Theme 18: Osmo 4 Flashcards
What is the main component of the formation of hypertonic urine in birds and mammals?
Loops of Henle
What does hypertonic urine mean?
that the urine is concentrated
true or false: the longer the loops of Henle in proportion to the rest of the nephron, the greater the horizontal osmotic graidient.
False: the longer the loops of Henle in proportion to the rest of the nephron, the greater the vertical osmotic gradient
What are juxtamedullary nephrons used for?
they are necessary for concentrating uring in the loops of Henle
What are required for the concentration of urine?
Juxtamedullary nephrons
Is it the longer or the shorter the loops of Henle, that something can concentrate its urine?
The longer the loops the more concentrated the urine
Which of the following cannot excrete urine five times more concentrated than seawater?
a) kangaroo rat
b) gerbil
c) golden hamster
d) common field mouse
d) the common field mouse can not excrete this concentration of urine
What is a nephron?
functional unit of the kidney which is responsible for the formation of urine
How many nephrons are in the mammalian kidney?
millions of nephrons
what do nephrons connect to?
one collecting duct
Which group have juxtamedullary nephrons with long loops of Henle?
a) Mammals and birds
b) fish and reptiles
c) rodents
mammals and birds
what do nephrons do?
they allow production of hypertonic urine to conserve water
Where are nephrons found?
the medulla and cortex of kidneys
where are bowmans capsules found?
the cortex - outer layer of kidneys
What are the three basic nephron processes?
1_ Glomerular Filtration
- Tubular Reabsorption
- tubular secretion
What is the filtering of blood into tubulle forming the primary urine called?
Glomerular Filteration
What is Glomerular Filtration?
the filtering of blood into tubule forming the primary urine
What is Tubular Reabsorption?
reabsorption of substances needed by body from tubule back to blood
What is the reabsorption of substances needed by body from tubule back to blood called?
Tubular Reabsorption
What is the secretion of substances to be eliminated from the body into the tubule from the blood called?
Tubular Secretion
What is Tubular secretion?
secretion of substnaces to be eliminated from the body into the tubule from the blood
What is the result of the three basic nephron processes?
urine
What four things are reabsorbed from the tubule?
amino acids
glucose
filtered water(65%)
filtered sodium (67%)
What two things are secreted into tubule?
the variable proton H+ for acid/base regulaiton
organic molecules
How is Na+ oumped out of the kidney, what happens to the Cl-?
the Na+ is pumped out by membrane pumps and the Cl- follows passibely down an electrostatic gradient
True or False: There is a slight change in concentration of filtrate in the tubule.
False. there is no change in concentration
What kind of mechanism is in the proximal convoluted Tubule II?
isomotic volume removal
How much urine is removed in teh 2nd step?
65%
What happens to the osmolarity in the medulla during the descending loop of henle?
the external osmolarity is high in the medulla and it increases as the tubule descends from outer to inner medulla
is the tubule permeable to water in the descending loop of henle?
yes
How much urine is removed in the loop of henle and how much is left?
20% removed, 15% left
There is no change in solute in tubule during the loop of henle, what does this mean?
concentration of filtrate in tubule is increased
What is the difference of the osmotic gradient in interstitial fluid of medulla?
a) 600-1000 mOsm outer to inner
b) 600-1200 mOsm inner to outer
c) 400-1200 mOsm outer to inner
400-1200 mOsm outer to inner
What happens in the ascending limb of the loop of henle where the Na+ reabsorption tubule is impermeable to water?
- concentrates interstitial fluid in medulla
- lowers NaCl concentration in the ultrafilrate (by active transport)
What is the purpose of the loop of Henle?
to establish a gradient of osmollarity in the interstitial fluid of the medulla
What is the relationship between the Na+ and concentration of the fluid in the ascending and descending limbs?
the more Na+ active transported out of the ascending loop, the more concentrated the fluid in descending lumb
water leaves by osmosis
What is the “hairpin” of the loop of Henle?
countercurrent multiplier system which maintains osmotic gradient in the medulla (water is reabsorbed back into the plasma)
What happens in the vasa recta?
- water is reabsorbed into the plasma of the blood vessels in ascending limb
- counter current exchange maintains osmotic gradient in the medulla
- removes excess water and solutes from filtrate
What do the permeability and transport properties of descending and ascending limbs establish in the interstitial fluid of medulla?
osmotic gradient to allow reabsorption from the distal collecting duct
What does sodium reabosrption do?
reduce osmotic pressure of the filtrate to ~100mOsm as it enters the distal convoluted tubule
what happens in the distal conoluted tubule II?
filtrate is diluted by transport of sodium out of tubule
- regulates sodium and potassium in the blood
How does the regulation of sodium and potassium happen?
In the distal convoluted tubule II:
- lose potassium (have enough for transport)
- controlled by aldosterone
- controlled by antidiuretic hormone to absorb water and concentrate the urine
Do desert animals or humans need longer loops of Henle?
Desert animals
What happens in the collecting duct?
rest of water is removed by osmosis by the osmotic gradient
What is water permeability of the tubule controlled by?
ADH - antidiuretic hormone - antipeeing hormone
If the ADH allows water to leave what happens?
- urine volume is reduced
- urine is more concentrated
- urea goes into the loop of henle (1/2 gone)
- extracellular osmollarity is increased
What are 4 uses of urine?
- munitions
- textiles
- agriculture
- historical
What are the 5 main parts of the urinary system?
- Glomerulus
- Bowman’s Capsule
- Descending loop of Henle
- Ascending loop of Henle
- Ureter
What is the full urinary system?
Glomerulus bowman's capsule proximal tubule descending loop of henle ascending loop of henle distal concoluted tubule collecting duct ureter
