Chapter 10 Muscular tissue

Question 1

What are three types of muscle tissue?

Answer 1

1. Skeletal
2. Cardiac
3. Smooth

Question 2

What are the functions of muscle tissue?

Answer 2

1. produce movement
2. stabilizing body positions
3. storing and mobilizing substance within the body
4. generate heat

Question 3

What are some properties of muscular tissue?

Answer 3

1. Electrical excitability
2. contractility
3. extensibility
4. elasticity

Question 4

What are three types of fascia?

Answer 4

1. epimysium
2. perimysium
3. endomysium

Question 5

What are two types of sacrolemma?

Answer 5

1. Sarcoplasm
2. Sarcoplasmic reticulum

Question 6

What are two types of contractile muscle proteins?

Answer 6

Myosin and actin

Question 7

What are muscle fascicle?

Answer 7

Bundle of muscle fibers wrapped in perimysium

Question 8

What are muscular fibers

Answer 8

Long cylindrical cell covered by endomysium and sarcolemma; contains sarcoplasm, myofibrils, many peripherally located nuclei, mitochondria, t tubules, sarcoplasmic reticulum and terminal cisterns. Striated appearance

Question 9

What is a myofibril?

Answer 9

Threadlike contractile elements within muscle fiber that extend entire length of fiber; composed of filaments

Question 10

What is a filament?

Answer 10

Contractile proteins within myofibrils that are two types: thick filaments composed of myosin and thin filaments composed of actin, tropomyosin, and troponin; sliding of thin filaments past thick filaments produces muscle shortening

Question 11

What are z discs?

Answer 11

Narrow, plated- shaped regions of dense material that separate one sarcomere from the next

Question 12

What is an A Band?

Answer 12

Dark, middle part of sarcomere that extends entire length of thick filaments and includes those parts of thin filaments that overlap thick filaments

Question 13

What is an I band?

Answer 13

Lighter, less dense areas of sarcomere that contains remainder of thin filaments but no thick filaments, A Z disc passes through center of each I band

Question 14

What is the H band?

Answer 14

Narrow region in center of each A band that contains thick filaments but no thin filaments

Question 15

What is a M line?

Answer 15

Region in center of H zone that contains proteins that hold thick filaments together at center of sarcomere

Question 16

What is the sliding filament mechanism?

Answer 16

1. Myosin pulls on actin, causing the thing filament to slide inward
2. Z disc move towards each other and the sarcomere shortens
3. Thanks to structural proteins, there is a transmission of force throughout the entire muscle, resulting in muscle contraction

Question 17

What is the excitation- contraction coupling?

Answer 17

This concept connects the events of a muscle action potential with the sliding filament mechanism

Question 18

What is the length- tension relationship?

Answer 18

The force of a muscle contraction depends on the length of the sarcomeres in a muscle prior to contraction

Question 19

What are the three ways to produce ATP?

Answer 19

1. Creatine phosphate
2. Anaerobic glycolysis
3. Aerobic respiration

Question 20

How does creatine phosphate (CP work)

Answer 20

Creatine kinase catalyzes the transfer of a phosphate group from CP to ADP to rapidly yield ATP

Question 21

How does Anaerobic Glycolysis work?

Answer 21

When CP stores are depleted, glucose is converted into pyruvic acid to generate ATP

Question 22

How does Aerobic respiration work?

Answer 22

Under aerobic conditions, pyruvic acid can enter the mitochondria and undergo a series of oxygen-requiring reactions to generate large amounts of ATP

Question 23

What is Muscle fatigue?

Answer 23

The inability to maintain force of contraction after prolonged activity

Question 24

The onset of fatigue is due to what four things?

Answer 24

1. Inadequate release of Ca2+ from ST
2. Depletion of CP, oxygen, and nutrients
3. Build up of lactic acid and ADP
4. Insufficient release of ACh at NMJ

Question 25

Why do you continue to breathe heavily for a period of time after stopping exercise?

Answer 25

1. To pay back your oxygen debt 2. Replenishing CP stores 3. Converting lactate into pyruvate 4. Reloading O2 onto myoglobin

Question 26

The strength of a muscle contraction depends on what?

Answer 26

How many motor units are activated

Question 27

A motor unit consists of what?

Answer 27

A somatic motor neuron and the muscle fibers it innervates

Question 28

Activating only a few motor units will generally result in what?

Answer 28

A weak muscle contraction

Question 29

Activating many motor units will generally result in what?

Answer 29

A strong muscle contraction

Question 30

What is motor unit recruitment?

Answer 30

The process in which the number of active motor units increases

Question 31

During muscle recruitment what is recruited first?

Answer 31

Weak motor units are recruited first, followed by stronger motor units

Question 32

Motor units contract alternatively to do what?

Answer 32

Sustain contractions for longer periods of time

Question 33

What is muscle tone?

Answer 33

The small amount of tension that skeletal muscles exhibit even at rest

Question 34

Tone is established by what?

Answer 34

Alternating, involuntary activation of small groups of motor units in a muscle

Question 35

What is isotonic?

Answer 35

When Tension is constant while muscle length changes

Question 36

How are two ways we can achieve isotonic?

Answer 36

1. Concentric 2. Eccentric

Question 37

What is isometric?

Answer 37

Muscle contracts but does not change length