Phys: Renal Flashcards
what are the main functions of the kidney?
waste excretion
electrolyte balance
BP control
acid base balance
what is the functional unit of the kidney?
the nephron
explain the kidney:
it is an excretory organ with an ENDOCRINE fxn.
it has 2 parts:
Cortex
Medulla
what are the 2 types of nephrons? how many nephrons in thebody?
Cortical- 80%
Juxta-medullary- 20%
nearly 1 million nephrons in the body. Cannot be regenerated.
what makes up the nephron?
Glomerulus- enveloped in a double layer Bowmans capsule
Two convuluted tubules- proximal & distal
two parts of the Loop of henle- two parts a thick and thin ascending, and a thin descending
what are the 2 hormones that are secreted by the kidney?
erythropoeitin
renin
what hormones act on the kidney?
ADH Aldosterone ANP 1,25 dihydroxycalciferol parathormone
the kidneys function is dependent on?
blood flow
how much does the kidney use of the cardiac out put?
20% (1 liter/min)
how much of the renal blood flow is the renal PLASMA flow?
60% (600 mL/minute)
course of blood flow in the kidney?
Renal art> interlobar> arcuate> interlobULAR> Afferent arteriole (in)> Glomerulus> Efferent arteriole (out)> peritubular cap.> Venules> interlobUlar vein> Arcuate vein> interlobar vein> renal vein> IVC
urine flow?
collecting duct> Calyx> renal pelvis> Ureter> bladder> urethra
how much do you filtrate a day?
180 L
purpose of bowmans capsule?
filtration due to fenestrations
pressure is -18 mm Hg
it pushes water back into the capillary
proximal tubule fxn?
reabsorption 100% of AA & glucose are filtered here 80% of bicarbonate & phoshate 60-70% of Na+ (exchanged for H+), Ca++, K+ 50% H2O and urea
podocytes are?
cells that form filtration membrane
loop of henle fxn?
concentration
vasa recta are?
thin-walled vessels, parallel loop of henle
distal tubule does?
aldosterone works here to reabsorb Na+ and secrete K+
reabsorption of filtrate in prox. tubule? distal tubule?
65% end of prox.
99% end of distal
what is the normal GFR?
120-125 mL/min
determined by hydrostatic pressure
what does hyrdostatic pressure?
pushes water out of the capillary (+60 mm Hg)
what does oncotic pressure do?
pulls water back into capillary (-32 mm Hg)
what is the renal threshold for glucose?
180 mg/dL- once reached glucose will pass through the urine
what is the thin descending loop of henle permeable to?impermeable? purpose?
H2O
impermeable: urea
P: concentrate the urine
what is the thick ascending part impermeable to? purpose?
H2O
it is the diluting segment of the loop
what are juxtaglomerular cells for?
mechanoreceptors for BP entrance afferent arteiole
what are macula densa for?
chemoreceptors for JG cells
sensitive to Na+ conc.
located in the DCT
Aldosterone is from? purpose?
from Zona Glomerulosa
absorbs Na+, excretes K+
results from RA system
thus water
renin is from? stimulated by?
JG apparatus
stim. by dec. in pressure in afferent arterioles
erythropoeitin does?
RBC production
why is the RAA system stimulated? explain
drop in BP
Renin-Angiotensin- Aldosterone system
Angiotensinogen- protein produced in liver
Renin- enzyme made by JG cells
Angiotensin I- travels in blood
ACE- made in lungs (converts angio I into angio II)
Angiotensin II- constricts BV (inc. BP), stimulates release of- Aldosterone- inc. bp by inc. Na+ reabsorption
renin converts?
angitoensinogen> angintensin I
ACE converts?
angiotensin I> angitensin II
respiratory acidosis is? cause? compensate?
inc pCO2 & dec pH
HYPOventilation: COPD & CHF
renal: inc H+, inc HCO3-
respiratory alkalosis is? cause? compensate?
dec. pCO2 & inc pH
HYPERventilation
renal: dec. H+, dec. HCO3-
Metabolic acidosis is? cause? compensate?
dec. HCO3-, dec. pH
diarrhea, diabetic ketoacidosis, renal dysfx, Aspirin overdose
respiratory:Hyperventilation
metabolic alkalosis is? cause? compensate?
inc. HCO3-, inc pH
drugs, vomiting, diuretics: conns disease
respiratory: hypoventilation
what does ADH do?
increases water perm in the collecting ducts by acting on the aquaporins
secreted by supra-optic nucleus in the hypothalamus
what does ANP do?
decrease Na+ reabsorption in the DCT; results in increased urine ouput
peptide hormone produced in the atrial myocardial fibers
what does 1,25 dihydroxycarboxylase do?
acts on DCT by increasing Ca++ absorption
it is the active form of Vit. D
what is the pH of the blood?
7.35-7.45
what is volatile acid?
produced when CO2 reacts with h2O to form carbonic acid
what are examples non-volatile acid?
lactic acid suulfuric acid phosphoric acid keto-acids-acetone acetoacetate hydroxybutrate
what is the major buffer in the blood?
bicarbonate
