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Bio E5100. Medical Physiology
Exam 1
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1. Some cells secrete chemicals into the extracellular fluid that act on cells in the same tissue. Which of
the following refer to this type of regulation?
A. Neural
B. Endocrine
C. Neuroendocrine
D. Paracrine
E. Autocrine
2. Which of the following is an example of paracrine regulation?
A. Somatostatin: growth hormone secretion
B. Somatostatin: glucagon secretion
C. Dopamine: prolactin secretion
D. Norepinephrine: secretion of corticotropin-releasing hormone
E. Thyrotropin-releasing hormone: thyroid-stimulating hormone (TSH) secretion
3. An example of neuroendocrine secretion is the release of which of the following?
A. Somatostatin
B. Cortisol
C. Growth hormone
D. Prolactin
E. ACTH
4. Which of the following peptide second messengers are incorrectly paired?
A. Glucagon and cAMP
B. Insulin and cAMP
C. TSH and cAMP
D. ACTH and cAMP
E. ADH V2 receptor and cAMP
5. Which of the following statements about peptide or protein hormones is usually true?
A. They have longer half-lives than steroid hormones.
B. They have receptors on the cell membrane.
C. They have a slower onset of action than both steroid and thyroid hormones.
D. They are not highly stored in endocrine-producing glands.
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6.
a.
b.
c.
d.
Which type of receptor is found in the sympathetic and parasympathetic ganglia?
Nicotinic
Muscarinic
Adrenergic
Dopaminergic
7.
a.
b.
c.
d.
In which organ systems do sympathetic and parasympathetic stimulation have opposite effects?
Heart
Gastrointestinal tract
Urogenital systems
All of the above
8.
a.
b.
c.
d.
Muscarinic receptors are found on which of the following?
Sympathetic effector cells
Sympathetic ganglionic cells
Parasympathetic effector cells
Parasympathetic ganglionic cells
9.
a.
b.
c.
d.
Autonomic ganglion cells release which one of the following neurotransmitters?
Acetylcholine
Norepinephrine
Epinephrine
Dopamine
10.
a.
b.
c.
d.
Which of the following receptor types mediates an increase in heart rate and contractility?
Alpha1 receptors
Alpha2 receptors
Beta1 receptors
Beta2 receptors
11.
The skeletal muscle sarcomere
normally has a narrow range of lengths in
vivo, but sarcomere length can vary greatly in
vitro under nonphysiological conditions. The
diagram shows sarcomeres at various lengths.
At which length can the sarcomere exert its
maximum force during an isometric
contraction?
A. 1.6 µm
B. 2.1 µm
C. 2.8 µm
D. 3.0 µm
E. 3.5 µm
1.6 µm
2.3 µm
3.7 µm
2.0 µm
3
12.
A physiology experiment is conducted in which a skeletal muscle twitch is initiated using an
electrical stimulator. Which factor contributes to the termination of a typical skeletal muscle twitch?
A. Calcium uptake by sarcoplasmic reticulum
B. Closure of transverse tubules
C. Depletion of calcium stores from sarcoplasmic reticulum
D. Exhaustion of muscle ATP stores
E. Stimulation of dihydropyridine (DHP) receptors
200
13.
The length-tension diagram
shown on the right was obtained
from a skeletal muscle with equal
numbers of red and white fibers.
Supramaximal tetanic stimuli were
used to initiate an isometric
contraction at each muscle length
studied. The resting length was 20
cm.What are the values (in grams)
of preload, active tension, and total
tension when the muscle length is
30 cm?
A.
B.
C.
D.
E.
Preload
100
150
50
50
50
150
Tension
(grams)
100
50
0
0
10
Active tension
50
100
50
50
100
20
30
Length (cm)
40
Total tension
150
50
50
150
150
14.
A 23-year-old medical student goes to the local gym to lift weights. She begins by bench-pressing
100 pounds as a warm-up procedure and then gradually increases the weight. Which of the following
occurs as she adds more weight?
A. Decreased frequency of motor nerve action potentials
B. Decreased velocity of motor nerve action potentials
C. Increased frequency of motor nerve action potentials
D. Increased velocity of motor nerve action potential
E. Involvement of fewer motor units
15.
During the contraction of a skeletal muscle fiber, the actin and myosin filaments slide past each
other. Which of the following represent the changes in the widths of I-bands and A-bands during the
contraction process?
I-band width
A-band width
A.
↑
↔
B.
↓
↑
C.
↓
↓
D.
↓
↔
E.
↔
↑
4
16.
A 39-year-old college professor complains to his physician of muscle fatigue that worsens later in
the day. A particularly troublesome problem is slurred and unintelligible speech that occurs toward the
end of a 2-hour lecture. The physician notices that the man has droopy eyelids and seems to have an
overall weakness in his muscles. After the intravenous administration of Tension, which blocks
degradation of acetylcholine, the droopy eyelids and symptoms of muscle weakness appear to subside.
The physician suspects myasthenia gravis. Myasthenia gravis is an autoimmune disease in which
antibodies damage or destroy part of the muscle fiber. What specifically?
17.
A 3-year-old child is admitted to the emergency department of University Hospital. The child
exhibits extreme salivation, lacrimation, tremors, and tachycardia. The slight erythema and mild edema
found on the child's hand suggest a spider bite. The mother acknowledges that the child has a fascination
with spiders and has seen black widow spiders in the yard. The neurotoxic venom of the black widow
spider (i.e., latrotoxin or latrophilin) can increase the flux of calcium ions into the presynaptic terminal.
What is the likely outcome of a black widow spider bite?
F. Decreased acetylcholine release from nerve terminals
G. Hyperpolarization of postsynaptic membranes
H. Hyperpolarization of presynaptic membranes
I. Increased acetylcholine release from nerve terminals
J. Inhibition of acetylcholinesterase
18.
A 23-year-old man celebrates the New Year with his friends and consumes a large amount of
ethanol. He loses consciousness while driving home, hits a tree, and dies within 15 minutes. The police
find his stiff body 5 hours later. Rigor mortis is caused by a decrease in which of the following?
A. Acetylcholine
B. Actin-myosin cross-bridges
C. Myoplasmic calcium levels
D. Interstitial lactate levels
E. Muscle ATP levels
19.
A father and his 10-year-old daughter died suddenly of suffocation after ingesting smoked
whitefish chubs from the Great Lakes. Three other family members are sick, complaining of dry mouths
despite drinking copious amounts of fluids. Their upper eyelids droop. Their vision is clear, but their
pupils are wide and do not narrow when a light is flashed. Two of them require artificial respiration. The
suspect is botulism (Clostridium botulinum). The surviving patients begin improving soon after receiving
the only treatment available, E antitoxin. The deadly effect of botulinum toxin results from?
20.
Calcium is critically important for initiating the contraction of skeletal muscle, cardiac muscle,
and smooth muscle. Skeletal muscle and cardiac muscle contract when calcium binds to which structure
or molecule?
A. Active sites
B. Calmodulin
C. Myosin head
D. Tropomyosin
E. Troponin
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21.
Smooth muscle and skeletal muscle have many similarities, as well as some important
differences. Unlike skeletal muscle, the contraction of smooth muscle requires which of the following?
A. Activation of ryanodine receptors
B. Phosphorylation of myosin light chains
C. The presence of intracellular calcium
D. Troponin binding of calcium
E. Voltage activation of dihydropyridine receptors
22.
Tension development in smooth muscle is controlled by various factors that are not important for
the regulation of skeletal muscle contraction. Which of the following factors are important for initiating
smooth muscle contractions?
Hormones
Paracrine factors
Autonomic nervous system
A.
No
No
No
B.
No
No
Yes
C.
Yes
No
Yes
D.
Yes
Yes
No
E.
Yes
Yes
Yes
23.
The sensitivity of the smooth muscle contractile apparatus to calcium can increase. This increase
in calcium sensitivity can be attributed to a decrease in the levels of which of the following substances?
A. Actin
B. Adenosine triphosphate (ATP)
C. Calcium-calmodulin complex
D. Calmodulin
E. Myosin light chain phosphatase
Intraventricular Pressure
(mmHg)
6
200
150
D
100
C
50
A
0
50
B
100
150
200
Left Ventricular Volume (ml)
24.
A 50-year-old man has a body weight of 110 kg. His resting heart rate is 90 beats/min, arterial
pressure is 120/70 mm Hg, arterial hematocrit is 35%, and body temperature is normal. His pressurevolume diagram for the left ventricle is shown. What is his resting cardiac output (in ml/min)?
A. 900
B. 8000
C. 9000
D. 10,000
E. 15,000
25.
Which of the following will result in spastic contraction of the heart?
A. Excess calcium ions in the blood
B. Excess potassium ions in the blood
C. Excess sodium ions in the blood
D. Decreased sympathetic stimulation
E. Decreased norepinephrine concentration in the blood
26.
A 60-year-old woman has a body weight of 110 kg. Her resting cardiac output is 9000 ml/min,
arterial pressure is 90/50 mm Hg, arterial hematocrit is 25%, and body temperature is normal. Her strokevolume output is 100 ml. What is her resting heart rate (in beats/min)?
A. 70
B. 80
C. 90
D. 100
E. 110
Intraventricular Pressure
(mmHg)
7
200
150
D
100
C
50
A
0
50
B
100
150
200
Left Ventricular Volume (ml)
27.
A 60-year-old woman has a body weight of 110 kg. Her resting cardiac output is 9000 ml/min,
arterial pressure is 90/50 mm Hg, arterial hematocrit is 25%, and body temperature is normal. Her
pressure-volume diagram for the left ventricle is shown. What event occurs at point A on the woman's
pressure-volume diagram?
A. A-V valves close
B. Aortic valve opens
C. Aortic valve closes
D. A-V valves open
E. Third heart sound
28.
If the sinus node stops discharging, what is the expected heart rate (in beats/min) if the
atrioventricular (A-V) node takes over as the cardiac pacemaker?
A. 15
B. 20
C. 35
D. 50
E. 72
29.
Which of the following conditions at the S-A node will decrease the heart rate?
A. Increased sodium permeability
B. Decreased acetylcholine levels
C. Increased norepinephrine levels
D. Increased potassium permeability
E. Increased calcium permeability
30.
In a resting adult, the typical ventricular ejection fraction is
A. 20%
B. 30%
C. 40%
D. 60%
E. 80%
8
31.
Describe the effects of increased parasympathetic stimulation of the heart?
32.
Which of the following conditions at the S-A node will decrease the heart rate?
A. Increased sodium permeability
B. Increased acetylcholine levels
C. Increased norepinephrine levels
D. Decreased potassium permeability
E. Increased calcium permeability
33.
The QT interval is the time that approximates the time of ventricular contraction. The normal QT
interval is
A. 0.04 seconds
B. 0.08 seconds
C. 0.16 seconds
D. 0.20 seconds
E. 0.35 seconds
34.
A 70-year-old woman had an electrocardiogram performed at her annual checkup, and the
following lead II recording was made. What is her heart rate (in beats/min)?
A. 68
B. 78
C. 84
D. 94
E. 104
9
35.
A 70-year-old woman had an electrocardiogram performed at her annual checkup, and the
following lead II recording was made. According to Einthoven's law, if the QRS voltage in lead III is
0.5 mV, what is the QRS voltage in lead I?
36.
Under control conditions, flow through a blood vessel occurs at 10 ml/min under a pressure
gradient of 100 mm Hg. What would the flow (in ml/min) through the vessel be after the diameter of the
vessel was increased twofold and the pressure gradient was maintained at 100 mm Hg?
A. 100
B. 160
C. 200
D. 360
E. 400
37.
A decrease in the diameter of an arteriole would most likely result in which of the following sets
of changes in the microcirculation?
A.
B.
C.
D.
E.
F.
G.
H.
Conductance








Blood flow








Resistance








10
38.
The velocity of blood flowing through the circulatory system is lowest in which of the following
parts of the circulation?
A. Venules
B. Veins
C. Aorta
D. Small arteries
E. Capillaries
39.
A 50-year-old woman has a renal blood flow of 1000 ml/min and hematocrit of 50. Her arterial
pressure is 120 mm Hg, and her renal venous pressure is 20 mm Hg. She has a plasma colloid osmotic
pressure of 25 mm Hg. Which of the following is the total renal vascular resistance (in mm Hg/ml/min) in
this woman?
40.
A.
B.
C.
D.
E.
Which one of the following statements regarding the circulation is correct?
Most of the blood volume is in the capillaries.
The capillaries have the greatest total cross-sectional area and velocity of blood flow.
Blood flow in the aorta is greater than blood flow in all capillaries.
The arteries serve as the largest reservoir of blood
The compliance of the veins is greater than that of the arteries.
41.
The table below depicts the pressure gradient, radius, and viscosity in various vessels of the same
length. Which vessel has the greatest flow?
Vessel
A.
B.
C.
D.
42.
Pressure gradient
100
50
25
10
Radius
1
2
4
6
Which vessel has the highest vascular resistance?
Vessel
Blood flow (ml/min)
A.
B.
C.
D.
E.
1000
1200
1400
1600
1800
Pressure gradient (mm
Hg)
100
60
20
80
40
Viscosity
10
5
2
1
11
43.
A 78-year-old woman has a mean arterial pressure of 120 mm Hg and a heart rate of 60
beats/min. She has a stroke volume of 50 ml, cardiac output of 3000 ml/min, and a right atrial pressure of
0 mm Hg. What is the total peripheral resistance (in mm Hg/ml/min) in this woman?
A. .01
B. .02
C. .04
D. .08
E. .10
44.
A.
B.
C.
D.
The tendency for turbulent flow is greatest in
Arterioles
Capillaries
Small arterioles
The aorta
A.
B.
C.
D.
Which one the following can cause the largest increase in blood flow?
A twofold increase in hematocrit
A twofold increase in arterial pressure
A twofold increase in arteriole diameter
A twofold increase in arteriole resistance
45.
46.
A decrease in which one of the following would tend to decrease the filtration rate across a
capillary wall?
A. Plasma colloid osmotic pressure
B. Hydraulic conductivity of the wall
C. Plasma albumin concentration
D. Interstitial hydrostatic pressure
E. Arteriole resistance
47.
An increase in arteriole resistance would most likely result in which of the following sets of
changes in a microcirculatory bed?
A.
B.
C.
D.
E.
F.
Interstitial hydrostatic
pressure






Capillary hydrostatic
flow






Lymph
flow






48.
A decrease in which one of the following would tend to increase the filtration rate across a
capillary wall?
A. Plasma colloid osmotic pressure
B. Hydraulic conductivity of the wall
C. Interstitial albumin concentration
D. Capillary hydrostatic pressure
E. Arteriole diameter
12
49.
A 65-year-old man has a 20-year history of alcoholism and liver disease. He visits his physician
complaining of swelling of his extremities. A decrease in which of the following is the most likely cause
of the ascites?
A. Capillary hydrostatic pressure
B. Arteriole conductance
C. Interstitial hydrostatic pressure
D. Plasma colloid osmotic pressure
E. Interstitial colloid osmotic pressure
50.
Histamine is injected into the brachial artery of a 25-year-old man. Which of the following sets of
changes would be expected to occur in response to histamine?
A.
B.
C.
D.
E.
Vascular
resistance





Vascular conductance





Capillary
filtration





51.
The diameter of a precapillary arteriole is increased in a muscle vascular bed. A decrease in
which of the following would be expected?
A. Capillary filtration rate
B. Vascular conductance
C. Capillary blood flow
D. Capillary hydrostatic pressure
E. Arteriole resistance
52.
An increase in tissue metabolism results in
53.
Reducing arterial pressure in a muscle artery from 100 to 80 mm Hg would result in which of the
following conditions?
A. Long-term reduction in blood flow
B. Reduction in arteriole diameter and increase in blood flow
C. Reduction in arteriole resistance and maintenance of normal blood flow
D. Decrease in vascular conductance
13
54.
Calculate the minute ventilation and the alveolar ventilation for a patient with a respiratory rate of
10 breaths/min, a tidal volume of 600 ml, and a dead space of 150 ml.
A.
B.
C.
D.
E.
Minute ventilation (L/min)
Alveolar ventilation (L/min)
4.5
6.0
8
10
12
3.0
4.5
6.5
8.5
10.5
54.
Before inspiration, alveolar pressure is 0 and intrapleural pressure is 5 cm H2O. At the end of an
inspiration in a healthy person, with the glottis open, these readings would be
A. Alveolar pressure of +2, intrapleural pressure of 8 cm H2O
B. Alveolar pressure of 2, intrapleural pressure of 8 cm H2O
C. Alveolar pressure of 0, intrapleural pressure of +5 cm H2O
D. Alveolar pressure of 0, intrapleural pressure of 5 cm H2O
E. Alveolar pressure of 0, intrapleural pressure of 8 cm H2O
56.
A.
B.
C.
D.
E.
Which of the following would be expected to increase the measured airway resistance?
Stimulation of parasympathetic nerves to the lungs
Low lung volumes
Release of histamine by mast cells
Forced expirations
All of the above
A.
B.
C.
D.
Which of the following tend to decrease airway resistance?
Asthma
Stimulation by sympathetic fibers
Treatment with acetylcholine
Exhalation to residual volume
57.
58.
If the oxygen (O2) concentrations of mixed venous and arterial blood are 16 and 20 ml/100 ml,
respectively, and O2 consumption is 300 ml/min, what is the total pulmonary blood flow?
A. 4 L/min
B. 5 L/min
C. 7.5 L/min
D. 10 L/min
59.
A.
B.
C.
D.
Blood flow in the lung
Is uniform in apical and basal regions in the supine position
Not affected by positive-pressure breathing
Is not influenced by left atrial pressure
Is independent of nervous system control
60.
A patient comes into the emergency department with a mean pulmonary arterial pressure of 25
mm Hg. Which of the following would be expected to happen?
14
61.
A.
B.
C.
D.
Pulmonary edema forms preferentially at the base of the lung because
PO2 is less at the base
PCO2 is higher at the base
Intravascular pressure is greater at the base
Vascular resistance is higher at the base
62.
If the mean pulmonary arterial and left atrial pressures are 20 and 8 mm Hg, respectively, and
total blood flow is 5 L/min, what is the pulmonary vascular resistance?
A. 0.4 mmHg/L/min
B. 1.2 mmHg/L/min
C. 2.4 mmHg/L/min
D. 3.6 mmHg/L/min
63.
If alveolar PO2 is 300 mm Hg and alveolar PCO2 is 40 mm Hg, what is the PIO2 (i.e., humidified
inspired PO2)?
A.
B.
C.
D.
E.
250 mm Hg
300 mm Hg
350 mm Hg
400 mm Hg
760 mm Hg
64.
As a tissue is cooled during surgery and the oxygen consumption decreases while the blood flow
remains the same, what will happen?
A.
B.
C.
D.
Tissue interstitial PO2 will remain normal.
Tissue interstitial PO2 will increase.
Tissue interstitial PO2 will decrease.
The amount of oxygen removed from the blood each minute will not change.
65.
Consider a patient with an anatomical dead space of 100 ml, a normal respiratory rate of 12
breaths/min, and a normal tidal volume of 600 ml under resting conditions. Match the condition with the
correct set of respiratory rate, tidal volume, and metabolic changes: Systemic arterial PO2 of
approximately 100 mm Hg.
Respiratory rate
6
24
16
A.
B.
C.
66.
A.
B.
C.
D.
Tidal volume
1100
500
400
Perfusion of capillaries without ventilation of an alveoli
Results in an decrease in alveolar PO2
Results in an increase in systemic arterial PO2
Results in an increase in alveolar PCO2
Results in a increase in systemic arterial PCO2
Metabolic rate
Normal
Normal
4 times normal
15
67.
occur?
A.
B.
C.
D.
E.
A patient with no respiratory problems is given a blood transfusion. Which of the following will
68.
Which of the following should decrease the affinity of hemoglobin for oxygen?
Low PCO2
Alkalosis
Acidosis
Decreased body temperature
A.
B.
C.
D.
Arterial PO2 will increase.
Arterial PCO2 will decrease.
Arterial saturation will increase.
Arterial oxygen content will decrease.
Arterial oxygen content will increase.
69.
An otherwise normal person has lost enough blood to decrease his body's hemoglobin
concentration from 15 g/100 ml of blood to 12 g/100 ml of blood. Which of the following would be
expected to decrease?
A. Arterial PO2
B. Blood oxygen-carrying capacity
C. Arterial hemoglobin saturation
D. Arterial carbon dioxide content
70.
A.
B.
C.
D.
Voluntary apnea (i.e., breath-holding) for 60 seconds will
Decrease alveolar PCO2
Increase arterial PO2
Inhibit the arterial chemoreceptors
Increase alveolar PCO2
A.
B.
C.
D.
Hyperventilation will result from
An increase in arterial PO2 greater than 150 mm Hg
Direct stimulation of the medulla's chemosensitive area by an increase in pH
An increase in alveolar PCO2
An increase in alveolar PN2
71.
72.
While playing ball, a child fell and injured his head producing a lesion in the respiratory center.
As a result he is hypoventilating. Twenty minutes after the accident the data that would best fit his
condition are:
pH
PCO2
PO2
A.
7.50
30
60
B.
7.35
60
100
C.
7.25
60
60
D.
7.30
70
80
E.
7.40
50
90
73.
A.
B.
C.
D.
E.
The main reason that respiratory compensation occurs in metabolic acidosis is stimulation of
The carotid bodies by CO2
The carotid bodies by H+
The central chemoreceptors by CO2
The central chemoreceptors by H+
The central chemoreceptors by O2