12 Know how blood volume sympathetic stimulation hear rate s

12. Know how blood volume, sympathetic stimulation, hear rate stroke volume affect blood pressure. What happens when there is an increase or decrease in them? What does that do to the blood pressure, do they vasoconstrict or vasodilate.

Solution

1.Blood volume:- A change in blood volume shows effect in arterial pressure by changing cardiac output.When blood volume increase it increases venous pressure which increase right artrial pressure,right ventricular end diastolic pressure and volume.Blood volume vasodilate causing decrease in arterial blood pressure and heart rate.   

2. Sympathetic stimulation :- They vasoconstrict blood vessels,increase peristalsis in esophagus, decrease movement of large intestines causing pupillary dilation,piloerection and perspiration and thus raising blood pressure.   

3. Heart rate stroke volume:- They vasodilate blood vessels causing increase in blood flow and decrease in vascular resistance. Dilation of arteries and arterioles leads to decrease in arterial blood pressure and heart rate.