NBME Physiology Questions and Verified Answers (complete solutions) GRADE A+!!

NBME Physiology Questions and Verified Answers (complete solutions) GRADE A+!! At what concentration is the transport mechanism for glucose saturated - ANS-300 mg/dl Define effective renal plasma flow. - ANS-ERPF = U (PAH) x V /P (PAH) = C (PAH) Define filtration fraction. - ANS-FF= GFR/ RPF Define free water clearance. - ANS-C(H2O) = V- C(osm) Define GFR. - ANS-GFR = U(inulin) x V/P (inulin) = C (inulin) GFR also equals the difference in (osmotic pressure of the glomerular capillary minus Bowman's space) and (hydrostatic pressure of the glomerular capsule minus Bowman's space). Define renal blood flow. - ANS-RBF = RPF/1 - Hct Define renal clearance. - ANS-Cx = UxV/Px The volume of plasma from which the substance is cleared completely per unit time. Define urine flow rate. - ANS-V = urine flow rate C (osm) = U(osm)V/P(osm) How are amino acids cleared in the kidney - ANS-? reabsorption occurs by at least 3 distinct carrier systems, with competitive inhibition within each group. How do NSAIDs cause renal failure - ANS-By inhibiting the production of prostaglandins which normally keep the afferent arterioles vasodilated to maintain GFR How high can the osmolarity of the medulla reach - ANS- mOsm How is ICF measured - ANS-ICF = TBW - ECF How is interstitial volume measured - ANS-Interstitial volume = ECF - PV How is PAH secreted - ANS-Via secondary active transport How is PAH transport mediated - ANS-Mediated by a carrier system for organic acids How much of the ECF is interstitial fluid - ANS-Three-fourths How much of the ECF is plasma - ANS-One-fourth How much of the total body water is part of intracellular fluid - ANS-Two-thirds How much of the total body water is part of the extracellular fluid - ANS-One-third If clearance of substance X is equal to GFR, what occurs - ANS-There is no net secretion or reabsorption If clearance of substance X is greater than GFR, what occurs - ANS-Net tubular secretion of X If clearance of substance X is less than GFR, what occurs - ANS-Net tubular reabsorption of X T/F. Secondary active transport of amino acids is saturable. - ANS-TRUE What 3 layers form the glomerular filtration barrier - ANS-1. Fenestrated capillary endothelium 2. Fused basement membrane with heparan sulfate 3. Epithelial layer consisting of podocyte foot processes What actions does ADH have on the kidney - ANS-- Increase water permeability of principle cells in collecting ducts -Increase urea absorption in CD. -Increase Na /K/2CI transporter in the thick ascending limb What actions does All have on the kidney - ANS-- Contraction of efferent arteriole increasing GFR -Increased Na and HC03 reabsorption in proximal tubule What actions does aldo have on the kidneys - ANS-- Increased Na reabsorption in distal tubule -Increased K secretion in DT -Increased H ion secretion in DT What actions does ANP have on the kidney - ANS-- Decreased Na reabsorption -Increased GFR What actions does PTH have on the kidney - ANS-- Increased Ca reabsorption -Decreased phosphate reabsorption -Increase 1,25- (0H)2 Vit D production What activates 1 alpha-hydroxylase - ANS-PTH What are the 4 actions of angiotensin II - ANS-1. Vasoconstriction 2. Release of aldo from adrenal cortex 3. Release of ADH from posterior pituitary 4. Stimulates hypothalamus to increase thirst What are the 4 endocrine functions of the kidney - ANS-1. EPO release 2. Vitamin D conversion 3. Renin release 4. Prostaglandins release What are the consequences of a loss in the charge barrier - ANS-- Albuminuria -Hypoproteinemia -Generalized edema -Hyperlipidemia What competitively inhibits the carrier system for PAH - ANS-Probenecid What constricts the efferent arteriole - ANS-Angiotensin II What dilates the renal afferent arteriole - ANS-Prostaglandins What do the collecting ducts reabsorb in exchange for Kor H - ANS-Na ions What does renin do - ANS-Cleave angiotensinogen into angiotensin I What does the anterior pituitary secrete - ANS-- FSH and LH -ACTH -GH -TSH -MSH -Prolactin What does the beta subunit do - ANS-The beta subunit determines hormone specificity What does the early distal convoluted tubule actively reabsorb - ANS-- Na ions -Cl ions What does the posterior pituitary secrete - ANS-ADH and oxytocin What does the secretion of prostaglandins from the kidney do - ANS-Vasodilates the afferent arterioles to increase GFR What does the thick ascending loop of Henle actively reabsorb - ANS-- Na ions -K ions -Cl ions What does the thick descending loop of Henle indirectly reabsorb - ANS-- Mg ion -Ca ions What effect does constriction of the efferent arteriole have - ANS-- Decreased RPF -Increased GFR -FF increases What effect does dilation of the afferent arteriole have - ANS-- Increased RPF -Increased GFR - FF remains constant What enzyme converts 25-0H Vit D to 1,25-(0H)2 Vit D - ANS-alpha-hydroxylase What happens to glucose in the kidneys when glucose is at a normal level - ANS-Glucose is completely reabsorbed in the proximal tubule. What hormones act on the kidney - ANS-1. ADH 2. Aldosterone 3. Angiotensin II 4. Atrial natriuretic Peptide 5. PTH What inhibits constriction of the efferent arteriole by All - ANS-ACE inhibitors What inhibits dilation of the afferent arteriole by prostaglandins - ANS-NSAIDS What is an important clinical clue to diabetes - ANS-Glucosuria What is angiotensin ll's overall function - ANS-To increase intravascular volume and increase blood pressure What is passively reabsorbed in the thin descending loop of Henle - ANS-Water via medullary hypertonicity (impermeable to sodium) What is reabsorbed in the early distal tubule under the control of PTH - ANS-Ca ions continues...