L19 Gene Models And Nephron Functions 3 Flashcards
What are the two cell types within the late DT and CCD?
Principal and intercalated cells
Intercalated cells within the late DT and CCD are divided into sub divisions. What are they?
Alpha intercalated cells (IC)
Beta intercalated cells
What does Late distal, connecting tubules and cortical collecting duct do?
- Controls concentration of urine
- Reabsorbs Na+ and water
- Secretes K+ and H+.
What are the functions of each cell type within the CCD and late DT?
1.Principal - Na+ and water reabsorption, K+ and H+ secretion
2.Intercalated - H+ secretion and HCO3 reabsortion in alpha cells and vice versa in beta cells.
What does ENaC stand for?
Epithelial sodium channel
Explain how ions are moved out within the Principal cell
- ENaC, located on the apical membrane, allows Na+ ions to enter the cell from the tubular fluid.
- Sodium- potassium pumps pumps 3 Na+ out and 2K+ into the cell
- ROMK and Kir2.3 pumps potassium ions out
What does Amiloride do?
Amiloride block ENaC in the collecting duct and laste distal tubule leading to reduced reabsorption of sodium ions which increases urine excretion.
What is Liddle’s syndrome?
How do diuretics help with high blood pressure? (I’ll do this one)
What forms the Epithelial Na+ channels (ENaC)?
It is formed of 3 subunits which are:
Alpha
Beta
Gamma
How does Liddle’s syndrome lead to hypertension ?
Increased sodium reabsorption which leads to water retention causing hypertension.
How does the conc of reabsorption of sodium ions directly affect the amount of potassium ions diffuse out?
Sodium ions is reabsorbed causing an increase, this increase causes an electrochemical gradient to pump out sodium ions through NaK pump, to mainatin the gradient K+ ions is simulataneously diffused out.
What is hypokalaemia?
Low pottasium levels in the blood.
Slide 11
Explain how excessive Na+ transport in the principal cell leads to hypertension
