Renal Flashcards
Removal of substances from blood into renal tubule at glomerulus.
Filtration
Removal of substances from blood into renal tubule at peritubular capillaries.
Secretion
Return of substances from renal tubule into blood at peritubular capillaries.
Reabsorption
Removal of substances from renal tubule through urine.
Excretion
Nephrons contain these parts:
- Renal corpuscle (glomerulus and Bowman’s capsule)
- Proximal convoluted tubule
- Loop of henle
- Distal convoluted tubule
- Collecting tubules
This part of the nephron actively transports sodium along with glucose, amino acids, etc. Water follows by solute drag. Counter transport of H+ and Na+. Almost all reabsorption occurs here but none of it is under hormonal regulation.
Proximal convoluted tubule
This part of the nephron reabsorbs sodium and potassium along with some water and generates interstitial salt gradient.
Loop of henle
This part of the nephron does the reabsorption of sodium, potassium reabsorption and secretion, hydrogen ion secretion, and is the site of aldosterone action.
Distal convoluted tubules
Water is reabsorbed here and it requires the interstitial salt gradient produced by the loop of henle. Site of ADH action.
Collecting tubules
The volume filtered from the glomeruli into Bowman’s space per unit of time.
Glomerular filtration rate
GFR is around this per day:
180 liters per day
This is an index of functioning renal mass.
Total GFR
The major driving force for filtration.
Hydrostatic pressure
The forces opposing filtration.
Osmotic pressure
Urine formed by these 3 processes:
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
This system helps regulate blood pressure and maintain blood volumes.
Renin-angiotensin system
Is released from the posterior pituitary and acts on renal tubules to allow for water reabsorption that depends upon the formation of a salt gradient by the loop of henle.
ADH
This hormone is released from cells of the cardiac atria in response to increased stretch and work to: counter fluid conserving effects to reduce blood volume and relieve blood pressure.
Atrial natriuretic peptide ( ANP)
ANP works generally opposite of
Aldosterone
The process of emptying the bladder.
Micturation
Specific gravity of urine should be:
1.003 to 1.030
A measure of urea in the blood
BUN
This reflects GFR and functional capacity of kidneys.
Serum creatinine
Provides an assessment of renal function.
GFR
Agents that increase water excretion.
Diuretics
Act at the proximal tubule to shift the osmotic balance. Ex mannitol
Osmotic diuretic
These work by inhibiting transports in the loop of Henle. This destroys the salt gradient generated by the loop of Henle and prevents water reabsorption under the influence of ADH from the collecting duct. Ex Lasix
Loop diuretics
These block the Na+ Cl- symporter in the DCT to block sodium reabsorption, this water remains in the lumen of the renal tubule for excretion.
Thiazide diuretics
These inhibit aldosterone, blocks Na+ reabsorption and increased K+ retention. Ex spironolactone
Potassium sparing diuretics
Represents several pathological states and usually involves inflammation of the glomerulus. May present with hematuria or proteinuria.
Glomerularnephritis
Is characterized by the passage of both protein and red blood cells out of the urine.
Nephritic syndrome
Five categories of glomerular disease:
- Acute nephritic syndrome
- Rapidly progressive glomerulonephritis (RPGN)
- Nephrotic syndrome
- Asymptomatic hematuria or proteinuria
- Chronic glomerulonephritis