Term
| Urine Formation is responsible for? |
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Definition
•Filtration of blood to form an ultrafiltrate of urine and tubular re-absorption of electrolytes and nutrients needed to maintain constancy of internal environment while eliminating waste materials
•Movement of fluid thru glomerular capillaries is determined by the same factors: capillary filtration pressure, colloidal osmotic pressure and capillary permeability
•Glomerular filtrate similar to plasma without proteins; 125 ml of filtrate formed each minute (glomerular filtration rate or GFR)
•Arterioles innervated by SNS and sensitive to angiotensin II; shock constricts afferent arteriole and markedly decreases renal blood flow/urine |
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Term
| What is the Urine Formation rate |
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Definition
| 125 ml of filtrate formed each minute (glomerular filtration rate or GFR) |
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Term
| Role of anti-diuretic hormone |
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Definition
regulates the ability of the kidneys to concentrate urine.
Anti=prevents dieresis, retain water.
•Osmoreceptors in hypothalamus sense increase in osmolality of extracellular fluids and stimulate the release of ADH from the posterior pituitary gland.
•ADH also known as vasopressin binds to vasopressin receptors on blood side of tubular cells; this leads to opening of water channels on luminal aide of tubular cells producing a marked increase in water permeability
•H20 goes from tubule to peritubular capillary to return to vascular system
•Without ADH, water channels are closed, tubular cells lose water permeability and dilute urine is formed |
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Term
| Renal threshold definition e.g. blood glucose |
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Definition
•is plasma level at which the substance appears in urine – exceeds the transport mechanism
e.g. uncontrolled diabetes 320mg/minute spills into urine |
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Term
| Tubular Reabsorption and Secretion rate? |
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Definition
•Only 1 ml of 125 ml formed each minute is excreted in urine (other 124 is reabsorbed in tubules).
-Average urine output is 60 ml/hr |
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Term
| Regulation of renal blood flow |
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Definition
Angiotensin II, ADH, and endothelins produce vasoconstriction of renal vessels
•Kidneys perfused with 1000-1300ml blood flow per minute or 20-25% of CO; needed to ensure sufficient GFR for waste removal
•SNS innervates
•Dopamine, nitric oxide and prostaglandins dilate
•Constancy of renal blood flow is maintained by autoregulation
•Juxtaglomerular complex represents feedback control system linking GFR with renal blood flow; controls release of renin |
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Term
| Function of kidney focuses on elimination of? |
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Definition
•water, waste products, excess electrolytes, unwanted substances
•Renal clearance is volume of plasma that is completely cleared each minute of any substance finding its way to urine |
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Term
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Definition
| is a product of creatine metabolism in muscles; formation/release are relatively constant; freely filtered in glomeruli and not reabsorbed from tubules and is only minimally secreted into tubules; serum value depends closely on GFR –used as a measure of renal function |
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Term
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Definition
| - product of protein metabolism, normal adult produces 25-30 G/day, quantity rises with increased intake, tissue breakdown or GI bleeding. |
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Term
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Definition
| conserves HCO3; eliminates H+ |
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Term
Regulation of NA and K
Role of Aldosterone |
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Definition
•Atrial natriuretic peptide
-synthesized in muscle cells of atria and released with atria are stretched; -vasodilation of arterioles, inhibits Na reabsorption/ ADH release |
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Term
| Endocrine function of kidney including RAA, |
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Definition
| renin is synthesized and stored in juxtaglomerular cells of kidney, release in response to decrease in renal blood flow or change in composition of distal tubular fluid or SNS stimulation |
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Term
| Endocrine function of kidney including Erythropoietin |
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Definition
| polypeptide hormone that regulates the differentiation of RBC in bone marrow, 89-95% formed in kidneys, tissue hypoxia is stimulus for production |
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Term
| Vitamin D (activation occurs where?) |
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Definition
| occurs in kidney and is needed to increase Ca absorption from GI tract and regulate deposition in bone |
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Term
| ESRD End stage renal disease patients are unable to? |
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Definition
| transform Vitamin D to active form and must rely on supplements |
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Term
Urine and blood tests for kidney function (you will not be responsible for actual values)
•Urine test |
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Definition
-single or 24 hour specimen
–First voided and fresh best
–Casts are molds of distal nephron lumen
–Less than 150 mg of protein/24 hours; microalbumin
–Specific gravity valuable index of hydration status and functional status of kidney-1.010-1.025 |
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Term
| What substances are normally found in urine? |
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Definition
| None. Glucose, protein, ketones should never be in urine. |
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Term
Urine and blood tests for kidney
This test sample what to things to calculate the GFR? |
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Definition
| –Sample of blood and urine used to calculate |
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Term
Urine and blood tests for kidney
•Blood test measures? |
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Definition
–Serum creatinine – (0.6-1.2) screening measure; reflects GFR
–Value of cystatin C as a marker of GFR??
–Blood urea nitrogen (8-20 mg)-influenced by protein intake, GI bleeding and hydration status. Normal BUN to creatinine ratio 10:1-ratios greater than 15:1 represent a prerenal condition such as CHF or GI bleed |
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Term
Urine and blood tests for kidney
Distal Convoluted Tubules and Ducts |
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Definition
| •10% of filtered NaCl is reabsorbed in distal convoluted tubule; site of thiazide diuretics |
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Term
| What impact does aldosterone have on NA? |
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Definition
| •exerts its action on Na and K reabsorption in late distal tubule/collecting tubule; only responsible for 2-5% of NaCl reabsorption but is largely responsible for final sodium concentration of urine; also major site for regulation of K excretion by kidney |
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Term
| What effect does ADH have on water? |
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Definition
| •exerts its effect medullary collecting ducts; maintains extracellular volume by returning water to vascular compartment and leads to production of concentrated urine by removing H2O from tubular filtrate |
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Term
| What conditions have decreased ADH? |
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Definition
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