Renal: Regulation of Extracellular Fluid Volume and Osmolarity Flashcards
Average Intake = Average Output
Mass Balance
What percentages of our fluids contribute to average intake?
60% - Beverages
30% - Food
10% - Metabolism
What is the human body’s average intake and output?
Intake - 2.5L/day
(Metabolism = .3 L, Food = .9L, Drink = 1.3L)
Output - 2.5L/day
(Feces = .1L, Respiration/Sweat = .9L, Urine = 1.5L)
What percentages of our fluids contribute to average output?
4% - Feces
8% - Sweat
28% - Insensible losses via skin and lungs
60% - Urine
Excess water ingested leads to Increase water excreted because?
Blood Flow increases greatly (increases Blood Volume and Pressure)…Vasa Recta washes away gradient
True/False:
With injection of Saline, osmolarity stays the same over time
True
True/False:
With injection of Water, osmolarity can change over time
True
What’s the Excretion Equation?
“Filtration” is same as “Filtered Load”
Excretion = Filtration - Reabsorption + Secretion
*Example for Sodium: Excretion = (GFR x Plasma concentration) - Reabsorption
True/False:
Sodium is filtered, reabsorbed, excreted but not SECRETED
True
Water follows Sodium. How does Sodium impact volume and GFR?
Decrease Sodium level, Decrease Volume, Decrease GFR
Increase Sodium level, Increase Volume, Increase GFR
How does altering GFR impact sodium excretion?
Decrease GFR, Decrease Sodium Excretion
Increase GFR, Increase Sodium Excretion
How does altering GFR impact filtered load of sodium?
Decrease GFR, Decrease Filtered Load of Sodium
Increase GFR, Increase Filtered Load of Sodium
a. If Filter Load of Sodium is 100mg/min, what is Excretion of Sodium?
b. If Filter Load of Sodium is 1000mg/min, what is Excretion of Sodium?
a. E = 100mg/min - 99mg/min
E= 1 mg/min
b. E = 1000mg/min - 990mg/min
E = 10 mg/min
Baroreceptors release what?
Renin
Renin causes Angiotensinogen to form into Angiotensin I Angiotensin II is formed. What are the impacts?
Aldosterone secretion, Reabsorption at Proximal Tubule, Sympathetic Activity, Arteriolar vasoconstriction, ADH secretion
Aldosterone secretion, Reabsorption at Proximal Tubule, Sympathetic Activity, Arteriolar vasoconstriction, ADH secretion. All are effects from what?
Renin-Angiotensin-Aldosterone System (RAAS)
When is Angiotensin II released?
when there’s LOW BP and BV levels
Why is slow flow of the Vasa Recta essential?
To maintain the medullary gradient
What are the Neurohumoral controls of renal sodium reabsorption?
Sympathetic nerves
RAAS
Aldosterone
ANP
How do Sympathetic Nerves impact the Renal System?
Increase Renin secretion
Increase afferent and efferent arteriole constriction (Decreases GFR)
Increase sodium reabsorption in proximal tubule (Transporter in Proximal Tubule is UNKNOWN)
What hormone increases Na channels on apical membrane and Na/K ATPase pumps on basolateral membrane?
Aldosterone
What hormone increases Aldosterone?
Angiotensin II
Increases Na/H exchangers in Proximal Tubule (Bicarbonate Reclamation)…increasing Na+ reabsorption
Angiotensin II
What hormone has stretch receptors and is released when Blood Pressure is too High?
ANF/ANP
