Topic 8 Part C Controlling Reabsorption Flashcards
Glomerulartubular Balance allows an increase in what?
Allows an increase in reabsorption rate when there is an increase in tubular load (increased tubular inflow)
If GFR went from 125 mls/minute to 150 mls/minute rate of reabsorption in proximal tubule would go from 81 mls/minute [65% of GFR] to 97.5 mls/minute [65% of GFR] SAME PERCENT !!!!
Glomerulartubular Balance works to maintain Na and Volume homeostasis how?
Prevents large changes in fluid flow to distal tubules even though there have been significant changes in MAP
Peritubular Capillary & Interstitial Forces there is a relationship between what three things?
Relationship of hydrostatic and oncotic pressures AND filtration coefficient
Normal–net force for reabsorption
Peritubular Capillary & Interstitial
Normal–net force for reabsorption of 10 mmHg
IN (πc 32 + Pif 6 = 38) –OUT (Pc 13 + if π15 = 28) = 38-28
Peritubular Capillary & Interstitial Normal Reabsorption Rate? (ml/min)
Normal reabsorption rate of 124 mls/minute
Large filtration coefficient equation?
Reabsorption rate / net force
Affected by transfer surface area & hydraulic conductivity (permeability)
ex: 24 mls/min / 10 mmHg = 12.4 mls/min/mmHg
Factors Affecting Peritubular Capillary Reabsorption
Peritubular hydrostatic pressure (PHP) Peritubular oncotic pressure (POP) Filtration Coefficient (FC)
Increased PHP - (Peritubular hydrostatic pressure) does what to reabsorption?
DECREASES Reabsorption
Increased Arterial Pressure does what to PHP and Reabsorption?
INCREASE PHP and DECREASES Reabsorption
Increases Resistance of afferent & efferent arteriole does what to PHP and Reabsorption?
Decreases PHP and Increases Reabsorption
Increased Peritubular oncotic pressure (POP) does what to reabsorption?
INCREASES reabsorption
Increase Plasma protein concentration, does what to plasma oncotic pressure, POP, and reabsorption?
INCREASES plasma oncotic pressure, INCREASES POP, and INCREASES reabsorption
Filtration fraction equation
(GFR/RPF)
Increases Filtration Fraction
INCREASES protein concentration (more fluid is actually filtered)
INCREASES POP
INCREASES reabsorption
Renal interstitial hydrostatic and colloid osmotic pressures are affected by changes in what?
reabsorptive forces of peritubular capillaries
DECREASED capillary reabsorption does what to interstitial solute and water?
PRODUCES INCREASE in interstitial solute AND interstitial water
DECREASED capillary reabsorption does what to interstitial hydrostatic and oncotic pressure?
PRODUCES INCREASE in interstitial hydrostatic pressure AND in interstitial oncotic pressure
DECREASED capillary reabsorption does what to the net movement of solute and water from the renal tubules to renal interstitial space?
PRODUCES DECREASE in net movement (i.e. reabsorption) of solute & water from renal tubules to renal interstitial spaces
Decreased Peritubular reabsorption does what to solute & water accumulation in interstitial space
INCREASES solute & water accumulation in interstitial space
Decreased Peritubular reabsorption does what to backflow of solute and water from interstitial space into tubular lumen?
INCREASES backflow of solute and water from interstitial space into tubular lumen
Forces that increase peritubular capillary reabsorption also increase movement of solute and water from where?
solute and water (reabsorption) from the tubular lumen to the renal interstitial spaces [Reverse also true]
Increased Capillary surface area does what to FC & reabsorption?
Increases FC & reabsorption
Increased Capillary permeability area does what to FC and reabsorption?
Increases FC and reabsorption
Filtration Coefficient will be affected by what?
Coefficient remains constant under most physiologic conditions. Will be affected by renal disease
When arterial pressure is increased what happens to angiotensin II release? and does what?
Angiotensin II release is decreased
Less stimulation of sodium reabsorption by angiotensin II
Less stimulation of aldosterone production which means less stimulation of sodium reabsorption
Angiotensin II works where? (4)
Proximal tubule; Thick ascending loop of Henle / distal tubule; Collecting duct
Antidiuretic Hormone works where? (3)
Distal tubule; Collecting tubule & duct
Atrial natriuretic peptide works where? (3)
Distal tubule; Collecting tubule & duct
Parathyroid Hormone works where? (3)
Proximal tubule; Thick ascending loop of Henle; Distal tubule
Aldosterone works where? (2)
Collecting tubule & duct