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neurologyYou need to know

• Homeostasis is the regulation of the internal conditions of the body to maintain stable optimum conditions for cells and enzymes.
• Homeostasis is important because cells need stable conditions such as body temperature, blood glucose concentration and water levels for enzyme-controlled reactions to work efficiently.
• A control system has receptors that detect a stimulus, a coordination centre that processes information, and effectors such as muscles or glands that produce a response.
• The nervous system uses electrical impulses carried by neurones and is very fast, while the endocrine system uses hormones carried in the blood and is usually slower but longer lasting.
• A reflex action is a rapid, automatic response to a stimulus that does not require conscious thought.
• In a reflex arc, the stimulus is detected by a receptor, impulses travel along a sensory neurone to the central nervous system, cross a relay neurone, then travel along a motor neurone to an effector, which produces a response.
• Reflex actions are important because they protect the body from harm by producing quick responses, such as pulling a hand away from a hot object.
• A synapse is the small gap between two neurones where information is passed from one neurone to another.
• At a synapse, an electrical impulse causes neurotransmitter chemicals to be released, the chemicals diffuse across the gap, and they bind to receptors on the next neurone to start a new electrical impulse.
• A hormone is a chemical messenger released by an endocrine gland and carried in the blood to a target organ.
• The endocrine system includes glands such as the pituitary gland in the brain, thyroid gland in the neck, adrenal glands above the kidneys, pancreas near the stomach, ovaries in females and testes in males.
• The pituitary gland is called the master gland because it secretes several hormones that act on other endocrine glands and control important body processes.
• The pancreas monitors blood glucose concentration and releases insulin when blood glucose is too high.
• Insulin lowers blood glucose concentration by causing body cells to take in glucose and causing the liver and muscle cells to store glucose as glycogen.
• Type 1 diabetes is usually caused by the pancreas producing little or no insulin and is treated with insulin injections and careful control of diet and exercise.
• Type 2 diabetes is usually caused by body cells becoming less responsive to insulin and can often be treated with a carbohydrate-controlled diet, exercise and sometimes medication.
• FSH causes an egg to mature in an ovary and stimulates the ovaries to release oestrogen during the menstrual cycle.
• Oestrogen helps rebuild the uterus lining and stimulates the release of LH, while LH triggers ovulation.
• Progesterone maintains the uterus lining after ovulation, and its level falls if pregnancy does not occur, causing menstruation.
• Hormonal contraception changes hormone levels to prevent pregnancy, while non-hormonal contraception prevents fertilisation or implantation without altering hormone levels.

• Calculate reaction time from experimental data, using the correct units and comparing results to identify the fastest and slowest responses.
• Describe a reflex arc in the correct sequence, including stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector and response.
• Explain synaptic transmission by linking neurotransmitter release, diffusion across the synapse and binding to receptors on the next neurone.
• Extract and interpret data from graphs, charts and tables, including identifying patterns, comparing values and using evidence to support conclusions.
• Explain negative feedback in blood glucose control by linking changes in glucose concentration to pancreatic hormone release and effects on target organs.
• Compare type 1 and type 2 diabetes using cause, effect on insulin action and treatment as criteria.
• Evaluate hormonal and non-hormonal contraceptive methods by weighing effectiveness, side effects, protection from sexually transmitted infections and user reliability.
• Explain how fertility treatment uses hormones, including FSH to mature eggs and LH to trigger ovulation, and link these to the stages of IVF.
• Evaluate infertility treatment from patient and doctor perspectives, considering success rate, emotional impact, cost, health risks and ethical issues.