Chapter 23 - Guyton Flashcards
first heart sound
A-V valves closing at the beginning of systole
second heart sound
semilunar valves closing at the end of systole
What causes the heart sounds?
vibration of the taut valves immediately after closure, along with vibration of the adjacent walls of the heart and major vessels around the heart
What causes the “third heart sound”?
middle third of diastole, blood rushing into the ventricles
What causes the “fourth heart sound” (not heard by auscultation)?
atrial contraction
By far the greatest number of valvular lesions results from _________ ______.
rheumatic fever (autoimmune disease in which the heart valves are likely to be damaged or destroyed)
A valve in which the leaflets adhere to one another so extensively that blood cannot flow through it normally is said to be _________.
stenosed
When the valve edges are so destroyed by scar tissue that they cannot close as the ventricles contract, __________ (backflow) of blood occurs when the valve should be closed.
regurgitation
If you hear a heart sound several feet away from a patient, what might the patient have?
aortic stenosis
What might a patient have if you hear a murmur during diastole?
aortic regurgitation; blood flows backward from the high-pressure aorta into the left ventricle, causing a “blowing” murmur of relatively high pitch with a swishing quality heard maximally over the left ventricle
What might a patient have if you hear a murmur during systole?
mitral regurgitation; blood flows backward through the mitral valve into the left atrium during systole
Why might you not hear a murmur in a patient with mitral stenosis?
During the early part of diastole, a left ventricle with a stenotic mitral valve has so little blood in it and its walls are so flabby that blood does not reverberate back and forth between the walls of the ventricle.
Murmurs that occur during systole versus diastole.
systole - aortic stenosis and mitral regurgitation; diastole - aortic regurgitation and mitral stenosis
What effect would aortic stenosis and aortic regurgitation have on stroke volume?
decreased
What are two compensations in the body for aortic stenosis and aortic regurgitation?
hypertrophied left ventricle and increased blood volume
The buildup of blood in the left atrium (from mitral valvular disease) causes progressive increase in left atrial pressure, and this eventually results in?
pulmonary edema
In late stages of mitral stenosis, atrial fibrillation usually occurs. Why?
The high left atrial pressure in mitral valvular disease also causes progressive enlargement of the left atrium, which increases the distance that the cardiac electrical excitatory impulse must travel in the atrial wall (circus movements).
Three major types of congenital anomalies of the heart and its associated vessels:
stenosis, left-to-right shunt (bypass systemic circulation), right-to-left shunt (bypass lungs)
What is the ductus arteriosus?
the pulmonary arterial blood to flow through a special artery present in the fetus that connects the pulmonary artery with the aorta called the ductus arteriosus, thus bypassing the lungs (blood is oxygenated by the placenta)
The major effects of patent ductus arteriosus on the patient are decreased _______ and _________ reserve
cardiac, respiratory (left ventricle is pumping about two or more times the normal cardiac output and body can never sustain increased activity)
By age 1-3 years, a baby with patent ductus arteriorsus will exhibit which audible heart murmur?
machinery murmur
Abnormalities of Tetralogy of Fallot.
aorta originates from right ventricle, pulmonary artery is stenosed, left ventricle flows into right ventricle, enlarged right ventricle (this baby will be blue)
What is used during cardiac surgery to maintain circulation?
extracorporeal circulation (heart-lung machine)
