1.Adequate cardiac output is necessary in order to supply oxygen and other nutrients to all body tissues. Cardiac output is influenced by stroke volume and heart rate. Factors affecting the stroke volume include PRELOAD, CONTRACTILITY and AFTERLOAD.
In the following conditions, indicate what factor/s influence the cardiac output: PRELOAD, CONTRACTILITY, AFTERLOAD, HEART RATE. Explain why the factor/s affects cardiac output in 1 to 2 sentences.
A. High blood pressure
Constricted arteries brought on by high blood pressure that restrict the volume of blood reaching different regions of the body, along with the heart and brain. High blood pressure or hypertension raises the afterload, which frequently causes a decrease in the volume of the stroke and a reduction in the amount of blood that is discharged.
B. Massive bleeding
Our blood volume rapidly decreases when a hemorrhage or significant bleeding occurs. Furthermore, there is also a reduction in stroke volume, preload, also known as venous return, and cardiac output.
C. The drug dopamine
When dopamine was supplied, the heart rate as well as the mean aortic pressure, were both key factors that caused the cardiac output to rise. Additionally, this drug will have an impact on contractility in conjunction with the other two components.
D. Running a sprint
Muscles work harder than usual during a sprint, which increases the amount of blood needed to return to the lungs for oxygen. Together with the increase in preload or venous return, and the heart rate all contributed to a significant increment in cardiac output.
E. Hyperthyroidism with increased secretion of thyroid hormones
In hyperthyroidism, preload or the venous return rises and cardiac output rises. On the other hand, a reduction in peripheral vascular resistance and an elevation in heart rate happen.
F. Massive myocardial infarction (cardiac tissue death)
Massive myocardial infarction occurs when a shortage of blood in a specific area of the heart muscle occurs. Comparable to an oxygen shortage, this condition affects the cardiac output through a decline in contractility, which raises afterload and heart rate.
G. Hypothermia
A reflex called adrenergic vasoconstriction (noradrenalin) of the skin occurs with a decrease in core body temperature (hypothermia). As a result, our body responds by constricting its blood vessels, which then leads to the increase in contractility, cardiac output and the volume of smoke that the heart generates.
H. Emotional distress
The body responds to emotional distress by increasing oxygen consumption, cardiac output, heart rate, and contractility. Furthermore, blood pressure is also elevated, whereas peripheral resistance is reduced.
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