Homeostasis- Controlling Blood Water Potential Flashcards
Why does the amount of water in the blood need to be kept constant?
As water is essential to keep the body functioning
How is water lost in mammals?
Through excretion and through sweat
What is osmoregulation?
The kidneys regulate the water potential of the blood so the body has the right amount of water
What happens when the water potential of the blood is too low (the body is dehydrated)?
More water is reabsorbed by osmosis into the blood from the tubules of the nephrons- urine is more concentrated so less water is lost during excretion
What happens when the water potential of the blood is too high (the body is too hydrated)?
Less water is reabsorbed by osmosis into the blood from the tubules of the nephrons- urine is more dilute so more water is lost during excretion
Where is water reabsorbed into the blood?
Along almost all of the nephron
Where does regulation of water potential take place?
Loop of Henle, DCT and collecting duct
What controls the volume of water reabsorbed by the DCT and the collecting duct?
Hormones
Where is the loop of Henle located?
In the medulla of the kidneys
What is the loop of Henle made up of?
The descending limb and the ascending limb
What do the limbs in the loop of Henle control?
The movement of sodium ions so that water can be reabsorbed by the blood
What happens near the top of the ascending limb?
Sodium ions are pumped out into the medulla using active transport
Why does water stay inside the tubule of the ascending limb?
It is impermeable to water
What does water staying inside the ascending limb create?
A low water potential in the medulla because there’s a high concentration of ions
Why does water move out of the descending limb into the medulla by osmosis?
Because there’s a lower water potential in the medulla than the descending limb
