Kidney Flashcards
What are the normal GFR values for Osmolarity, Na, Cl and Glucose Concentrations and flow rates?
300mOsm, 140mMol/L Na+, 100mMol/L Cl-, 5mMol/L glucose, 6L/h
What is the function of the proximal tubule?
To reabsorb all glucose, amino acid and all other useful material from the tubular fluid, as well as large amounts of salt and osmotic reabsorption of water
What are the normal values for Osmolarity, Na, Cl and Glucose Concentrations and flow rate at the end of the proximal tubule?
300mOsm, 140mMol/L Na+, increase in Cl- concentration, 0 glucose mMol/L 1.2L/h
What is the function of the descending loop of henle?
As it is highly permeable to water and receives NaCl pumped by cells across from the ascending limb it results in increasing the osmolarity of the tubular fluid to generate a salty medulla
What are the normal values for Osmolarity, Na, Cl and Glucose Concentrations at the tip of the proximal tubule?
600 mOsm for short loops, 1200 mOsm for long loops, 0mMol/L of glucose increase in NaCl concentration
What is the function of the ascending limb of the loop of henle?
Is impermeable to water and can therefore pump out NaCl without losing water to return the tubular fluid to a normal osmolarity while helping to generate a hypotonic environment
What are the normal values for Osmolarity, Na, Cl and Glucose Concentrations and flow rate at the end of the loop of henle/distal tubule?
280mOsm, 1L/h, 0mMol/L glucose, very low NaCl concentration
What is the function of the collecting duct?
It turns through the salty medulla and allows for reabsorption of water from the urine dependant on hormonal factors such as the level of ADH
Why are water and salt regulated independently?
Solute concentrations must be fixed for important physiological functions such as the setting of the membrane potential however this cannot be done at the expense of dehydration
What is the difference between long and short loops?
Long loops penetrate the inner medulla and can provide GFR reabsorption of up to 15%
