Renal function

Question 1

what makes up the renal system

Answer 1

paired kidneys
paired utterers
bladder
urethra

Question 2

What is the primary role of the renal system in homeostasis?

Answer 2

regulates body fluid balance, acid-base balance, blood pressure

Question 3

How does the renal system regulate blood volume and pressure?

Answer 3

By adjusting the amount of water reabsorbed or excreted, the kidneys control blood volume, which directly affects blood pressure.
RAAS responds to low blood pressure

Question 4

How does the renal system contribute to acid-base balance?

Answer 4

excreting hydrogen ions (H⁺) and reabsorbing bicarbonate (HCO₃⁻

Question 5

How do the kidneys respond to dehydration?

Answer 5

increase water reabsorption by concentrating urine. This is mediated by antidiuretic hormone (ADH)

Question 6

How does the renal system contribute to erythropoiesis?

Answer 6

The kidneys release erythropoietin (EPO) in response to low oxygen levels, stimulating red blood cell production in bone marrow, which helps maintain oxygen delivery throughout the body

Question 7

What waste products does the renal system eliminate to maintain homeostasis?

Answer 7

urea creatinine and excess ions to prevent toxin build up

Question 8

How do the kidneys help regulate calcium and phosphate balance?

Answer 8

They convert vitamin D to its active form, calcitriol, which promotes calcium absorption in the gut

Question 9

How do the kidneys contribute to glucose homeostasis?

Answer 9

filter glucose from the blood, reabsorb it in the proximal tubules, and engage in gluconeogenesis, especially during fasting

Question 10

Where in the kidney does glucose reabsorption primarily occur?

Answer 10

Glucose reabsorption primarily occurs in the proximal tubule. Here, glucose transporters (SGLT2 and SGLT1) reabsorb glucose from the filtrate back into the blood, preventing glucose loss in urine

Question 11

What is SGLT2 , and what roles does it play in glucose reabsorption?

Answer 11

sodium glucose transporter 2
is responsible for reabsorbing about 90% of filtered glucose in the early proximal tubule, 1Na:1glucose ratio

Question 12

What is SGLT1 , and what roles does it play in glucose reabsorption?

Answer 12

sodium glucose transporter 1
reabsorbs the remaining 10% in the later proximal tubule at a 2Na:1 glucose ratio

Question 13

What happens if blood glucose levels exceed the renal threshold?

Answer 13

glucose is excreted in the urine (glucosuria) occurs in uncontrolled type 1 diabetes

Question 14

How do the kidneys participate in gluconeogenesis?

Answer 14

The kidneys perform gluconeogenesis, particularly in the renal cortex, producing glucose from non-carbohydrate sources (e.g., lactate, glutamine) during prolonged fasting or metabolic stress. This process is regulated by hormones like cortisol and glucagon

Question 15

How does diabetes affect glucose handling in the kidneys?

Answer 15

can increase SGLT2
can worsen hyperglycemia by promoting excessive glucose reabsorption instead of allowing excretion

Question 16

How do SGLT2 inhibitors affect glucose handling in the kidneys?

Answer 16

SGLT2 inhibitors block glucose reabsorption in the proximal tubule, increasing urinary glucose excretion. This helps lower blood glucose levels in people with type 2 diabetes, also leading to a mild diuretic effect that can aid in blood pressure reduction

Question 17

What hormones regulate renal glucose handling?

Answer 17

insulin and glucagon

Question 18

What role does the GLUT2 transporter play in kidney glucose handling and where is it located?

Answer 18

located on the basolateral membrane of proximal tubule cells, facilitates passive diffusion of reabsorbed glucose into the bloodstream after it has been transported from the filtrate via SGLT2 and SGLT1

Question 19

what is the glomerular filtration rate

Answer 19

125 ml/min-1

Question 20

renal glucose handling is intrinsic/extrinsic?

Answer 20

intrinsic

Question 21

what mediate gluconeogenesis and where does it mostly occur

Answer 21

glucose 6 phosphate
liver

Question 22

higher plasma glucose = _____________ glucose filtration rate

Answer 22

higher

Question 23

uncontrolled diabetes leads to

Answer 23

glucose in urine = glucosuria
increase volume of urine = polyuria
increased thirst = polydipsia

Question 24

What is the renal threshold for glucose, and how does it relate to glucose reabsorption?

Answer 24

10mM
Above this threshold, the glucose transporters in the proximal tubule become saturated, and any excess glucose cannot be reabsorbed and is instead excreted.

Question 25

site of SGLT1

Answer 25

Intestine and kidney

Question 26

site of SGLT2

Answer 26

kidney

Question 27

renal location of SGLT1

Answer 27

Late proximal tubule

Question 28

renal location of SGLT2

Answer 28

early proximal tubule

Question 29

which SGLT has a high affinity for glucose and which one has a low affinity

Answer 29

SGLT1 has high
SGLT2 has low as plenty glucose available

Question 30

treatment for type 2 diabetes

Answer 30

inhibition of SGLT2
eg canagliflozin, dapagliflozin, empagliflozin, ertugliflozin