Gene Models & Nephron Function Flashcards
What brings blood into the glomerular capillaries
afferent arteriole
What does the bowman’s capsule filter?
plasma
What is permitted to move through glomerular filtration
water, small molecules, ions
What does glomerular filtration restrict
blood cells, proteins
What does the ultra filtrate produce
protein free plasma
Where does secretion occur from in glomerular filtration
from capillary into lumen of tubule
What are the two pathways for transport
transcellular, paracellular
What is transcellular transport
transport across the cell
Describe reabsorption
lumen into the capillary
What is paracellular transport
between cells
What is the main role of the proximal tubule
bulk reabsorption of filtrate
What organelle does the proximal tubule have lots of
mitochondria
Why does the proximal tubule have lots of mitochondria
need ATP for reabsorption
What channels are located on the apical side of the proximal tubule
SGLT1, SGLT2, NaPiII, NHE3
What channels are located on the basolateral side of the proximal tubule
sodium potassium ATPase, potassium channel
Why does the proximal tubule have a high SA
maximise transport
What is reabsorbed in the proximal tubule
100% glucose and AAs, 90% bicarbonate, 70% water and sodium
What is the key transport protein on the basolateral membrane of proximal tubule
sodium potassium ATPase
What sets up the negative membrane potential on the basolateral side of the proximal tubule
Sodium potassium ATPase, potassium channel
What happens in NaPiII knockout mouse
less phosphate reabsorption, phosphate lost into urine, plasma phosphate low
What are the symptoms of NaPiII knockout mouse
renal mineralisation, bone mineralisation, increased calcification, stones
How is familial renal glycosuria inherited
autosomal recessive
Describe the characteristics of familial renal glycosuria
increased urinary glucose, normal plasma glucose levels
What is the function of carbonic anhydrase
breaks down carbonic acid into CO2 and water
How does water move into the cell in the proximal tubule
Aquaporin 2
Where is carbonic anhydrase located in the proximal tubule
extracellular surface, inside the cell
What is the function of bicarbonate
maintain and regulate normal body pH
What are the symptoms of renal NHE3 knockout mice
bicarbonate excreted in urine, pH acidic, systolic BP low,
Why is BP low in renal NHE3 knockout mice
ECF volume decrease
TRUE or FALSE - Renal NHE3 knockout mice exhibit reduction in water reabsorption by proximal tubule
True
What is inhibited in the NHE3 knockout mouse?
H+ secretion across apical membrane, Na+ and HCO3- transport
Why does the NHE3 knockout mouse have a lower plasma pH
lower plasma HCO3-
What is the function of SGLT1 and SGLT2
reabsorb glucose across apical membrane
What is the function of NaPiII
reabsorb phosphate - across apical membrane
What is the function of NHE3
secrete hydrogen ions across the apical membrane
What happens if phosphate isn’t reabsorbed across apical membrane
less phosphate reabsorption, phosphate lost into urine, low phosphate plasma levels
How are glucose levels affected in familial renal glycosuria
normal
How are urinary glucose levels affected in familial renal glycosuria
increased
TRUE or FALSE - CO2 can diffuse across the membrane in the proximal tubule
TRUE
What is recycled across the apical membrane in the proximal tubule
hydrogen ions
What does the normal function of NHE3 allow
breakdown of carbonic acid
What does NHE3 help to maintain
normal bicarbonate levels in plasma
