PGY 451 RENAL EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026

PGY 451 RENAL EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026 What causes release of renin by juxtaglomerular cell? - Answers 1. Low BP 2. Fired sympathetic nerves 3. Macula densa cells in dital convolited tubule that sense low Na levels(probably bc not enough Na gets in at glomerulus due to low BP) What are juxtaglomerular cells? - Answers Smooth muscle cells in tunica media of afferent arteriole What are inside juxtaglomerular cells? - Answers Granular cells that contains small renin proteins What does renin do? - Answers It increases blood pressure What does RAAS stand for? - Answers Renin Angiotensin Activating System How many nephrons per kidney? - Answers 1.5 million What is angiotensinogen? - Answers A protein secretes by liver cells that is inactive (note -ogen ending) material after 11/16 - Answers osmolarity - Answers must be dissolvable solute in solvent osmotic pressure - Answers is in reference to pure water. Anything dissolved in water will have an osmotic pressure. Can only be created using a semipermeable membrane. Can only be created by an osmotic imbalance. Measured by mm of Hg (mercury). In capillaries, proteins form this pressure because they are too big to pass. Tonicity - Answers cell volume change by movement of water (isotonic/hypotonic/hypertonic) Effective Osmolarity - Answers links osmotic pressure to tonicity Reflection coefficient - Answers If it's 0, it moves very quickly. If it's 1, completely impermeable. If it's between 0 and 1, it's variable. 1 mole of NaCl outside water - Answers 6.02x10^24 molecules of salt 1 mole of NaCl in water - Answers 2(6.02x10^24) particles of ions osmotic pressure vs mercury - Answers we don't need large pressure imbalance to give us a large difference in mercury. small Albumin and immunoglobulin - Answers enough to give us a large pressure difference The plasma - Answers indirectly affects the interstitial and the intracellular compartments. Diseases affecting GFR and filtration - Answers proteinuria, hematuria, reduced GFR, hypoproteinemia, edema (swelling) Hydrostatic Pressures across renal vasculatures - Answers most regulated, regulated by: diameter of afferent arteriole. Affect the driving force across the glomerulus. Poiseuille's Equation - Answers g=(pi.r^4)/8n.1. Because radius is to the 4th, a very small change will greatly affect it. 2 fold change. Conductance - Answers 1/resistance Control of GFR - Answers 1. renal autoregulation (seconds) 2. hormonal (renin, angiotensin 2, prostaglandins, ANP) 3. ANS (sympathetic) (days) GFR - Answers usually pretty constant. 80-120 range. renal plasma flow - Answers pretty constant, reabsorption into peritubular capillaries increase pressure - Answers will increase resistance change in renal pressure - Answers get up quickly or something else that raises BP Autoregulation - Answers Change in vessel diameter in response to pressure to maintain GFR and keep it constant Increase artery pressure - Answers Afferent constricts bc of high pressure, some pressure is used for glomerular filtration, efferent relaxes because of low pressure. Affect: glomerular filtration remains close to normal b/c one increased/one decreased Decrease artery pressure - Answers afferent dilates bc of low pressure, efferent constricts. Affect: glomerular filtration remains close to normal. Hormonal - Answers Tubuloglomerular feedback through juxtaglomerular cells that release renin. Juxtaglomerular cells - Answers lead to sustained changes Macula Densa cells - Answers 10% of initial plasma. The sensors detect ion Na, K, Cl. When they detect the ions, to increase calcium through adenosine, to constrict afferent arterioles. TGF/JGA - Answers When flow rate increases in distal tube, filtration across glomerulus slows down. mediated through adenosine and NO. RAAS sytem - Answers Renin Angiotensin Aldosterone System What is angiotensinogen - Answers an inactive large protein (450+) amino acids Angiotensinogen + renin meet? - Answers Renin activates it. Renin cuts angiotensinogen to make Angiotensin 1 (10 amino acids). This is active. What is ACE? Where is it? - Answers Angiotensin converting enzyme. It is on endothelial cells of capillaries Angiotensin 1 + ACE - Answers Makes 8 amino acid called Angiotensin 2 change in P = Q x R - Answers flow x resistance. Flow = (SVxHR) x R What does angiotensin 2 do? - Answers 1. rapidly goes to smooth muscle in blood vessels to cause vasoconstriction 2. slowly goes to kidneys to cause salt reabsorption 3. goes to pituitary gland to cause release of ADH to cause water reabsorption. 4. goes to adrenal gland to cause release of aldosterone to cause salt reabsorption Mechanisms for reabsorbing water - Answers 1. If the cells are permeable to water, Na gets reabsorbed and water follows. (what the kidneys and adrenal glands do) 2. If the cells are impermeable to water, water gets reabsorbed through water channels. (what ADH does) What does reabsorbing water do? - Answers It increases stroke volume. (and blood pressure) What triggers Aldosterone release? - Answers 1. Angiotensin 2 release 2. Increase in Potassium Where on the nephron does Aldosterone affect? - Answers The distal part of the distal convoluted tube made of principal cells, and the collection duct. 1. It will cause the Na/K pump on the basolateral side to pump more Na into the blood. 2. It will cause the K channel on the apical side to pump more K into the urine of the tube. 3. It will cause the Na channel on the apical side to pump Na from urine to cell, and then to blood using the Na/K pump. 4. more sodium in the blood causes more water to be reabsorbed in the blood What does reabsorbing water via aldosterone do? - Answers It increases stroke volume (and blood pressure) How does aldosterone affect the alpha intercalated cell? - Answers It stimulates the H/ATPase and the Na/H channel to get H into the urine. How does bicarbonate get into the blood? - Answers water + co2 in the alpha intercalated cell makes proton plus bicarbonate. Bicarbonate gets pumped into the blood in exchange for one Cl- coming into the cell. Once the bicarbonate is in the blood, it will combine with the proton to make water and co2 again. What builds in the alpha intercalated cell? - Answers Proton and Cl- What happens to the proton? - Answers Gets pumped into urine via either 1. Proton ATPase 2. Na/H channel 3. K/H ATPase Where is ADH made? - Answers In hypothalamus, also called vasopressin. 9 amino acids long. What are triggers for ADH release? - Answers 1. High blood concentration (high osmolarity or salty blood) 2. Low blood volume. detected in the rt atrium via the veins because the wall of the heart is less stretched than normal. 3. Decrease in blood pressure. detected by baroreceptors via the arteries. 4. Angiotensin 2 What does ADH do? - Answers It increases BP by absorbing more water in collecting duct region: It makes the aquaporin channels of the collecting duct cells fuse to the side, so that water can come into the blood. What are the targets of ADH? - Answers 1. smooth muscle to cause them to constrict to increase resistance to increase pressure 2. Acts collecting duct to increase water reabsorption What is the direction of blood/urine in the collecting duct? - Answers Blood goes up, urine goes down Why does saltiness increase as we go deeper into the medulla? - Answers It allows us to concentrate our urine Contrast Aldosterone/ADH Relationship - Answers Aldosterone: