Exam 4 Flashcards
5 phases of cardiac cycle
Phase 1: Atrial systole or ventricular diastole
Phase 2: Isovolumetric ventricular systole
Phase 3: Ventricular ejection (semilunar valves open)
Phase 4: Isovolumetric ventricular relaxation (aortic valve closes)
Phase 5: Passive ventricular filling (mitral & tricuspid valves open)
shortens conduction time through AV node
acetylcholine
permit rapid transmission of theaction potentialinto the cell
T-tubules
During the cardiac cycle, why do the aortic and pulmonic valves close after the ventricles relax?
a. Papillary muscles relax, which allows the valves to close.
b. Chordae tendineae contract, which pulls the valves closed.
c. Reduced pressure in the ventricles creates a negative pressure, which pulls the valves closed.
d. Blood fills the cusps of the valves and causes the edges to merge, closing the valves.
d. Blood fills the cusps of the valves and causes the edges to merge, closing the valves.
During the cardiac cycle, which structure directly delivers action potential to the ventricular myocardium?
a. Sinoatrial (SA) node
b. Atrioventricular (AV) node
c. Purkinje fibers
d. Bundle branches
c. Purkinje fibers
A patient has a problem with Phase 0 of the cardiac cycle. What electrolyte imbalance would the healthcare professional associate most directly with this problem?
a. Hyperkalemia
b. Hyponatremia
c. Hypercalcemia
d. Hypomagnesemia
b. Hyponatremia
What period follows depolarization of the myocardium and represents a period during which no new cardiac potential can be propagated?
a. Refractory
b. Hyperpolarization
c. Threshold
d. Sinoatrial (SA)
a. Refractory
A patient has a disorder affecting ventricular depolarization. What ECG finding would the healthcare professional associate with this condition?
a. Shortened PR interval
b. Prolonged QRS interval
c. QT interval variability
d. Absence of P waves
b. Prolonged QRS interval
What is the effect of epinephrine on E3 receptors on the heart?
a. Decreases coronary blood flow
b. Supplements the effects of both E1 and E2 receptors
c. Increases the strength of myocardial contraction
d. Prevents overstimulation of the heart by the sympathetic nervous system
d. Prevents overstimulation of the heart by the sympathetic nervous system
Within a physiologic range, what does an increase in left ventricular end-diastolic volume (preload) result in?
a. Increase in force of contraction
b. Decrease in refractory time
c. Increase in afterload
d. Decrease in repolarization
a. Increase in force of contraction
The resting heart rate in a healthy person is primarily under the control of which nervous system?
a. Sympathetic
b. Parasympathetic
c. Somatic
d. Spinal
b. Parasympathetic
What is the initiating event that leads to the development of atherosclerosis?
a. Release of the inflammatory cytokines
b. Macrophages adhere to vessel walls.
c. Injury to the endothelial cells that line the artery walls
d. Release of the platelet-deprived growth factor
c. Injury to the endothelial cells that line the artery walls
When endothelial cells are injured, what alteration contributes to atherosclerosis?
a. The release of toxic oxygen radicals that oxidize low-density lipoproteins (LDLs)
b. Cells are unable to make the normal amount of vasodilating cytokines.
c. Cells produce an increased amount of antithrombotic cytokines.
d. Cells develop a hypersensitivity to homocysteine and lipids.
b. Cells are unable to make the normal amount of vasodilating cytokines.
What effect does atherosclerosis have on the development of an aneurysm?
a. Atherosclerosis causes ischemia of the intima.
b. It increases nitric oxide.
c. Atherosclerosis erodes the vessel wall.
d. It obstructs the vessel
c. Atherosclerosis erodes the vessel wall.
Nicotine increases atherosclerosis by the release of which neurotransmitter?
a. Histamine
b. Nitric oxide
c. Angiotensin II
d. Epinephrine
d. Epinephrine
Which elevated value may be protective of the development of atherosclerosis?
a. Very low-density lipoproteins (VLDLs)
b. Low-density lipoproteins (LDLs)
c. High-density lipoproteins (HDLs
d. Triglycerides
c. High-density lipoproteins (HDLs
Which laboratory test is an indirect measure of atherosclerotic plaque?
a. Homocysteine
b. Low-density lipoprotein (LDL)
c. Erythrocyte sedimentation rate (ESR)
d. C-reactive protein (CRP)
d. C-reactive protein (CRP)
In systolic heart failure, what effect does the renin-angiotensin-aldosterone system (RAAS) have on stroke volume?
a. Increases preload and decreases afterload
b. Increases preload and increases afterload
c. Decreases preload and increases afterload
d. Decreases preload and decreases afterload
b. Increases preload and increases afterload
Which of the following events initiates the process of atherosclerosis?
Oxidation of LDL in the vessel wall
Formation of the fatty streak in the tunica media
Thrombosis in the vessel lumen
Endothelial injury and release of cytokines
Endothelial injury and release of cytokines
The most common consequence of atherosclerosis is:
A. increased blood flow through the diseased vessels.
B. formation of aneurysms.
C. autoimmune destruction of the vessel wall.
D. obstruction of the blood vessel lumen.
D. obstruction of the blood vessel lumen.
Which of the following white blood cells play a role in the development of the fatty streak in atherosclerosis?
Mast cells
Neutrophils
Macrophages
Lymphocytes
Macrophages
Which of the following forms of dyslipidemia is associated with the development of the fatty streak in atherosclerosis?
High LDL
Low LDL
High HDL
Low triglycerides
A) High LDL
Growth factors, including Angiotensin II, contribute to the development of atherosclerosis by stimulating which of the following events?
Smooth muscle proliferation
Endothelial injury
Cardiac muscle toxicity
Activation of phagocytes
smooth muscle proliferation
A risk factor that is associated with atherosclerosis and primary hypertension is:
a high-sodium diet.
advanced age.
hyperhomocysteinemia.
a low-potassium diet.
A) advanced age.
Atherosclerosis of the aorta can cause isolated systolic hypertension by:
promoting thrombus formation.
stimulating increased cardiac output.
decreasing arterial distensibility.
increasing lumen diameter.
decreasing arterial distensibility.
Congestive heart failure (CHF) results in which of the following intraventricular hemodynamic changes?
Increased left ventricular preload
Increased ejection fraction
Decreased right ventricular preload
Decreased right ventricular end-diastolic pressure
Increased left ventricular preload
Of the following diseases, which is the most common cause of right heart failure?
Primary hypertension
Infective endocarditis
Left heart failure
Pericarditis
Left heart failure
Manifestations of increased left atrial and pulmonary venous pressures in left (congestive) heart failure include:
syncope.
weak pulses and decreased skin temperature.
oliguria.
dyspnea and cough.
dyspnea and cough.
a net movement of sodium into the cell, and the membrane potential decreases, or “moves forward,” from a negative value (in millivolts) to zero
depolarization
negative polarity of the resting membrane potential is reestablished.
repolarization
Activation
Inside of the cell becomes less negatively charged.
depolarization
: Deactivation
Membrane potential
repolarization
6 steps of action potential
phase 4 - resting potential
phase 0 - sodium channels open
phase 1 - sodium channels close
phase 2 - calcium channels open/ fast K channels close
phase 3 - calcium channels close/ slow K channel open
phase 4- resting potential,
Increases electrical conductivity and the strength of the myocardial contraction
Sympathetic nerves
Slows conduction of action potentials through the heart and reduces the strength of contraction.
Parasympathetic nerves (vagal)
increased filling pressure of the right heart results in increased cardiac output.
Frank-Starling law of the heart
Is the pressure generated at the end of diastole.
Preload
also called left ventricular end-diastolic pressure (LVEDP).
two primary factors of preload
Amount of venous return to the ventricle
Blood left in the ventricle after systole or end-systolic volume
When _____ exceeds physiologic range, further muscle stretching causes a decline in cardiac output.
preload
Is the resistance to ejection during systole.
Afterload
is a good index of afterload for the left ventricle.
Aortic systolic pressure
_________ afterload: Heart contracts more rapidly.
Decreased
________ afterload: Slows contractions and increases work load.
Increased