The Muscular System

Question 1

What is cardiac muscle?

Answer 1

Striated involuntary muscle tissue found in the heart.

Question 2

What is smooth muscle?

Answer 2

Muscle tissue in the gut and internal organs that is involuntarily controlled.

Question 3

What are skeletal muscles?

Answer 3

The voluntary muscles attached to bones via tendons (thick fibrous connective tissue) that produce human movement.

They are the most common muscle found in the human body.

Question 4

How many types of muscle tissue are there and what are they?

Answer 4

There are three types: cardiac, smooth, and skeletal muscle.

Question 5

What is a tendon?

Answer 5

A strong, fibrous cord made of collagen that attaches muscle to bone.

Question 6

What is a neurotransmitter?

Answer 6

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

Question 7

What are the two type of skeletal muscle fibers?

Answer 7

Slow-twitch muscle fibers and fast-twitch muscle fibers.

Question 8

What are Type 1 fibers?

Answer 8

Slow-twitch, fatigue resistant muscle fibers with high mitochondrial density.

(Cross-country runners, triathletes, distance swimmers, cyclists, nordic skiers)

Question 9

What are Type IIA and Type IIX fibers?

Answer 9

Type IIA: fast-twitch, moderately fatigable muscle fibers with moderate mitochondrial density.

Type IIX: fast-twitch, fast fatigable muscle fibers with low mitochondrial density.

(Weightlifters, gymnasts, baseball players, paddle sport players, wrestlers)

Question 10

What is the size principle of fiber recruitment?

Answer 10

Principle stating that motor units are recruited in order according to their recruitment thresholds and firing rates.

Fibers with a high level of liability are recruited first (smalled and slowest) and those with lower levels of liability ( largest and fastest) are recruited last.

Picking up something light (low-threshold motor unit) vs. Something heavy (high threshold motor units)

Question 11

What is the fusiform (few-zuh-form) muscle?

Answer 11

A spindle shaped muscle.

Examples: biceps brachii, sartorius, and sternohyoid)(sterno-hi-oid)

Question 12

What are convergent muscles?

Answer 12

Also known as fan-like triangular muscle.

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.)

Examples: pectoralis major.

Question 13

What is a circular muscle?

Answer 13

Muscle fibers surrounding an opening in the body.

Example: sphincters, eye muscles, gastrointestinal tract.

Question 14

What are parallel muscles?

Answer 14

Muscle fibers running parallel to the axis of the muscle.

Example: sartorius, rectus abdominus, biceps brachii.

Question 15

What are pennate muscles?

Answer 15

Have a feather-like shape
Muscles with fascicles that attach obliquely (diagonally)

Example: Deltoid, obliques, extensor digitorum longus, rectus femoris.

Question 16

What is a unipennate muscle?

Answer 16

Muscle fibers extending from one side of a central tendon.

Example: Flexor pollicis longus. (Muscle in forearm that helps flex the thumb)

Question 17

What is a bipennate muscle?

Answer 17

Muscle fibers extending from both sides of a central tendon.

Example: Soleus

Question 18

What is a multipennate muscle?

Answer 18

Muscle fibers extending from both sides of multiple central tendons.

Example: Deltoid

Question 19

What are the three types of muscles actions and what muscle actions do they perform?

Answer 19

There are three types:
Concentric: when the length of a muscle shortens as tension is produced.
(Bicep curl, sit-up, push-up, calf raise)

Eccentric: when the length of a muscle increases as tension is produced.
(Pull-up, lunge, shoulder press)

Isometric: when the length of a muscle remains constant as tension is produced.
(Wall sit, plank, side plank, glute bridge, squat hold, dead hang, leg extension, bicep curl, tricep extension)

Question 20

What is the stretch-shortening cycle?

Answer 20

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