fong I Flashcards
where are most of the interstitial fluids?
in the ECF
the volume of the ECF is determined by what organ?
the kidneys
during acidosis, how does the kidney compensate?
the proximal tubules compensate by oxidizing glutamine to form HCO-/3 (absorbed into blood) and NH+/4 is excreted
when does gluconeogenesis happen in the kidney?
in times of fasting
what important regulatory hormones does the kidney produce or regulate?
renin, 1-alpha 25-dihydroxvitamin D3, and erythropoietin
generally the kidneys function to maintain what?
homeostasis
total body water comprises what percentage of body weight?
~60%
how much of the water in our bodies is in the ICF? ECF?
ICF = 2/3 ECF = 1/3
how does the body govern the amount of fluid in a particular compartment?
- hydrostatic pressure
- oncotic pressure
- Starling forces
- osmotic pressure
what is oncotic pressure?
the pressure that is exerted by large molecules in a solution
oncotic pressure does what to water?
oncotic pressure DRAWS water
hydrostatic pressure does what to water?
hydrostatic pressure PUSHES water
what is Kf in the Starling force eq?
filtration coefficient
what is Pc in the Starling force eq?
hydrostatic pressure, capillary
what is Pi,i in the Starling force eq?
oncotic pressure, interstitial
what is Pi in the Starling force eq?
hydrostatic pressure, interstitial
what is Pi,c in the Starling force eq?
oncotic pressure, capillary
what happens when blood pressure affects the distribution of volume between the IVF and ISF?
edema
what does renin involved in?
regulating blood pressure
what is 1-alpha,25-dihyroxvitamin D3 involved in?
calcium homeostasis
what is erythropoietin involved in?
RBC production
one of the most important functions of the kidney is what?
to maintain the COMPOSITION and VOLUME of the ECF
the volume in a given compartment depends on the ?
NUMBER of solute particles in that compartment
the volume in a given compartment does NOT depend on?
any specific property of a solute (eg. charge, size, shape)
what does osmotic gradients govern?
water movements
lower concentration of osmotically active solutes exerts what kind of osmotic pressure?
lower osmotic pressure
higher concentration of osmotically active solutes exerts what kind of osmotic pressure?
higher osmotic pressure
are most biological membranes permeable to water?
yes
water permeation across a membrane requires what?
osmotic gradient
what is the concept of set point?
- system requires SENSORS/DETECTORS
- coordination of sensed signals
- feedback/adjustment mechanisms: EFFECTORS