question 29

What are synergist muscles?

Answer 29

Assist the agonist.

Question 30

What is the diaphragm's function?

Answer 30

Primary breathing muscle.

Question 31

Which muscles elevate the jaw during mastication?

Answer 31

Masseter and Temporalis.

Question 32

Name the rotator cuff muscles.

Answer 32

* Supraspinatus * Infraspinatus * Teres Minor * Subscapularis

Question 33

What is the function of the quadriceps?

Answer 33

Knee extension.

Question 34

What do the hamstrings do?

Answer 34

Knee flexion.

Question 35

What is myasthenia gravis?

Answer 35

Autoimmune disorder causing muscle weakness due to ACh receptor degradation.

Question 36

What causes muscle fatigue?

Answer 36

ATP depletion and lactic acid accumulation.

Question 37

What is a hernia?

Answer 37

Protrusion of an organ through muscle tissue.

Question 38

What is tendonitis?

Answer 38

Inflammation of a tendon due to overuse.

Question 39

What criteria are used for naming muscles?

Answer 39

* Location * Shape * Size * Direction of Fibers * Number of Origins * Action

Question 40

What is the difference between synarthrosis and diarthrosis joints?

Answer 40

Synarthrosis are immovable joints; diarthrosis are freely movable joints.

Question 41

What type of joint is a ball-and-socket joint?

Answer 41

Allows multi-directional movement.

Question 42

What type of movement does a hinge joint allow?

Answer 42

Flexion and extension.

Question 43

What is the function of the trapezius muscle?

Answer 43

Role in shoulder movement and stabilization.

Question 44

True or False: Fast-twitch fibers are more fatigue-resistant than slow-twitch fibers.

Answer 44

False.

Question 45

What is the role of extrinsic muscles?

Answer 45

Control movement from outside a specific region.

Question 46

What movements are involved in inversion and eversion?

Answer 46

Inversion turns the sole inward; eversion turns it outward.