An Introductory Guide to Terms and Function

Facts about animal cells

• Structurally, animal cells are remarkably similar to plant cells.
• The animal cell includes many structures similar to those found in the plant cell.
• A major handicap of all animal cells is their inability to synthesize their own food. Energy rich substances (food) must be absorbed or ingested into the animal cell in order to extract its chemical energy for metabolic uses.
• 50 000 of the cells in your body will die and be replaced with new cells, all while you have been reading this sentence!
• On average, every square centimetre of your skin contains about 60 cm of nerve fibres, 200 nerve cells, 20 sweat pores, 500 000 cells and 50 cm of blood vessels.

Animal Cells

Animal cell: cell membrane chromosomes cytoplasm mitochondrion nucleus vaculoles (flagellum) (cilia)
	Enlarge

Staying Healthy

• The cells in your skin act as a "freshness seal" against bacteria. Some bacteria and spores that land on your skin die due to the natural bacterial flora found on your skin. If your body didn't produce these substances you would wake up in the morning with a layer of mould growing on your skin!
• Crying and sneezing are good for you. The cells that produce your tears and mucus also secrete an enzyme that breaks down the cell walls of many of the bacteria with which you come in contact.
• Lymph nodes contain filtering tissue and a large number of lymph cells. When fighting certain bacterial infections, the lymph nodes swell with bacteria and the cells fighting the bacteria, to the point where you can actually feel them. Swollen lymph nodes are therefore a good indication that you have an infection of some sort.