Pathology of cardiac disease. in this activity, you will identify the symptoms
of cardiac conditions. valvular disease. heart valves can become damaged with
disease or infection. two complications result from valvular disease: volume
overload and pressure overload. both of these conditions can lead to shortness
of breath with fluid accumulation in the lungs and the potential for irregular
and ineffective contractions in both atria. consequently blood flow through
the heart slows and blood clots may develop in the ventricles. cerebral
vascular accidents are caused when Emboli are ejected from the heart into the
circulatory system of the brain. let's look at some examples of blood flow. with
a normal valve, blood flow is freely forward. there is no backflow of blood.
with stenosis less blood flows through a smaller opening there is no backflow of
blood. with an incompetent valve blood flows freely forward but blood leaks
backward through the valve. valve problems increase the workload of the
heart and require the heart to pump harder to force blood through a stenosed
valve or to maintain adequate flow if blood is seeping back into an
insufficient valve. most defects are detected by the presence of heart
murmurs. all significant defects result in a decreased oxygen supply to the
tissues unless compensation is available. as these conditions progress symptoms of
heart failure develop. here we see decreased cardiac output,
incomplete atrial emptying, narrowing of the aortic valve limits
blood leaving the ventricle, and left ventricular hypertrophy.
myocardial infarction. in the case of an MI, or heart attack, a coronary artery is
partially or completely blocked and the heart muscle does not get enough oxygen.
during an mi part of the heart muscle dies. if a substantial section of the
heart is damaged the heart will stop and the person may die. here is the area of
necrosis or infarction. coronary artery disease. CAD develops over a period of
years the internal wall of an artery can become injured by years of smoking or
high blood pressure. once damaged the wall becomes prone to
collecting plaque. the artery narrows and allows less blood to pass through it. the
disease process is called atherosclerosis coronary artery disease
here we see a normal artery intimal layer is damaged by atherosclerosis
fatty Street lipoproteins penetrate smooth muscle cell. fibrous
plaque composed of lipoprotein filled smooth muscle cells and collagen
decreases blood flow in the artery. platelets adhere to rough damaged
surface of the arterial wall and necrosis or calcification weakens the
arterial wall congestive heart failure congestive heart failure results when
the heart is unable to pump effectively and fluid backs up into the lungs or
other parts of the body. fluid overload is serious because it puts a greater
workload on the heart. CHF usually occurs as a complication
secondary to another heart condition such as an infarction or valve defect.
CHF may also be caused by increased cardiac output due to hypertension or
lung disease. left-sided congestive heart failure.
high pressure in pulmonary capillaries leads to pulmonary congestion or edema.
blood backs up into the pulmonary vein the left ventricle weakens and cannot
empty cardiac output to the system is decreased decreased renal blood flow
stimulates renin-angiotensin and terrowin secretion this results in
vasoconstriction and increased blood volume and increases the heart's
workload. right-sided congestive heart failure.
very high venous pressure causes a distended neck vein and cerebral edema
blood backs up into the systemic circulation increased venous pressure
results in edema in the legs liver and abdominal organs the right ventricle
weakens and cannot empty. cardiac output to the system is decreased. decreased
renal blood flow stimulates renin-angiotensin and aldosterone
secretion. this results in vasoconstriction and
increased blood volume and increases the heart's workload.
You have completed this activity, pathology of cardiac disease.