CPRS 40: Glomerular Filtration Flashcards
Compare the position of nephrons between Cortical Nephron and Juxtamedullary nephron
Describe with reference to the position of cortex
Compare the position of nephrons between
Cortical Nephron and Juxtamedullary nephron
Cortical: At outer cortex
Juxtamedullary: Deep in the cortex
Consider the Glomerular Basement Membrane
- What is the charge of it
- What does it repel
- Name 2 changes near the GBM which can lead to proteinuria
Consider the Glomerular Basement Membrane
- What is the charge of it- negative
- What does it repel- proteins
- Name 2 changes near the GBM which can lead to proteinuria:
A. Fusion or collapse of pedicels
B. Splitting of the GBM
Consider the forces in Ultrafiltration
Name 1 force favouring filtration
Name 2 forces opposing filtration
Derive a formula for the net filtration pressure
Consider the forces in Ultrafiltration
Name 1 force favouring filtration
- Glomerular Capillary Blood Pressure
Name 2 forces opposing filtration
- Hydrostatic pressure in Bowman’s Capsule
- Oncotic pressure in glomerulus (By proteins in the glomerulus, draws back water from capsule to glomerulus)
Formula:
Glomerular Capillary Blood Pressure - Hydrostatic Pressure in Bowman’s Capsule - Oncotic Pressure in Glomerulus
Vasodilation of afferent arteriole
Vasoconstriction of efferent arteriole
= > Leads to __________in filtration pressure
Vasoconstriction of afferent arteriole
Vasodilatation of efferent arteriole
= > Leads to _________ in filtration pressure
Vasodilation of afferent arteriole
Vasoconstriction of efferent arteriole
= > Leads to increase in filtration pressure
Vasoconstriction of afferent arteriole
Vasodilatation of efferent arteriole
= > Leads to decrease in filtration pressure
What is the normal glomerular filtration rate
Express in mL/min
90-140 mL/min
Relate excretion with
Filtration, reabsorption, secretion
Use the above terms to answer the following:
- GFR reflects _________
- Clearance reflects __________
- What is the relationship between GFR and Clearance
Excretion = Filtration + Secretion - Reabsorption
Use the above terms to answer the following:
- GFR reflects filtration
- Clearance reflects excretion
- What is the relationship between GFR and Clearance: NO RELATIONSHIP
Consider the following substances
fill with percentages
- Glucose: ______ filtered + _______ reabsorbed
- Inulin: _____ filtered + _______ reabsorbed + _______ secreted
- Creatinine: _____ filtered + _______ reabsorbed + _______ secreted
What can estimate GFR by clearance
What can reflect GFR by clearance
Consider the following substances
fill with percentages
- Glucose: 100% filtered + 100% reabsorbed
- Inulin: 100% filtered + 0% reabsorbed + 0% secreted
- Creatinine: 100% filtered + 0% reabsorbed + little secreted
What can estimate GFR by clearance: Creatinine
What can represent GFR by clearance: Inulin
Consider Loop of Henle
- Where is it located?
- Purpose: To build up a high concentration of ______ at the interstitial fluid between the ascending limb and the collecting duct, so more _____ can be reabsorbed by osmosis from the collecting duct to further _________ the urine
- Descending limb is permeable to ______ but not _______
- Ascending limb is permeable to ______ but not _______
Consider Loop of Henle
- Where is it located? Medulla
- Purpose: To build up a high concentration of salt (NaCl) at the interstitial fluid between the ascending limb and the collecting duct, so more water can be reabsorbed by osmosis from the collecting duct to further concentrate the urine
- Descending limb is permeable to WATER but not SALT
- Ascending limb is permeable to SALT but not WATER
In the ascending loop of Henle, how are the salt being reabsorbed?
- __________ pumps out ___ from cell to interstitial fluid; while pumps in ____ from interstitial fluid to cell, creating a concentration gradient
- ________ channels pump in _______ ions for reabsorption
In the ascending loop of Henle, how are the salt being reabsorbed?
- Na-K ATPase pumps out Na+ from cell to interstitial fluid; while pumps in K+ from interstitial fluid to cell, creating a concentration gradient
- NKCC channels pump in Na+, Cl- ions for reabsorption
Consider the cycle of salt reabsorption of the loop of Henle
- ________ is being pumped out from the ascending limb
- ________ (salt concentration) of the _______ increases
- ________ leaves the descending limb
- _________ (salt concentration) of the _________ increases, thus the ascending limb
- Cycle repeats
Consider the cycle of salt reabsorption of the loop of Henle
- Salt is being pumped out from the ascending limb
- Osmolality (salt concentration) of the interstitial fluid increases
- Water leaves the descending limb
- Osmolality (salt concentration) of the descending limb increases, thus the ascending limb
- Cycle repeats
Consider the collecting duct
- Location? It spans through the ______ and ______
- Which type of cell is responsible for Water reabsorption?
- Which type of cell is responsible for acid-base balance?
Consider the collecting duct
- Location? It spans through the cortex and medulla
- Which type of cell is responsible for Water reabsorption? Principal Cells
- Which type of cell is responsible for acid-base balance? Intercalated Cells
Consider the water reabsorption process by Vasopressin
1. Vasopressin binds to _____ receptors on the ________ membrane (apical/ basolateral)
2. ________ water channels will be phosphorylated at position ________
3. _________ water channels are trafficked to the _______ membrane (apical/ basolateral)
4. _____________ of ________ network
More water reabsorption from the channels
Note: Vasopressin is ________
Fill in with diuretic/ anti-diuretic
Consider the water reabsorption process by Vasopressin
1. Vasopressin binds to V2R receptors on the basolateral membrane (apical/ basolateral)
2. AQP2 water channels will be phosphorylated at position Ser256
3. AQP2 water channels are trafficked to the apical membrane (apical/ basolateral)
4. Depolymerization of actin network
More water reabsorption from the channels
Note: Vasopressin is anti-diuretic
How is Vasopressin synthesized
- _________ and _______ detect the stimuli
- Vasopressin is synthesized in _______ and _____
- Vasopressin transported through the long axon to the ___________
- When action potential arrives, it will increase the ______ influx
- _________ of secretory vesicles containing the vasopressin
How is Vasopressin synthesized
- PVN and SON detect the stimuli
- Vasopressin is synthesized in PVN and SON
- Vasopressin transported through the long axon to the posterior pituitary gland
- When action potential arrives, it will increase the calcium influx
- exocytosis of secretory vesicles containing the vasopressin
Consider Osmoreceptors
- Cation channel with how many transmembrane domains?
- There is a poor loop segment between the ___ and ___ domain, what is it for?
- If cations rush inside, what does it mean? Depolarization or hyperpolarization?
- There is a specialized mechanosensitive receptor, what is it called?
Consider Osmoreceptors
- Cation channel with how many transmembrane domains? 6
- There is a poor loop segment between the 5th and 6th domain, what is it for- For cations to rush inside
- If cations rush inside, what does it mean? Depolarization
- There is a specialized mechanosensitive receptor, what is it called? TRPV
Consider OVLT and SFO
- They lack _________ and they can sense plasma _______
- They will send the signals to _____ and _____
PVN and SON
- DO they have osmoreceptors?
- They receive signals from ______ and ______
Consider OVLT and SFO
- They lack blood-brain barrier and they can sense plasma osmolality
- They will send the signals to PVN and SON
PVN and SON
- DO they have osmoreceptors? YES
- They receive signals from OVLT and SFO
