Renal function and glucose homeostasis Flashcards
1
Q
Functions of the kidney
A
- maintain water balance
- maintain osmolarity of body fluids
- regulate the quantity and concentration of most ECF ions
- maintain plasma volume
- maintain acid-base balance
- excrete end products of bodily metabolism
- excrete foreign compounds
- producing erythropoietin
- producing renin
- converting vit D into active form
- glucose homeostasis
2
Q
What is the urinary system composed of?
A
- 2 kidneys
- renal arteries and veins
- ureter
- urinary bladder
- urethra
3
Q
Where does filtration, absorption and secretion take place
A
nephron
4
Q
Glomerular filtration
A
- from blood protein-free plasma (~20%)
- filters through glomerular capillaries into the Bowman’s Capsule at a rate of ~125ml/min
5
Q
Tubular reabsorption
A
- substances of value are returned to the particular capillary plasma
6
Q
Tubular secretion
A
Selective transfer of substances from the peritubular capillary blood into the tubular lumen
7
Q
Gluconeogenesis
A
- synthesis of new glucose from non-carbohydrate sources
- mediated by glucose-6-phosphate
- occurs mostly in liver and also in kidney
8
Q
Rate limiting step in secondary active transport in kidney
A
how much glucose can enter body and how much can be absorbed
9
Q
Secondary active transport of glucose into kidney
A
- co-transported with sodium
- sodium gradient is maintained by ATP-driven Na-K pump
- SGLT (SGLT1 and SGLT2 in kidney)
10
Q
Rate limiting factor of glucose filtration
A
Renal threshold
11
Q
Side effects of inhibiting SGLT1
A
- low bioavailability
- rapid degradation
- hydrolysed in the gut to phloretin
- phloretin inhibits GLUT1
- acts on SGLT1 in the GI tract, causing glucose and galactose malabsorption, dehydration and diarrhoea
12
Q
Side effects of SGLT2 inhibitors
A
- glucosuria (intended)
- weight loss
- decreases in blood pressure
- increased incidence of genitourinary infections
- polyuria
- increased dehydration
- raised ketones
