Muscles

Question 1

What are the functions of muscles?

Answer 1

• Movement (muscles produce movement by pulling on bones as muscles contract)
• Posture (a continuous, low-strength muscle contraction called tonic contraction (muscle tone) enables us to maintain body position)
• Heat production (contraction of muscle fibres produces most of the heat required to maintain normal body temperature)

Question 2

3 types of muscles

Answer 2

• Skeletal - Voluntary, striated
• Smooth - Involuntary, non striated
• Cardiac - involuntary, striated

Question 3

Regions of a skeletal muscle

Answer 3

• origin (attachment to the bone that remains relatively STATIONARY or fixed when movement at the joint occurs)
• insertion (point of attachment to the bone that MOVES when a muscle contracts)
• Body (main part of the muscle)

Question 4

What attaches muscle to bone?

Answer 4

Tendons

Question 5

What are muscle cells called?

Answer 5

Muscle fibers

Question 6

What is needed for muscle contraction to occur?

Answer 6

• Myosin

- Actin

Question 7

Which myofilaments contain myosin?

Answer 7

Thick ones

Question 8

Which myofilaments contain actin?

Answer 8

Thin ones

Question 9

What is the basic functional contractile unit called?

Answer 9

A sarcomere (separated by Z lines)

Question 10

What is happening when muscles contract?

Answer 10

Thick and thin myofilaments slide past each other

Question 11

What 2 things are required for muscle contraction?

Answer 11

Calcium and ATP molecules

Question 12

What 3 things happen for muscle contraction?

Answer 12

1 - nerve impulse travels to a muscle fiber through a motor neurone
2 - the impulse triggers the release of calcium ions
3 - calcium ions bind to thin filaments and permit actin to react with myosin

Question 13

What is a motor unit?

Answer 13

A combination of a motor neurone with the muscle fibres it controls

Question 14

What is a neuromuscular junction?

Answer 14

Point of contact between a nerve ending and the muscle fiber

Question 15

What is a motor neuron?

Answer 15

the specialized nerve that transmits an impulse to a muscle, causing contraction

Question 16

What is the difference between a twitch and tetanic contractions?

Answer 16

Twitches are single involuntary muscle contractions, whereas tetanic contractions are CONSTANT MUSCLE CONTRACTIONS

Question 17

What are isotonic contractions?

Answer 17

Contractions that produce movement at a joint because the muscle changes length
- further broken down into concentric contractions (muscle shortens at the insertion end of the muscle to move toward the point of origin)
and
-eccentric contractions (muscle lengthens under tension, thus moving the insertion from the origin)

Question 18

What are isometric contractions?

Answer 18

Contractions that do not produce movement; the muscle as a whole does not shorten. Although no movement occurs, tension within the muscle increases
(i.e. wall sit)

Question 19

What is fatigue and what causes it?

Answer 19

• Fatigue is reduced strength of muscle contraction caused by repeated muscle stimulation without adequate periods of rest

Question 20

What systems contribute to movement and fatigue?

Answer 20

• Respiratory, circulatory, nervous, muscular, and skeletal

Question 21

What is flexion and extension?

Answer 21

• flexion = decreasing the angle

- extension = increasing the angle

Question 22

What is abduction and adduction?

Answer 22

• abduction = away from the midline
• adduction = toward the midline
• rotation = around an axis

Question 23

What is rotation and circumduction?

Answer 23

• rotation = around an axis

- circumduction = move distal end of a part in a circle

Question 24

What is supination and pronation?

Answer 24

• Hand positions that result from twisting the forearm, supination = up, pronation = down

Question 25

What are dorsiflexion, plantar flexion, inversion, and eversion?

Answer 25

All foot movements; dorsiflexion is upward, plantar flexion is downward ankle movements, inversion and eversion are side to side

Question 26

Where is the sternocleidomastoid muscle?

Answer 26

Neck

Question 27

Where is the pectoralis major?

Answer 27

“Pecs”; chest

Question 28

Where are the deltoids?

Answer 28

Shoulders

Question 29

Where are the biceps brachii?

Answer 29

Anterior upper arm, has 2 heads

Question 30

Where are the triceps brachii?

Answer 30

Posterior upper arm, has 3 heads

Question 31

Where are the rectus abdominis?

Answer 31

“abs”, ventral

Question 32

Where are the quadriceps group?

Answer 32

Anterior thigh

Question 33

Where are the hamstrings group?

Answer 33

Posterior thigh

Question 34

Where are the gastrocnemius?

Answer 34

“Calf”, posterior lower leg

Question 35

Where are the tibias anterior?

Answer 35

Anterior lower leg

Question 36

Where are the gluteus maximus?

Answer 36

“glutes”, posterior, butt

Question 37

Where are the trapezius?

Answer 37

“Traps”, upper back

Question 38

Where are the latissimus dorsi?

Answer 38

“Lats”, large larger back muscle

Question 39

What is muscular dystrophy?

Answer 39

The degeneration of muscle fibers. Duchesnes is most common