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30 Cards in this Set
- Front
- Back
What are the quantity and composition of body fluids dependent on?
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- Input (food, fluids, etc)
- Metabolism - Output (urine) |
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How much fluid is filtered through the glomeruli every day?
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180 L
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How much fluid flows through the kidneys every day?
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1728 L
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All but how much of the glomerular filtrate (180L) is reabsorbed per day?
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1.2 L (excreted)
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What is contained within the 1.2 L of daily excreted urine?
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By-products of metabolism as well as excess electrolytes
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What range of pH can the kidneys adjust the pH of urine within? Why?
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pH: 4.5 - 8.0
Allows it to excrete either base or acid to maintain constant plasma pH in vicinity of 7.4 |
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How can urine be used to determine disease states?
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- Abnormal metabolism will lead to abnormal end products of metabolism in urine (eg, porphyria)
- Presence of glucose indicates blood glucose level exceeds threshold value for total reabsorption (indicates diabetes mellitus) - Protein in urine indicates glomerular disease |
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What does the volume and osmolarity of urine tell us about a person?
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Body's state of hydration
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How does a severely restricted fluid intake affect the volume and osmolarity of urine?
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- Very little urine output
- Concentration of electrolytes (Na+ and K+), and solutes will be relatively high |
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What is the best index of dietary intake of Na+ and K+?
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24 hour excretion of Na+ and K+, respectively
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What happened in the renal experiment / dry lab?
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- Each subject ingested 1.5% body weight of specific fluid in 30 min or they have been given a drug to increase urine output
- Subjects provided urine samples at hourly intervals for 3 consecutive hours |
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How do you calculate Cosm (osmolar clearance)
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Cosm = (urine flow rate * Uosm) / Posm
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How do you calculate C_H2O?
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C_H2O = urine flow rate - Cosm
Cosm = (urine flow rate * Uosm) / Posm |
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What were the 7 treatment groups?
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- Ingestion of 1L of water
- Ingestion of 1L of water + ADH administration - Ingestion of 300 mL beef broth - Ingestion of 1L of kool-aid made up in a 30 mM sodium bicarb sol'n - Ingestion of 1L of beer - Injection of 10 mg/kg furosemide (inhibits Na+ reabsorption in thick ascending loop) - Injection of Acetazolamide (carbonic acid inhibitor that inhibits Na+ reabsorption in PT) |
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How do you calculate Urine Flow Rate?
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UF = (Urine Volume) / (Time of Collection)
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How do you calculate Clearance?
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Cx = [Ux] * UF / [Px]
Cx = clearance of substance X [Ux] = urine concentration of substance X UF = urine flow rate = urine volume / time [Px] = plasma concentration of substance X |
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How do you calculate the excretion rate of X?
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Excretion Rate of X = [Ux] * UF
[Ux] = urine concentration of substance X UF = urine flow rate = urine volume / time |
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What were the 7 treatment groups?
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- Ingestion of 1L of water
- Ingestion of 1L of water + ADH administration - Ingestion of 300 mL beef broth - Ingestion of 1L of kool-aid made up in a 30 mM sodium bicarb sol'n - Ingestion of 1L of beer - Injection of 10 mg/kg furosemide (inhibits Na+ reabsorption in thick ascending loop) - Injection of Acetazolamide (carbonic acid inhibitor that inhibits Na+ reabsorption in PT) |
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Which of the treatment groups can be distinguished based on having the highest pHs? Why?
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- Injection of Acetazolamide (carbonic acid inhibitor that inhibits Na+ reabsorption in PT)
- Ingestion of 1L of kool-aid made up in a 30 mM sodium bicarb sol'n (Both will have high pH) |
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How are bicarb solution and Acetazolamide similar? How can you distinguish them?
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- Both have high pH by hour 3
- Distinguish based on free water clearance - Bicarb (open squares) will excrete more free water |
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Which of the treatment groups will be the most different (very high urine flow, very high osmotic clearance, very high Na+ and K+ excretion)?
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Furosemide (inhibits Na+ reabsorption in thick ascending loop) = black diamonds
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Which of the treatment groups will have no changes for first couple of hours but then changes at 3rd time point? What kind of changes?
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- Ingestion of 1L of water + ADH administration (open triangles)
- No urine flow, osmotic clearance, or free water clearance until hour 3 - ADH and H2O cancel each other out until ADH wears off between hours 2 and 3, then H2O has its effect - ADH has no effect on Na+ or K+ |
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Which treatment groups stick out for having high free water clearance?
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- 1 L water (free water)
- 1 L beer (basically free water + alcohol) |
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How are 1L water and 1L beer similar? How can you distinguish them?
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- Both have high free water clearance
- Beer will cause more excretion of urine and free water clearance d/t alcohol (open circle) - 1L water is by default the other high free water clearer (dark triangle) |
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What treatment group remains and is determined by default
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Beef Broth (dark circles)
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A patient's plasma concentration of Na+ is 150 mM, GFR is 100 ml/min, urinary conc. of Na+ is 200 mM, and urine flow rate is 1.5 ml/min. Patient's fractional excretion of Na+ is what? What equation do you use?
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Fractional excretion of Na+ = ([Una] * UF) / (GFR * [Pna])
= (200 mM * 1.5 ml/min) / (100 ml/min * 150 mM) 2% |
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Adding a hypertonic solution to the systemic circulation cause what change in volume / osmolarity?
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- ↑ Extracellular Fluid Volume
- ↓ Intracellular Fluid Volume - ↑ Extracellular and Intracellular Fluid Osmolarity |
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As the tubular fluid moves from the beginning to the end of proximal tubule, how does the creatinine concentration change?
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Increased conc.:
- Not reabsorbed - As fluid is reabsorbed along PT, creatinine conc. is concentrated |
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Which mechanism most importantly contributes to the auto-regulation of GFR?
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Tubularglomerular Feedback (senses changes in Na+ delivery to distal tubule (often d/t change in GFR) and sends signals to glomerulus to bring GFR back to normal
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Stimulation of renal sympathetic nerves will do what?
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Constricts renal vessels → ↓ GFR & stimulates tubular reabsorption of Na+ and H2O by increasing renin release (AngII, Aldosterone)
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