renal part 7 Flashcards
What is the definition of pH, and why is it important to maintain plasma pH within a given range?
A) pH is the concentration of H+ ions in a solution; maintaining plasma pH is crucial to prevent metabolic disorders.
B) pH is the negative logarithm of H+ ion concentration; maintaining plasma pH is essential to ensure proper enzyme function and cellular activities.
C) pH is the ratio of HCO3- to CO2 in the blood; maintaining plasma pH is necessary to regulate oxygen transport.
D) pH is the balance between volatile and non-volatile acids; maintaining plasma pH ensures that H+ is effectively excreted.
pH is the negative logarithm of H+ ion concentration; maintaining plasma pH is essential to ensure proper enzyme function and cellular activities.
Which of the following best defines a buffer?
A) A strong acid that neutralizes strong bases to maintain pH balance
B) A system composed of a weak acid and its conjugate base that resists changes in pH
C) A mechanism that only removes excess H+ from the body through renal excretion
D) A molecule that reacts with CO2 to form bicarbonate, stabilizing the blood pH
A system composed of a weak acid and its conjugate base that resists changes in pH
*a buffer is any substance that binds to H+
how are protons buffered in the body?
- mostly by extraceullar and intracellular fluid
- CO2/HCO3- os the extracellular buffer system
- phosphate ions and hemoglobin are the intracellular buffers
What is the primary difference between acidosis and alkalosis?
A) Acidosis is a decrease in [H+], whereas alkalosis is an increase in [H+]
B) Acidosis is a decrease in pH below 7.35, whereas alkalosis is an increase in pH above 7.45
C) Acidosis is caused by excess HCO3-, while alkalosis is caused by excessive CO2 retention
D) Acidosis always results from respiratory dysfunction, while alkalosis is always metabolic
Acidosis is a decrease in pH below 7.35, whereas alkalosis is an increase in pH above 7.45
what is the equation that maintains homeostasis of pH in the body?
H20 + CO2 <—>H2CO3<—> HCO3- + H+
the body ensures that levels of water, CO2, HCO3= and H+ are balanced in the body
what makes up volatile acids and non-volatile acids?
CO2 is a volatile acid
sources other than CO2 (organic and inorganic) is a non-volutile acid
Which of the following contributes to H+ gain in the body? and why?
- hypoventilation (more CO2 in the body)
- diarrhea or other gi fluids (losing HCO3-)
- producing nonvolatile acids/metabolism of amino acids and organic molecules
- loosing HCO3- in urine
why does diarrhea cause a gain of protons, and why does vomiting lower the amount of protons
diarrhea=less bicarbonate in the digestive tract means there is less buffering of H+
vomiting= there is a loss of protons because the stomach secretes H+ and the concentration lowers cus some of the stomach acid is excreted out
How do the lungs help regulate changes in pH?
A) The lungs eliminate CO2, which shifts the bicarbonate buffer system and modulates H+ concentration
B) The lungs excrete H+ directly into the alveoli, maintaining acid-base balance
C) The lungs increase bicarbonate absorption to compensate for metabolic acidosis
D) The lungs release lactic acid during hyperventilation, which decreases plasma pH
The lungs eliminate CO2, which shifts the bicarbonate buffer system and modulates H+ concentration
. Which of the following is true about respiratory acidosis?
A) It results from increased CO2 retention due to hypoventilation
B) It occurs due to excessive bicarbonate excretion in the kidneys
C) It is commonly seen in individuals who hyperventilate at high altitudes
D) It can only be corrected by increasing bicarbonate reabsorption
) It results from increased CO2 retention due to hypoventilation
A patient experiencing prolonged vomiting is likely to develop which condition?
A) Metabolic acidosis due to bicarbonate loss
B) Metabolic alkalosis due to excessive loss of gastric H+
C) Respiratory acidosis due to increased CO2 retention
D) Respiratory alkalosis due to hyperventilation caused by fluid loss
Metabolic alkalosis due to excessive loss of gastric H+
when you vomit you loose protons because your stomach makes H+
How does the body balance changes in H+ concentration in the short term versus the long term?
The lungs regulate H+ concentration in the short term by altering CO2 exhalation, while the kidneys manage long-term balance by adjusting H+ excretion and bicarbonate reabsorption.
why does an increase in proton concentration stimulate ventilation
to get rid of more CO2 in the body and lower the concentration of protons
why does a low proton concentration inhibit ventilation?
to hold onto more CO2, which increases the concentration of protons
what do the kidneys do to combat alkalosis? what aboit in acidosis
alkalosis= kidneys excrete more bicarbonate because bicarbonare is a buffer and binds to protons, which decreases the proton concentration
during acidosis, the kidneys will SYNTHESIZE bicarbonate and send it to the blood to decrease H+
How is HCO₃⁻ reabsorbed in the nephron?
A) HCO₃⁻ is freely filtered and directly reabsorbed into the blood without modification.
B) HCO₃⁻ is converted to CO₂ and H₂O in the tubule lumen before being reabsorbed as CO₂.
C) HCO₃⁻ is passively transported across the tubular membrane and into the peritubular capillaries.
D) HCO₃⁻ is actively secreted into the tubule and then reabsorbed into the bloodstream.
(HCO₃⁻ in the filtrate reacts with H⁺, forming CO₂ and H₂O, which diffuse into the tubular cells, where CO₂ is converted back into HCO₃⁻ and transported into the blood.)
b
Which of the following transport mechanisms are involved in the reabsorption of HCO₃⁻?
A) H⁺ ATPase, Na⁺/K⁺ ATPase, Na⁺/H⁺ exchanger
B) H⁺/K⁺ ATPase, Cl⁻/HCO₃⁻ exchanger, passive diffusion of CO₂
C) Na⁺/H⁺ exchanger, passive diffusion of CO₂, and H⁺ ATPase
D) Na⁺/K⁺ ATPase, H⁺/Cl⁻ exchanger, and NH₄⁺/H⁺ counter-transport
(HCO₃⁻ reabsorption is dependent on H⁺ secretion, which occurs through the Na⁺/H⁺ exchanger and H⁺ ATPase, while CO₂ diffuses passively into cells.)
c
How does the kidney add new HCO₃⁻ to plasma during acidosis?
A) By directly filtering and reabsorbing additional HCO₃⁻ molecules into the blood.
B) By excreting excess NH₄⁺ and HPO₄²⁻, allowing more HCO₃⁻ to be generated inside tubular cells.
C) By reducing CO₂ levels in the blood, which drives the conversion of HCO₃⁻ to H₂CO₃.
D) By inhibiting the Na⁺/H⁺ exchanger to reduce acid excretion.
By excreting excess NH₄⁺ and HPO₄²⁻, allowing more HCO₃⁻ to be generated inside tubular cells.
*making new bicarbonate=more buffer=less h+ in blood
(H⁺ binds with phosphate (HPO₄²⁻) or ammonium (NH₄⁺) in the tubule, allowing new HCO₃⁻ to be synthesized in the tubular cells and added to plasma.)
explain what happens during acidosis
- increased protons
- new bicarbonate is generated with non bicarbonate buffers and tubular glutamine metabolism and both are reabsorbed in plasma
how does the body respond to alkalosis?
few H+ ions in filtrate, the kidneys secrete excess bicarbonate into the urine
a decrease of ammonium excretion and glutamate metabolism helps increase the concentrations of protons
