12.4.13 kin 272 class notes- GFRo Component that you could measure based on how much you clear creatinine (byproduct of phosphogen system) use urinanalysis  125 mL/min daily filtration rate quite a bit…lot of fluido how much is going to be filtered depends on series of factors blood pressure blood volume both are adequately necessary to maintain filtration rates kidneys job is to maintain these pieceso blood volume alter sodium done by kidney increase red blood cell productiono blood pressure kidney releases certain hormoneso affecting other systems: circulatory, cardiovascular an individual undergoing kidney failure – nephrons don’t work makes sense that you also in heart failure – pump will suffer (higher load – uncontrollable blood pressure/volume) how to regulate these? GFR- regulate GFR o 1. Autoregulation local control what can I do in kidney first before getting something else involved change diameter of afferent & efferent arteriole- dialate/constrict based on pressure components GFR decreases, afferent arteriole will dialate while the efferent arteriole will constrict- this increases volume on inside of glomarulis- more fluid in there, doesn’t allow it back out- filtration rate goes up if this doesn’t work… hormonal control then neural control- this is unlikely- hormonal control takes longer- in the case of blood pressure…o 2. Hormones renin (rennin/angiotensin system)- hormone released from kidney itself (don’t have to rely pituitary gland…)- faster to use hormone than get involved in nervous system- this system will be activated anytime there is a decrease in filtration rate – can also activate if there is a decrease in plasma, decrease in cardiac output, decrease in blood volume, decrease in blood pressure, decrease in sodium concentration in the blood- most of these things cause decrease in filtration rate- rennin is released from the kidney itself- rennin is responsible for angiotensin  angiotensin Io angiotensin I doesn’t really do anythingo needs enzyme from blood vessels near the heart; needs to be converted into angiotensin IIo ultimately the hormone that does all the changeso in order to convert: angiotensin converting enzyme- angiotensin IIo induces/causes increase in vasoconstrictiono increase mean arteriole pressureo filtration rate should go back upo cause in increase in retaining of sodiumo retain sodium because… push sodium back into peritubular capillaries(water follows sodium)o blood volume goes back upo activation of adrenal gland releases aldosterone two tiny fatty nodules located above each kidney glands, part of endocrine system job is to tell DCT/PCT to save sodium, more conservation of sodium! More water conservation Stimulates pituitary gland (makes you thirsty)- Thirsty stimulus is from ADH (kidneys)- ace inhibitoro angiotensin converting enzyme inhibitoro decreases blood pressure! natriuretic peptide- released from kidney, some from atria- reverse effect- released when filtration rate is high- release or remove sodium- trying to decrease the amount of plasma/blood volume- this is the only hormonal link to decreasing GFR ADHo 3. Nervous system Sympathetic nervous system Result in vasoconstriction of afferent arterioles Any need to decrease GFR That means sympathetic ns comes into play to slow down production Any other need for acute adjustment – immediate change in blood pressure/blood volume Typically that’s a last resort Kidney is good at fixing that prior to getting nervous system involved- Countercurrent multiplicationo Loop of henle contains sodium pump that maintains the oncotic balance in the peritubular fluid, tubules, and peritubular capillaries.o Maintain osmotic pressureo By the time this material gets to the sodium pump, pushes out to capillaries based on amount in bloodo Loop of henle is nice and kind of tighto Put sodium in peritubular fluid – water in tube is going to be pulled outo End up removing watero Pull h2o out of thin descending limbo Ton of sodium? Only appears so Pump will push more sodium out Na+ out of thin ascending loopo Two currents moving in opposite direction, alters oncotic balanceo So close in proximity, increases oncotic pressure on the other sideo Filtration rate goes up and downo You need to drink a lot of water everyday because it maintains appropriate GRF Keep cells adequately hydrated- Six major functions of the digestive systemo 1. Ingestion put food in moutho 2. Mechanical processing squishing foods together cement mixer turns it into dough like formo 3. Digestion chemical breakdowno 4. Secretion water, acid, enzymes, and buffers added into food stuffso 5. Absorption movement of necessary components into the bodyo 6. Excretion getting rid of whatever is left that we don’t need removal of non-digestible items- Mechanical processing o Movement of stuffo Chewing Happens in the moutho Segmentation Cycles of waving contractions What your stomach does Happen in stomach when it takes sandwich and breaks it down into a liquido Peristalsis Circular wave like contractions to move food along a tube Series of contractions behind the item to move the item forward Large intestineo Mass movement Occurs in the small intestine Occur once or twice per day Completely eliminate a