. Give reason for the following


(a) The walls of the left ventricle are thicker than the walls of all the chambers.

(b) Blood flowing away from the stomach and intestines is put into circulation via the liver and not directly.

(c) The blood groups of both the donor and recipient must be known before transfusing blood.

(d) Only the veins and not the arteries are provided with valves.

(e) Atrial wall is less muscular than the ventricular wall.

(f) The arteries are deep seated in the body.

 

Best Answer

(a) The left ventricle has thicker walls than the walls of all the chambers because, the left ventricle pumps blood up to the farthest points in the body, such as, up to the toes in the feet or up to the brain against gravity.

(b) The veins starting from the stomach and intestine do not directly convey the blood to the posterior vena cava. Instead, they first enter the liver as a combined hepatic portal vein breaks up into capillaries in contrast to the general characteristics of a vein and a new vein called hepatic vein.

(c) Sometimes it becomes necessary to inject blood into the body of patients undergoing a surgical operation. This is called a blood-transfusion. Blood taken from a healthy person (donor) is introduced through one of the patient’s veins. But for doing so, it is necessary that the kind or the type of blood to be transfused should match with the type of the blood of the receiving person (recipient).

RBC’s of human being have specific proteins on their surface. These proteins are called antigens. The plasma of the blood has its complementary antibodies.

(d) Only the veins and not the arteries are provided with valves because Veins carry blood away from an organ and towards the heart and have valves in their inner lining to prevent the backward flow of blood. But arteries carry blood away from the heart and into an organ have no valves in their inner lining.

(e) Atrial wall is less muscular than the ventricular wall because, the ventricle pumps blood up to the lungs for oxygenation and ventricle pumps blood up to the farthest points in the body, such as, up to the toes in the feet or up to the brain against gravity. But atrial major function is to receive blood from the body and pump it into the very next ventricles.

(f) Arteries carry oxygenated blood away from the heart to the tissues. The blood flows in the artery under high pressure and in spurts. If arteries are located superficially then there is a high possibility of their damage which could lead to a lot of blood loss. To prevent this damage and blood loss, the arteries are deep-seated in the body.

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