The Muscular System

Question 1

Name the three different types of muscle tissue.

Answer 1

1. Cardiac
2. Smooth
3. Skeletal

Question 2

What type of muscle tissue makes up blood vessels?

Answer 2

Smooth muscle tissue.

Question 3

What is the cytoplasm of a muscle fiber called?

Answer 3

Sarcoplasm

Question 4

What are myofibrils?

Answer 4

Parallel filaments that form muscle.

Question 5

What are myofilaments?

Answer 5

The filaments of myofibrils composed of actin and myosin.

Question 6

Name the two types of myofilaments.

Answer 6

1. Actin
2. Myosin

Question 7

What are the thin filaments of muscle myofilaments where myosin bind to contract muscles?

Answer 7

Actin

Question 8

What are the thick filaments of myofilaments with a fibrous head, neck, and tail that bind to actin?

Answer 8

Myosin

Question 9

What is a sarcomere?

Answer 9

The contractile unit of muscle tissue.

Question 10

What is endomysium?

Answer 10

The connective tissue covering each muscle fiber.

Question 11

Label the following diagram:

Answer 11

Question 12

What is the fibrous elastic tissue that surrounds a muscle?

Answer 12

Epimysium

Question 13

What are fasciculi?

Answer 13

Bundles of muscle fibers (the singular is “fascicle”).

Question 14

What is the connective tissue that covers a bundle of muscle fibers?

Answer 14

Perimysium

Question 15

What is the name for a strong, fibrous cord made of collagen that attaches muscle to bone?

Answer 15

Tendon

Question 16

What is periosteum?

Answer 16

A dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.

Question 17

Describe the process for the musculature of the musculoskeletal system to contract.

Answer 17

1. It must receive a signal from the CNS
2. These signals (action potentials) travel along the nervous system and eventually connect with muscles via motor neurons.
3. The motor neurons meet with the muscle cell at a synapse called the neuromuscular junction, and…
4. A unique neurotransmitter called acetylcholine is released.

Question 18

What is the space between a motor neuron and muscle fiber?

Answer 18

Neuromuscular junction

Question 19

What is a neurotransmitter?

Answer 19

A chemical messenger that transmits messages between neurons or from neurons to muscles.

Question 20

What is acetylcholine?

Answer 20

The neurotransmitter released by an action potential at the neuromuscular junction.

Question 21

Describe the process of muscle contraction.

List of 10 points.

Answer 21

1. Brain sends out electrical signal
2. Signal travels through the spinal cord
3. To the spinal nerves
4. To the motor neurons
5. Resulting in the propagation of an electrical current through the muscle fiber
6. Electrical signal triggers the release of calcium inside the muscle fiber
7. The released calcium binds to the contractile protein ACTIN
8. This permits its interaction with the MYOSIN contractile protein
9. ATP provides the energy that permits the “walking” of MYOSIN across the ACTIN
10. This pulling action of the MYOSIN across the ACTIN results in the shortening of the muscle fiber during MUSCLE CONTRACTION.

Question 22

What is the sliding-filament theory?

Answer 22

The interaction of actin and myosin that describes the process of muscle contraction.

Question 23

What is the component of a cell that is most noted for energy production?

Answer 23

Mitocohondria

Question 24

Describe the attributes of slow-twitch muscle fibers.

Answer 24

1. Type I
2. Fatigue-resistant
3. High mitochondrial density
4. Derive energy from aerobic metabolism
5. Ideal for endurance and low-intensity activities of longer duration
6. Also called oxidative fibers
7. Contract relatively slowly

Question 25

Describe the attributes of fast-twitch muscle fibers.

Answer 25

1. Contract quickly and with greater force 2. Type IIa and Type IIx 3. Selectively recruited for high-intensity activities requiring strength and power 4. Type IIa are moderately fatigable muscle fibers with moderate mitochondrial density (meaning they can contract through most intermittent athletic activity and recover well) 5. Derive energy from anaerobic metabolism 6. Type IIx are fast-fatigable muscle fibers with low mitochondrial density 7. Also known as "super fibers"

Question 26

What does liability of recruitment refer to? | Muscular system.

Answer 26

How easily and quickly muscle fibers can be recuited. The higher the liability, the more likely a muscle fiber will fire more easily and quickly compared to a lower liability muscle fiber.

Question 27

Which muscle fibers have the highest liability to recruitment?

Answer 27

Type I (slow-twitch) fibers

Question 28

What is the principle that states that fibers with a high level of liability are recruited first and that those with lower levels of liability are recruited last? (Principle stating that motor units are recruited in order according to their recruitment thresholds and firing rates.)

Answer 28

The size principle of fiber recruitment (also called the Henneman principle)

Question 29

What is the name for a spindle-shaped muscle with a large belly?

Answer 29

Fusiform muscle

Question 30

Muscle fibers converging from a broad origin (fixed point where the muscle attaches closest to the torso) to a single tendon of insertion (fixed point where the muscle attaches furthest from the torso) is referred to as... (?)

Answer 30

Convergent muscle

Question 31

What is the name for muscle fibers surrounding an opening in the body?

Answer 31

Circular muscle (also called sphincters)

Question 32

Muscle fibers running parallel to the axis of the muscle are called... (?)

Answer 32

Parallel muscle

Question 33

Describe pennate muscles.

Answer 33

Muscles with fascicles that attach obliquely (diagonally).

Question 34

Describe unipennate muscle.

Answer 34

Muscle fibers extending from one side of a central tendon.

Question 35

Describe bipennate muscle.

Answer 35

Muscle fibers extending from both sides of a central tendon.

Question 36

Describe multipennate muscle.

Answer 36

Muscle fibers extending from both sides of multiple central tendons.

Question 37

Name the three types of muscle actions.

Answer 37

1. Concentric 2. Eccentric 3. Isometric

Question 38

When the length of a muscle shortens as tension is produced it is called what type of muscle action?

Answer 38

Concentric

Question 39

When the length of a muscle increases as tension is produced it is called what type of muscle action?

Answer 39

Eccentric

Question 40

When the length of a muscle remains constant as tension is produced it is called what type of muscle action?

Answer 40

Isometric

Question 41

Rank the three types of contractions in order of strength, from strongest to weakest.

Answer 41

1. Eccentric 2. Isometric 3. Concentric

Question 42

Label the following muscle fiber patterns:

Answer 42

Question 43

In what muscle fiber arrangement do muscle fibers run parallel to the axis of the muscle?

Answer 43

Parallel muscles

Question 44

In what muscle fiber arrangement do muscles have fascicles that attach obliquely (diagonally)?

Answer 44

Pennate muscles

Question 45

In what muscle fiber arrangement do muscle fibers run diagonally in respect to the tendon similar to a feather?

Answer 45

Penniform

Question 46

In what muscle fiber arrangement do muscle fibers extend from one side of a central tendon?

Answer 46

Unipennate

Question 47

In what muscle fiber arrangement do muscle fibers extend from both sides of a central tendon?

Answer 47

Bipennate

Question 48

In what muscle fiber arrangement do muscle fibers extend from both sides of multiple central tendons?

Answer 48

Multipennate

Question 49

What is the Stretch-Shortening Cycle (SSC)? | Muscle Actions

Answer 49

The cycling between the eccentric (stretch) action of a muscle and the concentric (shortening) action of the same muscle.