Antarctic fish species requires an adaptation to cold environment. Living at cold temperature environment would demand certain biological responses such as cutaneous respiration, enlarged blood vessels, and producing greater amounts of fat. Most of these fat are composed of higher phospolipid levels which are primarily due to phosphatidylethanolamine. This phospolipid is responsible for destabilizing cell membranes and make it more fluid thereby allowing unrestricted blood flow. The fatty acid composition of the membrane lipid is important for membrane fluidity, this is mainly attributed to unsaturated fatty acids which are responsible for decreasing the order of membrane lipids thereby decreasing viscosity. At extremely low temperatures, organisms with low concentration of unsaturated fatty acids would freeze cell membranes. That's why antarctic fishes have higher levels of unsaturated fatty acids.
Systemic circuit is defined as one of the two circuit of circulation that occurs in human body.
<h3><u>Explanation</u>:</h3>
The circulatory system is divided into two phases in the human body. They are:
A. Pulmonary circulation
B. Systemic circulation.
The pulmonary circulation is the short circuit of circulation that starts from the right ventricle, goes to lungs via pulmonary artery and returns to left auricle via pulmonary vein.
The systemic circulation is the bigger circuit that starts from the left ventricle, goes to each and every organ of the body via aorta, and returns to the right auricle via venacava.
Explains the heart and breathing rate