Week 7 A&P

Question 1

How much of the total body weight of an average adult is muscle tissue?

a) 20-30%
b) 30-40%
c) 40-50%
d) 50-60%
e) 60-70%

Answer 1

c) 40-50%

Question 2

Which of the following is NOT a major function of muscle tissue?

a) moving blood throughout the body
b) generating heat through contractions
c) stabilizing the movement of joints
d) promoting the movement of body structures
e) production of vitamins

Answer 2

e) production of vitamins

Question 3

This is the property of muscle that gives it the ability to stretch without damage:

a) electrical excitability
b) contractility
c) extensibility
d) elasticity
e) thermogenesis

Answer 3

c) extensibility

Question 4

This is the property of muscle that gives it the ability to stretch without damage:

a) electrical excitability
b) contractility
c) extensibility
d) elasticity
e) thermogenesis

Answer 4

c) extensibility

Question 5

This is the outermost layer of connective tissue surrounding a skeletal muscle:

a) tendon
b) ligament
c) endomysium
d) epimysium
e) perimysium

Answer 5

d) epimysium

Question 6

How many arteries and veins usually accompany a singe nerve penetrating a skeletal muscle?

a) one artery and one or two veins
b) two arteries and two veins
c) three arteries and two veins
d) one artery and three veins
e) one artery and a varied amount of veins

Answer 6

a) one artery and one or two veins

Question 7

After the fusion of myoblasts, the muscle fiber loses its ability to do what?

a) grow
b) lengthen
c) contract
d) go through cell division
e) all of the answer choices

Answer 7

d) go through cell division

Question 8

The mitochondria in skeletal muscle fiber are arranged:

a) randomly throughout the sarcoplasm
b) in circles around the T-tubules
c) around the nuclei
d) in rows near the contractile muscle proteins
e) close to the sarcolemma

Answer 8

d) in rows near the contractile muscle proteins

Question 9

The contractile organelles of a skeletal muscle fiber are thread-like structures called:

a) myofibrils
b) myoglobin
c) mitochondria
d) Z discs
e) M lines

Answer 9

a) myofibrils

Question 10

Release of calcium from these structures triggers skeletal muscle contraction

a) myofibrils
b) mitochondria
c) terminal cisterns of sarcoplasmic reticulum
d) T-tubules
e) none of the answer choices

Answer 10

c) terminal cisterns of sarcoplasmic reticulum

Question 11

The sarcoplasmic reticulum reticulum in skeletal muscle fibers is used for storing

a) oxygen
b) ATP
c) PO43-.
d) Na+.
e) Ca2+.

Answer 11

e) Ca2+.

Question 12

Myofibrils contain:

a) contractile proteins
b) regulatory proteins
c) structural proteins
d) all of these answers are correct
e) none of these answers are correct

Answer 12

d) all of these answers are correct

Question 13

Which of the following functions as a motor protein in all three types of muscle tissue?

a) actin
b) myosin
c) troponin
d) titin
e) tropomyosin

Answer 13

b) myosin

Question 14

What regulatory proteins can be found in the thin filaments of skeletal muscle fibres?

a) troponin and titin
b) tropomyosin and troponin
c) myosin and titin
d) titin and toposyosin
e) tropomyosin and myosin

Answer 14

b) tropomyosin and troponin

Question 15

Which of the following proteins is used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons?

a) troponin
b) tropomyosin
c) myosin
d) actin
e) dystrophin

Answer 15

e) dystrophin

Question 16

What energises the myosin head?

a) the actin filaments
b) calcium ions
c) potassium ions
d) ATP hydrolysis reaction
e) ADP synthesis

Answer 16

d) ATP hydrolysis reaction

Question 17

Skeletal muscle contraction will continue to occur as long as the following chemicals are available in the cytosol of the muscle fiber

a) ATP and acetylcholine (ACh)
b) calcium ions and ATP
c) ACh and potassium ions
d) sodium ions and ATP
e) calcium and ACh

Answer 17

b) calcium ions and ATP

Question 18

To stimulate skeletal muscle contraction, acetylcholine must cross the __________ of the neuromuscular junction and bind to receptors on the motor endplate.

a) node of the Ranvier
b) synaptic cleft
c) sarcolemma
d) synaptic end bulb
e) transverse tubule

Answer 18

b) synaptic cleft

Question 19

Which of teh following are commonly used to produce ATP during the skeletal muscle contraction?

a) creatine phosphate
b) anaerobic cellular respiration
c) aerobic cellular respiration
d) All of these choices are correct
e) None of these choices are correct

Answer 19

d) All of these choices are correct

Question 20

In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately:

a) 15 seconds
b) 15 minutes
c) 1.5 minutes
d) 5 seconds
e) one minute

Answer 20

a) 15 seconds

Question 21

Which of the following microscopic structures is only found in the cardiac muscle tissue?

a) myosin
b) tropomyosin
c) sarcomeres
d) intercalated discs
e) striations

Answer 21

d) intercalated discs

Question 22

Which of the following types of muscle tissue contract when excited by their own autorythmic muscle fibres?

a) cardiac muscle
b) slow twitch oxidative skeletal muscle
c) multi-unit smooth muscle
d) fast twitch glycolytic skeletal muscle
e) all of these choices are correct

Answer 22

a) cardiac muscle

Question 23

Smooth muscle tone is maintained by the prolonged presence of __________ in muscle cell’s cytosol?

a) ATP
b) calcium ions
c) phosphate ions
d) myoglobin
e) none of these choices

Answer 23

b) calcium ions

Question 24

Hyperplasia is:

a) an increase in the size of muscle fibers
b) a decrease in the size of muscle fibers
c) an increase in the number of muscle fibers
d) a decrease in the number of muscle fibers
e) none of these choices

Answer 24

c) an increase is the number of muscle fibers

Question 25

Which of the following disorders is characterised by the wasting away of muscles due to the progressive loss of myofibrils ?

a) muscular hypertrophy
b) muscular atrophy
c) fibromyalgia
d) myasthenia gravis
e) tremors

Answer 25

b) muscular atrophy

Question 26

Which of the following best describes the condition known as muscular hypertrophy?

a) decrease in diameter of muscle fibers
b) torn sarcolemmas and damaged myofibrils
c) increase in diameter of muscle fibres
d) actin and myosin remain attached by cross bridges and the muscle is rigid
e) damaged neuromuscular junctions

Answer 26

c) increase in diameter of muscle fibres

Question 27

Which of the following is NOT seen in exercise-induced muscle damage?

a) torn sarcolemmas
b) damaged myofibrils
c) sore muscles
d) progressive degeneration of muscles
e) disrupted Z-discs

Answer 27

d) progressive degeneration of muscles

Question 28

Which event does not occur during the onset of rigor mortis?

a) enzymes from lysosomes digest crossbridges
b) cellular membranes become leaky
c) myosin heads bind to actin
d) calcium ions leak out of the sarcoplasmic reticulum
e) ATP synthesis ceases

Answer 28

a) enzymes from lysosomes digest crossbridges

Question 29

Which is the correct sequence of events in the onset of rigour mortis?

a) cellular membranes become leaky -> myosin heads bind to actin -> calcium ions leak into the sarcoplasm -> muscles are in a state of rigidity
b) cellular membranes become leaky -> calcium ions leak into the sarcoplasm -> myosin heads bind to actin -> muscles are in a state of rigidity
c) myosin heads bind to actin -> cellular membranes become leaky -> calcium ions leak into the sarcoplasm -> muscles are in a state of rigidity
d) calcium ions leak into the sarcoplasm -> cellular membranes become leaky -> myosin heads bind to actin -> muscles are in a state of rigidity
e) calcium ions leak into the sarcoplasm -> myosin heads bind into actin -> muscles are in a state of rigidity -> cellular membranes become leaky

Answer 29

b) cellular membranes become leaky -> calcium ions leak into the sarcoplasm -> myosin heads bind to actin -> muscles are in a state of rigidity

Question 30

an EMG can be used to determine each of the following except:

a) the source of muscle weakness
b) paralysis due to muscle malfunction
c) paralysis due to nerve supplying the muscle
d) diagnose certain muscle disorders like muscular dystrophy
e) find the precise location of a muscle tumor

Answer 30

d) diagnose certain muscle disorders like muscular dystrophy

Question 31

which of the following types of abnormal contractions of skeletal muscle may be caused by holding a position for a prolonged period?

a) spasm
b) fasciculation
c) tremor
d) fibrillation
e) cramp

Answer 31

e) cramp

Question 32

Which of the following types of abnormal contractions of skeletal muscle is a rhythmic, involuntary, purposeless quivering or shaking movement?

a) tetanus
b) fasciculation
c) tremor
d) fibrillation
e) cramp

Answer 32

c) tremor

Question 33

Which of the following types of abnormal contractions of skeletal muscle is caused by a twitch of an entire motor unit an dis visible under the skin?

a) tic
b) fasciculation
c) tremor
d) fibrillation
e) cramp

Answer 33

b) fasciculation

Question 34

Which of the following types of abnormal contractions of skeletal muscle is caused by a single muscular finer, is spontaneous, and is not visible under the skin?

a) tic
b) fasciculation
c) tremor
d) fibrillation
e) cramp

Answer 34

d) fibrillation

Question 35

cross bridges are formed during muscle contraction when ________ on the thick filaments binds to _________ on the thin filaments.

a) myosin; troponin
b) myosin; troponin
c) myosin; actin
d) actin; myosin
e) actin; tropomyosin

Answer 35

c) myosin; actin