Chapter 2 - Basic Exercise Science: Muscular System

Question 1

The Muscular System

Answer 1

The device that the NS can command to move the skeletal system

Question 2

3 Major Muscle Types in Body

Answer 2

Skeletal, cardiac, and smooth muscle

Question 3

Skeletal Muscle Make-Up

Answer 3

Made up of individual muscle fibers

Question 4

Muscle Definition

Answer 4

Multiple bundles of muscle fibers held together by connective tissue

Question 5

1st Bundle of Muscle Fiber

Answer 5

Actual muscle itself wrapped by an outer layer of CT called fascia and an inner layer called epimysium

Question 6

Epimysium

Answer 6

Outermost layer

-Layer of CT that is underneath the fascia and surrounds the muscle

Question 7

2nd Bundle of Muscle Fiber

Answer 7

Fascicle

-Each fascicle wrapped by perimysium

Question 8

Perimysium

Answer 8

Middle layer

-Surrounds the fascicles

Question 9

Endomysium

Answer 9

Deepest layer of CT that surrounds individual muscle fibers

Question 10

Fascia Definition

Answer 10

Outer layer of CT that wraps the actual muscle

Question 11

Fascicle Definition

Answer 11

The compartments that contain bundles of muscle cells, surrounded by perimysium

Question 12

Tendons

Answer 12

Connective tissues that attach muscle to bone and provide an anchor for muscles to produce force

Question 13

Sarcolemma

Answer 13

Plasma membrane that encases muscle fibers

Question 14

Sarcoplasma

Answer 14

Cellular plasma within muscle fiber

Question 15

Sarcoplasma Elements

Answer 15

Contains glycogen, fats, minerals, and oxygen-binding myoglobin, as well as nuclei, and mitochondria

Question 16

Myofibrils

Answer 16

Structure of muscle fibers that contain myofilaments that are actual contractile components of muscle tissue
-Actin and Myosin

Question 17

Actin

Answer 17

Thin filaments

Question 18

Myosin

Answer 18

Thick filaments

Question 19

Sarcomere

Answer 19

The functional unit of muscle that produces muscular contraction and consists of repeating sections of actin and myosin

Question 20

Two Lines of Sarcomere

Answer 20

Z Lines

-Each Z line denotes another sarcomere along the myofibril

Question 21

2 Protein Structures Important to Muscle Contraction

Answer 21

Tropomyosin and Troponin

Question 22

Tropomyosin

Answer 22

Located on the actin filament and keeps myosin from attaching to actin when the muscle is in a relaxed state

Question 23

Troponin

Answer 23

Plays a role in muscle contraction by providing binding sites for both calcium and tropomyosin on the actin filament when a muscle needs to contract

Question 24

Neural Activation Definition

Answer 24

The contraction of a muscle generated by neural stimulation

Question 25

Neuromuscular Junction

Answer 25

The point at which the motor neurons meets an individual muscle fiber

Question 26

Motor Unit Definition

Answer 26

A motor neuron and all of the muscle fibers it innervates

Question 27

Synapse Definition

Answer 27

Small gap between the nerve and muscle fiber

Question 28

Action Potentials

Answer 28

Electrical impulses that are transported from the CNS down the axon of the neuron

Question 29

Impulse Reaching End of Axon (Axon Terminal)

Answer 29

Neurotransmitters are released

Question 30

Neurotransmitters

Answer 30

Chemical messengers that cross the synapse to transmit electrical impulses from the nerve to the muscle

Question 31

Acetylcholine (ACh)

Answer 31

The neurotransmitter used by the neuromuscular system

-Stimulates the muscle fibers to go through a series of steps that initiates muscle contractions

Question 32

Sliding Filament Theory

Answer 32

Describes how thick and thin filaments within the sarcomere slide past one another, shortening the entire length of the sarcomere and thus shortening the muscle and producing force

Question 33

Excitation-Contraction Coupling

Answer 33

The process of neural stimulation creating a muscle contraction
-A series of steps that start with the initiation of a neural message and end with a muscle contraction

Question 34

Motor Units and the “All or Nothing” Law

Answer 34

Motor units cannot vary the amount of force they generate, they either contract maximally or not at all.

Question 35

Strength of Skeletal Muscle Contraction

Answer 35

Depends on size of motor unit recruited and number of motor units that are activated at a given time

Question 36

Size of Motor Units Related to Function of Muscle

Answer 36

Large muscle required to general more powerful movements will have much more muscle fibers in each of their motor units, vice versa

Question 37

Muscle Fiber Types

Answer 37

Type I and Type II

Question 38

Type I Muscle Fibers

Answer 38

Slow-Twitch

• More capillaries, mitochondria, and myoglobin
• Increased oxygen delivery
• Smaller in size
• Less force produced
• Slow to fatigue
• Long-term contraction (stabilization)

Question 39

Type II Muscle Fibers

Answer 39

Fast-Twitch

• Fewer capillaries, mitochondira, and myoglobin
• Decreased oxygen delivery
• Larger in size
• More force produced
• Quick to fatigue
• Short-term contractions (force and power)

Question 40

Type II Muscle Fibers

Answer 40

Subdivided into Typer IIa and Type IIx based on their chemical and mechanical properties

Question 41

Type IIx

Answer 41

Low oxidative capacity and fatigue quickly

Question 42

Type IIa (Combination of Type I and Type II)

Answer 42

Higher oxidative capacity and fatigue more slowly

-Intermediate fast-twitch fibers as they can use both aerobic and anaerobic metabolism almost equally to create energy

Question 43

Muscles as Movers

Answer 43

Agonist, Synergist, Stabilizer, Antagonist

Question 44

Agonist

Answer 44

Prime movers, most responsible for the movement

Question 45

Synergist

Answer 45

Assist prime movers during movement

Question 46

Stabilizer

Answer 46

Support and stabilize while prime mover and synergist work

Question 47

Antagonist

Answer 47

Perform opposite action of prime mover