Ion Exchange 2 Flashcards
The conversion of ammonium to uric acid or urea is dependent on what
Energy
Animals excrete ___ & ___ & ___
Ammonium, Urea, Uric acid
Ammoni(a/um) can be controlled and transported as
Glutamine
What happens after ammoni(a/um) is converted to glutamine
- Transported to other tissues
2. Deaminated by glutaminase - releasing ammonia and glutamate
What is GDH
Glutamate dehydrogenase
What is GS
Glutamine synthesis (Know the pathway in the slide!)
In what cycle is urea produced
Orthinine-urea cycle (Know the pathway in the slide!)
What does CPS stand for
Carbamoyl phosphate synthase
Where is urea produced
Liver
What happens after urea is produced
Released into the blood, then excreted by the kidney
What are the kidney’s role in homeostasis
1) Ion Balance
2) Osmotic Balance
3) Blood Pressure
4) pH Balance
5) Excretion
6) Hormone Production (metabolism/conversion)
What is the functional unit of the kidney
Nephron
Where does the efferent arteriole go to
Away from the kidney
Where does the afferent arteriole go to
To the kidney (Bowman’s Capsule)
What forms filtration sites in the epithelium of the Bowman’s Capsule
Podocytes
Fenestration by podocytes in the Bowman’s capsule allows for what
Allows fluids and solutes to flow into the Bowman’s Capsule
What do podocytes prevent the filtration of into the Bowman’s Capsule
Proteins
What is in the filtrate of the Bowman’s Capsule
- Salt
- Glucose
- Vitamins
- Nitrogenous wastes
What is the lumen of the Bowman’s Capsule called
Ultrafiltrate
What is the driving force that pushes material into the glomerulus to the Bowman’s Capsule
- Hydrostatic Pressure
2. Oncontic pressure
Sympathetic innervation of the glomerulus does what
Vasoconstriction (Reduction in blood flow)
How is the glomerulus locally regulated
Stretch-sensitive ion channels
What are the stretch-sensitive ion channels in the glomerulus responsible for
Contracts upon stimulation/depolarization
How are stretch-sensitive ion channels activated
Increased blood pressure
Where are the stretch-sensitive ion channels located
Membrane of the afferent arteriole smooth muscle
What does GFR stand for
Glomerular filtration rate
What is the osmolarity relationship between primary urine and blood
Iso-osmotic
How much of the volume of the primary urine is recovered by the kidney
99%
What is the average GFR
~7.5 L/hr (~45 gallons/day)
The total blood volume is filtered through the renal tubules in approximately ___ min
40 minutes
How much primary urine do we produce per hour
7.5 L/hr
How much final urine do we excrete per hour
75mL/hr
What happens to the primary urine as it goes through the nephron’s tubule
Solutes are reabsorbed (TO the blood) and secreted (TO the urine)
Where does most solute and water reabsorption occur in the nephron
Proximal Tubule
What solutes are reabsorbed in the proximal tubule through ACTIVE transport
- Na+
- H+
- Glucose
- Amino acids
- Vitamins (organic molecules)
What solutes are reabsorbed in the proximal tubule through PASSIVE transport
- Cl-
- K+
- NH3 (urea)
- HCO3-
What is happening on the apical side of the proximal tubule
Secondary active transport of Na+ & Glucose (faces lumen of proximal tubule)
What is happening on the basolateral side of the proximal tubule
Primary active transport of Na+ & K+ (faces blood of proximal tubule)
As the Na+/Cl- concentration in the blood increases, what direction does water move in respect with the proximal tubule
Out of the proximal tubule, into the blood and the primary urine is still iso-osmotic
What does the Loop of Henle consist of
Descending limb, Ascending limb, Countercurrent exchanger/multiplier
What is the thin descending limb of the Loop of Henle specialized for
Reabsorption of water into the kidney interstitial fluid FROM the lumen (out of the tubule)
What is the thick ascending limb of the Loop of Henle specialized for
Reclaiming the solutes into the kidney interstitial fluid FROM the lumen (out of the tubule)
What is created as a result of the thin descending loop of henle and the thick ascending loop of henle
An osmotic gradient which makes the Loop of Henle a countercurrent exchanger
What happens in the distal tubule of the nephron
- K+ is secreted (into the lumen)
2/ Na+ & Water are reclaimed (into the interstitial fluid)
What happens in the collecting duct of the nephron
- K+ is secreted (into the lumen)
2/ Na+ & Water are reclaimed (into the interstitial fluid)
What parts of the nephron can be regulated by hormones
Distal Tubule & Collecting Duct
When the collecting duct is passing through the cortex and outer medulla of the kidney, what is it permeable to
Water only (comes in)
When the collecting duct is passing through the inner medulla of the kidney, what is it permeable to
Urea & Water (goes out)
What is vasopressin (ADH, AVP)
Anti-diuretic that alters the permeability of the collecting duct to water.
Vasopressin molecular pathway
- Vasopressin binds to GPCR
- G-protein activates Adenlyl cyclase
- ATP to cAMP
- Activates PKA
- Stimulates aquaporin vesicles to fuse with membrane
What does aldosterone do
Increases Na+ reclamation from the urine, thereby increasing water reclamation.
Aldosterone molecular pathway
- Since steroid, diffuses into nucleus and binds to transcription factor
- Transcribes genes for protein channel transporters
- Proteins made in ER
- Exported by vesicles
- Fuse with membrane
What does Renin/Angiotensin do
Regulates blood pressure (see pathway on slide!)
What is happening on the apical side of the proximal tubule
Secondary active transport of Na+ & Glucose (faces lumen of proximal tubule)
What is happening on the basolateral side of the proximal tubule
Primary active transport of Na+ & K+ (faces blood of proximal tubule)
As the Na+/Cl- concentration in the blood increases, what direction does water move in respect with the proximal tubule
Out of the proximal tubule, into the blood and the primary urine is still iso-osmotic
What does the Loop of Henle consist of
Descending limb, Ascending limb, Countercurrent exchanger/multiplier
What is the thin descending limb of the Loop of Henle specialized for
Reabsorption of water into the kidney interstitial fluid FROM the lumen (out of the tubule)
What is the thick ascending limb of the Loop of Henle specialized for
Reclaiming the solutes into the kidney interstitial fluid FROM the lumen (out of the tubule)
What is created as a result of the thin descending loop of henle and the thick ascending loop of henle
An osmotic gradient which makes the Loop of Henle a countercurrent exchanger
What happens in the distal tubule of the nephron
- K+ is secreted (into the lumen)
2/ Na+ & Water are reclaimed (into the interstitial fluid)
What happens in the collecting duct of the nephron
- K+ is secreted (into the lumen)
2/ Na+ & Water are reclaimed (into the interstitial fluid)
What parts of the nephron can be regulated by hormones
Distal Tubule & Collecting Duct
When the collecting duct is passing through the cortex and outer medulla of the kidney, what is it permeable to
Water only (comes in)
When the collecting duct is passing through the inner medulla of the kidney, what is it permeable to
Urea & Water (goes out)
What is vasopressin (ADH, AVP)
Anti-diuretic that alters the permeability of the collecting duct to water.
Vasopressin molecular pathway
- Vasopressin binds to GPCR
- G-protein activates Adenlyl cyclase
- ATP to cAMP
- Activates PKA
- Stimulates aquaporin vesicles to fuse with membrane
What does aldosterone do
Increases Na+ reclamation from the urine, thereby increasing water reclamation.
Aldosterone molecular pathway
- Since steroid, diffuses into nucleus and binds to transcription factor
- Transcribes genes for protein channel transporters
- Proteins made in ER
- Exported by vesicles
- Fuse with membrane
What does Renin/Angiotensin do
Regulates blood pressure by regulating Aldosterone (see pathway on slide!)
What is ANP
Atrial natriuretic peptide
What does ANP do
Reduces blood volume & blood pressure
What is natriuresis
Sodium excretion
What is diuresis
Increased urine production
What does ANP do
- Increases glomerular filtration rate
- Decreases renin production
- Vasodilation