Blood and Lymph

• plasma

• red blood cell

• hemoglobin

• white blood cell

• platelet

• lymphatic system

Vocabulary

• What are the components of blood?

• What determines the type of blood that a person can receive in a transfusion?

• What are the structures and functions of the lymphatic system?

Key Concepts

Blood and Lymph

• lymph

• lymph node

Discover Activity

What Kind of Cells Are in Blood?

1. Look at the provided documents of human blood.

2. Look carefully at the different kinds of cells that you see.

3. Make several drawings of each kind of cell. Use red pencil for the red blood cells.

Think it Over
Observing: How many kinds of cells did you see? How do they differ from one another?

While riding your bike through your neighborhood, you take a tumble and scrape your knee. Your knee begins to sting, and you notice blood oozing from the wound. You go inside to clean the wound. As you do, you wonder...

"Just what is blood?"

Blood

Blood may seem like just a plain red liquid, but it is actually a complex tissue that has several parts. Blood is made up of four components: plasma, red blood cells, white blood cells, and platelets. About 45 percent of the volume of blood is cells. The rest is plasma.

Multiple Choice

How many components is blood made up of?

• One

• Two

• Three

• Four

Multiple Choice

What are the components that make up blood?

• plasma, red blood cells, white blood cells, platelets

• plasma, red blood cells, carbon dioxide, oxygen

• red blood cells, white blood cells, blue blood cells, oxygen

• plasma, red platelets, white platelets, green blood cells

Plasma

Most of the materials transported in the blood travel in the plasma. Plasma is the liquid part of the blood. Water makes up 90 percent of plasma. The other 10 percent is dissolved materials. Plasma carries nutrients, such as glucose, fats, vitamins, and minerals. Plasma also carries chemical messengers that direct body activities such as the uptake of glucose by your cells. In addition, many wastes produced by cell processes are carried away by plasma.

plasma - the liquid part of the blood that is made up of 90 percent water and 10 percent dissolved materials.

Plasma (continued)

Protein molecules give plasma its yellow color. There are three groups of plasma proteins. One group helps to regulate the amount of water in blood. The second group, which is produced by white blood cells, helps fight disease. The third group of proteins interacts with platelets to form blood clots.

Multiple Choice

What is the liquid part of the blood?

• glucose

• red blood cells

• white blood cells

• plasma

Multiple Choice

What makes up 90 percent of plasma?

• waste materials

• dissolved materials

• water

• platelets

Multiple Choice

True or False:

Plasma carries nutrients, such as glucose, fats, vitamins and minerals.

• True

• False

Red Blood Cells

Without red blood cells, your body could not use the oxygen that you breathe in. Red blood cells take up oxygen in the lungs and deliver it to cells elsewhere in the body. Red blood cells, like most blood cells, are produced in bone marrow. Under a microscope, these cells look like disks with pinched-in centers. Because of their pinched shape, red blood cells are thin in the middle and can bend and twist easily. This flexibility enables them to squeeze through narrow capillaries.

red blood cells - cells that take up oxygen in the lungs and deliver it to cells elsewhere in the body.

Red Blood Cells (continued)

A red blood cell is made mostly of hemoglobin (HEE muh gloh bin), which is an iron-containing protein that binds chemically to oxygen molecules. When hemoglobin combines with oxygen, the cells become bright red. Without oxygen, the cells are dark red. Thus, blood leaving the heart through the aorta is bright red, whereas blood returning from the body to the heart through veins is dark red. Hemoglobin picks up oxygen in the lungs and releases it as blood travels through capillaries in the rest of the body. Hemoglobin also picks up some of the carbon dioxide produced by cells. However, most of the carbon dioxide is carried by plasma. The blood carries the carbon dioxide to the lungs, where it is released from the body.

hemoglobin - an iron-containing protein that binds chemically to oxygen molecules.

Red Blood Cells (continued)

Mature red blood cells have no nuclei. Without a nucleus, a red blood cell cannot reproduce or repair itself. Mature red blood cells live only about 120 days. Every second, about 2 million red blood cells in your body die. Fortunately, your bone marrow produces new red blood cells at the same rate.

Open Ended

Blood consists of liquid plasma and three kinds of cells - red blood cells, white blood cells, and platelets.

Describe the shape of a red blood cell.

Multiple Choice

What is hemoglobin?

• an iron-containing carbohydrate that binds chemically to carbon dioxide molecules

• an iron-containing fat molecule that binds mechanically to bile

• an iron-containing protein that binds chemically to oxygen molecules

• an iron-containing glucose molecule that binds chemically to starch

Lesson Complete

Great Job!