Physiology Exam 3 (Multiple Choice)
Questions with Correct Answers
Capillary hydrostatic pressure is 38 mm Hg, capillary colloidal osmotic pressure is 28
mm Hg, interstitial fluid pressure is 2 mm Hg and interstitial colloidal osmotic pressure is
4 mm Hg. The net filtration or absorption pressure is:
a. 10 mm Hg (filtration)
b. 12 mm Hg (filtration)
c. 12 mm Hg (absorption)
d. 14 mm Hg (filtration)
e. 14 mm Hg (absorption)
(2009) - ANSWERS12 mm Hg (filtration)
Increasing the length of a skeletal muscle prior to an isometric contraction
Choose one answer.
a. Has no effect on the force of contraction
b. Can only decrease the force of contraction
c. Can only increase the force of contraction
d. May either decrease or increase the force that can be developed, depending on the
original length of the muscle
e. Is not possible
(2009) - ANSWERSMay either decrease or increase the force that can be developed,
depending on the original
length of the muscle
An increase in arterial PCO2 leads to:
a. A decrease in CO2 in cerebrospinal fluid
b. Activation of the carotid baroreceptors
c. Decreased activity of the carotid bodies (chemoreceptors)
d. Stimulation of medullary inspiratory neurons
e. All of the answers provided
(2009) - ANSWERSStimulation of medullary inspiratory neurons
Sinoatrial "pacemaker" cells are:
a. Stable with regard to their membrane potentials
b. Found in both atria
c. Innervated by the vagus nerve
d. Unable to generate impulses when completely denervated
,e. Connected to the AV node by Purkinje fibers
(2009) - ANSWERSInnervated by the vagus nerve
When the radius of resistance vessels is increased, which one of the following is
increased?
a. Systolic blood pressure
b. Diastolic blood pressure
c. Viscosity of blood
d. Hematocrit
e. Capillary blood flow
(2009) - ANSWERSCapillary blood flow
During isovolumetric (isometric) ventricular contraction in the healthy heart:
a. The entry and exit valves are closed
b. Pressure in the aorta rises
c. Pressure in the atria falls
d. You hear the third heart sound
e. Corresponds with the QRS complex in the electrocardiogram
(2009) - ANSWERSThe entry and exit valves are closed
The primary role of calcium in the activation of cardiac and skeletal muscle is to:
a. Provide the energy necessary for contraction
b. Activate myosin molecules so that they can interact with actin filaments
c. Cause depolarization of the muscle cell plasma membrane
d. Remove the inhibition of the reaction between the actin filaments and the myosin
filaments
e. Bind to calmodulin and increase the entry of sodium ions in the muscle fiber
(2009) - ANSWERSRemove the inhibition of the reaction between the actin filaments
and the myosin filaments
Which characteristics are found in skeletal muscle fibers best adapted to produce fast
and powerful movements?
a. High capillary density, red color, resistant to fatigue, mostly aerobic metabolism
b. Large fiber diameter, extensive sarcoplasmic reticulum, white color, mainly anaerobic
metabolism
c. Gap junctions and capable of responding to circulating hormones
d. Part of a small motor unit (few fibers per alpha motor neuron)
e. Controlled by the autonomic nervous system
(2009) - ANSWERSLarge fiber diameter, extensive sarcoplasmic reticulum, white color,
mainly anaerobic metabolism
According to the sliding filament hypothesis for contraction of striated muscle:
, a. The length of muscle does not affect the force of contraction
b. Movement is caused by the actions of calcium ions on thick filaments
c. Movement occurs due to shortening of the myofilaments
d. Muscle cannot shorten if the myofilaments are overlapped
e. Cyclic interactions between myosin filament crossbridges and actin filaments cause
the muscle to shorten
(2009) - ANSWERSCyclic interactions between myosin filament crossbridges and actin
filaments cause the muscle to shorten
The overall resistance to blood flow is greatest at the level of the:
a. Aorta
b. Arterioles
c. Capillary
d. Venule
e. Veins
(2009) - ANSWERSArterioles
According to the sliding filament hypothesis for muscle contraction:
a. Movement occurs due to shortening of the myofilaments.
b. Cyclic interactions between myosin filament crossbridges, and actin filaments cause
the muscle to shorten.
c. Movement is caused by the action of calcium ions on the thick filaments.
d. The length of muscle does not affect the force of contraction.
e. Muscle cannot shorten if the myofilaments are overlapped.
(2009) - ANSWERSCyclic interactions between myosin filament crossbridges, and actin
filaments cause the muscle to shorten.
Arterioles do not:
a. Play a major role in regulating local blood flow
b. Play a major role in regulating arterial blood pressure
c. Offer most resistance to flow than capillaries
d. Have a rich sympathetic innervation
e. Have a larger total cross-sectional area than do capillaries
(2009) - ANSWERSHave a larger total cross-sectional area than do capillaries
In complete heart block:
a. Fainting may occur because the atria are unable to pump blood into the ventricles
b. Ventricular fibrillation is common
c. The atrial rate is lower than the ventricular rate
d. Fainting may occur because of prolonged periods during which the ventricles fail to
contract
Questions with Correct Answers
Capillary hydrostatic pressure is 38 mm Hg, capillary colloidal osmotic pressure is 28
mm Hg, interstitial fluid pressure is 2 mm Hg and interstitial colloidal osmotic pressure is
4 mm Hg. The net filtration or absorption pressure is:
a. 10 mm Hg (filtration)
b. 12 mm Hg (filtration)
c. 12 mm Hg (absorption)
d. 14 mm Hg (filtration)
e. 14 mm Hg (absorption)
(2009) - ANSWERS12 mm Hg (filtration)
Increasing the length of a skeletal muscle prior to an isometric contraction
Choose one answer.
a. Has no effect on the force of contraction
b. Can only decrease the force of contraction
c. Can only increase the force of contraction
d. May either decrease or increase the force that can be developed, depending on the
original length of the muscle
e. Is not possible
(2009) - ANSWERSMay either decrease or increase the force that can be developed,
depending on the original
length of the muscle
An increase in arterial PCO2 leads to:
a. A decrease in CO2 in cerebrospinal fluid
b. Activation of the carotid baroreceptors
c. Decreased activity of the carotid bodies (chemoreceptors)
d. Stimulation of medullary inspiratory neurons
e. All of the answers provided
(2009) - ANSWERSStimulation of medullary inspiratory neurons
Sinoatrial "pacemaker" cells are:
a. Stable with regard to their membrane potentials
b. Found in both atria
c. Innervated by the vagus nerve
d. Unable to generate impulses when completely denervated
,e. Connected to the AV node by Purkinje fibers
(2009) - ANSWERSInnervated by the vagus nerve
When the radius of resistance vessels is increased, which one of the following is
increased?
a. Systolic blood pressure
b. Diastolic blood pressure
c. Viscosity of blood
d. Hematocrit
e. Capillary blood flow
(2009) - ANSWERSCapillary blood flow
During isovolumetric (isometric) ventricular contraction in the healthy heart:
a. The entry and exit valves are closed
b. Pressure in the aorta rises
c. Pressure in the atria falls
d. You hear the third heart sound
e. Corresponds with the QRS complex in the electrocardiogram
(2009) - ANSWERSThe entry and exit valves are closed
The primary role of calcium in the activation of cardiac and skeletal muscle is to:
a. Provide the energy necessary for contraction
b. Activate myosin molecules so that they can interact with actin filaments
c. Cause depolarization of the muscle cell plasma membrane
d. Remove the inhibition of the reaction between the actin filaments and the myosin
filaments
e. Bind to calmodulin and increase the entry of sodium ions in the muscle fiber
(2009) - ANSWERSRemove the inhibition of the reaction between the actin filaments
and the myosin filaments
Which characteristics are found in skeletal muscle fibers best adapted to produce fast
and powerful movements?
a. High capillary density, red color, resistant to fatigue, mostly aerobic metabolism
b. Large fiber diameter, extensive sarcoplasmic reticulum, white color, mainly anaerobic
metabolism
c. Gap junctions and capable of responding to circulating hormones
d. Part of a small motor unit (few fibers per alpha motor neuron)
e. Controlled by the autonomic nervous system
(2009) - ANSWERSLarge fiber diameter, extensive sarcoplasmic reticulum, white color,
mainly anaerobic metabolism
According to the sliding filament hypothesis for contraction of striated muscle:
, a. The length of muscle does not affect the force of contraction
b. Movement is caused by the actions of calcium ions on thick filaments
c. Movement occurs due to shortening of the myofilaments
d. Muscle cannot shorten if the myofilaments are overlapped
e. Cyclic interactions between myosin filament crossbridges and actin filaments cause
the muscle to shorten
(2009) - ANSWERSCyclic interactions between myosin filament crossbridges and actin
filaments cause the muscle to shorten
The overall resistance to blood flow is greatest at the level of the:
a. Aorta
b. Arterioles
c. Capillary
d. Venule
e. Veins
(2009) - ANSWERSArterioles
According to the sliding filament hypothesis for muscle contraction:
a. Movement occurs due to shortening of the myofilaments.
b. Cyclic interactions between myosin filament crossbridges, and actin filaments cause
the muscle to shorten.
c. Movement is caused by the action of calcium ions on the thick filaments.
d. The length of muscle does not affect the force of contraction.
e. Muscle cannot shorten if the myofilaments are overlapped.
(2009) - ANSWERSCyclic interactions between myosin filament crossbridges, and actin
filaments cause the muscle to shorten.
Arterioles do not:
a. Play a major role in regulating local blood flow
b. Play a major role in regulating arterial blood pressure
c. Offer most resistance to flow than capillaries
d. Have a rich sympathetic innervation
e. Have a larger total cross-sectional area than do capillaries
(2009) - ANSWERSHave a larger total cross-sectional area than do capillaries
In complete heart block:
a. Fainting may occur because the atria are unable to pump blood into the ventricles
b. Ventricular fibrillation is common
c. The atrial rate is lower than the ventricular rate
d. Fainting may occur because of prolonged periods during which the ventricles fail to
contract
