GENERAL HISTOLOGY

Detailed explanation-1: -In unicellular animals, such as amoeba, exchange of gases takes place through cell surface. They absorb oxygen from the surrounding air or water and give out carbon dioxide through plasma membrane by diffusion. The cells use the oxygen absorbed for cellular respiration and derive energy.

Detailed explanation-2: -Respiration ensures that cells, tissues, and major organs of the body receive an adequate supply of oxygen and that the carbon dioxide, a waste product, is efficiently removed; the exchange of oxygen and carbon dioxide occurs via diffusion across cell membranes.

Detailed explanation-3: -Once in the lungs, oxygen is moved into the bloodstream and carried through your body. At each cell in your body, oxygen is exchanged for a waste gas called carbon dioxide. Your bloodstream then carries this waste gas back to the lungs where it is removed from the bloodstream and then exhaled.

Detailed explanation-4: -In single celled organisms diffusion is sufficient to meet all their requirements of food, exchange of gases or removal of wastes but it is not in case of multicellular organisms.

Detailed explanation-5: -The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration.