Chapter 10 - Muscle Tissue - REVIEW

Question 1

The connective tissue coverings of a skeletal muscle from superficial to deep are….

Answer 1

epimysium, perimysium, endomysium

Question 2

The command to contract is distributed deep into the muscle fiber by the…

Answer 2

transverse tubules

Question 3

The DETACHMENT of myosin cross-bridges is directly triggered by….

Answer 3

the hydrolysis of ATP

Question 4

A muscle producing near-peak tension during rapid cycles of contraction and relaxation is said to be in…

Answer 4

incomplete tetanus

Question 5

They type of contraction in which the tension rises but the load does not move, is…..

Answer 5

an isometric contraction

Question 6

Do FILAMENTS consist of bundles of MYOFIBRILS?

Answer 6

NO
(myofibrils consist of bundles of filaments)

Question 7

Are myofibrils attached to the plasma membrane at both ends of a muscle fiber?

Answer 7

ye

Question 8

do myofibrils extend the full length of a skeletal muscle fiber?

Answer 8

yes

Question 9

An action potential can travel quickly from one cardiac muscle cell to another because of….

Answer 9

gap junctions and intercalated discs

Question 10

What 3 layers of connective tissue are part of each muscle?
What functional role does each layer play?

Answer 10

epimysium, perimysium, endomysium

epimysium - surrounds the entire muscle
perimysium - surrounds muscle bundles (fascicles)
endomysium - surrounds skeletal muscle fibers

Question 11

The ____ contains vesicles filled with acetylcholine

Answer 11

synaptic terminal

Question 12

What structural feature of a skeletal muscle fiber is responsible for conducting action potentials into the interior of the cell?

Answer 12

t tubules

Question 13

What 5 interlocking steps are involved in the contraction process?

Answer 13

1. exposure of active sites
2. attachment of cross bridges
3. pivoting of myosin heads (power stroke)
4. detachment of cross bridges
5. activation of myosin heads (cocking)

Question 14

What 2 factors affect the amount of tension produced when a skeletal muscle contracts?

Answer 14

-the frequency of motor stimulation
-the number of motor units involved

Question 15

What forms of energy reserves do skeletal muscle fibers contain?

Answer 15

resting skeletal muscles contain ATP, creatine phosphate, and glycogen

Question 16

What 2 mechanisms are used to generate ATP from glucose in muscle cells/

Answer 16

Aerobic metabolism and glycolysis

Question 17

What is the calcium-binding protein in smooth muscle tissue?

Answer 17

Calmodulin

Question 18

-50 meter dash
-pole vault
-weight lifting competition

would this require aerobic or anaerobic endurance?

Answer 18

anaerobic

Question 19

Where are 2 places where you would NOT expect to find slow fibers?

Answer 19

the eye and the hand

Question 20

During relaxation, give 4 reasons why muscles return to their original length

Answer 20

-the contraction of opposing muscles
-the pull of gravity
-the elastic nature of the sarcolemma
-elastic forces

Question 21

According to the length-tension relationship….

Answer 21

-the greater the zone of overlap in the sarcomere, the greater tension the muscle can develop
-there is an optimal range of actin and myosin overlap that will produce the greatest amount of tensio

Question 22

For each portion of a myogram tracing a twitch in a stimulated calf muscle fiber, describe the events that occur within the muscle

Answer 22

latent period: an action potential generated in the muscle triggers the release of calcium ions from the sarcoplasmic reticulum

contraction phase: calcium binds to troponin, cross bridges form, and tension begins to increase

relaxation phase: tension drops because cross bridges have detached and calcium levels have fallen; the active sites are once again covered by the troponin-tropomyosin complx

Question 23

What 3 processes are involved in repaying the oxygen debt during a muscle’s recovery period?

Answer 23

1. Oxygen is consumed by liver cells which must make a great deal of ATP to convert lactate to glucose
2. O2 for aerobic respiration is consumed by skeletal muscle fibers as they restore ATP, creatine phosphate, and glycogen to their former levels
3. The normal O2 concentrations in the blood and peripheral tissues is replenished

Question 24

how does a cardiac muscle tissue contract without neural stimulation?

Answer 24

The timing of cardiac muscle contractions is determined by specialized cardiac muscle fibers called pacemaker cells; this property is termed automaticity

Question 25

Atracurium is a drug that blocks the binding of acetylcholine to receptors. give an example of a site where such binding normally occurs, and predict the physiological effects of this drug

Answer 25

If atracurium blocked the ability of acetylcholine to bind to the receptors on the motor end plates of neuromuscular junctions, the muscle’s ability to contract would be inhibited

Question 26

Explain why a murder victim’s time of death can be estimated according to the flexibility or rigidity of the body?

Answer 26

The membranes of the dead cells are no longer selectively permeable. Thus, the SR is no longer able to retain calcium ions. As calcium ions enter the sarcoplasm, a sustained contraction develops, making the body extremely stuff. Contraction persists because the dead muscle cells can no longer make ATP required for cross-bridge detachment. Rigor mortis begins a few hours after death and ends 1-6 days, or when decomposition begins

Question 27

Maintaining an upright posture involves ____ contractions

Answer 27

isometric

Question 28

LOOK AT PHONE 4/6 PIC

Answer 28

CRITICAL THINKING AND CLINICAL APPLICATION