Unit 1 * 3.0 / 5 based on 1 rating ? BiologyGCSE Created by: covaCreated on: 18-05-11 18:53 Parts of nervous system The nervous system consist of the brain, spinal cord, spinal nerves and receptors. Its allows organisms to react to their surroundings and to coordinate their behavior. 1 of 10 Types of neurones Motor neurone: Impulse travels away from cell body. Sensory neurone: Impulse travels towards cell body. Relay neurone: Impulse travels firts towards and then away from cell body. Neurons are elongated to make connections between parts of the body. 2 of 10 Connections between neurons Neurons do not touch each other; there is a gap between them called a synapse. 3 of 10 Types of receptor Receptors detect stimuli. Light- receptors in the eyes. Sound- receptors in the ears. Change in position- receptors in the ears. Taste- receptor in the tonge. Smell- receptors in the nose. Touch, pressure, pain and temperature- receptors in the skin. 4 of 10 Reflex action Reflex action speeds up theresponse time by missing out the brain completly. The spinal cord acts as the coordinator and passes impulses directly from a sensory neurone to a motor neurone via a relay neurone. Reflex actions are automatic and quick. 5 of 10 Internal conditions Humans need to keep their internal environment relatively constant. Temperature: Increased by shivering and narrowing skin capillaries; Decreased by sweating and expanding skin capillaries. Water content: Gained by drinking; Lost by breathing via the lungs and sweating; Any excess is lost via the kidneys in urine. Ion content: Gained by eating and drinking; Lost by eating and drinking; Lost via sweating; Excess is lostvia the kidneys in urine. Blood sugar (glucose) levels: Glucose provides the cells with a constant supply of energy; Gained by eating and drinking. 6 of 10 How conditions are controlled? Many processes within the body are coordinated by hormones. Hormones are chemical substances. Hormones are produced by glands. Hormones are transported by the bloodstream. 7 of 10 Hormones and fertility Hormones regulate the functions of many organs and cells. A woman naturally produces hormones that cause the release of an egg from her ovaries. These hormones are produces by the pituitary gland and the ovaries. 8 of 10 Natural control of fertility Follicle stimulating hormone (FSH): Produced in the pituitary gland; Causes the ovaries to produce oestrogen and an egg to mature. Oestrogen: Produces in the ovaries; Inhibits the production of FSH and causes the production of luteinising hormone (LH). LH: From th epituitary gland; Stimulates the release of an egg in the middel of the menstrual cycle. 9 of 10 Artificial control of fertility FSH and oestrogen can be given to women in order to achieve opposing results. Increasing fertility: FSH is given as a fertility drug to women who don't produce enought naturally, to stimulate eggs. Reducing fertility: Oestrogen is given as an oral contraceptive to inhibit FSH production. This means that eggs don't mature in the ovary. 10 of 10
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