PATHOLOGY

Detailed explanation-1: -Most species employ a counter-current exchange system to enhance the diffusion of substances in and out of the gill, with blood and water flowing in opposite directions to each other. The gills are composed of comb-like filaments, the gill lamellae, which help increase their surface area for oxygen exchange.

Detailed explanation-2: -A gill lamella is a plate structure that assists the increase of amount of oxygen intake of the blood in a fish, as it contains blood capillaries. This structure contributes to a large surface area and a short distance for gas exchange to take place, increasing the rate of diffusion.

Detailed explanation-3: -In fish, gill lamellae are used to increase the surface area in contact with the environment to maximize gas exchange (both to attain oxygen and to expel carbon dioxide) between the water and the blood. In fish gills there are two types of lamellae, primary and secondary.