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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.
6. Which type of receptor is found in the sympathetic and parasympathetic ganglia?
a. / Nicotinicb. / Muscarinic
c. / Adrenergic
d. / Dopaminergic
7. In which organ systems do sympathetic and parasympathetic stimulation have opposite effects?
a. / Heartb. / Gastrointestinal tract
c. / Urogenital systems
d. / All of the above
8. Muscarinic receptors are found on which of the following?
a. / Sympathetic effector cellsb. / Sympathetic ganglionic cells
c. / Parasympathetic effector cells
d. / Parasympathetic ganglionic cells
9. Autonomic ganglion cells release which one of the following neurotransmitters?
a. / Acetylcholineb. / Norepinephrine
c. / Epinephrine
d. / Dopamine
10. Which of the following receptor types mediates an increase in heart rate and contractility?
a. / Alpha1 receptorsb. / Alpha2 receptors
c. / Beta1 receptors
d. / 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
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
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?
Preload / Active tension / Total tensionA. / 100 / 50 / 150
B. / 150 / 100 / 50
C. / 50 / 50 / 50
D. / 50 / 50 / 150
E. / 50 / 100 / 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 widthA. / ↑ / ↔
B. / ↓ / ↑
C. / ↓ / ↓
D. / ↓ / ↔
E. / ↔ / ↑
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
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 systemA. / 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
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 pressure-volume 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 stroke-volume output is 100 ml. What is her resting heart rate (in beats/min)?
A. 70
B. 80
C. 90
D. 100
E. 110
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%
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
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?
Conductance / Blood flow / ResistanceA. / / /
B. / / / ¯
C. / / ¯ / ¯
D. / / ¯ /
E. / ¯ / ¯ / ¯
F. / ¯ / ¯ /
G. / ¯ / /
H. / ¯ / / ¯
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. Which one of the following statements regarding the circulation is correct?
A. Most of the blood volume is in the capillaries.
B. The capillaries have the greatest total cross-sectional area and velocity of blood flow.
C. Blood flow in the aorta is greater than blood flow in all capillaries.
D. The arteries serve as the largest reservoir of blood
E. 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 / Pressure gradient / Radius / ViscosityA. / 100 / 1 / 10
B. / 50 / 2 / 5
C. / 25 / 4 / 2
D. / 10 / 6 / 1
42. Which vessel has the highest vascular resistance?
Vessel / Blood flow (ml/min) / Pressure gradient (mm Hg)A. / 1000 / 100
B. / 1200 / 60
C. / 1400 / 20
D. / 1600 / 80
E. / 1800 / 40
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. The tendency for turbulent flow is greatest in
A. Arterioles
B. Capillaries
C. Small arterioles
D. The aorta
45. Which one the following can cause the largest increase in blood flow?
A. A twofold increase in hematocrit
B. A twofold increase in arterial pressure
C. A twofold increase in arteriole diameter
D. A twofold increase in arteriole resistance
46. A decrease in which one of the following would tend to decrease the filtration rate across a capillary wall?