QUESTIONS AND ANSWERS SURE A+
✔✔Given these events:
1. Ca2+ combine with tropomyosin
2. Ca2+ combine with troponin
3. tropomyosin pulls away from actin
4. troponin pulls away from actin
5. tropomyosin pulls away from myosin
6. troponin pulls away from myosin
7. myosin binds to actin
Choose the arrangement that lists the events in the order they occur during muscle
contraction.
A) 1,4,7
B) 2,5,6
C) 1,3,7
D) 2,4,7
E) 2,3,7 - ✔✔E) 2,3,7
✔✔Which of these regions shortens during skeletal muscle contraction?
A) A band
B) I band
C) H zone
D) both a and b
E) both b and c - ✔✔E) both b and c
✔✔With stimuli of increasing strength, which of these is capable of a graded response?
A) nerve axon
B) muscle fiber
C) motor unit
D) whole muscle - ✔✔D) whole muscle
✔✔Considering the force of contraction of a skeletal muscle cell, multiple-wave
summation occurs because of
A) increased strength of action potentials on the plasma membrane.
B) a decreased number of cross-bridges formed.
C) an increase in Ca2+ concentration around the myofibrils.
D) an increased number of motor units recruited.
E) increased permeability of the sarcolemma to Ca2+. - ✔✔C) an increase in Ca2+
concentration around the myofibrils.
✔✔Which of these events occurs during the lag (latent) phase of muscle contraction?
A) cross-bridge movement
B) active transport of Ca2+ into the sarcoplasmic reticulum
C) Ca2+ bind to troponin
,D) the sarcomere shortens
E) ATP is broken down to ADP - ✔✔C) Ca2+ bind to troponin
✔✔A weight lifter attempts to lift a weight from the floor, but the weight is so heavy he is
unable to move it. The type of muscle contraction the weight lifter used was mostly
A) isometric.
B) isotonic.
C) isokinetic.
D) concentric.
E) eccentric. - ✔✔A) isometric.
✔✔An active tension curve illustrates
A) how isometric contractions occur.
B) that the greatest force of contraction occurs if a muscle is not stretched at all.
C) that passive tension can create active tension.
D) that optimal overlap of actin and myosin produces the greatest force of contraction.
E) that the greatest force of contraction occurs with little or no overlap of actin and
myosin. - ✔✔D) that optimal overlap of actin and myosin produces the greatest force of
contraction.
✔✔Which of these types of fatigue is the most common?
A) muscular fatigue
B) psychologic fatigue
C) synaptic fatigue
D) army fatigue - ✔✔B) psychologic fatigue
✔✔Given these conditions:
1. low ATP levels
2. little or no transport of Ca2+ into the sarcoplasmic reticulum
3. cross-bridges release
4. Na+ accumulate in the sarcoplasm
5. cross-bridges form
Choose the conditions that occur in both physiologic contracture and rigor mortis.
A) 1,2,3
B) 1,2,5
C) 1,2,3,4
D) 1,2,4,5
E) 1,2,3,4,5 - ✔✔D) 1,2,4,5
✔✔Jerry Jogger's 3 mile run every morning takes about 30 minutes. Which of these
sources provides most of the energy for his run?
A) aerobic respiration
B) anaerobic respiration
C) creatine phosphate
D) stored ATP - ✔✔A) aerobic respiration
,✔✔Which of these conditions would one expect to find within the leg muscle cells of a
world-class marathon runner?
A) myoglobin-poor
B) contract very quickly
C) primarily anaerobic
D) numerous mitochondria
E) large deposits of glycogen - ✔✔D) numerous mitochondria
✔✔Which of these increases the least as a result of muscle hypertrophy?
A) increase in number of sarcomeres
B) increase in number of myofibrils
C) increase in number of fibers
D) increase in blood vessels and mitochondria
E) increase in connective tissue - ✔✔C) increase in number of fibers
✔✔Relaxation in smooth muscle occurs when
A) myosin kinase attaches phosphate to the myosin head.
B) Ca2+ bind to calmodulin.
C) myosin phosphatase removes phosphate from myosin.
D) Ca2+ channels open.
E) Ca2+ are released from the sarcoplasmic reticulum. - ✔✔C) myosin phosphatase
removes phosphate from myosin.
✔✔Compared to skeletal muscle, visceral smooth muscle
A) has the same ability to be stretched.
B) when stretched, loses the ability to contract forcefully.
C) maintains about the same tension, even when stretched.
D) cannot maintain long, steady contractions.
E) can accumulate a substantial oxygen debt. - ✔✔C) maintains about the same
tension, even when stretched.
✔✔Which of these often have spontaneous contractions?
A) multiunit smooth muscle
B) visceral smooth muscle
C) skeletal muscle
D) both a and b
E) both b and c - ✔✔B) visceral smooth muscle
✔✔Which of these statements concerning aging and skeletal muscle is correct?
A) There is a loss of muscle fibers with aging.
B) Slow-twitch fibers decrease in number faster than fast-twitch fibers.
C) Loss of strength and speed is mainly due to loss of neuromuscular junctions.
D) There is an increase in density of capillaries in skeletal muscle.
, E) The number of motor neurons remains constant. - ✔✔A) There is a loss of muscle
fibers with aging.
✔✔The patellar or knee-jerk reflex is a classic example of
Select one:
a. the Golgi tendon reflex.
b. the withdrawal reflex.
c. the stretch reflex.
d. the crossed extensor reflex.
e. reciprocal innervation. - ✔✔c. the stretch reflex.
✔✔A man was in an accident and severed his spinal cord between C6 and C7. Which
of the following would NOT occur?
Select one:
a.
loss of sensation in the trunk below the shoulders, the lower limbs and portions of the
arms
b.
loss of use of the phrenic nerves and paralysis of the diaphragm
c.
loss of movement in the lower limbs
d.
loss of movement in the hands
e.
loss of sensation in hands and feet - ✔✔b.
loss of use of the phrenic nerves and paralysis of the diaphragm
✔✔A person with a lesion in the brain exhibited the following manifestations: normal
tension in skeletal muscle, disturbed fine motor control, exhibited tremors when
reaching for objects. What part of the brain is most likely damaged?
Select one:
a. the prefrontal lobe
b. the frontal lobe
c. the basal ganglia
d. the pyramids
e. the cerebellum - ✔✔e. the cerebellum
✔✔If you pinch your index finger in a door, pain sensations are carried via the ____
nerve.
Select one:
a. radial
b. median
c. axillary
d. musculocutaneous