Exam 1 Physio Flashcards
Eqn for extracellular osmolarity
ECF osm=2Na + Glc/18 + BUN/2.8
normal is about 300
Markers for total body water
tritium/deuterium
antipyrine
Markers for ECF
inulin
mannitol
radioactive sulfate
these cannot permeate cell walls
Markers for Plasma
radiolabeled albumin/colloid
evans blue
these cannot permate capillary walls
Effects of tonicity on cell
hypertonic soln- cell shrinks
hypotonic soln- cell swells
Fluid fractions intra and extracellular
intracellular=2/3
extracellular=1/3
Impact of adrenal insufficiency or overuse of diuretics on ECF/ICF
decrease ECF/[Na] in plasma
increase ICF
Impact of SIADH or bronchogenic tumors on ECF/ICF
increased ICF and ECF
decrease [Na] in plasma
Impact of Diabetes insipidus or excessive sweating on ECF/ICF
decrease ICF and ECF
increase [Na] in plasma
Impact of Cushing’s disease or primary aldosteronism on ECF/ICF
increased ECF
decreased ICF
increased [Na] in plasma
Causes of intracellular edema
decreased metabolism (ATPase not working) hyponatremia
How can the liver cause edema?
decreased synthesis of albumins
What is the cause of congenital nephrotic syndrome?
nephrin protein defect
Capillary oncotic pressure in kidneys
decreases along the length of glomerulus
dictates reabsorption of proximal tubulues in the peritubular capillaries
Filtration fraction eqn
FF=GFR/RPF
What do changes in filtration fraction mean?
increased FF-quicker saturation of oncotic pressure of glomerulus. Shows that more fluid is being filtered, leaving a higher concentration of protein in the peritubular capillaries
What impact the capillary coefficient (Kf)?
hydraulic conductivity
effective SA of filtration (Sf)
What can change the capillary coefficient?
change in SA by mesangial cells to hormones
DM/obesity increases thickness, decreases Kf
HTN can change Kf
Renal blood flow eqn
RBF=(renal artery P - renal vein P)/renal vascular resistance
Hormonal regulation of GFR and RBF
epi/NE/endothelin decrease GFR/RBF
PGE/NO increase GFR/RBF
Myogenic response autoregulation of kidneys
afferent arterioles are stretched and constrict in response
Tubuloglomerular feedback
macula densa sense increased GFR
causes afferent vasoconstriction
normalizes GFR
Juxtaglomerular cell regulation in the kidney
release of renin in response to decreased pressure
Effects of aldosterone
increase Na+ resorption/K+ secretion
increased Na+/K+ pump activity
increases intracellular K+ in principal cells
Eqn for molecule reabsorption in kidneys
Reabsorption=(GFRPx) - (VdotUx)
Px=plasma conc
Ux=urine conc
Vdot=urine flow volume
Threshold and splay in of Glc transport in kidneys
Threshold-below max, but start seeing Glc in urine
Splay-gradual appearance of Glc in urine nearing the transport maximum
Collecting duct water resorption
about 15% of total water resorption
regulated by ADH
uses Aquaporin-2
Transports in proximal tubule
Na+ cotransporters (with Glc/phos/aa) Na+/H+ exchanger and Cl-/HCO3- exchanger Na+/Cl- cotransporter Na+ uniporters AQP-1
Loop of Henle reabsorption
descending-only water permeable
ascending-only salt permeable, uses Na+/K+/Cl- transporter
Late distal tubule/collecting duct reabsorption
principal cells-Na+ resorption/K+secretion, responds to ADH and aldosterone
intercalated cells-alpha secrete acid, beta secrete bicarb
Neural regulation of kidneys
alpha-adrenergics increase NaCl resorption
Atrial natriuetic peptide
increases Na+ and water excretion
Imbalances of aldosterone
Addisons disease-hypo
Conn’s syndrome-hyper
Effects of aldosterone
increase K+ secretion and Na+/water resorption
increase Na+/K+ ATPase and ENaC expression
Effects of ADH
increase water resorption in collecting ducts
increased AQP-2
stimulated by hypothalamus->post pituitary releases
stimulated by increase osmolarity or decreased ECF
Imbalances of ADH
SIADH-excess ADH
Diabetes insipidus-no water resorbed due to no ADH
Action of ADH
Gs on principal cells
ATP to cAMP to PKA
causes release of AQP-2
Egn for clearance
Cx= (Ux*Vdot)/Px
Ux=urine conc
Vdot=urine flow
Px=plasma conc
Meaning of clearance ratios
Cx/Cinulin
ratio=1, just filtered
ratio1,secreted
Renal plasma flow eqn
RPF=(Upah*Vdot)/(RApah-RVpah)
Upah= urine PAH conc
RApah= renal artery PAH conc
RVpah= renal vein PAH conc
Extraction ration eqn
Epah=([PAH]plasma - [PAH]venous)/[PAH]plasma
Renal blood flow eqn
RBF=RPF/ (1-Hct)
Impact of diarrhea on ECF/ICF
decrease ECF only
Impact of dehydration on ECF/ICF
decrease ICF/ECF
increase osmolarity
Impact of adrenal insufficiency on ECF/ICF
Decrease ECF
Increase ICF
Decreased osmolarity
Impact of isotonic saline infusion on ECF/ICF
increase ECF only
Impact of excessive NaCl intake on ECF/ICF
increase ECF
decrease ICF
increase osmolarity
Impact of SIADH on ECF/ICF
increase ECF/ICF
decrease osmolarity
Effectors of renal blood flow
angiotensin II/sympathetics-decrease RBF
PGE2/PGI2/dopamine/bradykinin-increase RBF
RBF regulation
autoregulation between 80-200mmHg myogenic (contraction from stretch) tubuloglomerular feedback (macula densa)
Renal plasma flow measurement
measured with PAH clearance RPF=(U*V)/(Pa-Pv) U=urine conc V=urine volume Pa=arterial conc Pv=venous conc
Glomerular filtration rate measurement
measured with inulin clearance GFR=U*V/P U=urine conc V=urine volume P=plasma conc
