The Nephron- Renal tubule Flashcards
How long is the renal tubule?
3 cms
What three parts make the renal tubule?
1- Proximal convoluted tubule (PCT)
2- loop of Henle, which concentrates
3- Distal convoluted tubule (DCT)
The renal tubules are surrounded by ______ ______ and ________ _______.
Peritubular capillaries
Vasa recta
What is the function of peritubular capillaries and the vasa recta?
These small blood vessels allow the reabsorption of the kidney to proceed
Along the PCT, the epithelial cells have a microvilli_____ ______ on their apical surface (facing the filtrate) to allow them to bring back, or _______ some filtered water and solutes that the body can still use
brush border
reabsorb
Reabsorbed material will then go across the basal portion of the ______ cells, out into the ___ and finally towards surrounding blood vessels and thus, back into the _____..
epithelial
ECF
Blood
The kidneys reabsorb ___L of 180L filtered daily.
179L
The body must get rid of some ions and substances that are toxic or not needed. This process is called:
secretion
From the blood vessels along the PCT and DCT, these unwanted substances will be ______ _______ into the filtrate.
actively transported
90% of K+ are filtered, but most are _____ it’s fine-tuned by secretion.
reabsorbed
What is hyperkalemia?
More K+ A less negative membrane potential, therefore easier action potentials and cardiac arrest
What is hypokalemia?
Less K+ More negative membrane potential- hyperpolarized, leads to arrhythmias
How is ammonia formed in the body?
How is is secreted?
As a byproduct of protein metabolism
Is changed to urea and secreted
What is BUN
Blood
Urea
Nitrogen
What does BUN measure? In general, and specifically?
Evaluates kidney function
Measures nitrogen in the blood (from urea)
If glomerular filtration decreases severely, then BUN ______. What is the tx?
Rises steeply.
pt must minimize protein intake
Penicillin is ______ filtered from the blood. Can _____ it in urine. Must have _____ doses to counter secretion
Rapidly
Smell
Several
The nephron _______ blood
The nephron ______ needed liquid and solutes
Filters
reabsorbs
The nephron _______ what the body doesn’t want or need at the moment, thus forming the final product: ______
Secretes
urine
What is obligatory water loss? In mL?
The body must excrete 400mL of urine/day to rid the body of wastes
OR- the amount of urine that must be excreted to stay healthy
What is azotemia?
An excess of urea in the blood caused by insufficient urine output
Where does concentration of urine occur?
In the renal pyramid
In the pyramid there are many tubes:
Tubes that run down and up– ____ ___ ______
Vessels that run down and up- _____ ______
Tube that runs down only- _______ ______
Tubes that run down and up– loop of Henle
Vessels that run down and up- vasa recta
Tube that runs down only- collecting duct
** Many tubes running next to each other with interstitial tissue around them
What is countercurrent?
Fluid is going one way and right next door going the other way
The kidney has a unique and large ______ gradient.
Vertical
How do the vasa recta maintain the vertical gradient?
1- with sluggish flow
2- Freely permeable to Na+ Cl- and H2O
What mechanism concentrates urine?
Countercurrent multiplier mechanism
How does the countercurrent multiplier mechanism work?
The juxtamedullary nephrons long loops of Henle establish the vertical osmotic gradient and the vasa recta prevent the dissolution of the gradient while providing blood to the medulla.
The nephron loop is a _______ because it multiplies the salinity deep in the medulla and a ________ mechanism because it is based on fluid flowing in opposite directions in adjacent tubules.
multiplier
countercurrent
How does countercurrent multiplier work in the descending tubule?
Highly permeable to H2O, but doesn’t actively extrude Na+ or Cl-
Relatively impermeable to solutes
How does the countercurrent multiplier work in the ascending tubule?
Actively transports Na+ Cl- out of tubes into surrounding tissue
Is always impermeable to H2O, so slat leaves without H2O following
Why is there a different in mOsm between the ascending and descending tubules?
Always a 200 mOsm difference between the two tubes- reflects the power of the ascending tubes NaCl pumps
The more “___” the ascending limb extrudes, the more concentrated the delivered fluid will be
salt
ADH works on the _____ _____
Collecting duct
What are polyuria, oliguria, and anuria?
polyuria- More than 2L of urine/day
oliguria- Less than 500mL of urine/day
Anuria- 0-100 mL of urine a day
