SCIENCE

• The central nervous system consists of the brain and spinal cord, and the Peripheral nervous system consists of the bundles of nerves that relay messages between the sense organs the central nervous system.
• The Peripheral nervous system includes nerves that travel from your spinal cord and brain, to supply to your face and rest of your body. However the Central nervous system includes two organs which co-ordinates responses by the muscles and glands.
• a cell body is the part of the neuron that contains the nucleus and is the site of most of the cell's activitywhere the nucleus is located
• The olfactory receptor cells are the most frequently replaced neurons in the body.
• • Chemoreceptors are sensitive to chemicals, such as odour molecules in the air, and are located in the nose and tongue.
• • Mechanoreceptors are sensitive to touch, pressure, sound and motion and are located in the skin, the inner ear and muscles.
• • Pain receptors are sensitive to chemical changes in damaged cells and are located throughout the body, but most are located in the skin.
• • Thermoreceptors are sensitive to temperature changes and are located in the skin.
• • Photoreceptors are sensitive to light and are located in the eyes.