Question

The absorption of nutrients and exchange of respiratory gases between blood and tissues takes place in

• A. Veins
• B. Arteries
• C. Heart
• D. Capillaries

Answer 1

The correct option is D

Capillaries

The correct option is D:

Explanation for the correct option:

1. Capillaries are thin, delicate blood vessels found throughout the body.
2. The smallest blood vessels in the vascular system are called capillaries.
3. Capillaries contain two layers of cells: Endothelial cells are inside the capillary that control the flow of fluid, nutrients and gases and Epithelial cells that form a protective layer around the endothelial cells.
4. Oxygen and nutrients pass into the cells from the capillaries while carbon dioxide and waste are exchanged.

Explanation for the incorrect options:

Option A:

1. Veins are the blood vessels that carry deoxygenated blood from the tissues to the heart.
2. The exceptions are the pulmonary veins which carry oxygen-rich blood back to the heart.

Option B:

Arteries are the blood vessels that carry oxygen-rich blood from the heart to the body's tissues.

Option C:

The heart is a pumping organ of the body that transports oxygen all over the body.

Final answer: The absorption of nutrients and exchange of respiratory gases between blood and tissues takes place in capillaries.