PHPH 701: Renal/Acid-Base Physiology Comprehensive Exam Questions Fully Solved.

7 BMP Measurements and Their Normal/Standard Values - correct answer 1. Na- 140 2. K- 4 3. Cl- 104 4. HCO3 (bicarb)- 24 5. BUN- 15 6. Creatinine- 1 7. Glucose- 80 2 Compartments of Body Water - correct answer 1. Extracellular compartment- contains 1/3 of total body water, further divided into plasma and interstitial fluid 2. Intracellular compartment- contains 2/3 of total body water What percentage of the body mass is water? - correct answer 60% 5 Functions of the Kidney - correct answer 1. Big player in regulating extracellular electrolytes (Na, K, Cl, HCO3 in BMP, H+ in acid-base) 2. Regulates extracellular volume 3. Eliminates waste products- BUN (from protein metabolism) and creatinine (from skeletal m.) 4. Releases erythropoietin (Epo)- critical for RBC production 5. Final rate limiting step in synthesis of active vitamin D (calcitriol) 5 Main Components of Urinary System - correct answer 1. 2 Kidneys 2. Renal pelvis- fluid in here is called urine at this point 3. Ureter- takes urine to bladder 4. Bladder- stores urine 5. Urethra- connects bladder to external environment Gross Anatomy of Kidney - correct answer 1. Arterial blood enters via renal a., venous drainage is via renal v. 2. Cortex= outer portion 3. Medulla= inner portion 4. Collecting ducts of inner medulla coalesce to form renal papilla 5. Fluid in papilla is no longer modified and is thus called urine 6. Papilla coalesce (join together) to form renal pelvis Nephron - correct answer functional unit of the kidney, all sections lined by epithelial cells, distal part of nephron (late DT and CCD) have principal cells and intercalated cells Pathway of Flow Within Nephron - correct answer blood comes in from renal a. thru afferent arteriole (AA)--> glomerular capsule (GC)-->comes out thru efferent arteriole (EA)--> EAs join togeth to bring blood out ultimately forming renal v., from GC--> fluid moves into Bowman's space (BS)--> proximal tubule (PT)--> descending thin limb of loop of Henle (DTL)--> ascending limb of loop of Henle (ALH)--> ascending thick limb of loop of Henle (ATL)--> macula densa (MD)--> distal tubule (DT)--> cortical collecting duct (CCD)--> medullary collecting duct (MCD) Cortical Nephrons vs. Juxtamedullary Nephrons - correct answer 1. Cortical- most nephrons are these, have loop of Henle that barely gets into medulla, network of capillaries surrounding it called peritubular capillaries 2. Juxtamedullary- have long loops of Henle, network of capillaries surrounding it called vasa recta Where do collecting ducts run? - correct answer run thru the medulla--> coalesce to form papilla Renal Corpuscle - correct answer tissue surrounding afferent arteriole (AA), glomerular capillaries (GC), efferent arterioles (EA), and Bowman's space (space outside GC) 3 Parts of Juxtaglomerular (JG) Apparatus - correct answer 1. Granular cells of the afferent arteriole (AA) 2. Macula densa (MD) 3. Extraglomerular mesangial cells (no functional role) Function of the JG Apparatus - correct answer granular cells release renin- enzyme that converts angiontensinogen to AngI--> AngI rapidly converted to AngII by ACE, so if renin goes up--> AngII goes up 3 Stimuli for Renin - correct answer 1. Reduced perfusion pressure to kidney (BP falls) 2. Activation of symps (beta 1) 3. Reduced NaCl delivery to macula densa Glomerular Capillaries - correct answer very leaky capillaries so Kf (filtration coefficient) is high, have negative charges on them that prevent proteins from crossing so sigma (reflection coefficient) is high, therefore the GCs filter a lot (since high Kf) but don't filter proteins (since sigma is high) Nephritic Syndrome - correct answer inflammatory interaction in GCs where fluid cannot easily filter thru capillary membrane around RBCs--> 5 signs: 1. Hematuria (RBCs in urine) 2. Proteinuria (protein in urine) 3. Oliguria- not filtering much so low urine output 4. HTN- if not filtering, then not regulating extracellular enviro so BP goes up 5. Azotemia- if not filtering, then not getting rid of urea Nephrotic Syndrome - correct answer alteration in GC membrane, 5 signs: 1. Marked proteinuria- alteration allows proteins to pass 2. Edema- proteins keep water in vasculature so if they're lost, more fluid comes out 3. Hypoproteinemia- low proteins in blood since losing them in urine 4. Lipiduria- lipid soluble cmpds travel on proteins, so you'll have lipids in urine 5. Hyperlipidemia- see increase in lipids in blood What is the #1 cause of kidney problems? - correct answer diabetes mellitus 4 Basic Renal Processes - correct answer 1. Filtration (F)- from GC to BS 2. Reabsorption (R)- from lumen of nephron into capillary (peritubular or vasa recta) 3. Secretion (S)- from capillary (peritubular or vasa recta) into lumen of nephron 4. Excretion (E)- appears in urine and eliminated from body Overall Equation of the Basic Renal Processes - correct answer what gets excreted= (amount filtered-any reabsorption) + any secretion--> E= (F-R)+S About how much water is filtered and excreted by the kidneys daily? - correct answer 180L filtered, 1.8L excreted--> rest of it got reabsorbed About how much sodium is filtered and excreted by the kidneys daily? - correct answer 630g filtered, 3.2g excreted About how much glucose is filtered and excreted by the kidneys daily? - correct answer 180g filtered, 0g excreted because the kidneys don't regulate glucose About how much urea is filtered and excreted by the kidneys daily? - correct answer 56g filtered, 28g excreted--> this is about 50% because urea is a waste product so kidneys want to get rid of it Pathway of Renal Hemodynamics/Blood Flow - correct answer comes in AA--> GCs--> EA--> peritubular capillaries/vasa recta Overview of Renal Hemodynamics - correct answer 1. 2 Resistors (arterioles) in a series- AA and EA 2. 2 Capillary beds (glomerular and peritubular) 3. 2 Capillary pressures- glomerular (PGC) which is the upstream P ~60 and also peritubular (PPC) which is the downstream P ~20 4. High resting flow- 25% of CO 5. High venous O2 What does high venous O2 in the kidneys indicate? - correct answer there's more blood flow than needed- kidneys are way over perfused for their metabolic demand but not for their function to filter the blood Free Flow (Q): Vasoconstriction vs. Vasodilation - correct answer 1. Vasoconstriction- blood flow (Q) goes down, R goes up, deltaP goes up: upstream P goes up, downstream P goes down 2. Vasodilation- Q goes up, R goes down, deltaP goes down: upstream P goes down, downstream P goes up What occurs when there's vasoconstriction of afferent arteriole (AA)? - correct answer renal blood flow (RBF) goes down, glomerular and peritubular capillaries are both downstream from AA--> downstream P goes down when vasoconstrict--> PGC and PPC both go down, since PGC goes down--> GFR goes down What occurs when there's vasodilation of afferent arteriole (AA)? - correct answer renal blood flow (RBF) goes up, glomerular and peritubular capillaries are both downstream from AA--> downstream P goes up when vasodilate--> PGC and PPC both go up, since PGC goes up--> GFR goes up What occurs when there's vasoconstriction of efferent arteriole (EA)? - correct answer renal blood flow (RBF) goes down, glomerular capillaries are upstream from EA and peritubular capillaries are downstream from EA--> upstream P goes up and downstream P goes down when vasoconstrict--> PGC goes up and PPC goes down, since PGC goes up--> GFR goes up What occurs when there's vasodilation of efferent arteriole (EA)? - correct answer renal blood flow (RBF) goes up, glomerular capillaries are upstream from EA and peritubular capillaries are downstream from EA--> upstream P goes down and downstream P goes up when vasodilate--> PGC goes down and PPC goes up, since PGC goes down--> GFR goes down Autoregulation - correct answer maintenance of a relatively constant flow despite changes in P within a certain range of Ps, this local at the tissue itself, kidney is a very good autoregulator, if P goes up--> we vasoconstrict to increase R to keep flow constant, if P goes down--> we vasodilate to decrease R to keep flow constant 2 Autoregulation Mechanisms of the Kidney - correct answer 1. Myogenic 2. Tubuloglomerular feedback (TGF) Tubuloglomerular Feedback (TGF) - correct answer alterations in tubular flow are sensed by MD and the RBF is adjusted accordingly, MD responds to Na delivery, delivery=flow x concentration (MD is apart of tubule so this is tubular flow and tubular Na concentration), the more Na delivered to MD--> the more MD releases adenosine and ATP--> both of these vasoconstrict AA--> tubular flow is reduced in order to keep it constant What is the adaptive benefit of TGF? - correct answer if there is too much tubular flow--> we can vasoconstrict AA to reduce it in order to keep it constant 6 Vasoactive Agents Involved in Regulation of RBF - correct answer 1. Sympathetics- alpha mediated vasoconstriction 2. AngII- vasoconstriction