Renal Physiology 2 Flashcards
___________: only a fraction of the plasma presented to the glomeruli is filtered.
Filtration Fraction: only a fraction of the plasma presented to the glomeruli is filtered.
________ of plasma is filtered.
20-30% of plasma is filtered.
Filtration rate is measured in units of _______.
Filtration rate is measured in units of mL/min.
Secretion, Reabsorption and Excretion are measured in units of _________.
Secretion, Reabsorption and Excretion are measured in units of mg/min.
Excretion (E) = _______________
Excretion (E) = Filtration (F) + Secretion (S) - Reabsorption (R)
___________: maximum rate at which nephron epithelium can remove substances from plasma and secrete them into filtrate
Transport Maximum: maximum rate at which nephron epithelium can remove substances from plasma and secrete them into filtrate
Secretion transport is dependent on
Secretion transport is dependent on the number/density of membrane transporters that allow for secretion or reabsorption
When transport maximum is reached, substances that should be secreted _____________.
When transport maximum is reached, substances that should be secreted accumulate in plasma.
When transport maximum is reached, substances that should be reabsorbed __________.
When transport maximum is reached, substances that should be reabsorbed may be lost in urine.
“Splay” in graphs of [Glucose] reflects what
Heterogenicity of nephrons
Glucose in the urine can be due to:
Hemorrhage
Increased [Glucose} in plasma
Proximal tubule damage
Explain how Fight or Flight response increases plasma glucose
SNS stimulation releases epinephrine that increases glycogenolysis at the liver.
Why is the Fight or Flight response important in some species and not others in regards to [Glucose]
In some species the [Glucose] in plasma caused by the Fight or Flight response exceeds transport maximum
In what species is the Fight or Flight Response important to be aware of in regards to [Glucose]
Bovine
_______ is secreted when there is increased [Glucose] in plasma.
Insulin is secreted when there is increased [Glucose] in plasma.
[Glucose] in plasma and Filtration of Glucose is a __________ relationship.
[Glucose] in plasma and Filtration of Glucose is a linear relationship.
Normal [Glucose] in plasma for dog
70-100 mg/dL
Glucose Transport Maximum of dog
180-200 mg/dL
Decreased transport maximum means what in regards to the concentration of a substance in plasma.
More of the substance is excreted in urine when it is increased in plasma.
The _________ is the major portion of the nephron responsible for reabsorption and secretion.
The proximal tubule is the major portion of the nephron responsible for reabsorption and secretion.
The _______ does not modify osmolarity.
The Proximal Tubule does not modify osmolarity.
__________ of water is reabsorbed at the proximal tubule.
50-80% of water is reabsorbed at the proximal tubule.
_________ work at the proximal tubule to increase reabsorption of water.
NE, E, AGII work at the proximal tubule to increase reabsorption of water.
Increased reabsorption at the proximal tubule can be due to
Decreased blood pressure
Increased osmolarity
_______ of water is reabsorbed at the dLoH
20% of water is reabsorbed at the dLoH
At the ______ there is more water reabsorption than osmolyte.
At the dLoH there is more water reabsorption than osmolyte.
The ________ is considered a passive structure.
The dLoH is considered a passive structure.
Filtrate at the dLoH is _____osmotic.
Filtrate at the dLoH is hyperosmotic.
Urea from the MCD is secreted at the ________.
Urea from the MCD is secreted at the dLoH.
The _______ puts solute into the interstitium.
The aLoH puts solute into the interstitium.
The ______ has no aquaporins.
The aLoH has no aquaporins.
_______ at the aLoH increase reabsorption of water by the dLoH
NE and E at the aLoH increase reabsorption of water by the dLoH
__________ increases the reabsorption of solute at the aLoH
AcH and Aldosterone increases the reabsorption of solute at the aLoH
_________ at the MCD increases the number of aquaporins and urea transporters
ADH at the MCD increases the number of aquaporins and urea transporters
__________ at the MCD decreases Na+ reabsorption.
ANP at the MCD decreases Na+ reabsorption.
__________ at the MCD increases Na+ reabsorption.
Aldosterone at the MCD increases Na+ reabsorption.
Osmolytes become non freely filterable when
Osmolytes become non freely filterable when they are bound by plasma protein
Secretion of organic molecules occurs only in the ___________.
Secretion of organic molecules occurs only in the proximal tubule.
__________________________
Exception: Urea is secreated in the dLoH
Reabsorption of organic molecules occurs only in the ____________.
Reabsorption of organic molecules occurs only in the proximal tubule.
_______________________
Exception: Urea at the MCD
Urea (increases/decreases) along the nephron.
Urea (increases/decreases) along the nephron.
At the dLoH [Urea] (increases/decreases)
At the dLoH [Urea] (increases/decreases)
________________
To allow for diffusion into the filtrate
After the aLoH filtrate is ______osmotic
After the aLoH filtrate is hyposmotic
All medullary interstitium is ______osmotic.
All medullary interstitium is hyperosmotic.
Fractional Excretion = _____________
Fractional Excretion =
Clearance of X (mL/min) / GFR (mL/min)
UrineX:UrineCreatinine
Test comparing the ratios of substances in urine to known normals
Elevated UrineProtein:UrineCreatinine can be caused by
Tubular Disease
Glomeruplopathies
Lower Urinary Tract Disease
UrineCortisol:UrineCreatinine is used as a diagnostic tool for
Cushings Disease
Osmolar Clearance = __________.
Osmolar Clearance = Vu x Uosm / Posm.
Free Water Clearance = ______________
Free Water Clearance = Vu - Osmolar Clearance
Uosm _______ Posm:
Free water clearance = 0
No net gain or loss of plasma water
Isosmotic urine
Uosm = Posm
Uosm _______ Posm:
Free water clearance +
Net loss of plasma water
Hyposmotic urine
Uosm < Posm
Uosm _______ Posm:
Free water clearance -
Net gain of plasma water
Hyperosmotic urine
Uosm > Posm
As blood pressure decreases, the concentration of osmolytes in the urine __________.
As blood pressure decreases, the concentration of osmolytes in the urine increases
___________ urine = neither excretion nor reabsorption of solute free water and urine flow equals urine
Isosmotic urine = neither excretion nor reabsorption of solute free water and urine flow equals urine
__________ urine is divided into 2 virtual volumes; once contains solute and is isosmotic to plasma with urine flow rate equal to osmolar clearance and the second is solute free.
Hyposmotic urine is divided into 2 virtual volumes; once contains solute and is isosmotic to plasma with urine flow rate equal to osmolar clearance and the second is solute free.
__________ urine represents the volume of solute free water that would have to be added to urine to make it isosmotic to plasma, solute free water reabsorbed by the kidneys.
Hyperosmotic urine represents the volume of solute free water that would have to be added to urine to make it isosmotic to plasma, solute free water reabsorbed by the kidneys.
_________: quantifies the actual voluem of solute fre water that is being conserved by the animal over time.
Free water clearance : quantifies the actual voluem of solute fre water that is being conserved by the animal over time.
__________: ratio of the density of a volume of solution to the density of an identical volume of water.
Specific Gravity (USG): ratio of the density of a volume of solution to the density of an identical volume of water.
Free water has a USG of _______.
Free water has a USG of 1.000.
True/False: USG is a precise measure of osmolality
False