Renal anatomy, disease and gene models Flashcards
What are the proportions of each type of fluid in the body?
Transcellular- 1.5-2L
Plasma- 3-4L
Interstitial- 3-4L
Intracellular- 15-30L
What are the two types of nephron and how common are they?
Superficial nephron- mostly in the cortex, 85%
Juxtamedullary nephron- mostly in the cortex and outer medulla, loop of henle in the inner medulla 15%
What are examples of kidney congenital abnormalities?
Renal agenesis- absence of one or both kidneys
Ectopic kidney- leads to damage and stones
Horseshoe kidney- kidneys fused across the midline, renal stones
General kidney morphology
5.5 x 10 cm, 150g
From 12th thoracic to 3rd lumbar
What is renal failure? What are the two types of renal failure?
A fall in glomerular filtration rate- leads to an increase in serum urea and creatinine
Acute- reversible
Chronic- irreversible and needs dialysis or transplant
What is peripheral neuropathy? What type of renal failure is it present in?
Peripheral nerve damage leading to problems with sensations and movement
Chronic renal failure
What happens as renal failure progresses? What are this group of symptoms known as?
Thickening of glomerular membranes
Damaged glomeruli and progressive scarring which is called glomerulosclerosis
Tubular atrophy, interstitial inflammation and fibrosis
Reduction in renal size
Uraemia
What does failure to reabsorb salt and water lead to ?
Hypertension
The causes hyperkalaemia and mild acidosis
What does glomerular filtration permit and restrict?
Permits- water and small molecules
Restricts- blood cells and proteins
What is ultrafiltrate?
Consists of protein free plasma
What is transcellular reabsorption and secretion?
Transcellular reabsorption- from lumen of tubule to the peritubular capillary
Transcellular secretion- from the peritubular capillary to the lumen of the tubule
What is the function of the proximal tubule?
Bulk reabsorption, 70% of filtrate
70% of water and Na+
100% of glucose and amino acids
90% of HCO3-
What moves into the apical membrane of the proximal tubule? What channels are used?
Na+ and PO42- co-transported by NaPi II
Na+ and glucose- co-transpsorted by SGLT1 and SGLT2
Amino acids + Na+ also move in, water follows and is reabsorbed
What moves out of the basolateral membrane of the proximal tubule into the blood?
Glucose, PO42-, amino acids and K+
3Na+ out, 2 K+ in using ATPase pump
What happens when NaPi II gene is knocked out?
Less phosphate reabsorption
More loss in urine
Renal mineralisation
What is nephrolithiasis and nephrocalcinosis?
Nephrolithiasis- intraluminal kidney stones
Nephrocalcinosis- stones in renal parenchyma
From lack of phosphate re-absoprtion using NaPi II
What is the function of NHE3?
On the apical membrane of proximal tubule
As a Na+ ion comes in, H+ leaves and then forms carbonic acid with bicarbonate
Carbonic anhydrase dissociates it into CO2 and water which then move into cell
Reabsoprtion of sodium and bicarbonate into the plasma for pH regulation, water follows
What happens when NHE3 is knocked out?
Inhibition of sodium secretion- can’t reabsorb bicarbonate which leads to acidosis
Systolic BP falls due to reduction in ECF volume
What are the 2 systems of secretion in the proximal tubule?
What is the purpose of secretion here?
Organic anions
Inorganic cations
Removal of plasma protein bound substances and foreign compounds
What is the function of the loop of henle?
Concentration of urine
Reabsorption of Na+, Cl-, H2O, Ca2+, Mg2+
Site of action of loop diuretics
What is the structure of the loop and what does each part do?
Thin descending limb- water moves out
Thin ascending limb- Na+ and Cl- moves out
Thick ascending limb- Na+ and Cl- moves out
What proteins are found on the apical side of the thick ascending limb?
NKCC2
ROMK
What is the purpose of the Na+/K+ ATPase pump and the K+ channel on the basolateral membrane of cells in both the proximal tubule and the thick ascending limb of the loop?
Setting a negative membrane potential and a low intracellular Na+ concentration to drive the influx of Na+ into the cell
What is the function of NKCC2?
Brings 2 chloride ions and 1 potassium ion into the cell along with Na+
What substances experience net reabsorption in the TAL? What is the purpose of this?
Na+ and Cl-
Provides driving force of the transport of water in other segments as it sets up osmotic gradients for the other parts of the nephron
What channel does Cl- move out of on the basolateral side of the TAL?
CLCK
What is Barttin?
Not a channel- protein classes as a beta/accesspry subunit
Regulates CLCK- they only function when Barttin is also present