Question

In reference toTHE FUNDAMENTAL UNIT OF LIFE: CELL
What happens when something hits hard on the apithaleal tissue(skin)?
Why does that part get swollen up?
What kind of reaction takes place?

Answer 1

(1) When something hit hard on your skin, there may be different injuries which can occur depending upon the object you hit with and the intensity with which the object hit. It may also happen that there is no injury at all.
(2) It is not necessary that swelling always occurs. Swelling only occurs when the interstitial fluid gets accumulated in the tissues.
(3) Interstitial fluid or tissue fluid is the fluid that surrounds the cells, it is formed when blood passes through the capillaries. The capillary walls are permeable to small solute molecules and ions, but not to red blood cells, platelets and plasma proteins, tissue fluid is therefore a water like liquid which resembles plasma minus its proteins. If this tissue fluid continues to build up then the tissues would swell and this condition is known as oedema.