Renal physiology Flashcards
Two actions of ADH other than increasing water permeability in the collecting duct.
increase urea absorption in the collecting duct; increase NA/K2Cl activity in thick ascending limb
WHat is the mechanism stimulating renin release?
decrease in blood pressure in kidneys
What type of fluid disturbance is caused by drinking too much water (ex SIADH)? How does it effect osmolarity, Hct, and plasma protein concentration?
hyposmotic volume expansion
Increase ICF
Osmolarity: Decrease
Hct: NC
Plasma protein conc: Decrease
Class of drugs that can cause renal failure in high vasoconstrictive states due to inhibition of prostaglandin production?
NSAIDS. prostaglandins are keeping the afferent arterioles vasodilated to maintain GFR. Inhibition of prostaglandin production leads to acute renal failure.
What is the main source of anions in the ECF?
Chloride
Cells in this part of the nephron have well-developed apical brush border and extensive basolateral infoldings with a large number of mitochondrias.
proximal tubular cells
At what plasma glucose level does glucosuria begin?
200 mg/dL
What is the compensation for metabolic alkalosis?
increased CO2 by decreased respiration
What is the Henderson-Haselbach equation?
pH= pKa+Log (HCO3-)/(.03pCO2)
Angiotensin I is then cleaved by ___, primarily in the ___ to make ___?
angiotensin converting enzyme, lung capillaries, angiotensin II
How does nephrotic syndrome cause edema?
loss of proteins results in decreased oncotic pressure in the capillaries. Relative excess hydrostatic pressure then pushes water into ISF
ECF volume expansion____ (increases/decreases) reabsoprtion in proximal tubules.
decreases
Substances regulated by aldosterone in collecting tubules. (2)
Na+, K+
Which hormones are stimulated to be released by a decrease in blood volume?
ADH, aldosterone, angiotensin II (via renin)
What are the vasa recta of the kidney and what purpose do they serve?
they are branches of the peritublar capillaries that follow the loops of Henle and help with water conservation. Water and solutes excreted by the loop of Henle are absorbed here.
What percentage of HCO3-is reabsorbed?
over 90%
What percentage of the blood to the kidney goes to the cortex?
over 90%
Name four actions of angiotensin II.
- potent vasoconstriction
- release of aldosterone from adrenal cortex
- release of ADH from posterior pituitary
- stimulates hypothalamus to increase thirst
Name the hormone that inserts aquaporins in the principle cells of the late distal tubule and collecting ducts in response to water deprivation.
ADH
What does kallikrein do?
it activates bradykinin
What is the primary disturbance in metabolic alkalosis?
increased bicarbonate
What is the compensation for metabolic acidosis?
a drop in CO2 by hyperventilation
What type of fluid disturbance may be caused by dehydration, sweating, fever or diabetes insipidus? How does it effect osmolarity, Hct, and plasma protein concentration?
hyperosmotic volume contraction
reduce ICF
Osmolarity: increase
Hct: NC
Plasma protein conc: Increase
Class of drugs that inhibits production of angiotensin II?
ACE inhibitors
Endothelial cells of peritubular capillaries secrete which hormone in response to hypoxia?
erythropoietin
T/F: There is no active transport in thin loop of loops of Henle
true
High pH, high pCO2 (high HCO3-) causes which metabolic condition?
metabolic alkalosis
What are some actions of aldolsterone on distal tubules and collecting duct? (3)
- on principle cells:
- increases Na+ reabsorption
- increase K+ secretion - on intercalated cells
- increases H+ secretion
What is the primary disturbance in respiratory acidosis?
a build-up in CO2
How much of the tubular fluid is absorbed through the intercalated cells in the loop of Henle?
very little, there are no aquaporins here
What are some common causes of alkalosis?
hyperventilation, high altitude, pneumonia and pulmonary embolus (hypoxemia causes hyperventilation)
Where is glucose absorbed in the nephron?
proximal tubule (100%)
Of the 120ml per min filtered into the nephron, how much is returned to the plasma in the tubules?
119ml, meaning only about 1 ml per min of urine is produced by the kidney each minute
Compare the osmolarity in the different fluid compartments.
mostly the same between all compartments because most cells are very permeable to water.
Which juxtaglomerular apparatus cells are located in the walls of thick ascending LH and DST; wedged between the afferent and efferent arterioles. They can detect osmolarity and volume changes in the tubular fluid.
macula densa
Where is the juxtaglomerular apparatus located?
next to each glomerulus, it makes contact with the beginning of the distal tubule.
How does the kidney compensate for respiratory acidosis? (2)
increase in HCo3 absorption
Increase in H+ excretion
What are the seven physiological responses to high altitude?
- acute increase in ventilation
- chronic increase in ventilation
- increase in EPO leading to an increase in hematocrit and hemaglobin (chronic hypoxia)
- increase in 2,3-DPG,
- Cellular changes (increase in mitochondria)
- increase in excretion of bicarbonates to compensate for respiratory alkalosis, 7. Chronic hypoxic pumonary vasoconstriciton results in RVH
Substances reabsorbed in the early proximal tubule. (5)
all glucose and amino acids, most bicarbonate, sodium, and water
ECF volume contraction___ (increases/decreases) reabsorpiton in proximal tubules.
increases
Which cells secrete erytropoetitin?
juxtaglomerular cells