PHIS 206 1st Edition Lecture 21 Outline of Last Lecture I Functions of the Kidneys II Excretory System III Nephron IV 2 Types of Nephrons V Blood Supply VI 3 Processes VII Filtration VIII Reabsorption IX Pressure Difference X Reabsorption and Active Transport Outline of Current Lecture I Glucose II Diabetes III Active Reabsorption of Na IV Passive Reabsorption V Secretion VI Urine Output VII Plasma Clearance VIII Inulin IX Creatinine X p Aminohippuric acid PAH Current Lecture I Glucose 100 reabsorbed for a normal person only fuel brain can use active transport system all reabsorbed in proximal tubule must have a carrier protein that is saturable These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute input of Energy moves it outside nephron finite capacity that the protein can carry Maximum rate transport maximum amount entering tubular load o concentration in glomerulal filtrate filtration rate Transfer Maximum Tm Glucose 400 mg min Normal Tubular Load 125 mg min 100 gets reabsorbed in proximal tubule Plasma Glucose Level 1 min 125 mg min 0 in urine 2 min 250 mg min 0 in urine 3 min 375 mg min 0 in urine 4 min 500 mg min 100 in urine 5 min 625 mg min 225 in urine greater than T 400 mg min 6 min 750 mg min 350 in urine m II Diabetes Diabetes melatis honeylike Diabetes insipitis without sugar III Active Reabsorption of Na causes passive reabsorption of Cl since cation of Na and anion of Cl must equal out When Na and Cl reabsorbed water follows osmotically IV Passive Reabsorption things can diffuse out of nephron passively best example urea non toxic most aquatic animals produce ammonia that diffuse away fast before storage we have to convert toxic ammonia to something safer convert ammonia into urea urea is 2nd fastest to diffuse after water osmotically reabsorb water as water decreases urea increases urea diffuses up when left in high concentrations sequence of events 1 Actively transport solutes 2 Water follows PASSIVE 3 Things that can diffuse urea will diffuse down conc gradient PASSIVE urea more in plasma V Secretion add stuff to tubule add Extracellular Fluid in tubules which is plasma in capillaries actively transfer into nephron from capillaries MOST IMPORTANT THING SECRETED H proximal distal collecting vessel Number of anions actively secreted too Anionated groups attach to drugs and are excreted through urine VI Urine Output 1 2 L day normal urine output 1 mL min Gfr 180 L day Reabsorbed 179 L day urine output 1 L day VII Plasma Clearance know how much you are excreting and concentration of stuff in plasma then you know the number of mL of plasma to provide some specific compound each minute Definition of Plasma Clearance plasma clearance tells you how efficiently you are removing the compound from the kidneys plasma clearance large to provide stuff that is actively secreted VIII Inulin freely filtered but not reabsorbed or secreted amount in glomerulal filtrate is amount that entered if you measure inulin clearance you are actually measuring the Gfr not normal in blood unless you love garlic or artichokes IX Creatinine creatinine clearance also gives you Gfr not reabsorbed weakly secreted more commonly used to measure Gfr X p Aminohippuric acid PAH actively secreted so almost none left in renal vein whatever enters winds up in urine mainly plasma clearance for PAH renal plasma flow renal blood flow is approximately 2 plasma flow
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