Файл: BRS_Physiology_6E_2014_1.pdf

15.  A key difference in the mechanism of excitation–contraction coupling between the muscle of the pharynx and the muscle of the wall of the small intestine is that

(A)  slow waves are present in the pharynx, but not in the small intestine

(B)  adenosine triphosphate (ATP) is used for contraction in the pharynx, but not in the small intestine

(C)  intracellular [Ca2+] is increased after excitation in the pharynx, but not in the small intestine

(D)  action potentials depolarize the muscle of the small intestine, but not of the pharynx

(E)  Ca2+ binds to troponin C in the pharynx, but not in the small intestine, to initiate contraction

16.  A 40-year-old woman has an arterial pH of 7.25, an arterial Pco2 of 30 mm Hg, and serum [K+] of 2.8 mEq/L. Her blood pressure is 100/80 mm Hg when supine and 80/50 mm Hg when standing. What is the cause of her abnormal blood values?

(A)  Vomiting

(B)  Diarrhea

(C)  Treatment with a loop diuretic

(D)  Treatment with a thiazide diuretic

17.  Secretion of HCl by gastric parietal cells is needed for

(A)  activation of pancreatic lipases

(B)  activation of salivary lipases

(C)  activation of intrinsic factor

(D)  activation of pepsinogen to pepsin

(E)  the formation of micelles

18.  Which of the following would cause an increase in glomerular filtration rate (GFR)?

(A)  Constriction of the afferent arteriole

(B)  Constriction of the efferent arteriole

(C)  Constriction of the ureter

(D)  Increased plasma protein concentration

(E)  Infusion of inulin

19.  Fat absorption occurs primarily in the

(A)  stomach

(B)  jejunum

(C)  terminal ileum

(D)  cecum

(E)  sigmoid colon

20.  Which of the following hormones causes constriction of vascular smooth muscle through an inositol 1,4,5-triphosphate (IP3) second messenger system?

(A)  Antidiuretic hormone (ADH)

(B)  Aldosterone

(C)  Dopamine

(D)  Oxytocin

(E)  Parathyroid hormone (PTH)

21.  A 30-year-old woman has the anterior lobe of her pituitary gland surgically removed because of a tumor. Without hormone replacement therapy, which of the following would occur after the operation?

(A)  Absence of menses

(B)  Inability to concentrate the urine in response to water deprivation

(C)  Failure to secrete catecholamines in response to stress

(D)  Failure to secrete insulin in a glucose tolerance test

(E)  Failure to secrete parathyroid hormone (PTH) in response to hypocalcemia

22.  The following graph shows three relationships as a function of plasma [glucose]. At plasma [glucose] less than 200 mg/dL, curves X and Z are superimposed on each other because

(A)  the reabsorption and excretion of glucose are equal

(B)  all of the filtered glucose is reabsorbed

(C)  glucose reabsorption is saturated

(D)  the renal threshold for glucose has been exceeded

(E)  Na+–glucose cotransport has been inhibited

(F)  all of the filtered glucose is excreted

23.  Which of the following responses occurs as a result of tapping on the patellar tendon?

(A)  Stimulation of Ib afferent fibers in the muscle spindle

(B)  Inhibition of Ia afferent fibers in the muscle spindle

(C)  Relaxation of the quadriceps muscle

(D)  Contraction of the quadriceps muscle

(E)  Inhibition of α-motoneurons

Questions 24 and 25

A 5-year-old boy has a severe sore throat, high fever, and cervical adenopathy.

24.  It is suspected that the causative agent is Streptococcus pyogenes. Which of the following is involved in producing fever in this patient?

(A)  Increased production of interleukin-1 (IL-1)

(B)  Decreased production of prostaglandins

(C)  Decreased set-point temperature in the hypothalamus

(D)  Decreased metabolic rate

(E)  Vasodilation of blood vessels in the skin

25.  Before antibiotic therapy is initiated, the patient is given aspirin to reduce his fever. The mechanism of fever reduction by aspirin is

(A)  shivering

(B)  stimulation of cyclooxygenase

(C)  inhibition of prostaglandin synthesis

(D)  shunting of blood from the surface of the skin

(E)  increasing the hypothalamic set-point temperature

26.  Arterial pH of 7.52, arterial Pco2 of

26 mm Hg, and tingling and numbness in the feet and hands would be observed in a

(A)  patient with chronic diabetic ketoacidosis

(B)  patient with chronic renal failure

(C)  patient with chronic emphysema and bronchitis

(D)  patient who hyperventilates on a commuter flight

(E)  patient who is taking a carbonic anhydrase inhibitor for glaucoma

(F)  patient with a pyloric obstruction who vomits for 5 days

(G)  healthy person

27.  Albuterol is useful in the treatment of asthma because it acts as an agonist at which of the following receptors?

(A)  α1 Receptor

(B)  β1 Receptor

(C)  β2 Receptor

(D)  Muscarinic receptor

(E)  Nicotinic receptor

28.  Which of the following hormones is converted to its active form in target tissues by the action of 5α-reductase?

(A)  Adrenocorticotropic hormone (ACTH)

(B)  Aldosterone

(C)  Estradiol

(D)  Prolactin

(E)  Testosterone

29.  If an artery is partially occluded by an embolism such that its radius becomes one-half the preocclusion value, which of the following parameters will increase by a factor of 16?

(A)  Blood flow

(B)  Resistance

(C)  Pressure gradient

(D)  Capacitance

30.  If heart rate increases, which phase of the cardiac cycle is decreased?

(A)  Atrial systole

(B)  Isovolumetric ventricular contraction

(C)  Rapid ventricular ejection

(D)  Reduced ventricular ejection

(E)  Isovolumetric ventricular relaxation

(F)  Rapid ventricular filling

(G)  Reduced ventricular filling

Questions 31 and 32

A 17-year-old boy is brought to the emergency department after being injured in an automobile accident and sustaining significant blood loss. He is given a transfusion of 3 units of blood to stabilize his blood pressure.

31.  Before the transfusion, which of the following was true about his condition?

(A)  His total peripheral resistance (TPR) was decreased

(B)  His heart rate was decreased

(C)  The firing rate of his carotid sinus nerves was increased

(D)  Sympathetic outflow to his heart and blood vessels was increased

32.  Which of the following is a consequence of the decrease in blood volume in this patient?

(A)  Increased renal perfusion pressure

(B)  Increased circulating levels of angiotensin II

(C)  Decreased renal Na+ reabsorption

(D)  Decreased renal K+ secretion

33.  A 37-year-old woman suffers a severe head injury in a skiing accident. Shortly thereafter, she becomes polydipsic and polyuric. Her urine osmolarity is 75 mOsm/L, and her serum osmolarity is 305 mOsm/L. Treatment with 1-deamino-8-d-arginine vasopressin (dDAVP) causes an increase in her urine osmolarity to 450 mOsm/L. Which diagnosis is correct?

(A)  Primary polydipsia

(B)  Central diabetes insipidus

(C)  Nephrogenic diabetes insipidus

(D)  Water deprivation

(E)  Syndrome of inappropriate antidiuretic hormone (SIADH)

34.  Which diuretic inhibits Na+ reabsorption and K+ secretion in the distal tubule by acting as an aldosterone antagonist?

(A)  Acetazolamide

(B)  Chlorothiazide

(C)  Furosemide

(D)  Spironolactone

35.  Which gastrointestinal secretion has a component that is required for the intestinal absorption of vitamin B12?

(A)  Saliva

(B)  Gastric secretion

(C)  Pancreatic secretion

(D)  Bile

36.  Secretion of which of the following hormones is stimulated by extracellular fluid volume expansion?

(A)  Antidiuretic hormone (ADH)

(B)  Aldosterone

(C)  Atrial natriuretic peptide (ANP)

(D)  1,25-Dihydroxycholecalciferol

(E)  Parathyroid hormone (PTH)

37.  Which step in the steroid hormone synthetic pathway is stimulated by angiotensin II?

(A)  Aldosterone synthase

(B)  Aromatase

(C)  Cholesterol desmolase

(D)  17,20-Lyase

(E)  5α-Reductase

Questions 38 to 41

Use the diagram of an action potential to answer the following questions.

38.  The action potential shown is from

(A)  a skeletal muscle cell

(B)  a smooth muscle cell

(C)  a sinoatrial (SA) cell

(D)  an atrial muscle cell

(E)  a ventricular muscle cell

39.  Phase 0 of the action potential shown is produced by an

(A)  inward K+ current

(B)  inward Na+ current

(C)  inward Ca2+ current

(D)  outward Na+ current

(E)  outward Ca2+ current

40.  Phase 2, the plateau phase, of the action potential shown

(A)  is the result of Ca2+ flux out of the cell

(B)  increases in duration as heart rate increases

(C)  corresponds to the effective refractory period

(D)  is the result of approximately equal inward and outward currents

(E)  is the portion of the action potential when another action potential can most easily be elicited

41.  The action potential shown corresponds to which portion of an electrocardiogram (ECG)?

(A)  P wave

(B)  PR interval

(C)  QRS complex

(D)  ST segment

(E)  QT interval

42.  Which of the following is the first step in the biosynthetic pathway for thyroid

hormones that is inhibited by propylthiouracil?

(A)  Iodide (I−) pump

(B)  I− →I2

(C)  I2 + tyrosine

(D)  Diiodotyrosine (DIT) + DIT

(E)  Thyroxine (T4)→triiodothyronine (T3)

43.  Arterial pH of 7.29, arterial [HCO3−] of 14 mEq/L, increased urinary excretion of NH4+, and hyperventilation would be observed in a

(A)  patient with chronic diabetic ketoacidosis

(B)  patient with chronic renal failure

(C)  patient with chronic emphysema and bronchitis

(D)  patient who hyperventilates on a commuter flight

(E)  patient who is taking a carbonic anhydrase inhibitor for glaucoma

(F)  patient with a pyloric obstruction who vomits for 5 days

(G)  healthy person

44.  Activation of which of the following receptors increases total peripheral resistance (TPR)?

(A)  α1 Receptor

(B)  β1 Receptor

(C)  β2 Receptor

(D)  Muscarinic receptor

(E)  Nicotinic receptor

45.  The receptor for this hormone has tyrosine kinase activity.

(A)  Adrenocorticotropic hormone (ACTH)

(B)  Antidiuretic hormone (ADH)

(C)  Aldosterone

(D)  Insulin

(E)  Parathyroid hormone (PTH)

(F)  Somatostatin

46.  If an artery is partially occluded by an embolism such that its radius becomes one-half the preocclusion value, which of the following parameters will decrease by a factor of 16?

(A)  Blood flow

(B)  Resistance

(C)  Pressure gradient

(D)  Capacitance

47.  Which phase of the cardiac cycle is absent if there is no P wave on the electrocardiogram (ECG)?

(A)  Atrial systole

(B)  Isovolumetric ventricular contraction

(C)  Rapid ventricular ejection

(D)  Reduced ventricular ejection

(E)  Isovolumetric ventricular relaxation

(F)  Rapid ventricular filling

(G)  Reduced ventricular filling

48.  A receptor potential in the pacinian corpuscle

(A)  is all-or-none

(B)  has a stereotypical size and shape

(C)  is the action potential of this sensory receptor

(D)  if hyperpolarizing, increases the likelihood of action potential occurrence

(E)  if depolarizing, brings the membrane potential closer to threshold

49.  Compared with the base of the lung, in a person who is standing, the apex of the lung has

(A)  a higher ventilation rate

(B)  a higher perfusion rate

(C)  a higher ventilation/perfusion (V/Q) ratio

(D)  the same V/Q ratio

(E)  a lower pulmonary capillary PO2

50.  A 54-year-old man with a lung tumor has high circulating levels of antidiuretic hormone (ADH), a serum osmolarity of 260 mOsm/L, and a negative free-water clearance (CH2O ) . Which diagnosis is correct?

(A)  Primary polydipsia

(B)  Central diabetes insipidus

(C)  Nephrogenic diabetes insipidus

(D)  Water deprivation

(E)  Syndrome of inappropriate antidiuretic hormone (SIADH)

51.  End-organ resistance to which of the following hormones results in polyuria and elevated serum osmolarity?

(A)  Antidiuretic hormone (ADH)

(B)  Aldosterone

(C)  1,25-Dihydroxycholecalciferol

(D)  Parathyroid hormone (PTH)

(E)  Somatostatin

52.  Which diuretic causes increased urinary excretion of Na+ and K+ and decreased urinary excretion of Ca2+?

(A)  Acetazolamide

(B)  Chlorothiazide

(C)  Furosemide

(D)  Spironolactone

53.  Arterial Pco2 of 72 mm Hg, arterial [HCO3−] of 38 mEq/L, and increased H+ excretion would be observed in a

(A)  patient with chronic diabetic ketoacidosis

(B)  patient with chronic renal failure

(C)  patient with chronic emphysema and bronchitis

(D)  patient who hyperventilates on a commuter flight

(E)  patient who is taking a carbonic anhydrase inhibitor for glaucoma

(F)  patient with a pyloric obstruction who vomits for 5 days

(G)  healthy person

54.  In a skeletal muscle capillary, the capillary hydrostatic pressure (Pc) is 32 mm Hg, the capillary oncotic pressure (πc) is 27 mm Hg, and the interstitial hydrostatic pressure (Pi) is 2 mm Hg. Interstitial oncotic pressure (πi) is negligible. What is the driving force across the capillary wall, and will it favor filtration or absorption?

(A)  3 mm Hg, favoring absorption

(B)  3 mm Hg, favoring filtration

(C)  7 mm Hg, favoring absorption

(D)  7 mm Hg, favoring filtration

(E)  9 mm Hg, favoring filtration

55.  Which of the following substances has the lowest renal clearance?

(A)  Creatinine

(B)  Glucose

(C)  K+

(D)  Na+

(E)  Para-aminohippuric acid (PAH)

56.  Atropine causes dry mouth by inhibiting which of the following receptors?

(A)  α1 Receptor

(B)  β1 Receptor

(C)  β2 Receptor

(D)  Muscarinic receptor

(E)  Nicotinic receptor

57.  Which of the following transport mechanisms is inhibited by furosemide in the thick ascending limb?

(A)  Na+ diffusion via Na+ channels

(B)  Na+–glucose cotransport (symport)

(C)  Na+–K+–2Cl− cotransport (symport)

(D)  Na+–H+ exchange (antiport)

(E)  Na+,K+-adenosine triphosphatase (ATPase)

58.  Which of the following conditions decreases the likelihood of edema formation?

(A)  Arteriolar constriction

(B)  Venous constriction

(C)  Standing

(D)  Nephrotic syndrome

(E)  Inflammation

59.  Which of the following conditions causes hypoventilation?

(A)  Strenuous exercise

(B)  Ascent to high altitude

(C)  Anemia

(D)  Diabetic ketoacidosis

(E)  Chronic obstructive pulmonary disease (COPD)

60.  A 28-year-old man who is receiving lithium treatment for bipolar disorder becomes polyuric. His urine osmolarity is 90 mOsm/L; it remains at that level when he is given a nasal spray of dDAVP. Which diagnosis is correct?

(A)  Primary polydipsia

(B)  Central diabetes insipidus

(C)  Nephrogenic diabetes insipidus

(D)  Water deprivation

(E)  Syndrome of inappropriate antidiuretic hormone (SIADH)

61.  Inhibition of which step in the steroid hormone synthetic pathway blocks the production of all androgenic compounds in the adrenal cortex, but not the production of glucocorticoids or mineralocorticoids?

(A)  Aldosterone synthase

(B)  Aromatase

(C)  Cholesterol desmolase

(D)  17,20-Lyase

(E)  5α-Reductase

62.  Arterial pH of 7.54, arterial [HCO3] of 48 mEq/L, hypokalemia, and hypoventilation would be observed in a

(A)  patient with chronic diabetic ketoacidosis

(B)  patient with chronic renal failure

(C)  patient with chronic emphysema and bronchitis