muscular system old exam questions

Question 1

which muscle protein given muscle elasticity and returns the sarcomere to resting length after relaxation

1. titin
2. myomesin
3. dystrophin
4. troponin

Answer 1

titin

Question 2

skeletal muscle fibers are formed during development through the fusion of embryonic cells called

1. sarcomeres
2. myofibrils
3. myoblasts
4. fascicles

Answer 2

myoblasts

Question 3

according to the sliding filament mechanism

1. the A band does not change in length during concentric muscle contraction
2. the I band increases in length during concentric muscle contraction
3. the zone of overlap decreases during concentric muscle contraction
4. the H zone increases during concentric muscle contraction

Answer 3

the A band does not change in length during concentric muscle contraction

Question 4

electrical signals in the t-tubule membrane cause the sarcoplasmic reticulum to release ___ in the ___ fluid

1. acetylcholine; extracellular
2. Na+; extracellular
3. Ca2+; intracullular
4. K+; intracellular

Answer 4

Ca2+, intracellular

Question 5

place in order the following list of events associated with neuromuscular transmission

1. acetylcholine diffuses across the synaptic cleft
2. electrical signal is generated in the muscle cell membrane
3. synaptic vesicles fuse with the cell membrane and release their contents
4. acetylcholine binds to the acetylcholine receptor on the motor end plate
5. electrical signal reaches the synaptic terminal of a motor neuron

Answer 5

5,3,1,4,2

Question 6

motor units..

1. are recruited on the basis of size (smallest motor units are recruited first) during voluntary contraction
2. consists of all motor neurons that innervate a particular muscle
3. can include multiple muscle fiber types in a simple motor unit
4. can include multiple muscle fiber types in a single motor unit

Answer 6

are recruited on the basis of size (smallest motor units are recruited first) during voluntary contraction

Question 7

the type of contraction in which the muscle fibers generate tension while they lengthen is called

1. isokinetic
2. concentric
3. eccentric
4. isometric

Answer 7

eccentric

Question 8

temporal summation in a skeletal muscle fiber occurs when

1. there is an increase in the frequency of action potentials sent to the muscle fiber
2. aadditional motor units are recruited to increase tension
3. one action potential cause increased tension in a muscle fiber
4. the thick and thin filaments are maximally overlapped

Answer 8

there is an increase in the frequency of action potentials sent to the muscle fiber

Question 9

which of the following could contribute to fatigue

1. high levels of free phosphate in the sarcoplasm
2. depletion of glycogen from the sarcoplasm
3. high levels of lactic acid in the sarcoplasm
4. all of the above

Answer 9

4. all of the above

Question 10

place in order the following list of the events that occur during skeletal muscle contraction, beginning with the arrival of an electrical signal at the t-tubule membrane

1. myosin heads bind to actin forming cross bridges
2. calcium ions is released from the SR
3. the myosin head pivots toward the center of the sarcomere
4. calcium ions binds to troponin
5. the myosin head binds an ATP molecule and detaches from actin

Answer 10

2,4,1,3,5

Question 11

anaerobic glycolysis..

1. occurs in the cytoplasm and is very fast
2. is the most efficient method to produce ATP
3. can support from 40 minutes to several hours of skeletal muscle contraction
4. requires oxygen to run for any length of time

Answer 11

occurs in the cytoplasm and is very fast

Question 12

in skeletal muscle the myosin binding sites on actin become exposed and available for cross bridging formation immediately after

1. actin binds to ATP
2. calcium binds to tropomyosin on the thick filament
3. troponin on the thin filament binds to myosin
4. calcium binds to troponin on the thin filament

Answer 12

calcium binds to troponin on the thin filament

Question 13

the muscle twitch

1. is the result of a series of action potentials that quickly stimulate the muscle fiber
2. duration is longer in slow oxidative fibers compared to fast glycolytic fibers
3. includes the latent period which tension is increasing
4. is the primary mechanism of muscle contraction in skeletal muscle contraction while performing daily activities like walking

Answer 13

duration is longer in slow oxidative fibers compared to fast glycolytic fibers

Question 14

which of the following statements about skeletal muscle fiber types is true

1. FG fibers have low levels of creatine phosphokinase
2. SO fibers have a lot of mitochondria
3. FG fibers have a lot of myoglobin
4. SO fibers produce a lot of force

Answer 14

SO fibers have a lot of mitochondria

Question 15

choose the answer that best completes the following statement. in skeletal muscle cross bridges form between

1. actin and tropomyosin
2. troponin and tropomyosin
3. actin and troponin
4. actin and myosin

Answer 15

actin and myosin

Question 16

in the cori cycle lactic acid

1. is converted to creatine after strenuous exercise
2. is converted to glucose in liver cells
3. is used directly by mitochondria to produce ATP
4. is converted by glycolysis in muscle cells

Answer 16

is converted to glucose in liver cells

Question 17

the most important factor in decreasing the intracellular concentration of ca2+ during relaxation of skeletal muscle is

1. active transport of Ca2+ into the SR
2. actie transport of Ca2+ out of the SR
3. diffusion of Ca2+ out of the cell
4. diffusion of Ca2+ into the SR

Answer 17

active transport of Ca2+ into the SR

Question 18

what best describes the mechanism responsible for an increase in skeletal muscle mass following exercise training that involves repeated exhaustive contraction

1. atrophy of muscle fibers
2. hypertrophy of muscle fibers
3. hyperplasia of muscle fibers
4. Both b and c are correct

Answer 18

hypertrophy of muscle fibers

Question 19

which of the following is most closely related to the phenomenon of oxygen debt

1. the consumption of oxygen that occurs during cross bridge cycling
2. the fall in oxygen consumption below resting levels after anaerobic exercise
3. the basal level of oxygen consumption that occurs during rest
4. the elevation of oxygen consumption above resting oxygen consumption that follows an aerobic exercise

Answer 19

the elevation of oxygen consumption above resting o2 consumption that follows an aerobic exercise

Question 20

the area of a resting sarcomere that does not contain any thick filaments is the

1. M Line
2. A band
3. I band
4. H zone

Answer 20

I band

Question 21

which region of the sarcomere contains no thin filaments

1. the A band
2. the I band
3. the H zone
4. the Z disc

Answer 21

the H zone

Question 22

which of the following options below correctly lists skeletal muscle elements from smallest to largest

1. fascicle, muscle fiber, myofibril, sarcomere, thick filament
2. fascicle, myofibril, mucsle fiber, thick filament, sarcomere
3. muscle fiber, fascicle, sarcomere, thick filament, myofibril
4. myofibril, muscle fiber, sarcomere, thick filament, fascicle

Answer 22

1. fascicle, muscle fiber, myofirbil, sarcomere, thick filament

Question 23

which ion enters a muscle fiber once Ach molecules binds to ACh receptors on the motor end plate

1. Ca2+
2. Cl-
3. inorganic phosphate
4. Na+

Answer 23

Na+

Question 24

anaerobic glycolysis

1. occurs in the cytoplasm
2. is the fastest method of ATP resynthesis
3. uses oxygen to produce ATP
4. all over the above are correct

Answer 24

1. occurs in the cytoplasm

Question 25

with regard to adaptation to exercise how do strength training and endurance training differ 1. hypertrophy only occurs for strength training 2. capillary density and mitochondrial density increase more for endurance training 3. strength training is harder so all adaptations will be greater for those athletes 4. the adaptation are exactly the same from strength training and endurance training

Answer 25

capillary density and mitochondrial density increase more for endurance training

Question 26

in a first class lever 1. the fulcrum is between the load and the effort 2. the load is between the fulcrum and the effort 3. the effort is between the fulcrum and the load 4. there is no fulcrum

Answer 26

1. the fulcrum is between the load and the effort

Question 27

myoglobin 1. is a protein that can transfer its phosphate group to ADP to make ATP quickly 2. is abundant in slow oxidative muscle fibers 3. facilitates higher rates of anaerobic metabolism 4. is found primarily in type 2b fibers

Answer 27

2. is abundant in slow oxidative phosphorylation

Question 28

exercise training leads to specific adaptations in the muscle fibers recruitment during exercise. which of the following is a training adaptation to endurance exercise? 1. an increase in mitochondrial activity 2. a decrease in capillary density 3. an increase in the number of muscle fibers 4. a decrease in myoglobin

Answer 28

1. an increase in mitochondrial activity

Question 29

in an eccentric contraction.. 1. the load is greater than the effort and the muscle is shortening 2. the effort is greater than the load and the muscle is shortening 3. the load is greater than the effort and the muscle is lengthening 4. the effort is greater than the load and the muscle is lengthening

Answer 29

3. the load is greater than the effort and the muscle is lengthening

Question 30

according to the length-tension relationship muscle tension is dependent on the length of the muscle at the beginning of contraction. which of the following statements is true? 1. muscle produces the most tension at its shortest length 2. muscle produces the most tension at its intermediate length 3. muscle produces the most tension at its longest length 4. muscle tension is not associated with muscle length

Answer 30

2. muscle produces the most tension at its intermediate length

Question 31

in an isometric skeletal contraction 1. the muscle shortens but the sarcomere does not change in length 2. the muscle does not change in length but the sarcomere shortens 3. the muscle lengthens and the sarcomeres shorten 4. the muscle and the sarcomeres do not change in length

Answer 31

2. the muscle does not change in length but t he sarcomere shortens

Question 32

which of the following statements is correct regarding the connective tissue coverings of muscle 1. muscle fibers are covered by epimysium 2. fascicles are covered by perimysium 3. muscle groups are covered by endomysium 4. myofibrils are covered by deep fascia

Answer 32

2. fascicles are covered by perimysium

Question 33

which skeletal muscle structure contracts and generates force 1. SR 2. myofibrils 3. sarcolemma 4. t-tubules

Answer 33

2. myofibrils

Question 34

all muscle types 1. can generate tension 2. use sliding filaments to contract 3. need to have an increase in cytoplasmic calcium to contract 4. all of the above

Answer 34

4. all of the above

Question 35

sarcomeres are found in all of the following muscle types except.. 1. smooth muscle 2. cardiac muscle 3. skeletal muscle 4. all muscle types contain sarcomeres

Answer 35

1. smooth muscle

Question 36

which of the following is NOT a characteristic of smooth muscle 1. dense bodies 2. thick filaments located throughout the cytoplasm 3. intercalated discs 4. contraction mechanism requires Ca2+ sensitive cytoplasmic enzymes

Answer 36

3. intercalated discs

Question 37

which of the following is a similarity between skeletal muscle and cardiac muscle? 1. there are no motor units 2. every contraction is a single long twitch 3. there is no obligatory need for extracellular Ca2+ for muscle contractions 4. Ca2+ interacts with regulatory proteins on the thin filament

Answer 37

4. Ca2+ interacts with regulatory proteins on the thin filament

Question 38

calcium 1. enters the motor neuron and causes synaptic vesicles to release ACh into the synaptic cleft 2. enters the smooth muscle cell and activates enzymes that lead to muscle contraction 3. binds to regulatory proteins on the thin filament of cardiac muscle fibers 4. al of the above

Answer 38

4. all of the above

Question 39

which of the following muscles is an antagonist for the abduction of the arm? 1. latissimus dorsi because it adducts the arm 2. deltoid because it abducts the arm 3. pectoralis minor because it abducts the arm 4. biceps brachii because it adducts the arm

Answer 39

1. latissimus dorsi because it adducts the arm

Question 40

rigor mortis occurs when one of the following events of cross bridge cycling no longer happens. which of the events listed below does NOT happen in rigor mortis 1. myosin forms cross bridges with actin 2. calcium ion binds to troponin 3. calcium ion is released from the SR 4. the myosin head binds an ATP molecule and detaches from actin

Answer 40

4. the myosin head binds to an ATP molecule and detaches from actin