GENERAL HISTOLOGY

EXCRETORY SYSTEM

EXCRETORY SYSTEM ALL QUESTIONS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
During gas exchange, which substance moves from the alveoli into the blood?
A
carbon dioxide
B
oxygen
C
water
D
nitrogen
Explanation: 

Detailed explanation-1: -In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells.

Detailed explanation-2: -Oxygen breathed in from the air passes through the alveoli and into the blood and travels to the tissues throughout the body. Carbon dioxide travels in the blood from the body’s tissues and passes through the alveoli to be breathed out.

Detailed explanation-3: -Alveoli are in direct contact with capillaries (one-cell thick) of the circulatory system. Such intimate contact ensures that oxygen will diffuse from alveoli into the blood and be distributed to the cells of the body.

There is 1 question to complete.