Osmoregularity:
-the water potential in the blood is monitored by osmo-receptors in the hypothalamus,
-when water potential is low, osmoereceptors lose water by osmosis, which causes them to shrink and stimulate neurosecretory cells in the hypothalamus,
-the neurosecretory cells are specialised neurones that release ADH, it flows down the axon into posterior pituitary gland, when they are stimulated they send action potentials down their axons and release ADH,
-which enters the blood,
-it's slowly broken down,
-the walls of the collecting duct responds to the level of ADH in the blood,
-cells in the wall have membrane bound receptors or ADH. The ADH binds to them and causes a chain of enzyme-controlled reactions inside the cells, which inserts vesicles containing water-permeable channels, into the surace membrane,
-the move ADH in blood, the more aquaporins, the more permeable to water,
-if there is less ADH, the plasma membrane olds towards to create new vesicles that remove aquaporins,
Control of Heart rate in humans:
-The heart muscle is myogenic,
-it has its own pacemaker called SAN,
-it's supplied by nerves from the medulla oblongata of the brain, which connect to SAN-they don't initiate contraction, but they affect the frequency of the contractions,
-action potentials sent down the accelerator nerve increase the heart rate, action potentials sent down the vagus nerve decrease the heart rate,
-it responds to adrenaline in the blood,
-when we exercise, muscles produce CO2 some of this reacts with the water in the blood plama and reduces its pH, Which is detected by chemoreceptors in the carotid arteries, the aorta and the brain, -the chemoreceptors send impulses to the cardiovascular centre, which increases the heart rate,
-when we stop exercising the concentration of CO2 in the blood falls, the activity in the accelerator pathway falls, heart rate declines,
kidney failure:
-body is unable to remove excess water and certain waste products from the blood, which includes urea and certain salts,
dyalisis:
-removes wastes, excess fluid+salt combined,
kidney transplants:
-freedom, less limited diet, feels better, better quality of life,
-infection, risk of surgery, need immunorepressants for rest of kidney life,
urine sample
pregnancy testing:
-hCG secreted when pregnant,
-special antibodies only bind to hCG,
-hCG attaches to antibody tagged with a blue bead,
-hCG antibody complex moves up the strip until it sticks to a band of immobilised enzymes,
anabolic steroids:
-gas chromatography, sample is vapourised and eventually comes out of gas is absorbed by the lining,
-which is analysed to create chromatogram,
Diabetes Mellitus:
type I diabetes:
-insulin dependent,
-autoimmune response, bodys own immune system attacks the b-cells and destroys them,
-body is no loner able to manufacture sufficient insulin and can't store excess glucose as glucagon,
type II diabetes:
-non insulin-dependent,
-can still produce insulin,
-as people their responsiveness to insulin declines,
-the specific receptors on the surface of the liver and muscle cells decline and the cells lose their ability to respond to the insulin,
treatment:
-type II diabetes is usually treated by careful monitoring and control of the diet, match carbohydrate intake and use,
-this may eventually be supplemented by insulin injections or use of other drugs which slows the absorption of glucose from the digestive system,
-type I diabetes is treated using insulin injections the blood glucose concentration must be monitored and the correct dose of insulin must be administered to ensure that the glucose concentration remains fairly stable,
-stem cells-pancreas of adult mice,
-exact copy, less chance of developing tolerance or rejection, cheaper, more moral,