Curriculum Portal

neurologyYou need to know

• Homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
• Homeostasis is important because enzymes and cells need stable internal conditions, such as temperature, blood glucose concentration and water levels, to work effectively.
• A control system has three key elements: receptors that detect stimuli, coordination centres that process information, and effectors that bring about a response.
• The nervous system uses electrical impulses carried by neurones and is usually very fast, short-lived and targeted, whereas the endocrine system uses hormones carried in the blood and is usually slower, longer-lasting and more widespread.
• A stimulus is a change in the environment, and a response is the reaction of an organism or body part to that change.
• A reflex action is an automatic and rapid response to a stimulus that does not require conscious thought.
• In a reflex arc, impulses travel from a receptor along a sensory neurone to the central nervous system, across a relay neurone, then along a motor neurone to an effector.
• Reflex actions are important because they protect the body from harm by producing a rapid response before conscious awareness of danger.
• A synapse is the small gap between two neurones where information is passed from one neurone to the next.
• At a synapse, an electrical impulse causes neurotransmitter chemicals to be released, diffuse across the gap, bind to receptors on the next neurone, and trigger a new electrical impulse.
• A hormone is a chemical messenger produced by a gland and carried in the blood to target organs where it causes a response.
• The endocrine system includes the pituitary gland in the brain, thyroid gland in the neck, adrenal glands above the kidneys, pancreas near the stomach, ovaries in the female reproductive system, and testes in the male reproductive system.
• The pituitary gland is called the master gland because it secretes several hormones into the blood that act on other glands and cause them to release hormones.
• Adrenaline is released by the adrenal glands and prepares the body for ‘fight or flight’ by increasing heart rate and boosting glucose supply to the brain and muscles.
• Thyroxine is released by the thyroid gland and regulates the basal metabolic rate, and it also has important roles in growth and development.
• Negative feedback is a control mechanism in which a change away from the normal level is detected and responses bring the condition back towards the normal level.
• The pancreas monitors blood glucose concentration and secretes insulin when blood glucose is too high and glucagon when blood glucose is too low.
• Insulin lowers blood glucose concentration by causing body cells to take up glucose and causing liver and muscle cells to convert glucose into glycogen for storage.
• Type 1 diabetes is caused by the pancreas producing little or no insulin and is usually treated with insulin injections, whereas type 2 diabetes is linked to body cells not responding properly to insulin and is commonly treated with lifestyle changes and sometimes medication.
• FSH causes an egg to mature in an ovary and stimulates oestrogen production, oestrogen thickens the uterus lining and stimulates LH release, LH triggers ovulation, and progesterone maintains the uterus lining after ovulation.

• Calculate reaction time from experimental results, using consistent units and comparing values to decide which response is faster or slower.
• Describe a reflex arc in the correct sequence, naming the stimulus, receptor, sensory neurone, central nervous system, motor neurone, effector and response.
• Explain synaptic transmission by linking neurotransmitter release, diffusion across the synapse, binding to receptors, and initiation of an impulse in the next neurone.
• Extract and interpret data from graphs, charts and tables, including identifying patterns, comparing values and using evidence to support conclusions.
• Explain blood glucose control as negative feedback, linking high glucose to insulin release and low glucose to glucagon release.
• Compare type 1 and type 2 diabetes by identifying the cause, effect on blood glucose regulation and suitable treatments for each.
• Interpret hormone-level graphs from the menstrual cycle, linking changes in FSH, oestrogen, LH and progesterone to ovulation and changes in the uterus lining.
• Evaluate hormonal and non-hormonal contraception methods by comparing effectiveness, advantages, disadvantages, side effects and whether they protect against sexually transmitted infections.
• Explain how fertility treatment uses hormones, including FSH and LH to stimulate egg maturation and ovulation in IVF.
• Evaluate infertility treatment from patient and doctor perspectives, considering success rate, emotional impact, health risks, cost and ethical issues.