Kidney and drug excretion Flashcards
Kidneys receive 20% of cardiac output. True or false?
True
What is the role of the kidneys?
Elimination of nitrogen-containing waster e.g urea and uric acid
Maintain water, ionic and pH balance in body fluids
Central role in filtering blood and forming urine
Production of hormones
Elimination of drugs and metabolites
Which region of the kidney filters blood?
glomerular
Where is the renal pyramid found?
In the medulla
The nephron represents a functional unit of the kidney. True or false?
True
What does the renal corpuscle consist of?
Bowman’s capsule
Glomerulus
What are the functions of the renal corpuscle?
Filter the blood (glomerular filtration)
After blood has been filtered, the remaining blood leaves the glomerulus via ___________
efferent arterioles
The renal copuscle has two arteries - one going in and one going out. True or false?
True
What is the advantage of using inulin?
There isn’t any present in the body unless it is administered so it gives a good indication for GFR
What factors influence GFR?
Body size
Gender
Age
GFR in men is higher than women. True or false?
True
Where does glomerular filtration take place?
From the glomerular capillaries to the Bowman’s capsule
Glomerular filtration is an active process. True or false?
False - it is a passive, non-selective process
How does tubular secretion work?
Selective transport of molecules from the peritubular fluid to the lumen of renal tubules - facilitates excretion
Tubular excretion involves either transporters or passive diffusion. True or false?
True
Tubular excretion takes place in proximal tubules only. True or false?
False - takes place in distal tubules too
Which transporters are expressed in the basolateral membrane of the renal epithelia?
OAT1
OAT3
OCT2
What does OAT1 transport?
Small organic anionic drugs
What does OCT2 transport?
Small organic cationic drugs
Transporters are present only on one side of the basolateral membrane of the renal epithelia. True or false?
False - present on both sides
How does tubular reabsorption work?
Selective transport of molecules from the lumen of the renal tubules back to the plasma
Is the descending loop of Henle permeable to Na+?
No
Is the ascending loop of Henle permeable to Na+?
Yes
Ascending loop of Henle passively absorbs Na+ and is not permeable to water. True or false?
False - actively reabsorbs
What affects the rate and extent of reabsorption of drugs?
Lipophilicity
Degree of ionisation
Unbound and unionised form of drug crosses the membrane. True or false?
True
Renal drug excretion is a net effect of which 3 processes?
Glomerular filtration
Secretion
Reabsorption
Nephron units are bad at removing nitrogenous wastes and conserving water and mineral ions. True of false?
False - very efficient at doing both
Why do diabetics experience increased urination?
Because there is glucose in the urine so an increase in osmotic pressure in the renal tubule, leading to decrease in water reabsorption and an increase in urination
For renal impairment, when is a dose adjustment needed?
If the fraction of drug excreted unchanged is more than 50%
Drugs with a narrow therapeutic window
Patient with impaired metabolism
