Renal Lec 1 Flashcards
renal means
anything to do with the kidneys
the most general function of kidneys
-process plasma, regulate composition and volume of plasma
kidneys regulate (specific) (4)
- blood volume and pressure
- water concentration and fluid volume
- inorganic ion composition
- acid-base balance
kidneys excrete
- urea, uric acid, creatinine, bilirubin
- remove foreign chemicals (drugs, food additives, pesticides)
uric acid is a metabolic product of
-nucleic acid (purines)
urea is a metabolic product of
-proteins
kidneys synthesize (1)
glucose (gluconeogenesis)
kidneys secrete (general)
- hormones
- enzymes
kidneys secrete (specific)
- erythropoietin (hormone)
- 1,25-dihydroxy vitamin D (hormone)
- renin (enzyme)
erythropoietin is a
- hormone produced by kidneys
- stimulates RBC production in response to cellular hypoxia
1,25-dihyrdoxy vitamin D is the
active form of vitamin D
also a hormone
Renin is an
enzyme that helps control blood pressure
adult male (70 kg) total body water (TBW)
42 L
TBW of adult male percentage of total body weight
60%
fluid volume in each compartments changes in
- health disorders
- by rapid movement of water (osmosis)
ICF (intracellular fluid) definition
fluid inside the cell
ECF (extracellular fluid) definition
fluid outside the cell
plasma defintion
liquid, non-cellular part of blood
fluid found inside blood vessels
ECF includes
plasma +interstitial fluid + cerebrospinal fluid
ICF percentage of TBW
40%
ECF percentage of TBW
20%
Interstitial fluid is majority of
ECF
key ions of body fluid compartments
Na+
K+
Na+ (majority in ICF or ECF)?
ECF
K+ (majority in ICF or ECF)?
ICF
Ca++ (majority in ICF or ECF)?
ECF
Mg++ (majority in ICF or ECF)?
ICF
Cl- (majority in ICF or ECF)?
ECF
HCO3- (majority in ICF or ECF)?
ECF
Pi- (majority in ICF or ECF)?
ICF
Protein (majority in ICF or ECF)?
ICF
polar substances diffuse through CM
slowly or not all
ex. aa, glucose, water
nonpolar substance diffuse through CM
- rapidly
ex. CO2, fatty acids, steroids
diffusion is
a process in which movement of molecules from one location to another occur as a result of their random thermal motion (high conc. to low conc.)
-over time there is even distribution
rate of water diffusion depends on
- aquaporins: water channels)
- water concentration
water concentration is measured in
osmoles
1 osmoles (osm) =
1 mole of solute particles
osmolarity
- number of solutes per unit volume of solution expressed in osmoles per liter
- measure of solute concentration
low osmolarity ( ___water concentration)
high
high osmolarity ( ___water concentration)
low
when membrane is permeable to both water + solute,
the movement of water and solute equalized both solute + water concentration
osmosis
net diffusion of water across a selectively permeable membrane from a region of high water concentration to one with a lower concentration
osmotic pressure
the pressure necessary to prevent solvent movement (osmosis) across semipermeable membrane
-opposes osmosis
when membrane is permeable to just water,
the movement of water only equalized solute concentration
opposing pressure required to stop osmosis completely is equal to
osmotic pressure
NPS (def. + examples)
- non-penetrating solutes (can’t pass CM)
- Na+/Cl- ions
tonicity is determined by
concentration of NPS of an extracellular solution compared to intracellular environment of cell; causes changes in cell volume
isotonic (isoosmotic)
-same concentration of NPS outside and inside the cell, cell volume does not change
hypertonic (hyperosmotic)
-higher concentration of NPS outside than inside the cell: cell shrink
hypotonic (hypoosmotic)
-lower concentration of NPS outside than inside of the cell: cell swell
normal osmolarity inside a cell
300 mOsm/L
Water flows from __ osmolarity to __ osmolarity
lower (high water concentration) to higher (low water concentration)
movement of solute/water out of blood (plasma)
filtration
movement of solute/water into blood (plasma)
absorption
capillary hydrostatic pressure (Pc)
pressure in blood vessels due to blood components (outwards)
capillary hydrostatic pressure (Pc)- arterial vs venous end
arterial: high Pc
venous: low Pc- favours absorption
interstitial fluid hydrostatic pressure (Pif)
pressure on blood vessels due to interstitial fluid components (inwards)
osmotic force due to plasma protein concentration (πc)
-osmosis into the blood vessels due to proteins in plasma (inwards)
osmotic force due to interstitial fluid protein concentration (πIF)
-osmosis into the blood vessels due to proteins in IF (outwards)
Net filtration pressure=
Pc + πIF - Pif - πc
ultimate goal of kidneys is to
maintain homeostasis: total body balance of substance
