McCormick lectures Flashcards
hypoxia results in what compared to normal?
INcreased ICF Na
ICF osmolarity is due to what?
K+
The cell membrane between ECF and ICF is permeable to what?
water
NO IONS
the capillary membrane between ECF compartments is permeable to what?
small ions
how is fluid distribution between plasma and interstitial fluid maintained?
balance of hydrostatic and osmotic forces across capillaries
how is fluid distribution between ECF and ICF determined?
osmotic effect of small solutes across cell membrane (highly permeable to water)
what fluids stay in the ECF only?
whole body?
crystalloid fluids
saline
lactated Ringer’s Solution
what kind of fluids contain large proteins and molecules which stay within the vascular space?
colloid fluids
dextran, albumin, mannitol
what is non-pitting edema?
swollen cells due to increased ICF volume
what is pitting edema
increased interstitial fluid volume
what are the 3 anatomical urinary tract divisions?
upper
bladder
urethra
what composes the upper urinary tract?
CPU
calyces
pelvis
ureters
what controls voiding of the urethra?
2 sphincters
internal sphincter:
smooth or skeletal m.?
Symp or PS?
voluntary/involuntary?
smooth
PS
involuntray
what is the afferent pathway for bladder fullness?
pelvic splanchnic nerve or hypogastric plexus
POSTERIOR column
afferent pathway for bladder pain?
pelvic splanchnic n. / hypogastric plexus in the
ANTEROLATERAL column
reflex arc from the bladder?
bladder –> sacral detrusor nucleus –> bladder
reflex arc from urethra?
urethra –> sacral pudendal nucleus/sacral micturition center –> voluntary sphincter
where do the reflex arcs occur?
S2-S4
what nt does Symp fiber use?
where does it originate?
what does it pass through?
function?
NE
intermediolateral spinal gray horn T10-L2
hypogastric plexus
inhibits voiding
what nt does PS use?
origin?
what does it pass through?
function?
Ach
sacral detrusor/micturition center S2-S4
pelvic splanchnic nerve
contracts detrusor, relaxes sphincter
somatic fiber origin?
passes through what?
function?
sacral pudendal nucleus, S2-S4
hypogastric plexus and pelvic splanchnic nerve
contracts external urethral sphincter (rhabdomyosphincters)
what overrides the urge to void?
how?
Pontine micturition center (barrington’s center) located at the pons
control of sacral micturition center and thoracolumbar sympathetic outflow
what does Barrington’s Center coordinate?
activity of bladder and urinary sphincters
Tension = ?
(P x r) / 2
where do bladder stretch receptors send sensory info to?
sacral micturition center –> activate PS
higher centers in brainstem, cerebral cortex –> inhibit PS
what is the cause of an atonic/flaccid bladder?
what happens to the bladder?
destruction of afferent inputs via injury, Diabetes, syphilis, MS
stretch info not transmitted, no contractions, bladder fills to capacity and overflows, walls get thin and distended
AA
what causes denervated (hypertrophic areflexic) bladder?
what is the result?
destruction of afferent and efferent
detrusor contractions cease, bladder becomes flaccid and distended
later the detrusor has spontaneous activity and bladder shrinks due to hypertrophy of wall
DD
what causes automatic (spastic) bladder?
result?
injury/severed spinal cord above sacral region cuts off brain communication
spinal shock suppresses micturition reflex makes flaccid bladder
control by brain is lost, spastic bladder
A.I.
what causes uninhibited neurogenic bladder (dysreflexia)?
destruction of somatic tracts for inhibition
micturition is activated by small amounts of urine (constantly stimulated)
detrusor hypertrophies, bladder capacity reduced
UTI
what causes UTI?
result?
E. coli
uninhibited contraction of detrusor m. w/micturition reflex
urinary freq and leakage
what is isosmotic volume contraction?
expansion?
vomiting, diarrhea, hemorrhage
infusion of 0.9 NaCl
what is hyperosmotic volume contraction?
loss of water
dehydration
diabetes insipidus
what is hyperosmotic volume expansion?
gain NaCl
excess NaCl intake
mannitol infusion
what is hyposmotic volume expansion?
gain water
SIADH
psychogenic polydipsia
hyposmotic volume contraction?
lose NaCl
hypoaldosteronism
adrenal insufficiency
diuretics
what is ECF osmolarity due to?
bc of what?
Na and Cl
Na-K ATPase pump
Do the glomerular capillaries have a high or low hydrostatic pressure?
net result?
HIGH
filtration into Bowman’s capsule
what kind of pressure do the peritubular capillaries have?
net result?
low hydrostatic pressure
water and solute reabsorbed
where do sympathetic neurons synapse to cause renin secretion?
granular cells
what are the effects of sympathetic discharge on the kidney?
DEC GFR
inc reabsorption of Na and water from PCT and DCT
thirst via AgII production
Filtration rate equation
filtration rate = GFR x plasma [ ] of substance
urinary excretion rate equation
= urine flow rate x [ ] of substance
clearance of substance X = ?
(Ux x V) / Px
[ ] of X in urine x urine volume / [ ] of X in plasma
what does inulin clearance equal?
GFR
what are some advantages of using Cystatin C for measuring GFR?
levels not affected by muscle mass, age, or gender
when do PAH estimations for RPF become less useful?
at higher plasma [ ]’s of PAH
what is filtration fraction equation?
FF = GFR/RPF
increased FF means what?
increased oncotic pressure of efferent arteriole, more reabsorption
RBF equation?
RBF = RPF / (1-Hematocrit)
what is main function of ADH?
makes the collecting ducts permeable to water
when is ADH released?
increased blood osmolarity
decreased blood volume
what is the main function of aldosterone?
reabsorb Na+ from DCT
secrete K+ into urine
what effects does aldosterone have on volume and osmolarity?
Increases volume
no change in osmolarity
what effects does ADH have on osmolarity and volume?
Decreases osmolarity
Increases volume
where are osmoreceptors located?
anterior hypothalamus
where are volume receptors located?
Right Atrium
what are the physiological causes of proteinuria?
orthostasis (esp. in children)
strenuous physical activity like running a marathon
what are the 4 pathological causes of proteinuria?
loss of charge barrier
loss of size barrier
failure of PCT to reabsorb protein
overload proteinura, inc. plasma [ ]’s of low mw, filterable proteins
what is RBF equation?
RBF = change in pressure / Resistance
what can change the Kf?
surface area
permeability (Lp)
what do mesangial cells do to GFR?
decrease it bc they decreases the s.a.
Puf equation?
Puf = Pgc - Pbc - pigc
what does a kidney stone or blockage do to GFR?
DECREASE it
how is GFR primarily regulated?
Pgc
what BPs is GFR regulated over?
80-170
what does sympathetic stimulation do?
constrict afferent and a little efferent
Dec GFR, DEC RBF
activate RAAS to raise BP and INC Na and water reabsorption
what is PG release enhanced by?
ADH and NO
what hormones decrease GFR?
NE
Epi
Endothelin
what hormones increase GFR?
NO
PG
what is the myogenic response of autoregulation in response to?
INC. systemic arterial pressure
what happens in myogenic response?
resistance of blood vessels stretch
vascular smooth m. contraction in response via INC Ca2+ movement into cells
Result is prevents INC RBF and GFR when BP INC.
what is the TGF response to INC renal perfusion pressure?
constriction of afferent arteriole (Decreases GFR) via Adenosine
what is the TGF response to decreased renal perfusion?
INC sympathetic discharge
activate RAAS to Inc efferent arteriole constriction
will reabsorb Na and water
what is the criteria for diagnosing a UTI?
if urine collected by clean catch need both pyuria and at least 50,000 colonies
if by catheter: pyuria and 50,000 or 10-50,000 cpm confirmed by repeat
if urine collected via suprapubic aspiration, what meets the criteria for diagnosis of uti?
pyuria and ANY growth on culture
what enzyme will present with a positive uti?
leukocyte esterase
gram negative bacteria?
gram positive?
PECK
SEnterococcusS
what is renal scarring?
loss of renal parenchyma between the calyces and renal capsule
what antibiotic do you use to treat uti?
cephalosporin or fluoroquinolones
when do you image with VCUG?
after 2nd uti
OR
after 1st uti with abnormal RBUS and temp > 39 C
what are the 2 major tests for detecting proteins and what are their major characteristics?
Dipstick test - color rxn to protein more sensitive to albumin
Sulfosalicylic acid test - detects all proteins, the more turbid, the higher the protein [ ]
