37-2 Key Concepts 1-5

List the main function of red blood cells, white blood cells, and platelets.

Red blood cells transport oxygen. White blood cells attack foreign substances or organisms. Platelets-make blood clotting possible by plasma proteins and cell fragments.

Describe the role of the lymphatic system.

The lymphatic system collects the fluid that is lost by the blood and returns it to the circulatory system.

Explain how blood clots.

When platelets come into contact with the edges of a broken blood vessel, their surfaces become sticky, and a cluster of platelets develops around the wound.

Infections sometimes cause severe swelling in the tissues. Explain why this happens.

Infections sometimes cause severe swelling in the tissue if more than 3 liters of fluid leak from the circulatory system into surrounding tissues.

What types of materials are dissolved in plasma?

Plasma is 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste products, and proteins called plasma proteins.