Homeostasis Past Paper Questions Study Guide 2023(100% Verified)

Outline how a negative feedback mechanism works (4) Oct/Nov 2017 V1 - 1 change in factor away from, the norm / set-point 2 detected / sensed by, receptor 3 hormone released or (nerve) impulse sent 4 (hormone / impulse) reaches, target organ / effector ; 5 (effector) performs corrective action- counteracts change 6 (factor) returns to, norm / set-poin Describe the role of the nervous system in the control of blood glucose concentration (4) Oct/Nov 2017 V1 - 1 hypothalamus detects change in blood glucose concentration 2 autonomic / motor / nerve, impulses 3 (so) β cells secrete insulin when blood glucose increases 4 (so) α cells secrete glucagon when blood glucose decreases ; 5 (so) adrenal gland secretes adrenaline either when blood glucose decreases or due to fear / shock / excitement / stress 6 nervous control supplements, endocrine control/ control by pancreas State how vasoconstriction, shivering and increasing secretion of adrenaline would bring the core temperature back up to normal (4) Oct/Nov 2017 V1 - vasoconstriction 1 arterioles in skin get narrow(er) ; 2 less blood flow through (skin / surface) capillaries 3 (so) less heat lost (to surroundings) ; shivering 4 muscle contraction ; 5 releases / provides / gives, heat / thermal energy increasing secretion of adrenaline 6 increases, rate of respiration / metabolic rate ; 7 more heat, released / provided / given (by respiration Outline the effect of ADH on the collecting ducts (3) Oct/Nov 2016 V1 - 1 ref. to enzyme / phosphorylase / signalling ; 2 ref. to aquaporins ; 3 vesicles (containing aquaporins), move towards / fuse with, (cell surface membrane) ; 4 idea of increased permeability ; 5 water leaves (lumen into cells), by osmosis / down water potential gradient Explain how the oral contraceptive pill works to prevent pregnancy (4) Oct/Nov 2016 V1 - 1 (acts on) anterior pituitary gland ; 2 FSH secretion inhibited ; I {FSH inhibited} 3 Graafian / dominant, follicle does not develop ; 4 LH secretion inhibited ; {I LH inhibited} 5 ovulation prevented / AW ; 6 ref. to negative feedback ; 7 cervical mucus thickens ; 8 ref. to thin endometrium Using examples outline the importance of homeostasis in mammals (7) Oct/Nov 2016 V1 - 1 ref. to maintenance of constant internal environment 2 blood or tissue fluid as e.g. of internal environment ; 3 ref. to norm / optimum value / set point / within narrow limits ; 4 (low) temperature and consequence ; e.g. slowed metabolism / enzymes less active 5 (high) temperature and consequence ; e.g. enzymes denatured 6 (low) water potential and consequence ; e.g. water leaving cells / cells shrink 7 (high) water potential and consequence ; e.g. water enters cells / cells burst 8 (low) blood glucose and consequence ; e.g. effect on respiration 9 (high) blood glucose and consequence ; e.g. water leaving cells/cells shrink/coma/damage small blood vessels 10 control of pH and consequence Describe the main stages of cell signalling in the control of blood glucose by adrenaline (8) Oct/Nov 2016 V1 - 1 adrenaline binds to receptors ; 2 in, cell surface membrane / plasma membrane ; 3 receptor changes conformation ; 4 G proteins activated ; 5 adenylyl cyclase activated ; A adenyl cyclase 6 cyclic AMP / cAMP, made ; 7 second messenger ; 8 activates kinase (protein) ; 9 ref. to enzyme cascade / signal amplification ; 10 ref. to phosphorylase ; 11 glycogen broken to glucose / glycogenolysis ; 12 glucose diffuses, out of cells / into blood ; 13 increase in blood glucose concentration Outline how the oestrogen/progesterone contraceptive pill works to prevent pregnancy (6) Oct/Nov 2015 V1 - 1 synthetic hormones used ; 2 as they do not get broken down quickly / act for longer ; 3 oestrogen / progesterone, concentrations remain high ; 4 inhibits secretion of, FSH / LH / GnRH ; {I stops} 5 from anterior pituitary gland ; 6 ref. to negative feedback ; 7 inhibits ovulation / no ovulation ; 8 alters cervical mucus (makes it thicker) to stop sperm ; 9 prevents implantation / effect on endometrium (thins it) ; 10 AVP ; e.g. taken daily for 21 days / stops for 7 days to allow menstruation (or) taken daily throughout month. Discuss the biological, ethical and social implications of using this contraceptive pill (9) Oct/Nov 2015 V1 - biological-negative 1 rise in blood pressure / increased chance of blood clots ; 2 nausea / headaches ; 3 increased risk of breast cancer ; 4 increase in STDs ; biological - positive 5 regular / no menstruation ; 6 reduced risk of developing, ovarian cysts / ovarian cancer / uterine cancer ; 7 reduced risk of uterine infections ; A pelvic social / ethical - negative 8 (sexual freedom has led to) more marriage breakdowns ; 9 (so more) single parent families ; 10 increase in promiscuity ; 11 religious / cultural, objection ; social / ethical - positive 12 reduction in, unwanted pregnancies / abortions 13 women have control over their fertility ; A 'bodies' 14 ref. to population control ; Compare the roles of the endocrine and nervous systems in control and coordination in animals. (8) May/June 2008 - endocrine 1 hormones ; 2 chemical messengers ; A chemicals that transfer information 3 ductless glands / (released) into blood ; 4 target, organs / cells ; 5 ref. receptors on cell membranes ; 6 example of named hormone and effect ; nervous 7 impulses / action potentials ; R electrical, signals / current 8 along, neurones / nerve fibres ; R nerves 9 synapse (with target) / neuromuscular junction ; 10 ref. receptor / effector / sensory / motor, neurones ; differences - endocrine 11 slow effect / ora ; 12 long lasting effect / ora