(final) Lecture 12 (5/18/16) PT. 1 Flashcards
What is hyperconcentration? What allows hyperconcentration of substances?
“concentrating the filtrate that we’re creating when we’re filtering our blood” - Noriega
Countercurrent exchange allows this
Definition of countercurrent exchange:
a pair of adjacent channels or tubes containing fluids flowing in opposite directions and having a gradient directed between one channel and the other
*stuff can flow between tubes
When the rate of transport from the top tube to the bottom tube is the same as the rate of transport from the bottom tube to the top tube, what is that called?
equilibrium
*no net transfer
If the concentration gradient remains the same the entire time those tubes are passing by each other, will it reach equilibrium?
No
*the top tube will continue to be able to transfer into the bottom tube
In a warm environment/on a hot day, you want to get rid of excess heat. Are we dealing with countercurrent exchange?
No; we’re trying to get rid of heat, not conserve it.
In a cold environment/on a cold day, you want to retain heat. Are we dealing with countercurrent exchange?
Yes; we’re trying to conserve as much heat as possible
What is the smallest functional unit of the kidney?
nephron
*filtration of blood
The kidney/renal lobe consists of…
renal pyramid (medulla)
renal cortex
*and a bunch of nephrons
True or false:
One collecting duct can collect from multiple nephrons.
true
The countercurrent exchange in a nephron is at the…
Loop of Henle
There is active transport in only one direction in the kidney. What’s being transported and to where?
Salts are being transported to concentrate salts in the urine
What makes up the renal corpuscle?
Bowman’s (nephron) capsule
Glomerulus
What does the glomerulus do?
It is a ball of capillaries that exchanges substances
What is the “beginning” of the nephron and also the tube/duct system of the nephron?
Bowman’s capsule
Where does the filtrate that comes from the renal corpuscle go?
The lumen of Bowman’s capsule
From Bowman’s capsule, where does the filtrate go?
Proximal convoluted tubule
After the proximal convoluted tubule, where does the filtrate go?
Loop of Henle
Is the Loop of Henle in the cortex or the medulla?
medulla
the filtrate goes from the cortex to the medulla to the cortex
After the Loop of Henle, where does the filtrate go?
Distal convoluted tubule
What’s the initial part of the Loop of Henle? What’s the later part?
Descending limb
Ascending limb
Through what does the filtrate go when it enters the renal corpuscle?
the afferent arteriole
What is the afferent arteriole doing?
bringing blood into the glomerulus
The blood goes through the capillaries in the glomerulus and comes out where?
the efferent arteriole
The afferent and efferent arterioles make a V with a little “crotch” in the middle. What is in between them?
the distal convoluted tubule
Why is it significant that the distal convoluted tubule is in between the afferent and efferent tubules?
There is a collection of cells in that area where the vessel and the tube are next to each other
What are the cells called that are in between the distal convoluted tubule and the glomerulus?
juxtaglomerular cells
What do the juxtaglomerular cells make up?
the juxtaglomerular apparatus
What do the juxtaglomerular cells sense?
pressure
What is the significance of the juxtaglomerular cells sensing pressure?
blood is made up of mostly plasma and plasma is mostly water; the cells are sensing the water pressure to see how much water there is in the body
*the higher the blood pressure, the higher the water pressure
What solvent is used in the kidney?
water
Kidney function:
flitration
water balance regulation
The filtration process begins with the…
filtration membrane at the renal corpuscle
Capillaries have holes called…
fenestration
What initiates concentration of glomerular filtrate?
proximal convoluted tubule
75% of _______ is removed by active transport in the proximal convoluted tubule. What follows passively?
sodium
chloride
The remaining fluid concentration in the nephron tube is ___________ as that of surrounding interstitial fluid.
about the same
Remember…
What do you need for depolarization?
sodium
Most of the sodium you’re recovering during reabsorption is going into the…
proximal convoluted tubule
“Drawing the sodium (positive) back in, the chloride (negative) does what?”
passively comes back in
What kind of cells are in the medulla?
mesenchymal
