| A | B |
|---|
| artery | a blood vessel that carries blood away from the heart |
| capillary | a tiny blood vessel; food, oxygen and other substances pass from the capillaries into the cells |
| cell | the basic unit of body structure |
| digestion | the process of physically and chemically breaking down food so that it can be absorbed for use by the cells |
| hemoglobin | the substance in red blood cells that carries oxygen and gives blood its color |
| hormone | a chemical substance secreted by the endocrine glands into the bloodstream |
| immunity | protection against a disease or condition; the person will not get or be affected by the disease |
| menstruation | the process in which the lining of the uterus breaks up and is discharged from the body through the vagina |
| metabolism | the burning of food for heat and energy by the cells |
| organ | groups of tissues with the same function |
| peristalsis | involuntary muscle contractions in the digestive system that move food down the esophagus through the alimentary canal |
| respiration | the process of supplying the cells with oxygen and removing carbon dioxide from them |
| system | organs that work together to perform special functions |
| tissue | a group of cells with similar functions |
| vein | a blood vessel that returns blood to the heart |
