Quiz 1 Flashcards
4 general renal functions
Excretion of endogenous and exogenous waste products
Regulation of water and electrolyte balance
Regulation of body fluid pH
Regulation of arterial blood pressure
2 examples of waste products excreted by kidneys
UREA (Blood Urea Nitrogen BUN)
Creatinine
what does angiotensin II do?
increase vasoconstriction
what does aldosterone do?
decrease urinary Na excretion
What does the renin-angiotensin-aldosterone system and Na+ balance regulate?
arterial blood pressure
If renal O2 delivery goes down, what occurs to regulate this?
renal erythropoietin synthesis increases to increase erythrocyte synthesis
What is the most important transcription factor for erythropoietin production?
Hypoxia-inducible factor-1 (HIF-1)
If there is normal O2 conc., what happens to HIF alpha?
degraded by prolyl hydroxylase
What occurs in erythrocyte production of O2 conc. is low?
HIF alpha and Beta dimerize–> increase EPO transcription/translation
What is HIF-1 dependent upon?
oxygen conc.
Where is the site of synthesis for EPO synthesis?
peritubular fibroblasts and endothelial cells
For the regulation of vitamin D activity, where is the site of activation?
Proximal tubule cells
Uremic toxicity:
Azotemia is specific for what occuring?
increase plasma creatinine and BUN
Plasma protein imbalance:
Edema
excess fluid deposition in the interstitial space
Metabolic acidosis has what type of pH
pH<7.4
Hyperkalemia has a plasma K+ at what level
plasma K+>4.0mEq/L
Body fluid homeostasis can be maintained until renal function decreases to what percent of normal?
20%
Is acute renal failure (ARF) reversible?
yes
Pre-renal ARF=
decrease renal blood flow–>decrease glomerular filtration rate
Intra-renal ARF=
acute tubular necrosis (ATN)-ischemia/toxin-induced
i.e structure is affected
Post-renal ARF=
urinary tract obstruction
Is chronic renal failure reversible?
no
Most common cause of chronic renal failure?
diabetes (34%)
What is an alternative to a kidney transplant?
dialysis
What is the dialysis principle?
Diffusion across artificial membrane (hemo-) or capillaries (peritoneal) dialysis
In the hemodializer model, what flows through the upper compartment and is RECIRCULATED?
blood
In the hemodializer model, what flows in the counter direction through the lower compartment and is frequently renewed (which means the old passes a couple times and then gets drained)
dialysis fluid
What happens with renal failure?
increase plasma cratinine (azotemia)
increase K+ concentration (hyperkalemia)
decrease plasma HCO3- conc. (metabolic acidosis)
fluid accumulation
Two primary forms of dialysis
hemodialysis
peritoneal dialysis
Fluid volume equation
amount of X added/conc. of X at equilibrium
What is the dilution principle?
1) Add known amount of a measurable substance X to unknown volume in the beaker
2) Mix until substance X distributes throughout the fluid
3) fluid volume=amount of X added/conc. of X at eq
Osmosis
Movement of H2O across cell membranes
Osmotic pressure
The driving force for movement of H20 across cell membranes
Osmolarity=
conc. X number of dissociable partiles (mOsm/L)
= mmol/L X # particles/molecules
OsmolaRity=
of solute particles per liter of solvent
OsmolaLity=
of solute particles per kilogram of solvent (temp. independent)
Tonicity of a solution is a term used when…
referring to membrane impermeability
Isotonic
no change is cell volume
hypotonic
cell swells
hypertonic
cell shrinks
Which kidney is a little higher than the other?
Left
Is the human kidney multipapillate or unipapillate?
multi
The apex of the renal pyramids terminates in a _____
papilla
What part of the kidney produces urine?
nephrons
what are nephrons located within?
corticomedullary tissue
How thick is each nephron?
one epithelial cell thick
Sub-segments pathway of the nephron
Proximal tubule–>loop henle–>distal tubule–>collecting tubule
What type of nephron is the short-looped nephron?
cortical (superficial)
Where does the cortical (short-looped) nephron make the u-turn?
b/w the outer and inner medulla. It never enters the inner medulla
What is the long-looped nephron?
Juxtamedullary
What is the juxtamedullary nephron important for?
urine concentration
Three principle elements of renal function
1) Glomerular filtration
2) Tubular reabsorption
3) Tubular secretion
Glomerular filtration
plasma filtered from glomerular capillaries into bowmans space
Tubular reabsorption and its function
movement of substances from lumen into the peritubular capillary
principle mechanism for modifying the composition of the filtered fluid
Tubular secretion
movement of substances from the peritubular capillary into the lumen
What must be known to draw conclusions about excretory capacity?
urine flow rate
Micturition reflex
As the bladder fills with urine: increase stretch–>increase parasympathetic activity–>increase detrusor muscle contraction
Abnormalities of micturition?
Automatic bladder
Atonic bladder
Automatic bladder
spinal cord damage above sacral region–>periodic unintended bladder emptying
Atonic bladder
loss of sensory nerve fibers
No micturition reflex therefore bladder overflows a few drops at a time - overflow incontinence
where is the site of ultrafiltration?
glomerulus
Major components of the Filtration Slit (Diaphragm)
Mutation in these components are associated with what?
Connector proteins
Linker proteins
Actin-cytoskeleton complex
Glomerular dysfunction
Mesangial cells functions
Provide structural support secrete ECM phagocytic activity secrete prostaglandins and cytokines has contractile activity
What gives the negative charge to the “filtration pathway”?
high glycoprotein content of the basement membrane
Oncotic pressure is what?
osmotic pressure due to protein
In contrast to systemic capillaries, hydrostatic pressure remains _____ along the glomerular capillary
What is this due to?
relatively constant
Presence of resistance points before and after the glomerular capillaries
In contrast to systemic capillaries, glomerular oncotic pressure progressively _____ along the capillary
Why?
increases
b/c as fluid is filtered out the concentration of non-filterable proteins increases
How is Glomerular Filtration Rate (GFR) primarily regulated?
By regulating glomerular capillary hydrostatic pressure (GC)
If theres a decrease in resistance in the afferent arterioles, what happens to PGC, GFR, and RPF
PGC increase
GFR increase
RPF increase
If theres an increase in resistance in the afferent arterioles, what happens to PGC, GFR, and RPF
all decrease
If theres a decrease in resistance in the efferent arterioles, what happens to PGC, GFR, and RPF
PGC decrease
GFR decrease
RPF increase
If theres an increase in resistance in the efferent arterioles, what happens to PGC, GFR, and RPF
PGC increase
GFR increase
RPF decrease
GFR is primarily physiologically regulated by what?
changing resistance (diameter) of afferent arterioles via renal sympathetic nerves (vasoconstriction to decrease GFR) and angiotensin II (vasoconstrictor)
Blood pressure has an inverse relationship with what?
sympathetic activity
angiotensin II
decrease in BP causes increase in symp. and angio to increase renal vasoconstriction = increases BP
Major vasodilators?
prostaglandins
What stimulates prostaglandin synthesis?
sympathetic activity
angiotensin II
Changes in intratubular pressure due to a ureteral obstruction like a ureteral stone causes what reflex? what does it do?
Ureterorenal reflex
Obstruction causes ureteral stretch->sympathetic reflex->renal arteriole constriction->decrease GFR
(If there is an obstruction, the kidney slows down the hydrostatic pressure to reduce GFR and also prevent increases in pressure at the obstruction site risking severe damage)
