Proximal and Distal Tubule Disorders Flashcards
How many sections are in the PT ?
Two, the first 2/3 is the PCT and the final 1/3 is the PST (parsa recta)
How many segments are in the PCT ?
Three, S1 S2 and S3
What are the functions of the PT ?
Reabsorption of Water and electrolytes
Secretion of organic compounds
Hormonal function in vitamin D synthesis
How is insulin taken in by the PT ?
Pinocytosis
Is H secreted in the PT ?
Yes, H+ is secreted by the Na-H exchanger
Is the PT succeptable to ischemia ?
Yes because it has a high level of mitochondria activity it is very dependent on ATP for proper function
What are the six basic defects in the PT ?
- Defective Solute Influx
- Leakage back into interstitum
3 Decreased Solute flux into blood - Defective energy generation
- Increased back-flux across tight junctions.
- Defective transport recycling
What is a generalized PT dysfunction ?
It is usually due to a defect in energy generation ( NaKATPase ) or dysfunctional cellular organelles affecting transport protein recycling
What is an isolated PT dysfunction ?
Usually a defect in a specific transport protein
What is renal glucosuria ?
An AR inherited trate affecting the SGLT-2 glucose transporter
What is Cystinuria ?
An AT inherited trare caused by a mutation in brush border transporter responsible for reabsorption of cystine and AA ornithine, lysine, and arginine
What will cystineuria cause ?
Cystine stones and cystine crystals in the urine
What are the inherited defects in phosphate reabsorption ?
X-Linked hypophosphatemia (PHEX)
A- Dom Hypophosphatemic Rickets (FGF23)
A-Rec Hypophosphatemic rickets
What is the acquired defect in phosphate transport ?
Oncogenic Hypophosphatemic Osteomalacia (FGF23)
What is the most common phosphate wasting disorder ?
X Linked Hypophosphatemia