unit 3 and 4 Flashcards by Duke A

In which phase of the ventricular muscle action potential is the potassium permeability the highest?

A) 0
B) 1
C) 2
D) 3
E) 4

D) 3

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In a resting adult, the typical ventricular ejection fraction
has what value?

A) 20%
B) 30%
C) 40%
D) 60%
E) 80%

D) 60%

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Which of the following statements about cardiac muscle is most accurate?

A) The T-tubules of cardiac muscle can store much less calcium than T-tubules in skeletal muscle

B) The strength and contraction of cardiac muscle depends on the amount of calcium surrounding cardiac myocytes

C) In cardiac muscle the initiation of the action potential causes an immediate opening of slow calcium channels

D) Cardiac muscle repolarization is caused by opening of sodium channels

E) Mucopolysaccharides inside the T-tubules bind chloride ions

B) The strength and contraction of cardiac muscle depends on the amount of calcium surrounding cardiac myocytes

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Which of the following is most likely to cause the heart to go into spastic ontraction?

A) Increased body temperature
B) Increased sympathetic activity
C) Decreased extracellular fluid potassium
ions
D) Excess extracellular fluid potassium ions
E) Excess extracellular fluid calcium ions

E) Excess extracellular fluid calcium ions

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Which of the following events occurs at the end of the period of ventricular ejection?

A) A-V valves close
B) Aortic valve opens
C) Aortic valve remains open
D) A-V valves open
E) Pulmonary valve closes

E) Pulmonary valve closes

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Which of the following phases of the cardiac cycle follows immediately after the beginning of the QRS wave?
A) Isovolumic relaxation
B) Ventricular ejection
C) Atrial systole
D) Diastasis
E) Isovolumic contraction

E) Isovolumic contraction

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Which of the following conditions will result in a dilated, flaccid heart?

A) Excess calcium ions in the blood
B) Excess potassium ions in the blood
C) Excess sodium ions in the blood
D) Increased sympathetic stimulation
E) Increased norepinephrine concentration in the blood

B) Excess potassium ions in the blood

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Which of the following events is associated with the first heart sound?

A) Closing of the aortic valve
B) Inrushing of blood into the ventricles during diastole
C) Beginning of diastole
D) Opening of the A-V valves
E) Closing of the A-V valves

E) Closing of the A-V valves

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Which of the following conditions at the A-V node will cause a decrease in heart rate?

A) Increased sodium permeability
B) Decreased acetylcholine levels
C) Increased norepinephrine levels
D) Increased potassium permeability
E) Increased calcium permeability

D) Increased potassium permeability

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Sympathetic stimulation of the heart

A) Releases acetylcholine at the sympathetic endings
B) Decreases sinus nodal discharge rate
C) Decreases excitability of the heart
D) Releases norepinephrine at the sympathetic endings
E) Decreases cardiac contractility

D) Releases norepinephrine at the sympathetic endings

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Which of the following best explains how sympathetic stimulation affects the heart?

A) Permeability of the S-A node to sodium decreases
B) Permeability of the A-V node to sodium decreases
C) Permeability of the S-A node to potassium increases
D) There is an increased rate of upward drift of the resting membrane potential of the S-A node
E) Permeability of the cardiac muscle to calcium decreases

D) There is an increased rate of upward drift of the resting membrane potential of the S-A node

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Which of the following structures will have the slowest rate of conduction of the cardiac action potential?

A) Atrial muscle
B) Anterior internodal pathway
C) A-V bundle fibers
D) Purkinje fibers
E) Ventricular muscle

C) A-V bundle fibers

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Which of the following conditions at the S-A node will cause heart rate to decrease?

A) Increased norepinephrine levels
B) Increased sodium permeability
C) Increased calcium permeability
D) Increased potassium permeability
E) Decreased acetylcholine levels

D) Increased potassium permeability

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What is the membrane potential (threshold level) at which the S-A node discharges?
A) 240 mV
B) 255 mV
C) 265 mV
D) 285 mV
E) 2105 mV

A) 240 mV

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Which of the following conditions at the A-V node will cause a decrease in heart rate?
A) Increased sodium permeability
B) Decreased acetylcholine levels
C) Increased norepinephrine levels
D) Increased potassium permeability
E) Increased calcium permeability

D) Increased potassium permeability

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Sympathetic stimulation of the heart normally causes which of the following conditions?

A) Acetylcholine release at the sympathetic endings
B) Decreased heart rate
C) Decreased rate of conduction of the cardiac impulse
D) Decreased force of contraction of the atria
E) Increased force of contraction of the ventricles

E) Increased force of contraction of the ventricles

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Which of the following conditions will usually result in right axis deviation in an EKG?

A) Systemic hypertension
B) Aortic valve stenosis
C) Aortic valve regurgitation
D) Excess abdominal fat
E) Pulmonary hypertension

E) Pulmonary hypertension

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A 50-year-old man has a blood pressure of 140/85 and weighs 200 lb. He reports that he is not feeling well, his EKG has no P-waves, he has a heart rate of 46, and
the QRS complexes occur regularly. What is his likely condition?

A) First-degree heart block
B) Second-degree heart block
C) Third-degree heart block
D) Sinoatrial heart block
E) Sinus bradycardia

D) Sinoatrial heart block

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An 80-year-old man had an EKG taken at his local doctor’s office, and the diagnosis was atrial fibrillation. Which of the following statements are likely conditions
in someone with atrial fibrillation?

A) Ventricular fibrillation normally accompanies atrial
fibrillation
B) P waves of the EKG are strong
C) Rate of ventricular contraction is irregular and fast
D) Atrial “a” wave is normal
E) Atria have a smaller volume than normal

C) Rate of ventricular contraction is irregular and fast

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Circus movements in the ventricle can lead to ventricular fibrillation. Which of the following conditions in the ventricular muscle will increase the tendency for
circus movements?

A) Decreased refractory period
B) Low extracellular potassium concentration
C) Increased refractory period
D) Shorter conduction pathway (decreased ventricular volume)
E) Increase in parasympathetic impulses to the heart

A) Decreased refractory period

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A 75-year-old man goes to the hospital emergency department and faints. Five minutes later he is alert. An EKG shows 75 P waves per minute and 35 QRS waves per minute with a normal QRS width. Which of
the following is the likely diagnosis?

A) First-degree A-V block
B) Stokes-Adams syndrome
C) Atrial paroxysmal tachycardia
D) Electrical alternans
E) Atrial premature contractions

B) Stokes-Adams syndrome

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A 60-year-old woman has been diagnosed with atrial fibrillation. Which of the following statements best describe this condition?

A) Ventricular rate of contraction is 140 beats/min
B) P waves of the EKG are pronounced
C) Ventricular contractions occur at regular intervals
D) QRS waves are more pronounced than normal
E) Atria are smaller than normal

A) Ventricular rate of contraction is 140 beats/min

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Which of the following is most characteristic of atrial fibrillation?

A) Occurs less frequently in patients with atrial enlargement
B) Ventricular heart rate is about 40 beats per min
C) Efficiency of ventricular pumping is decreased 20 to 30 percent
D) Ventricular beat is regular
E) Atrial P wave is easily seen

C) Efficiency of ventricular pumping is decreased 20 to 30 percent

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Which of the following decreases the risk of ventricular fibrillation?

A) Dilated heart
B) Increased ventricular refractory period
C) Decreased electrical conduction velocity
D) Exposure of the heart to 60-cycle alternating current
E) Epinephrine administration

B) Increased ventricular refractory period

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A 55-year-old man has been diagnosed with Stokes- Adams syndrome. Two minutes after the syndrome starts to cause active blockade of the cardiac impulse, which of the following is the pacemaker of the heart? ``` A) Sinus node B) A-V node C) Purkinje fibers D) Cardiac septum E) Left atrium ```

B) A-V node

An increase in shear stress in a blood vessel results in which of the following changes? ``` A) Decreased endothelin production B) Decreased cyclic guanosine monophosphate production C) Increased nitric oxide release D) Increased renin production E) Decreased prostacyclin production ```

C) Increased nitric oxide release

A 72-year-old man had surgery to remove an abdominal tumor. Pathohistologic studies reveal that the tumor mass contains a large number of blood vessels. An increase in which of the following is the most likely stimulus for the growth of vessels in a solid tumor? ``` A) Growth hormone B) Plasma glucose concentration C) Angiostatin growth factor D) Tissue oxygen concentration E) Vascular endothelial growth factor ```

E) Vascular endothelial growth factor

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) Arteriolar resistance ```

E) Arteriolar resistance

The diameter of a precapillary arteriole is decreased in a muscle vascular bed. Which of the following changes in the microcirculation would be expected? ``` A) Decreased capillary filtration rate B) Increased interstitial volume C) Increased lymph flow D) Increased capillary hydrostatic pressure E) Decreased arteriolar resistance ```

A) Decreased capillary filtration rate

A 72-year-old man had surgery to remove an abdominal tumor. Pathohistologic studies revealed that the tumor mass contained a large number of vessels. A decrease in which of the following is the most likely stimulus for the growth of vessels in a solid tumor? ``` A) Growth hormone B) Plasma glucose concentration C) Angiostatin growth factor D) Vascular endothelial growth factor E) Tissue oxygen concentration ```

E) Tissue oxygen concentration

An increase in which of the following would tend to increase lymph flow? ``` A) Hydraulic conductivity of the capillary wall B) Plasma colloid osmotic pressure C) Capillary hydrostatic pressure D) Arteriolar resistance E) A and C ```

E) A and C

Under normal physiological conditions, blood flow to the skeletal muscles is determined mainly by which of the following? ``` A) Sympathetic nerves B) Angiotensin II C) Vasopressin D) Metabolic needs E) Capillary osmotic pressure ```

D) Metabolic needs

Which of the following substances in plasma is the major factor that contributes to plasma colloid osmotic pressure? ``` A) Sodium chloride B) Glucose C) Albumin D) Cholesterol E) Potassium ```

C) Albumin

A healthy 22-year-old female medical student has an exercise stress test at a local health club. An increase in which of the following is most likely to occur in this woman’s skeletal muscles during exercise? ``` A) Vascular conductance B) Blood flow C) Carbon dioxide concentration D) Arteriolar diameter E) All of the above ```

E) All of the above

A two fold increase in which of the following would result in the greatest increase in the transport of oxygen across the capillary wall? ``` A) Capillary hydrostatic pressure B) Intercellular clefts in the capillary wall C) Oxygen concentration gradient D) Plasma colloid osmotic pressure E) Capillary wall hydraulic permeability ```

C) Oxygen concentration gradient

Which of the following vessels has the greatest total cross-sectional area in the circulatory system? ``` A) Aorta B) Small arteries C) Capillaries D) Venules E) Vena cava ```

C) Capillaries

Which of the following components of the circulatory system contains the largest percentage of the total blood volume? ``` A) Arteries B) Capillaries C) Veins D) Pulmonary circulation E) Heart ```

C) Veins

An increase in which of the following would be expected to decrease blood flow in a vessel? ``` A) Pressure gradient across the vessel B) Radius of the vessel C) Plasma colloid osmotic pressure D) Viscosity of the blood E) Plasma sodium concentration ```

D) Viscosity of the blood

Which of the following segments of the circulatory system has the highest velocity of blood flow? ``` A) Aorta B) Arteries C) Capillaries D) Venules E) Veins ```

A) Aorta

A decrease in which of the following tends to increase pulse pressure? ``` A) Systolic pressure B) Stroke volume C) Arterial compliance D) Venous return E) Plasma volume ```

C) Arterial compliance

An increase in which of the following tends to decrease capillary filtration rate? ``` A) Capillary hydrostatic pressure B) Plasma colloid osmotic pressure C) Interstitial colloid osmotic pressure D) Venous hydrostatic pressure E) Arteriolar diameter ```

B) Plasma colloid osmotic pressure

An increase in which of the following tends to increase capillary filtration rate? ``` A) Capillary wall hydraulic conductivity B) Arteriolar resistance C) Plasma colloid osmotic pressure D) Interstitial hydrostatic pressure E) Plasma sodium concentration ```

A) Capillary wall hydraulic conductivity

A decrease in which of the following tends to increase lymph flow? ``` A) Capillary hydrostatic pressure B) Interstitial hydrostatic pressure C) Plasma colloid osmotic pressure D) Lymphatic pump activity E) Arteriolar diameter ```

C) Plasma colloid osmotic pressure

Which of the following capillaries has the lowest capillary permeability to plasma molecules? ``` A) Glomerular B) Liver C) Muscle D) Intestinal E) Brain ```

E) Brain

Which of the following tends to increase the net movement of glucose across a capillary wall? A) Increase in plasma sodium concentration B) Increase in the concentration difference of glucose across the wall C) Decrease in wall permeability to glucose D) Decrease in wall surface area without an increase in the number of pores E) Decrease in plasma potassium concentration

B) Increase in the concentration difference of glucose across the wall

A 65-year-old man is suffering from congestive heart failure. He has a cardiac output of 4 L/min, arterial pressure of 115/85 mm Hg, and a heart rate of 90 beats/min. Further tests by a cardiologist reveal that the patient has a right atrial pressure of 10 mm Hg. An increase in which of the following would be expected in this patient? ``` A) Plasma colloid osmotic pressure B) Interstitial colloid osmotic pressure C) Arterial pressure D) Cardiac output E) Vena cava hydrostatic pressure ```

E) Vena cava hydrostatic pressure

Which of the following parts of the circulation has the highest compliance? ``` A) Capillaries B) Large arteries C) Veins D) Aorta E) Small arteries ```

C) Veins

The tendency for turbulent flow is greatest in which of the following? A) Arterioles B) Capillaries C) Small arterioles D) Aorta

D) Aorta

Autoregulation of tissue blood flow in response to an increase in arterial pressure occurs as a result of which of the following? A) Decrease in vascular resistance B) Initial decrease in vascular wall tension C) Excess delivery of nutrients such as oxygen to the tissues D) Decrease in tissue metabolism

D) Decrease in tissue metabolism

Which of the following would decrease venous hydrostatic pressure in the legs? A) Increase in right atrial pressure B) Pregnancy C) Movement of leg muscles D) Presence of ascitic fluid in the abdomen

C) Movement of leg muscles

Movement of solutes such as Na1 across the capillary walls occurs primarily by which of the following processes? A) Filtration B) Active transport C) Vesicular transport D) Diffusion

C) Vesicular transport

Which of the following has the fastest rate of movement across the capillary wall? A) Sodium B) Albumin C) Glucose D) Oxygen

D) Oxygen

Excess production of which of the following would most likely result in chronic hypertension? A) Atrial natriuretic peptide B) Prostacyclin C) Angiotensin II D) Nitric oxide

C) Angiotensin II

A decrease in which of the following would be expected to occur in response to an increase in sodium intake? A) Angiotensin II B) Nitric oxide C) Sodium excretion D) Atrial natriuretic peptide

C) Sodium excretion

An increase in atrial pressure results in which of the following? A) Decrease in plasma atrial natriuretic peptide B) Increase in plasma angiotensin II concentration C) Increase in plasma aldosterone concentration D) Increase in heart rate

D) Increase in heart rate

Which of the following is normally associated with an increased venous return of blood to the heart? ``` A) Decreased mean systemic filling pressure B) Acute large vein dilation C) Decreased sympathetic tone D) Increased venous compliance E) Increased blood volume ```

E) Increased blood volume

Which of the following is normally associated with an increased cardiac output? ``` A) Increased venous compliance B) Cardiac tamponade C) Surgically opening the chest D) Moderate anemia E) Severe aortic stenosis ```

D) Moderate anemia

In which of the following conditions would you normally expect to find a decreased cardiac output? ``` A) Hyperthyroidism B) Beriberi C) A-V fistula D) Anemia E) Acute myocardial infarction ```

E) Acute myocardial infarction

At the onset of exercise, which of the following normally occur? A) Decreased cerebral blood flow B) Increased venous constriction C) Decreased coronary blood flow D) Decreased mean systemic filling pressure E) Increased parasympathetic impulses to the heart

B) Increased venous constriction

If a person has been exercising for 1 hr, which of the following organs will experience the smallest decrease in blood flow? ``` A) Brain B) Intestines C) Kidneys D) Non-exercising skeletal muscle E) Pancreas ```

A) Brain

Which of the following increase the risk of adverse cardiac events? ``` A) Decreased blood levels of LDL B) Decreased blood levels of HDL C) Female gender D) Moderate hypotension E) Decreased blood triglycerides ```

B) Decreased blood levels of HDL

Which of the following vasoactive agents is usually the most important controller of coronary blood flow? ``` A) Adenosine B) Bradykinin C) Prostaglandins D) Carbon dioxide E) Potassium ions ```

A) Adenosine

Which of the following statements about coronary blood flow is most accurate? A) Normal resting coronary blood flow is 500 ml/min B) The majority of flow occurs during systole C) During systole the percentage decrease in subendocardial flow is greater than the percentage decrease in epicardial flow D) Adenosine release will normally decrease coronary flow

C) During systole the percentage decrease in subendocardial flow is greater than the percentage decrease in epicardial flow

Which of the following conditions normally cause arteriolar vasodilation during exercise? A) Decreased plasma potassium ion concentration B) Increased histamine release C) Decreased plasma nitric oxide concentration D) Increased plasma adenosine concentration E) Decreased plasma osmolality

D) Increased plasma adenosine concentration

Which of the following events normally occur during exercise? A) Arteriolar dilation in non-exercising muscle B) Decreased sympathetic output C) Venoconstriction D) Decreased release of epinephrine by the adrenals E) Decreased release of norepinephrine by the adrenals

C) Venoconstriction

Which of the following is the most frequent cause of decreased coronary blood flow in patients with ischemic heart disease? ``` A) Increased adenosine release B) Atherosclerosis C) Coronary artery spasm D) Increased sympathetic tone of the coronary arteries E) Occlusion of the coronary sinus ```

B) Atherosclerosis

Which of the following would be recommended for a patient with myocardial ischemia? ``` A) Use of alpha receptor stimulation B) Discontinue high blood pressure medication C) Lose excess body weight D) Angiotensin II infusion E) Isometric exercise ```

C) Lose excess body weight

Which of the following is one of the major causes of death after myocardial infarction? A) Increased cardiac output B) A decrease in pulmonary interstitial volume C) Fibrillation of the heart D) Increased cardiac contractility

C) Fibrillation of the heart

Which of the following is associated with the second heart sound? A) In-rushing of blood into the ventricles due to atrial contraction B) Closing of the A-V valves C) Closing of the pulmonary valve D) Opening of the A-V valves E) In-rushing of blood into the ventricles in the early to middle part of diastole

C) Closing of the pulmonary valve

Which of the following heart murmurs is heard during systole? ``` A) Aortic valve regurgitation B) Pulmonary valve regurgitation C) Tricuspid valve stenosis D) Mitral valve stenosis E) Patent ductus arteriosus ```

E) Patent ductus arteriosus

Which of the following is associated with the third heart sound? A) In-rushing of blood into the ventricles due to atrial contraction B) Closing of the A-V valves C) Closing of the pulmonary valve D) Opening of the A-V valves E) In-rushing of blood into the ventricles in the early to middle part of diastole

E) In-rushing of blood into the ventricles in the early to middle part of diastole

unit 3 and 4 Flashcards

(71 cards)