Renal Flashcards
What is the composition of intracellular and extracellular fluid?
extracellular is 1/3, intracellular is 2/3. infants have more extracellular than intra.
What is trancellular fluid?
synovial, cerebrospinal, GI, (note that dense connective tissue and bone is not interstitial)
What is thirst triggered by?
Osmolality, concentration of extracellular fluid
What molecules can freely pass through the lipid bilayer?
hydrophobic and small, uncharged, O2 CO2 N2 H2O urea glycerol
Nephron is made of what type of cells?
epithelial
What controls the amount of fluid in the urine?
ADH, aldosterone, ANP and BNP
Where is aldosterone produced from?
adrenal cortex, stimulated by angiotensin II and by increased concentration of K ions in the plasma
NP oppose the action of aldosterone but not?
NP is not as strong as aldosterone
What are the four processes of control of electrolyte homeostasis?
electrolyte intake, absorption, distribution, excretion
three major mechanisms regulate acid base balance?
- blood buffers 2. respiratory system 3. renal system
Blood buffers
Weak acids release hydrogen ions when a fluid is too alkaline and a base that takes up hydrogen; also have phosphate and hemoglobin buffers, carbonic acid buffers
4 types of blood buffers
Bicarb, phosphate, hemoglobin, protein
Bicarb buffer system
bicarbonate ions and carbonic acid, 20:1 bicarb to carbonic acid ratio
2nd line defense
Respiratory system; chemoreceptors in the brain sense CO2
What acid does the respiratory system not respond to?
carbonic acid
What is the third defense against AB imbalance?
Kidneys, can excrete any acid except for carbonic acid which is excreted by the lungs; excrete normal metabolic acids that the body makes
When the kidneys buffer, which buffers used require the making of a new bicarb?
phosphates and ammonia
Where does buffering occur?
in the proximal convoluted tubule (bicarb)
in the collecting duct: ammonia and phosphates
Increased excretion of H increases what production?
Ammonia
What reflects the effectiveness of renal regulation of metabolic acids?
Bicarb in the plasma
What reflects the relative amount of metabolic acid in the blood?
Bicarb in the plasm
What does a deceased plasma bicarb mean?
indicates a relative excess of metabolic acids, bicarb concentration is less than normal
What does an increased plasma concentration mean?
deficit of metabolic acids, an excess of base
How does your kidneys respond to carbonic acid?
Increases excretion of metabolic acids and H when you have high carbonic acids. Takes several days to fully work.
What is ammonia made from and where?
Glutamine in the epithelial cell in the collecting duct.
