Zoltan's Kidney Failure Flashcards
What is the apex of a medullary pyramid called?
A renal papilla
How many nephrons are there in a kidney?
1,000,000 (10^6)
Where are erythropoietin producing cells located?
In the renal cortex
Are kidneys intrapertioneal or retroperitoneal?
Retroperitoneal
Where is the main site of Mg2+ reabsorption?
Thick ascending limb
What happens to proteins larger than 70kD at the basal lamina of the glomerulus?
They are excluded and not filtered
What do loop diuretics inhibit?
Inhibit Na+-K+-2Cl- pump
What is the thin transparent tough capsule surrounding the kidneys?
Renal capsule
Why is the collecting tubule negative?
ENac channels
What is clearance equal to in terms of urine and plasma concentration and urine volume?
(urine conc. divided by plasma conc.) x urine volume
How long is the long axis of a normal kidney?
10 cm
Which cells detect [Na]+?
Macula densa cells
How is the pH of someone’s blood tested?
A sample of arterial blood
What is the current preferred term for impaired kidney function with rapid onset?
Acute kidney injury
Name a drug that causes K+-sparing diuresis
Spirolactone
What causes pressure diuresis?
Prostaglandins and nitric oxide
Where do renal arteries usually arise from?
Lateral aspect of the abdominal aorta just below the superior mesenteric artery at L1/2
What does ADH cause reabsorption of?
Water and urea
What is the retroperitoneal organ lying between the kidneys?
The pancreas
What is the fat deep to the renal fascia known as?
Perirenal fat
What is Tm for glucose?
380mg/min
Where are ENaC channels found?
Late distal tubule and collecting duct principle cells
Where do the afferent nerves of the kidney go to?
T10-11 carrying sensory information
Does the DCT or PCT contain more urea?
DCT
What is the pKa of bicarbonate?
6.1
Which receptors and second messengers does ADH work via?
cAMP, V2 receptors and aquaporin-2
What muscles do the kidneys come into contact with and how?
Diaphragm is superior to the kidneys
Transversus abdominis is lateral and posterior to the kidneys, quadratus lumborum is middle and posterior and psoas major is medial and posterior
Does angiotension II constrict the efferent or afferent arteriole more?
Efferent
What kind of muscle surrounds ureters?
Smooth muscle
Which part of the Loop of Henle pumps out Na-K-2Cl?
The thick ascending limb
Which substance has a clearance most closely reflecting GFR?
Inulin
Which cells secrete renin and when?
Juxtaglomerular cells in response to low plasma [Na+] and low blood pressure
Which part of the Loop of Henle is impermeable to water?
The whole ascending limb
Where is ADH released from?
The posterior pituitary
Where do the PCT and afferent arteriole come into contact?
At the juxtaglomerular apparatus
How does the vena cava lie at the level of the kidney?
Right and anterior to the aorta
When are renal blood flow and glomerular filtration rate increased?
After feeding
Where does net H+ secretion occur?
In the collecting duct
How does the liver respond to acidaemia?
Producing glutamine from glutamate
What does acidosis cause?
Hyperkalemia
Where is oncotic pressure higher than hydrostatic pressure
In part of the efferent arteriole and peritubular capillaries
What are the three zones of the cortex of the suprarenal glands?
Zona glomerulosa, zona fasciculata and zona reticularis
What is the NHE pump?
Na+/H+ antiporter to secrete H+
What is the most important buffer in blood?
HCO3-
Where are mesangial cells found?
In the glomeralus
What does the paracellular pathway allow reabsorption of?
Water and ions
What percentage of nephrons have a long loop of Henle?
12%
Where do anatomical end-arteries supply in the urinary system?
The kidney lobes but not sections of the ureter
Where do arcuate arteries run?
Between renal cortex and renal medulla
What does hypokalemia result in?
Neuromuscular depression
Where else except the kidney do renal arteries give branches?
A small inferior suprarenal branch to the suprarenal gland and a branch to the ureter
How are right and left suprarenal glands shaped?
Right: triangular
Left: crescent shaped
How is filtered protein reabsorbed?
Endocytosis
What does calcium bind to in DCT epithelial cells?
Calbindin
What does the counter-current multipler partially depend on?
Action of ADH on urea transport
What is the diameter of a filtration slit?
25-65 nm
What happens to the osmolality of fluid as it ascends the loop of Henle?
Decreases osmolality
What is a renal pyramid?
A segment of renal medulla ending at the renal papilla
What is a medullary ray?
A projection of renal medulla into renal cortex
What does the vasa recta supply?
The renal medulla
What is normal bicarbonate concentration?
24 mM
Where do thiazide diuretics work? What do they inhibit?
DCT. Na+-Cl-
Where are the kidneys located in terms of vertebra, costal cartilage and plane?
At vertebra T12- L3, 11-12th costal cartilage in the transpyloric plane
How are amino acids reabsorbed?
Via Na+ cotransporter
How much K+ is filtered and excreted?
5%
How many lobes does a kidney have?
10-18
What is the normal range for urine concentration?
60-1400 mOsm
What is the autonomic innervation of the kidney?
Sympathetic T10-12 controlling renal perfusion
How many litres of plasma do the kidneys filter per day?
180 L
Why is the basolateral membrane of the PCT covered in many interdigitations?
For many Na+/K+ATPase transporters
How is inulin treated by the kidneys?
Filtered and none reabsorbed
Where does ADH increase water reabsorption?
Collecting duct
Where are the ureters compressed?
The pelvo-ureteric junction, external iliac artery and uretero-vesical junction
What does the macula densa sense and what does it release?
Senses Na+, K+ and Cl-
Releases adenosine
What happens to kidneys during chronic kidney disease?
They shrink
What do thiazide diuretics inhibit?
Na+-Cl- pump in early DCT
What is normal H+ concentration?
40 nM
What is normal anion gap metabolic acidosis due to?
Bicarbonate loss
How is glomerular filtration rate autoregulated?
Intrinsic constriction of afferent arteriole and tubuloglomerular feedback from DCT
Where are macula densa cells found?
In the DCT
Which diuretics are often used together?
Furosemide and amiloride
What do mesangial cells do?
Carry out phagocytosis
What is the normal pH of urine?
3-5
What do podocytes share a basal lamina with?
Fenestrated glomerular endothelium
How does sodium excretion in kidney determine blood volume?
Indirectly, by altering plasma osmolarity
Which side does the renal vein receive the gonadal vein on?
The left
How do oncotic and hydrostatic pressures change as you move along the glomerular capillaries?
Hydrostatic remains the same and oncotic pressure goes from low to high
What is average glomerular filtration rate?
120ml/min
Where are Vitamin-D producing cells located?
In the proximal tubule
What does increased H+ conc. do to K+ conc.?
Increases it
When does the collecting duct become permeable?
In response to ADH
Where does ketoacidosis affect water reabsorption?
In the collecting duct
What can cause hyperkalemia?
Renal failure, ACE inhibitors
How is HCO3- treated by the kidneys?
Filtered and all reabsorbed
Which substance is completely filtered and secreted?
PAH
What is the glomerulus?
The ball of capillaries through which blood plasma enters the renal tubule
What do ROMK channels facilitate?
K+ efflux into the tubule
What is the maximum length of a kidney tubule?
55mm
What does renin cause?
Conversion of angiotensinogen to angiotensin
What finding may indicate kidney disease?
A GFR below 60 ml/min
Where is fluid hypotonic in the absence of ADH?
DCT and collecting duct
What does the clearance of a substance which is completely filtered and secreted equal?
Renal plasma flow
How much water and NaCl is absorbed in the PCT?
50% of both
What does the zona reticularis do?
Secretes precursors of steroid sex hormones
Where do osmotic diuretics work? What do they inhibit?
Entire tubule, none
Where does active reabsorption of NaCl take place?
In the thick ascending limb, distal tubule and collecting duct
Where do loop diuretics work? What do they inhibit?
Thick ascending limb. Na+-K+-Cl-
When will the clearance of a substance equal GFR?
When it is filtered, not secreted and not reabsorbed
What does aldosterone do to K+ and Na+?
Causes K+ excretion and Na+ reabsorption
Where does the suprarenal vein drain into on the right and left?
The vena cava on the right and the renal vein on the left
What are the resistances of afferent and efferent arterioles in the glomerulus?
Both high
How can diuretics cause hypokalemia?
K+ secretion in collecting duct
How is PAH treated by the kidneys?
Filtered, not reabsorbed, and secreted
Where does the ureter enter the bladder?
Obliquely into the base of the bladder at the apices of the trigone
Where does ADH work?
The principal cells of the collecting duct
How do renal arteries divide after they enter the hilum of the kidney?
Into 5 segmental arteries then into interlobar, arcuate and cortical radiate arteries before forming the afferent arteries for the glomeruli
How much Mg2+ is reabsorbed in the PCT?
30%
What is the consequence of segmental arteries being end arteries?
If they are tied off or blocked then the section of kidney that is supplied by that artery will die (become ischemic)
What is anuria?
Daily urine production of up to 50ml
What is hydrostatic pressure in Bowman’s space?
10 mmHg
What are the main urinary buffers?
HPO42- and NH3
What is the diaphragm between podocyte foot processes called?
A filtration slit
What is the half life of ADH?
15 min
How small must a molecule be for filtration of it to be unselective?
10kD
When is anion gap relevant?
In metabolic acidosis
Which part of the colon does the left kidney lie next to?
The splenic flexure, posteriorly
Which kidney does the duodenum lie next to?
Right kidney
What happens to H+ and HCO3- in type A intercalated cells of the collecting duct?
H+ is secreted and HCO3- synthesised
What can hyperkalemia result in?
Cardiac arrest
What does hyperkalemia cause?
Acidosis
What is the anion gap?
[measured plasma cations] - [measured plasma anions]
How does ANP work?
Inhibiting renin-angiotensin system and ENaC channels
Which cells detect blood pressure?
Juxtaglomerular cells
What substances does the sodium gradient in the PCT help recover?
Amino acids and glucose
What does the zona glomerulosa do?
Controls salt and water balance
Where are osmoreceptors located?
Hypothalamus
Where does the left kidney reach, posteriorly?
11th rib and L2-3
What kind of epithelium has thickened plaques of membrane which can be internalised?
Transitional epithlium
What does the zona fasciculata do?
Regulates body carbohydrates
What is minimum urine production a day?
400ml
What is a nephron composed of?
A renal corpuscle and a renal tubule
Where do K+-sparing diuretics work? What do they inhibit?
Collecting tubule. ENaC and ROMK
At what concentration will glucose appear in the urine?
11mM
What is normal GFR?
125ml/min
What is the main pump on the basolateral membrane of the PCT?
Na+-K+ATPase
What does the medulla of the suprarenal glands do?
Has chromaffin cells that augment the sympathetic nervous system by secreting adrenaline and noradrenaline
Which substance decreases in concentration along the length of the PCT?
HCO3-
Which physiological cation is secreted the most?
H+
What does Tm apply to?
Reabsorption and secretion
