Kidney physiology incomplete Flashcards
What are the 3 parts of the glomerular barrier?
Podocytes (visceral epithelium)
Glomerular basement membrane
Fenestrated capillary endothelium
Hilum of every glomerulus - juxtaglomerular cell + macula densa
in every single glomerulus - responsible for releasing renin
What factors determine filtration in the kidney?
pressure - blood pressure from either side, osmotic opposes - ions up to 10kDa
size of the molecule - -ve charge repelled
charge
rate of blood flow - afferent and efferent artery
protein binding - proteins not pass over, things that bind to them can’t cross ‘you shall not pass’
what forces favour and oppose filtration?
Favour - glomerular capillary blood pressure
Oppose - fluid pressure in Bowman’s space
Osmotic forces due to protein
What is a marker in kidney testing? What are properties of a good one?
Level of presence in the urine indicates kidney function
good one… freely filtered, not secreted or absorbed BY TUBULES, not metabolised
Most common markers used to look for a normal GFR? does it have all properties of a good marker? what is a normal GFR?
creatine most often used - muscle metabolite, constant production
doesn’t ‘not secreted or absorbed’ - there is tubular secretion
inulin is the ‘gold standard’ but difficult in practise
normal - 125ml/min
What is involved in regulation of glomerular filtration?
Renal autoregulation… (maintaining)
Myogenic mechanism
Tubuloglomerular feedback
neural regulation…
sympathetic nervous system
Hormonal regulation
RAAS system
Atrial Natriuretic Peptide
Intrarenal baroceptors…
Extracellular fluid volume…
Blood colloid osmotic pressure
Inflammatory mediators
LEARN ALL OF THESE
What causes vaso constriction?
What causes vaso dilation?
constriction - renin
dilation - nitrogen oxide
Effect of these hormones on glomerular filtration rate…
Norepinephrine
Epinephrine
Endothelin
Angiotensin II
Endothelial - derived nitric oxide
Prostaglandins
Norepinephrine - dec
Epinephrine - dec
Endothelin - dec
Angiotensin II - prevents dec
Endothelial - derived nitric oxide - inc
Prostaglandins - inc
How does vasodilation of the afferent arteriole affect rate of glomerular filtration?
Vasoconstriction of afferent?
Dilation - decreased resistance - inc RBF, Pg anf GFR
Constriction - increased resistance
How does vasodilation of the efferent arteriole affect rate of glomerular filtration?
Vasoconstriction of efferent?
Which cell type in the glomerulus is responsible for the filtration of blood?
A) podocytes
B) mesangial cells
C) endothelial cells
D) tubular cells
C) endothelial cells
What is the name of the network of capillaries within the Bowman’s capsule where blood filtration occurs?
A) Peritubular
B) Vasa recta
C) glomerular capillaries
D) Cortical radiate arteries
C) glomerular capillaries
Which hormone regulates the diameter of the afferent and efferent arterioles to control glomerular filtration rate?
A) Insulin
B) Aldosterone
C) Antidiuretic hormone (ADH)
D) Renin
D) Renin
What is clearance? (kidney)
The volume of plasma from which a substance is completely removed by the kidney per unit time
