Loop Of Henle Flashcards
What are the two parts of the loop of Henle?
Descending limb
ascending limb
What is a nephron?
Glomerulus+Bowman’s capsule+ proximal convoluted tubule + Loop of henle + distal convoluted tubule
How many nephrons are there typically?
2.4 million
What is the osmolality in the blood?
300 mosm
What is it when it leaves the PCT?
300 mosm
Why is it still 300 mosm?
65% was water 65% was sodium- reabsorbed same amount
It is isotonic with the blood plasma entering loop of henle mosm changes
What are the changes to osmolality in the renal medulla as we go down the loop of henle
It increases!
300–>500—>700—> 900 mosm—> 1200 mosm
What is happening to the plasma osmolality/medulla interstitial osmolality?
It’s getting saltier, more hypertonic as you go down the renal medulla.
Osmolality
High osmolality= high amounts of sodium and chorides/ solutes in the blood, and low water
Hypertonic^
Low osmolality= less solute, more water in the blood.
Hypotonic
solutes= water
Isotonic as it is the same
What does it mean when the osmolality is increasing as we go down the renal medulla?
Lot’s of solutes, very little water
Where are all these salts being pumped to?
Medullary interstitial space
How does this happen?
Sodium potassium 2 chloride co transporter!
how does the Sodium potassium 2 chloride co transporter work
Takes sodium, potasium, chlorine, from lumen of the filttrate into the tubule cell of the ascending limb
They have special channels on the basolateral membrane that correspond with the ions brought in
This causes the sodium, chlorine pushed out, and some potassium leaked out
What effect does this have?
It increases saltiness due to the transporter pumping out the salts
What part is this mechanism found in?
Ascending loop of henle
Descending limb
Water loves to follow the sodium and chlorine
If there is an accumulation of solutes outside the descending limb, water moves out of it
How does the water leave
Starts flowing out due to the obligatory water reabsorption
Water leaves through Aquaporin I channels
These channels are always open
What is the mechanism wherein water moves out in the descending limb, and solutes move out in the ascending limb?
Counter-Current Multiplier mechanism
Why can’t solutes move out of the descending limb?
It is completely impermeable to solutes!
What is special about the ascending limb?
Completely impermeable to water!
How many chlorines move out via the transporter
2 chlorines
How does osmolality inside the loop of henle change?
It equals the outside mosm (interstitial mosm)
What is the osmolality inside the descending limb at the bottom before the ascending limb?
1200 mosm
What does it mean if it has a high osmolality?
Lots of solute, less water
hypertonic
