Question

In an EKG, the P wave is generated when the

	A.	ventricles repolarize.
	B.	atria depolarize.
	C.	atria repolarize.
	D.	ventricles depolarize.

Which of the following does NOT contribute to venous blood pressure?

	A.	constriction of smooth muscle around veins by the sympathetic nervous system
	B.	increased abdominal pressure during breathing
	C.	venous anastomoses
	D.	skeletal muscle activity

Blood flow is ________ proportional to the difference in blood pressure. Blood flow is ________ proportional to the total peripheral resistance.

	A.	directly; directly
	B.	directly; inversely
	C.	inversely; inversely
	D.	inversely; directly

Answer 1

• in EKG p wave is generated because of atrial depolarisation. (p wave is the first wave on ECG and atrial depolarisation is the first recordable electrical activity of heart)
• venous anastomoses does not contribute to venous pressure. (venous pressure increases if the smooth muscles of the veins contract, and venous pressure increases on skeletal muscle pump activity. Respiratory pump activity cause abdominal pressure to rise during inspiration and it will compress the veins and venous pressure will rise.)
• blood flow is directly proportional to blood pressure difference(blood pressure gradient) and blood flow is inversely proportional to total peripheral resistance. (if the pressure difference between two points is more, faster will be the flow between them. And if there is more resistance to the flow, slower will be the flow)

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