Blood pressure questions and answers

 

Q:   Describe the venous pathway of blood in man?

 

ANS: VENOUS PATHWAY

           Superior vena cava brings deoxygenated blood from the upper region of the body while inferior vena brings deoxygenated blood from the lower part of the body.

 

SUPERIOR VENA CAVA

             Its is formed by the union of following veins which bring blood from head, neck and arms:

1-          Right and left internal jugular vein

2-          Right and left external jugular vein

3-          Right and left subclavian vein.

INFERIOR VENA CAVA

              Blood from the legs is received by the right and left femoral veins which run upward as right and left external iliac veins respectively. They also receive right and left internal iliac veins. The iliac veins of both sides unite to form inferior vena cava also receives following veins.

 

Q:  Give a detailed account of blood pressure or what is blood pressure. Explain systolic and diastolic pressure, and rate of blood flow.
 

ANS: BLOOD PRESSURE

           The blood pressure is defined as the force of blood against the walls of blood vessels. Blood pressure differs in various parts of the circulatory system. The blood leaving the ventricles and entering the aorta and the pulmonary artery is under high pressure where it is normally 140 mm mercury. It gradually decreases in arteries and arterioles, becoming lower in the capillaries and veins. The highest arterial blood pressure is found during the contraction of the heart ventricles and is called systolic pressure, while lowest blood pressure is observed at the relaxation of ventricles and it is called diastolic pressure, usually in the range of 70 to 85.

 

RATE OF BLOOD FLOW

                  The rate of blood flow differs in various blood vessels. It is high in the aorta (nearly 400 to 500 mm/second), decreasing along the arterial system, becoming greatly reduced in the capillaries (about 150 mm second). The decrease in the rate of blood flow in the capillaries is due to their smaller cross-sectional area than arteries. This slow rate of blood flow in capillaries is beneficial because it allows adequate time for the exchange of nutrients, hormones and metabolic wastes between the blood and tissues.

The blood flow also varies under certain conditions such as exercise, after eating and when the body is hot or cold. It also differs from organ to organ depending on the needs of the body, however steady flow of blood is maintained to important organs like brain and the heart.