GROSS ANATOMY

Detailed explanation-1: -Gas exchange occurs when oxygen from the air that is breathed in flows into an animal’s blood via a process called diffusion. In exchange, the carbon dioxide that cells produce as a waste product diffuses from the blood into the air and is breathed out.

Detailed explanation-2: -The carbon dioxide diffuses out of the red blood cells, through the capillary walls, and into the alveolar spaces f exhaled.

Detailed explanation-3: -Figure 4 During internal respiration, oxygen diffuses out of the capillary and into cells, whereas carbon dioxide diffuses out of cells and into the capillary.

Detailed explanation-4: -Carbon dioxide exits the cells, enters the bloodstream, travels back to the lungs, and is expired out of the body during exhalation. The primary function of the respiratory system is to deliver oxygen to the cells of the body’s tissues and remove carbon dioxide, a cell waste product.

Detailed explanation-5: -Some substances (small molecules, ions) such as carbon dioxide (CO2) and oxygen (O2), can move across the plasma membrane by diffusion, which is a passive transport process.