Muscular System

Question 1

Muscle functions

Answer 1

Produce movement, maintain posture and produce heat.

Question 2

Sarco-

Answer 2

Means flesh, but refers specifically to muscle.

Question 3

Muscle fiber

Answer 3

Muscle cell. Threadlike and often run the length of the muscle.

Question 4

Properties of muscle cells

Answer 4

Excitability, contractibility, extensibility and elasticity.

Question 5

Excitability

Answer 5

Ability to respond to a stimulus.

Question 6

Contractibility

Answer 6

Ability to shorten

Question 7

Extensibility

Answer 7

Ability to lengthen or stretch.

Question 8

Elasticity

Answer 8

Ability to return to precontraction length.

Question 9

Sarcolemma

Answer 9

Muscle cell membrane.

Question 10

Sarcoplasm

Answer 10

Intracellular fluid of a muscle cell.

Question 11

Sarcoplasmic reticulum

Answer 11

System of interconnected hollow tubes surrounding myofibrils. Stores and releases calcium ions.

Question 12

Epimysium

Answer 12

Thick outer connective tissue that surrounds the entire muscle or muscle group. Also called deep fascia.

Question 13

Perimysium

Answer 13

Middle layer of connective tissue that surrounds each muscle fascicle.

Question 14

Endomysium

Answer 14

The inner layer of connective tissue that surrounds individual muscle fibers. Continuous with tendons.

Question 15

Muscle connective tissues, superficial to deep

Answer 15

Epimysium, perimysium, endomysium

Question 16

Muscle component organization

Answer 16

Muscle, fascicle, muscle fiber, myofibril, myofilaments

Question 17

Neuromuscular junction

Answer 17

Synaptic connection between a motor neuron and a muscle fiber.

Question 18

Parts of a neuromuscular junction

Answer 18

Motor neuron, synaptic gap and motor end plate.

Question 19

Motor neuron

Answer 19

Neuron that transmits impulses from the nervous system to muscle fibers.

Question 20

Synaptic gap

Answer 20

Space between the motor neuron and the end plate. Acetylcholine crosses it.

Question 21

Motor end plate

Answer 21

Folded sections of sarcolemma that contain receptors for acetylcholine.

Question 22

Result of acetylcholine binding tot he motor end plate

Answer 22

The impulse travels through the T-tubules into the sarcoplasmic reticulum, causing calcium to be released.

Question 23

Contraction

Answer 23

Myosin heads bind to actin, then the thick and thin filaments slide past each other.

Question 24

Function of calcium ions in muscular contraction

Answer 24

They displace troponin and tropomyosin and allow for cross bridging and the subsequent power stroke.

Question 25

Motor unit

Answer 25

A single motor neuron and all of the muscle fibers that it innervates.

Question 26

Recruitment

Answer 26

More motor units are recruited to lift a heavier weight.

Question 27

Myoglobin

Answer 27

Protein that delivers oxygen to muscles.

Question 28

Muscle fatigue

Answer 28

A decline in a muscle’s ability to generate force.

Question 29

Causes of muscle fatigue

Answer 29

Running out of ATP, oxygen or glucose or a lack of nerve impulses.

Question 30

Isotonic contractions

Answer 30

The same weight is applied and the length of the muscle changes.

Question 31

Concentric contractions

Answer 31

Type of isotonic contraction in which the muscles shorten.

Question 32

Eccentric contractions

Answer 32

Type of isotonic contraction in which the muscles lengthen.

Question 33

Isometric contractions

Answer 33

The length of the muscle does not change.

Question 34

Slow twitch muscle fibers

Answer 34

Have lots of oxygenation and mitochondria. Have great capacity for long and slow contractions.

Question 35

Fast twitch muscle fibers

Answer 35

Have less oxygen and mitochondria. Have capacity for fast contractions but are susceptible to fatigue.

Question 36

Postural muscles

Answer 36

Are responsible for holding position.

Question 37

Phasic muscles

Answer 37

Are responsible for generating movement.

Question 38

Agonist

Answer 38

Prime movers which cause a desired action

Question 39

Synergist

Answer 39

Muscles which assist the prime movers.

Question 40

Fixators

Answer 40

Specialized synergists that stabilize a joint.

Question 41

Antagonist

Answer 41

Muscle which lengthens while the agonist shortens.