WIXLIB

Core questions – Unit 5 Biology – Homeostasis and responseNo. Question1What is 2526Why is homeostasis important for enzyme function?Give 2 examples of automatic control systems?What is the nervous system?What parts make up the nervous system?What is a receptor?What is a sensory neurone?What is the central nervous system (CNS)?What is a motor neurone?What is an effector?What does a muscle do when stimulated?What does a gland do when stimulated?What is a reflex action?What is a reflex arc (list the order)?What is a synapse?How is a nerve signal transferred across a synapse?What can be used to measure human reaction time?Why is it better to use a computer programme tomeasure human reaction time?What is the brain made of? (Triple only)What are the different regions of the brain? (Tripleonly)What is the function of the cerebral cortex? (Tripleonly)What is the function of the medulla? (Triple only)What is the function of the cerebellum? (Triple only)What range of methods do scientists use to investigatethe brain? (Triple only)Why is it difficult to investigate brain function? (Tripleonly)What is the eye? (Triple only)AnswerThe regulation of the internal conditions of a cell or organism to maintain optimum conditions forfunction in response to internal and external changesIt maintains optimum conditions for enzyme actionNervous response or chemical responseA system that enables humans to react to their surroundings and to coordinate their behaviourReceptors, neurones, spinal cord/brain, effectorsCells that detect a stimuliNeurones that carry electrical impulses from the receptors to the central nervous systemThe brain and the spinal cordNeurones that carry electrical impulses from the CNS to effectorsMuscles or glands, which bring about responsesContractSecretes a hormoneAutomatic and rapid response to a stimuli that does not involve the conscious part of the brainStimulus receptor coordinator effector responseThe connection between two neuronesChemicals diffuse across the gapThe ruler drop testIt removes human error making it more accurate and preciseBillions of interconnected neurones and has different regions that carry out different functionsCerebral cortex, cerebellum, medullaControls consciousness, intelligence, memory & languageControls unconscious activities like breathing and your heartbeatControls muscle coordinationStudy patients with brain damage already; electrically stimulate parts of the brain; use MRI scansIt is complex and delicate meaning it can be easily damaged, leading to problems with brainfunctionA sense organ containing receptors sensitive to light intensity and colour

27Label this picture of the(Triple only)2829What is accommodation? (Triple only)Describe the process of focussing on a near object?(Triple only)30Describe the process of focussing on a distant object?(Triple only)313233343536What is myopia? (Triple only)What is hyperopia? (Triple only)How are vision defects corrected? (Triple only)How does the iris react to bright light? (Triple only)How does the iris react to dim light? (Triple only)How is body temperature monitored and controlled?(Triple only)How are temperature changes detected in the body?(Triple only)How does the body respond when temperature is toohigh? (Triple only)How does the body respond when temperature is toolow? (Triple only)3738394041424344454647Why does shivering warm us up? (Triple only)What is the endocrine system?How are hormones transported in the body?What is a hormone?What are the main glands in the body?What is the function of the pituitary gland?What is the function of the ovaries?What is the function of the testes?eyeThe process of changing the shape of the lens to focus on near or distant objects The ciliary muscles contract The suspensory ligaments loosen The lens is then thicker and refracts light rays strongly The ciliary muscles relax The suspensory ligaments are pulled tight The lens is then pulled thin and only slightly refracts light raysShort sightednessLong sightednessSpectacle lenses which refract the light rays so that they do focus on the retina; laser eye surgeryCircular muscles in the iris contract and radial muscles relax, making the pupil smallerRadial muscles in the iris contract and circular muscles relax, making the pupil largerBy the thermoregulatory centre in the brainReceptors in the thermoregulatory centre detect changes in blood temperature;Temperature receptors in the skin send electrical impulses to the thermoregulatory centreBlood vessels supplying skin capillaries dilate (vasodilation)Sweat is produced from the sweat glands Blood vessels supplying skin capillaries constrict (vasoconstriction) Sweating stops Skeletal muscles contract rapidly (shivering)When muscles contract, respiration increases, releasing more energy (some as heat)Composed of glands which secrete chemicals called hormones directly into the blood streamIn the bloodA chemical molecule, released from glands, affecting a target organPituitary gland, thyroid, ovaries, testes, pancreas, adrenal glandProduces several hormones (known as the ‘master gland’)Produces oestrogenProduces testosterone

48495051What is the function of the thyroid?What is the function of the adrenal gland?What is the function of the pancreas?What are the differences between nerves andhormones?5253How is blood glucose levels monitored and controlled?Describe what happens when the blood glucose level istoo high?54Describe what happens when the blood glucose level istoo low? (HT only)55565758596061What is Type 1 diabetes?What are the symptoms of Type 1 diabetes?How is Type 1 diabetes treated?What is Type 2 diabetes?How is Type 2 diabetes treated?What is a major risk factor for Type 2 diabetes?What substances in the body will affect the function ofcells through osmotic changes? (Triple only)Why does an imbalance of ions or wa(Triple only)ter inthe body negatively affect cells?How do ions and water leave the body? (Triple only)626364656667Produces thyroxineProduces adrenalineProduces insulin Nerves act fast, hormones act slow Nerves act for short period of time, hormones can act for long periods of time Nerves act on a very precise area, hormones act in a more general wayThrough blood flow in the pancreas Blood glucose level detected by the pancreas Pancreas releases insulin into the blood Glucose is removed from the blood and stored as glycogen in the liver and muscles Blood glucose level detected by the pancreas Pancreas releases glucagon into the blood Glycogen is converted into glucose and released into the blood streamA disorder in which the pancreas fails to produce sufficient insulinUncontrolled high blood glucose levelsInsulin injectionsWhen the body cells no longer respond to insulin produced by the pancreasA carbohydrate controlled diet and an exercise regimeObesityIons and waterToo much water can enter or leave the cells through osmosisWater leaves via the lungs through exhalationWater and ions are lost from the skin in sweatWhat is the job of the kidneys? (Triple only)To remove excess water, ions and urea in the urineHow is urea formed in the body? (Triple only) (HT Only) Protein is broken down into amino acids Amino acids are deaminated to form ammonia Ammonia is toxic so is converted to ureaDescribe how the kidneys work? (Triple only)Kidneys filter the blood (everything is removed, except proteins)Selective reabsorption – useful substances like glucose, ions and some water are absorbed backinto the bloodUrea is excreted in the urineWhat is anti-diuretic hormones? (Triple only) (HT only) Controls how much water is reabsorbed back into the blood

6869How is the water level in the body monitored andcontrolled? (Triple only) (HT only)Describe what happens when water content in thebody is too low? (Triple only) (HT only)70Describe what happens when water content in thebody is too high? (Triple only)71What treatments can be offered to people with kidneyfailure? (Triple only)How does a dialysis machine work? (Triple only)7273747576777879808182Why do useful substances not leave the blood throughdialysis? (Triple only)How often do dialysis sessions take place? (Triple only)What are the disadvantages of kidney dialysis? (Tripleonly)What are the disadvantages of a kidney transplant?(Triple only)What are the stages of the menstrual cycle?What is menstruation?What hormones are involved in the menstrual cycle?What reproductive hormones are produced in theovaries?What productive hormones are produced in thepituitary gland?What is the function of oestrogen?It is monitored in blood flow through the brain and controlled by ADH which is released by thepituitary gland Receptor in the brain detects that the water content is too low Pituitary gland releases more ADH ADH makes the kidney tubules more permeable so more water is reabsorbed back into theblood Receptor in the brain detects that the water content is too high Pituitary gland releases less ADH ADH makes the kidney tubules less permeable so less water is reabsorbed back into the bloodRegular dialysisTransplant Persons blood flows between partially permeable membranes surrounded by dialysis fluid Dialysis fluid has the same concentration of dissolved ions and glucose as healthy blood Waste substances like urea leave the persons blood through diffusion into the dialysis fluidThe dialysis fluid contains the same concentration of useful substances as human bloodThree times a week, 3-4 hours each session May cause blood clots or infections Takes a long time It is expensive It could be rejected by the recipients body There are long waiting listsStage 1 – MenstruationStage 2 – The uterus lining builds upStage 3 – The egg is released (ovulation)Stage 4 – The wall is maintained until menstruationThe uterus lining breaks downOestrogen, progesterone, FSH, LHOestrogen and progesteroneFSH & LH Causes the lining of the uterus to growStimulates the release of LHInhibits the release of FSH