Understanding Capillaries

Capillaries are small blood vessels in the circulatory system that connect arteries and veins. They form capillary beds in tissues where they facilitate the exchange of oxygen, nutrients, carbon dioxide, and waste products. Capillaries are extremely narrow, allowing only one red blood cell to pass through at a time. They consist of a single layer of curved cells with tiny gaps, enabling substances to move in and out of the blood.

What role do capillaries play in the circulatory system?

• They transport blood from the heart to the lungs.

• They connect arteries and veins, facilitating nutrient and waste exchange.

• They store oxygen for later use.

• They produce red blood cells.

What happens to carbon dioxide in the capillary bed?

• It is absorbed by the tissues.

• It is converted into oxygen.

• It is stored in the capillaries.

• It is passed into the blood to be carried away.

What is unique about the size of capillaries?

• They are the same size as veins.

• They are so small that only one red blood cell can pass through at a time.

• They are the largest blood vessels in the body.

• They are large enough to allow multiple red blood cells to pass through at once.

What is the structural composition of capillaries?

• They are composed of muscle tissue.

• They have a single layer of curved cells with tiny gaps.

• They are made up of multiple layers of cells.

• They are made of bone tissue.

How do substances move in and out of capillaries?

• Through large openings in the vessel walls.

• Via a single layer of curved cells with tiny gaps.

• By diffusion through thick cell layers.

• Through active transport mechanisms.