First Aid for Corrections Officers Practice Test

What happens to blood in the capillaries?

1. Oxygen is absorbed into the veins

2. Nutrients are exchanged between blood and tissues

3. Blood is stored for future use

4. Carbon dioxide is expelled

The correct answer is: Nutrients are exchanged between blood and tissues

Blood in the capillaries plays a crucial role in the exchange of nutrients and waste products between the blood and surrounding tissues. Capillaries are the smallest and most numerous blood vessels in the body, providing a vast network for blood distribution. Their thin walls, composed of a single layer of endothelial cells, allow for easy diffusion. In the capillaries, oxygen from the blood is delivered to the tissues, while carbon dioxide and other metabolic waste products from the tissues diffuse into the blood. This process is essential for cellular respiration and maintaining homeostasis within the body. By facilitating the exchange of essential nutrients, such as glucose and amino acids, the capillaries help nourish the cells, ensuring they function properly. Thus, the correct understanding of what happens in the capillaries focuses on this critical exchange process between blood and tissues.