Renal 1 Flashcards
main function of the kidneys
- Filter and remove waste products
2. Regulate BP, fluid and acid/base balance
what is the glomerular filtration rate
about 120-140ml/min of plasma is filtered at the glomerulus and passes into the Bowman capsule.
GFR is related to…
GFR is related to the perfusion pressure of the glomerular capillaries
this is the functioning unit of the kidney
nephron
how many nephrons in a kidney
- 1 million nephrons in each
- Cortical nephrons- 85%
- Juxtamedullary nephrons- work to concentrate urine
the glomerulus is supplied by…
supplied by the Afferent Arteriole
the glomerulus is drained by…
drained by the Efferent Arteriole
these control renal blood flow
Macula Densa cells
what are the blood vessels in the kidneys
- Renal Arteries- off of the abdominal aorta
- Renal veins- empty into the SVC
- Glomerular capillaries and arterioles
- Other arteries- interlobar and arcuate
- Other capillaries- peritubular and vasa recta
what does renin trigger
water consumption through sodium
what triggers the renin-aldosterone-angiotensin response
juxtaglomerular kidney cells, which sense changes in renal perfusion pressure
how much blood flow goes to the kidneys
1/4 of total blood
the glomerulus regulates
blood pressure
what is blood flow determined by?
how much blood flow in body?
GFR
in shock what happens to the GFR
GFR is decreased with triggers a release of epi, norepi and renin system
is a hormone system that regulates blood pressure and fluid and electrolyte balance, as well as systemic vascular resistance
RAAS (renin-angiotensin–aldosterone system)
what is the RAAS stimulated by
Stimulated by low blood pressure or certain nerve impulses (e.g. in stressful situations), the kidneys release an enzyme called renin.
normal isotonic fluid is
270-300 mL
in renal failure pt what happens to them metabolically
become ACIDODIC (metabolic acidosis is RENAL FAILURE)
describe the distal tubes in the nephron
Distal tube has fluid (urea, nitrogen based products, K, and hydrogen ions) from lymph coming in
how do healthy kidneys prevent acidocis
(kidneys release hydrogen ions)
goal of Renal Blood Flow regulation
regulate bp with GFR
As arterial pressure drops
the stretch on the afferent arteriolar wall decreases and the arteriole relaxes leading to an INCREASE in Renal Blood Flow
As the arterial pressure increases
the arteriole contracts and leads to a DECREASE in Renal Blood Flow
As the flow rate and NACL concentration decreases at the Macula Densa of the juxtaglomerular cells, the afferent arterioles constrict and the GFR decreases…
this is the Tubuloglomerular feedback
**release of RENIN
how much urine should a healthy person expel and what color should it be
- Urine is clear yellow or amber in color
* *Amount: 1-3 L/day or 30ml/hour
If urine output drops to less than 400/day…
oliguric and no urine output is anuric
what is a normal urine pH and S.G.
- pH is 4.6 to 8.0, normally acidic to prevent bacteria from adhering
- S. G. is 1.001-1.035
these things should NOT be in the urine
Should not contain Glucose (but B.S. above 220mg/dl will show), Blood, bilirubin, ketones, protein, bacteria
this increases water permeability and reabsorption
ADH
describe ADH
- pituitary releases it as vasopressin
- prevents from diuresing too much
if too much ADH…
oliguric (less than 400 ml/day)
if too little ADH..
- diabetes insipidus
- diuresis, increase in water excretion (urinate a lot of clear urine)
Distal tubule received the hypoosmotic urine from the ascending loop, concentration is controlled by
ADH
stimulates the bone marrow to produce RBC’s in response to tissue hypoxia to the kidneys
Erythropoietin
erythropoeitin also activates what vitamin
activates vitamin D (to store and absorb calcium)
d/t the renal hormone erythropoetin, if kidneys are NOT working, pt is at chance of developing what
anemia (since it normally stimulates RBC production)
how much sodium should be excreted in urine in 24 hrs
100-260 mEq/24 hr
how much potassium should be excreted in urine in 24 hrs
25-100 mEq/24 hr
