Physiology Test

Question 1

A hormone is known to activate phospholipase C with subsequent release of calcium from internal stores.
The release of calcium most likely occurs as a result of an increase in the concentration of which of the following intracellular second messengers?

Accepted Answer

Inositol 1,4,5-trisphosphate

Answer

Calcium

Answer

cAMP

Answer

cGMP

Answer

Diacylglycerol

Question 2

A 28-year-old man with a history of intravenous drug use comes to the physician because of a 6-week history of fever, nonproductive cough, chills, and progressive shortness of breath. His temperature is 39°C (102.2°F), pulse is 110/min, respirations are 32/min and regular, and blood pressure is 120/80 mm Hg. Physical examination shows a white, patchy, loosely adherent exudate on the buccal mucosa bilaterally. A chest x-ray shows bilateral interstitial infiltrates. After receiving treatment for pneumonia, he agrees to participate in a clinical study of the effects of interleukin-2 (IL-2). After administration of IL-2, which of the following hematologic changes is most likely in this patient?

Accepted Answer

Increased CD4+ T lymphocytes

Answer

Decreased CD4+ T lymphocytes

Answer

Decreased erythrocytes

Answer

Decreased platelet count

Answer

Increased erythrocytes

Answer

Increased platelet count

Question 3

A 5-year-old girl falls through the ice while skating on an outdoor pond. She is removed from the water within 1 minute, but dry clothing is not available, and she is still cold and wet 20 minutes later. Which of the following mechanisms helps maintain the patient’s core temperature during the period following her rescue?

Accepted Answer

Shivering

Answer

Cutaneous vasodilation

Answer

Diving response

Answer

Increased thermoregulatory set point

Answer

Release of endogenous pyrogen

Question 4

A 39-year-old woman comes to the physician for a follow-up examination because she recently was diagnosed with hypertension. Her blood pressure is 156/100 mm Hg. Physical examination shows no other abnormalities. Serum studies show normal findings. A 24-hour urine collection shows three times the normal excretion of epinephrine and metanephrine. The excessive epinephrine production in this patient is most likely caused by which of the following cell types?

Accepted Answer

Chromaffin

Answer

Juxtaglomerular

Answer

Zona fasciculata

Answer

Zona glomerulosa

Answer

Zona reticularis

Question 5

The blood flow through an organ is measured while the perfusion pressure is varied experimentally. An abrupt, sustained increase in perfusion pressure increases flow initially, but over the course of 1 minute, the flow returns nearly to the baseline level despite continued elevation of the perfusion pressure. The organ under study is exhibiting which of the following?

Accepted Answer

Autoregulation

Answer

Active hyperemia

Answer

Ischemia

Answer

Reactive hyperemia

Question 6

After an overnight fast, a 52-year-old man undergoes infusion of acid through a catheter into the upper duodenum. This most likely will increase pancreatic secretion mainly through the action of which of the following substances?

Accepted Answer

Secretin

Answer

Cholecystokinin

Answer

Gastrin

Answer

Glucagon

Answer

Vasoactive intestinal polypeptide

Question 7

A 20-year-old woman is brought to the emergency department 20 minutes after being stung by a wasp. She says that she feels a lump in her throat and chest tightness. She has a history of allergy to wasp venom. Her pulse is 120/min, and blood pressure is 80/40 mm Hg. Physical examination shows eruptions that coalesce into giant urticaria. There is audible wheezing. Which of the following best describes the cause of this patient’s reaction?

Accepted Answer

Binding of antigen to preexisting cell-fixed IgE antibodies

Answer

Activation of macrophages by soluble immune complexes

Answer

Formation of IgG antibodies against extracellular matrix antigen

Answer

Formation of IgM antibodies against cell surface receptor antigens

Answer

Induction of a cytotoxic reaction by CD8+ T lymphocytes

Question 8

A demonstration is performed during a lecture on muscle physiology in which a student is asked to fully extend his right arm with the palm up. Two large textbooks are placed on his palm, one at a time. Which of the following facilitates the maximum amount of tension that allows the student to keep his arm extended in place under the increasing weight of the books?

Accepted Answer

Number of motor units recruited

Answer

Amount of Ca 2+ released from the sarcoplasmic reticulum

Answer

Amount of muscle phosphocreatine

Answer

Amplitude of the action potential

Answer

Rate of cross-bridge recycling

Question 9

During an experiment on the cough reflex in humans, a volunteer inhales air containing different amounts of particles that will impact and adhere to mucus primarily in the trachea. Blockade of which of the following receptors would most likely prevent this volunteer’s reflex to initiate a cough?

Accepted Answer

Irritant receptors

Answer

Chemoreceptors

Answer

J receptors

Answer

Proprioceptors

Answer

Stretch receptors

Question 10

A 35-year-old man has an adenoma of the parathyroid gland, with increased serum concentrations of parathyroid hormone (PTH) and calcium. In this patient, PTH induces which of the following processes to cause hypercalcemia?

Accepted Answer

Stimulation of osteoclast activity

Answer

Production of 25-hydroxycholecalciferol

Answer

Shift of Ca 2+ from the intracellular to the extracellular fluid compartment

Answer

Suppression of renal production of 1,25-dihydroxycholecalciferol

A hormone is known to activate phospholipase C with subsequent release of calcium from internal stores.The release of calcium most likely occurs as a result of an increase in the concentration of which of the following intracellular second messengers?

A hormone is known to activate phospholipase C with subsequent release of calcium from internal stores.
The release of calcium most likely occurs as a result of an increase in the concentration of which of the following intracellular second messengers?