Chapter 3 Discussion - Immunity

This will help you to understand the nature of blood and the different types of cells in the blood. You can refer back to this section of the textbook when these types of cells are discussed later. 

Then, read p. 24. The Lymphatic Circulation. 

Most of the work of the immune system takes place within the lymphatic fluid of the body. Lymphatic fluid is the water based fluid that occupies the spaces between the cells in our tissues and in our blood. It's a continuous ocean that fills up all of the space between our bones, muscles, organs, and within our organs and between the various types of cells in our blood. It's the liquid that keeps our cells moist, and the medium that allows salts, nutrients, proteins, growth factors, oxygen, carbon dioxide and other materials to diffuse freely from one cell to the next. If you've ever had a blister, you have seen the clear lymphatic fluid.

1. The following video gives you a glimpse of the distribution of the lymphatic fluid in the body. The first 5:05 minutes are sufficient for our course, but you can watch the full video if you wish: