Question

Blood circulation that starts as capillaries and terminates as capillaries are called:
(a) Hepatic circulation
(b) Portal circulation
(c) Renal circulation
(d) Lymphatic circulation

Answer 1

Hint: Usually, the blood passes from the heart in sequence through arteries, arterioles, capillaries, venules, and veins and then back to the heart. A way to ensure faster absorption of nutrients where it is required and removal of others requires a different circulation.

Complete answer:
A portal system is a type of blood circulation that begins and ends in capillaries. A portal vein passes blood from one network of capillaries into another. The name of the portal system gives the name of the second capillary location. In humans, two portal systems are observed, one associated with the pituitary gland called the hypophyseal portal system, and other known as hepatic portal circulation associated with the liver.
Additional information:
The hepatic portal circulation carries venous blood from the gastrointestinal organs and spleen to the liver. In this instance, the first set of capillaries occurs at the villi of the small intestine, and the second occurs in the liver. Blood passes from the capillaries of the intestine into venules that join to form the hepatic portal vein.
In the lymphatic system, small lymph capillaries gather up fluids from the body and pass onto the larger lymphatic vessels which resemble veins. These lymphatic vessels drain into the veins via one way valves which permit movement in one direction only.
The renal circulation takes place in the kidney wherein a renal artery when enters into the kidney, divides into multiple branches, each known as an interlobular artery. This artery further decreases in diameter and branches into afferent arteriole in the bowman’s capsule of the nephron. Here, a large volume of filtrate is removed from the blood and the rest is taken away by an efferent arteriole. It branches into a peritubular capillary network around the loop of Henle of the nephron to recover most of its nutrients and water. It later drains into the venous system by interlobular veins.
So, the correct answer is ‘Portal circulation.’

Note:
-The heart does not pump the fluid through the lymphatic system and thus the fluid when the vessels and capillaries alike are squeezed by the movements of the body’s muscles.
- The fluid collected between the spaces within the cells of the tissues is called lymph or interstitial fluid or tissue fluid.