Renal Physiology Part 2 Flashcards
What are the three defenses against pH change in the body.
1) Buffering Systems of the body 2) Respiratory Response 3) Renal response
What is the respiratory response
Elimination of PCO2 (Volatile Acid) Take 3-12 minutes to work
What is renal response
Excretion of H+ (or reabsorption) The slowest but the most powerful
What two things can alter a persons physiological pH
1) Diet (A.A/Fatty acids) 2) Metabolism
Any substance that can reversibly bind H+ is considered a
Buffer
Buffer systems are considered the _____line of defense to pH imbalance
FIRST
Through manipulating the Henderson Hasslebatch equation, we say that pH in the ECF is equal to
pH = [HCO3-]/PCO2
What organ has control over CO2 levels
LUNGS
What organ has control over HCO3-
Kidneys
CO2 is considered a
Volatile Acid
Give three examples of ECF buffers
1) Bicarbonate buffer system 2) Inorganic Phosphates 3) Blood Proteins
Four examples of intracellular buffers
1) Hemoglobin 2) ATP 3) ADP 4) Glucose-Phosphate
Respiratory Compensation is considered the ____ line of defense against pH imbalance
Second Line
What is the function of respiratory compensation
Compensate for changes in [HCO3-] levels. If we see a decrease in [HCO3-], we hyperventilate to breath the PCO2 out
Why is respiratory compensation a great tool
Because if someone is suffering from metabolic acidosis (meaning their [HCO3-] level are down) respiratory compensation can quickly act to buy the kidney time to fix pH.
What is renal compensation
Kidney compensates for changes in the PCO2 by adjusting [HCO3-] reabsorption
What mechanisms are associated with renal compensation
1) Secretion of H+ 2) Reasbsorption of filtered [HCO3-] 3) Production of new [HCO3-]
Explain how HCO3- gets reabsorbed back into our blood stream
HCO3- + H go from the tubule lumen into the cell of the PCT and re associate as carbonic acid and then degrading back into HCO3- + H. Once degraded, HCO3- enters the blood stream.
What part of the nephron is 80-90% of bicarbonate reabsorption occurring
PCT
What is secreted into the the alpha intercalcated cells of the distal tubule.
H+
How is H+ excreted out once the urine has reached an acidity of 4.5
Ammonia buffering Phosphate buffering
At the collecting duct of the nephron what occurs
1 Bicarbonate is reabsorbed 1 H+ is secreted
Metabolic Acidosis
Increase in [H+] and decrease in [HCO3-]
Metabolic Alkalosis
Decrease in [H+] and increase in [HCO3-]