Functions of the kidney - ANS 1. Excretory functions
2. Regulation of BP via hormone production
3. Production of RBC's by erythropoietin
4. Bone health via Ca-Phos homeostasis
5. Acid-base balance
Excretory functions of the kidneys - ANS Kidneys remove waste products includin...
Functions of the kidney - ANS 1. Excretory functions
2. Regulation of BP via hormone production
3. Production of RBC's by erythropoietin
4. Bone health via Ca-Phos homeostasis
5. Acid-base balance
Excretory functions of the kidneys - ANS Kidneys remove waste products including urea,
excess vit and minerals, metabolites of drugs/poisons
180 L of filtrate pass through daily, produces 1-2 L urine
Regulation of BP by kidneys - ANS Kidneys maintain BP using renin-angiotensin system:
Low BP-- glomerulus secretes renin which signals angiotensin causing vasoconstriction, higher
blood volume, and aldosterone secretion (increases sodium in blood)
Production of RBC's by kidneys - ANS Kidneys produce erythropoietin which stimulates
RBC production in bone marrow
Kidney failure causes normochromic, normocytic anemia and must be treated with EPO and Fe
Bone health by kidneys - ANS Kidneys maintain Ca-Phos homeostasis by producing active
form of Vit D which enhances calcium absorption. Also eliminate excess Ca & Phos in urine.
Long term kidney failure=high osteoporosis risk due to calcium released into bloodstream
Acid-base balance by kidneys - ANS Buffer system maintains blood pH ~7.4
Bicarbonate carries hydrogen ions to kidneys where they are removed from extracellular fluid by
tubules and returned to bloodstream as needed
Nephron - ANS Functional unit of kidney containing glomerulus connected to tubules
Glomerulus - ANS Mass of capillaries inside nephron
Produces ultrafiltrate and provides barrier to loss of Pro and RBC's
Obligatory urinary output (UOP) - ANS 500 mL/d
, Oliguria- <500 mL/d
Usually accompanied by Azotemia- presence of nitrogenous bodies in blood like urea
What is kidneys main concern? - ANS Maintaining tight control of Na+ and blood volume
(BP)
If stressed, kidneys will sacrifice other functions and release aldosterone and anti-diuretic
hormone causing retention of Na+ and water
What is glomerular filtration rate and how is it determined? - ANS Glomerular filtration rate
is the best test to measure level of kidney function and determine the stage of kidney disease,
estimates how much blood passes through the glomeruli each minute
How is GFR used to determine renal failure? - ANS A GFR less then 15 ml/min is
considered renal failure
Diabetic Nephropathy - ANS elevated serum glucose damages the nephrons in the kidneys
How does high BP cause kidney disease? - ANS Damages the small blood vessels in the
kidneys making them unable to filter blood effectively
Polycystic Kidney Disease (PKD) - ANS a hereditary kidney disease in which many cysts
grow in the kidneys, may lead to kidney failure
Why is renal failure usually a progressive disease? - ANS Adaptations in renal function
occur and improve function short term
What is the difference between acute and chronic renal failure? - ANS Acute is sudden
caused by blood loss, drugs, or poisons-- may be reversed.
Chronic is gradual and progressive-- can take decades to progress to end stage renal disease
Glomerular disease - ANS Affects barrier function of the glomerulus and its capacity to
ultrafiltrate- includes nephrotic syndrome and glomerulonephritis (nephritic syndrome)
Nephrotic Syndrome - ANS Caused by the basement membranes of the glomeruli--
associated with diabetes, glomerulonephritis, amyloidosis, lupus
Causes large protein losses
Glomerulonephritis aka Nephritic Syndrome - ANS Inflammation of capillaries in
glomerulus--typically follows UTI and usually resolves itself
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