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45 Cards in this Set
- Front
- Back
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Why do BUN and creatinine rise with declining renal function? |
Because the body produces and eliminates them at a constant rate when renal function is healthy. |
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Can the kidney synthesize bicarbonate? |
Yes |
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What hormone does the kidney produce for stimulating growth of red blood cells? |
Erythropoetin |
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What induces the production of EPO?
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Hypoxia
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How does hypoxia induce the production of EPO? |
Hypoxia-inducible factor-1 is degraded by prolyl hydroxylase and ubiquitin (PH/E3) in normal oxygen concentration, but when oxygen concentration drops, HIF-α dimerizes with HIF-ß to stimulate transcription to EPO. |
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What vitamin is regulated by the kidney?
What enzyme activates it? |
Vitamin D
1 alpha-hydroxylase |
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What is the product of 25-OH vitamin D and 1 alpha-hydroxylase? |
1, 25 dihydroxy vitamin D |
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In what part of the nephron is vitamin D activated? |
proximal tubule |
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What effect do the kidneys have on glucose metabolism?
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They make more glucose by gluconeogenesis.
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What do the kidneys do to peptide hormone?
How? |
clear them
Takes them internally and degrades them and then excrete amino acids |
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What happens when renal function drops significantly? (8) |
- Metabolic acidosis |
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What is the normal level of plasma potassium levels? |
4.0 mEq/L |
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What is uremic toxicity? |
Urea biproducts in blood increase as a result of renal dysfunction |
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What is azotemia? |
Increase in plasma concentrations of BUN and creatinine |
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What is the lowest percent of renal function that can still maintain body fluid homeostasis? |
20% |
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What happens to glomerular filtration rate (GFR) as renal blood flow decreases? |
It also decreases |
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What are two causes of nephrons breaking down?
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Drug toxicity and ischemia
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What are the 3 types of acute renal failure?
Describe them. |
Pre-renal ARF: reduced blood flow
Intra-renal ARF: acute tubular necrosis
Post-renal ARF: Urinary tract obstruction |
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What are 3 major causes of chronic renal failure? |
- Diabetes - Hypertension - Glomerulonephritis |
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How low must glomerular filtration rate reach before it is considered end-stage renal disease? |
Less than 10% |
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Is chronic renal failure reversible? |
No |
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What two options does a patient have for survival once they have reached renal failure? |
Kidney transplant or dialysis |
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Do ions move across a membrane during dialysis? |
Yes |
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What are the two types of dialysis? |
- Hemodialysis - Peritoneal dialysis |
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Do the blood and dialysis flow in the same direction? |
No, opposite directions |
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How is water pushed out of blood in hemodialysis to reduce blood volume? |
increasing hydrostatic pressure on the blood side of the dialysis membrane |
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How often would a patient need to get hemodialysis?
How long does it take? |
3-4 times a week
For 3-4 hours at a time |
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Why does body weight increase between dialysis events? |
Body retains water |
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What ratio of water is extracellular?
Intracellular? |
Extracellular - 1/3
Intracellular - 2/3 |
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What percentage of extracellular fluid comprises plasma?
Interstitial fluid? |
Plasma - 25%
Interstitial fluid - 75% |
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What percentage of extracellular fluid comprises trans-cellular fluid?
Give some examples. |
5%
CSF, aqueous humor, urine |
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What is the primary cation in intracellular fluid? Extracellular? |
Intracellular: potassium
Extracellular: sodium |
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What maintains the huge difference of sodium and potassium between inter and extracellular fluid compartments? |
Na/K ATPase |
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What are the intracellular primary anions? |
Intracellular: organic phosphates and proteins
Extracellular: chloride and bicarbonate |
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In what fluid compartment is extracellular protein contained? |
Plasma |
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What is an added benefit of having more protein stored in plasma rather than in interstitial fluid? |
Proteins can bind calcium and magnesium and increase their plasma concentrations |
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What equation can be used to estimate plasma osmolality? |
P-osm = 2[Na] + ([glucose]/18) + ([BUN]/2.8) |
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Describe the dilution principle. |
Add a known mass of substance into a fluid compartment and allow it to reach equilibrium, then take a known volume and use the amount added divided by the density extracted to calculate the fluid compartment volume |
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What substances can be used to determine the volume of extracellular fluid? (4) |
- Radiolabeled sodium - Sucrose - Mannitol - Inulin |
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What substances can be used to determine the volume of plasma? (2) |
- Iodinated albumin - Evans blue (T-1824) |
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What substances can be used to determine the volume of total body water? (3) |
- Tritiated water - Deuterated (heavy) water - Antipyrine |
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What precaution must be taken when using fluid volume markers to determine volume of fluid spaces? |
You must use the same one before and after experimental conditions have been applied bc of slight deviations in distribution. |
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Between osmolarity and osmolality, which is temperature dependent? |
Osmolarity |
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Why is 290 mOsm/L of urea is hypotonic? |
Because urea can penetrate membranes and thus reduce its extracellular concentration. |
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What are 4 things that can change tonicity of plasma? |
1) Ingesting water 2) Dehydration 3) I.V. infusions 4) Fluid losses |
