Tubular reabsorption and acid base balance basics Flashcards
What is responsible for reabsorption and secretion in the nephron tubules
proteins positioned in the cell membranes in the nephron
Why are the proteins in the cell membranes of the nephron important
-they are important sites for Rx targets
How are small proteins that made it past glomerular filtration reabsorbed
typically via pinocytosis
What are the 2 ways reabsorption can occur
- Paracellular =passive, between adjacent tubule cells thought to account for 50% of reabsorption
- Transcellular= passive and active, travels through tubule cell
What is meant by obligatory water reabsorption
water follows solutes almost always, this is how most water is reabsorbed in the PCT and descending LOH
Why does Glucosuria occur
Serum glucose is >200 mg/dL, renal symporters cannot work fast enough to reabsorb all the glucose so it is excreted in the urine
What substances are secreted into the tubules
- H ions
- K ions
- NH4
- Creatinine
- Certain drugs like Penicillin, elict drugs, anabolic steriods, EPO
True or false the wall of the glomerular capsule, renal tubule and renal ducts are a single layer of epithelial cells
True
What cell type compose the PCT
simple cuboidal epithelial cells with microvilli
What are the microvilli in the PCT used for
increasing surface area for reabsorption and secretion
What cell type compose the thin (descending and ascending) LOH
simple squamous epithelial cells
What cell type compose the thick ascending LOH
simple cuboidal to low columnar cells
What cell type compose the DCT
simple cuboidal cells
What over cell types does the last part of the DCT have when compared to the rest of the DCT
All DCT is simple cuboidal but the last part contains:
- Principle cells=have ADH and aldosterone receptors
- Intercalated cells= play a role in blood pH
What is the pH range of blood and ECF
7.35 to 7.45
What kind of acidosis or alkalosis is caused by too little or too much bicrab (HCO3)
metabolic
What kind of acidosis or alkalosis is caused by too little or too much partial pressure of carbon dioxide (pCO2)
respiratory
What is the body’s first line system against acid-base abnormalities
extracellular (HCO3) and intracellular (pCO2) buffer systems
Describe the extracellular buffer system
carbonic acid is dissociated to bicarb and H
Describe the intracellular buffer system
CO2 is moved into the cell and combines with water to make carbonic acid which then dissociates to bicarb in the extracellular space
What is the body’s second line system against acid-base abnormalities how does it react in an acidotic and alkalotic state
The respiratory system
- Acidosis=when pCO2 is high pH is low the body breathes off more pCO2 is low by increasing respiratory rate
- Alkalosis=when pCOs is low pH is high respiratory rate decreases
What is the body’s third line system against acid-base abnormalities and how does it react in an acidotic and alkalotic state
The renal system, because it takes longer to compensate compared to the other 2 systems
- Acidosis= decreased HCO3 , more H is secreted into tubules
- Alkalosis=increased HCO3, less H is secreted into the tubules
Remember ROME
respiratory opposites and metabolic equivalents
