Chapter 14 Renal Function PDF

Chapter 14 – Renal -What are the main functions of the kidney? Know the general structure/anatomical components. -Theoretically if you compare the renal artery to the renal vein, you’ll be able to figure out what the kidney did. -What is the nephron? What are the vascular components? Tubular c...

Chapter 14 – Renal -What are the main functions of the kidney? Know the general structure/anatomical components. -Theoretically if you compare the renal artery to the renal vein, you’ll be able to figure out what the kidney did. -What is the nephron? What are the vascular components? Tubular components? What are the two types of nephrons? Which is more numerous? What are the different functions? -Know the pathway of blood through the kidney focusing on only the pieces I said you needed to know. -Big picture: our kidney’s job is to filter the blood, we want to keep the good stuff and get rid of the bad via urine. Blood enters the kidney which then (1) filters into the tubular components. That filtrate then traverses the tubular components where it undergoes (2) reabsorption and (3) secretion until eventually we have produced urine. Urine is excreted via the ureters, bladder, urethra. -Know the difference between tubular reabsorption and tubular secretion -Know the micturition reflex. Where is there smooth muscle? Skeletal muscle? Where can we control? Where can we not control? -What does sympathetic activity do during the micturition reflex? What does parasympathetic activity do during the micturition reflex? GLOMERULUS -Go back and review the general rules of bulk flow across capillary beds. hydrostatic pressure > colloid osmotic pressure = ultrafiltration [ in glomerulus]  hydrostatic pressure < colloid osmotic pressure = reabsorption [in peritubular capillaries] -What are the three things that allow the glomerulus a greater rate of exchange? -Be able to think through what happens when I...what does this do to GFR? (1) constrict the afferent arteriole leave efferent alone (2) constrict the afferent arteriole and constrict the efferent (3) constrict the afferent arteriole and dilate the efferent (4) dilate the afferent arteriole leave efferent alone (2) dilate the afferent arteriole and constrict the efferent (3) dilate the afferent arteriole and dilate the efferent -what is NFP? What are the three pressures that go into it? What happens to GFR when NFP goes up? Down? -How are we able to keep the BP across the glomerulus constant? What is renal autoregulation? -What is the filtering membrane? What are the three components that make it up? -What effect does sympathetic stimulation have on GFR? -What is tubuloglomerular feedback (TGF) and how does it further autoregulate GFR? What cells are important in this feedback system and where are they located? -Understand why the filtrate in Bowman’s capsule reflects the composition of the blood. Why don’t we see proteins in the filtrate under normal physiological conditions? YOU HAVE TO KNOW THE PERCENTAGES AND WHERE THEY ARE AT THROUGHOUT THE NEPHRON PCT - understand secondary active transport and that Na is required for glucose to gain entry to proximal tubule cells. -Know the process for water reabsorption (2 methods) -Know the process for glucose reabsorption. SGLT1/2 transporter on apical membrane and GLUT transporter and Na/K pump on the basolateral membrane. Revisit transport maximums and what it means for glucose reabsorption. Should we see glucose in the urine under normal physiological conditions? -Understand the process for Urea reabsorption and why we reabsorb a waste product. -PCT is known for reabsorption of molecules, what is the main thing being secreted by the PCT? -Think about active vs passive transport. Where is ATP being used? LOOP OF HENLE -know the osmolarity of the filtrate as it moves through the tubule components. (isotonic, hypertonic, hypotonic) -what is reabsorbed in the descending limb? Why? -what is reabsorbed in the ascending limb? Why? What’s the difference between thin and thick limbs? -know the process of Na reabsorption in the thick ascending limb. NKCC2 transporter on apical membrane, Na/K pump Cl channel and K channel on the basolateral membrane. -Where does most of the K go (which membrane channel does it pass through)? Why? What effect does a net positive voltage in the urine have? What ions move as a result? -where do all those ions go that are moved by the NKCC2 transporter? Vertical osmotic gradient this is why we say the loop of henle creates the VOG. -How does Lasix work? What do they target? DCT -Know the differences in the early and late distal tubules. -What two ions are secreted by the DCT? - Early DCT: Know the process of Na reabsorption through the Na/Cl co-transporter - Early DCT: know the process of Ca reabsorption via hormone regulated calcium channels and what hormones control them. - Late DCT: What are principal cells? What do they do? What hormone do they respond to? -know the relationship between macula densa cells and JG cells. What are they detected, what are each communicating with, who produces Renin? -Once produced, where does Renin go? What does it do? -What is the RAAs system? How is it activated? What are it’s components? What does it ultimately do? ** you have to know the RAAS system. - Late DCT: What are the three things aldosterone does to principal cells to enhance Na reabsorption? - Late DCT: know the late DCT is impermeable to water under normal conditions. - Late DCT: What are the three things aldosterone does to principal cells to enhance potassium secretion? Understand this process. -Potassium homeostasis. Why do we so tightly regulate K levels in the blood? Where is most of our K in our body? What happens when we have hyperkalemia? What hormones help to “hide” K and stimulate the release of aldosterone by bypassing the RAAS system? -What causes K to enter the ECF? -What is our bodies immediate response to elevate K levels in the blood? Long term response? - Late DCT: What are alpha-intercalated cells and what do they secrete? COLLECTING DUCTS -What depends on the action of the thick ascending limb of the loop of Henle to move salts into the interstitial space AND the collecting ducts to move variable amounts of urea into the interstitial space? -When there is a weak VOG...what is creating it? Vs a strong VOG? -Understand which portions of the nephron are water permeable, impermeable, and have variable water permeability. -What affect does ADH have on the collecting duct? -Which aquaporin protein is dependent on ADH? Where is it located? -What type of urine is produced in the absence of ADH? Why? -What type of urine is produced in the presence of ADH? Why? -Know that ADH = vasopressin (two names for the same hormone) -Know the process by which ADH inserts AQ2 into the apical membrane of the collecting ducts. -ADH is secreted by the posterior pituitary and is released when very sensitive osmoreceptors in the brain detect the slightest change (1%) in ECF osmolarity. -ADH = water reabsorption = water conservation = small concentrated urine -no ADH = water loss = large volumes of dilute urine Terms to know : cortex, medulla, renal artery, renal vein, pyramids, calyx, renal pelvis, ureter, nephron, afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries, vasa recta, Bowman’s capsule, PCT, Loop of Henle (descending and ascending limb), DCT, collecting ducts, superficial or cortical nephrons, juxtamedullary nephrons, vertical osmotic gradient, detrusor muscle, internal sphincter, external sphincter, net filtration pressure, fenestration, glomerular basement membrane, podocytes, filtration slits, nephrotic syndrome, macula densa cells, isosmotic reabsorption, secondary active transport, osmosis, aquaporins, transport maximum, renal threshold, BUN test, organic ion secretion, Loop diuretics [ Lasix/furosemide], PTH, aldosterone, juxtaglomerular apparatus, hyperkalemia, insulin, epinephrine, aldosterone, Numbers to know: Kidney receives 20-25% of cardiac output = 1 – 1.2 L/ min (or 1,000/1,200 mL/min) GFR = 100-120 mL/min Urine flow rate = 1 mL/min Urine production = 1.0-1.5 L/day with a range of 0.5-15 L/day PCT: 67% Na reabsorbed 100% glucose 67% water reabsorbed 80% HCO 3 - 67% electrolytes 50% Urea Loop of Henle: Descending limb: 15% of water reabsorbed Ascending limb: 25% Na reabsorbed DCT: Early: 5% Na reabsorbed Late: variable 2-3% Na reabsorbed regulated by aldosterone Collecting Ducts 8-17% of water reabsorbed regulated by ADH