Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
What three body systems maintain the acid-base homeostasis?
|
Intracellular and Extracellular buffers.
Lungs Kidneys |
|
IC and EC buffers and lungs are responsible for ____ pH changes whereas the kidneys are responsible for _____ changes.
|
IC/EC/lungs: rapid pH changes.
Kidneys: long-term changes. |
|
What are some IC and EC buffers?
|
Hemoglobin
Carbonates Phosphates HCO3 |
|
What do kidneys secrete the majority of for acid-base balance?
|
H+
|
|
True or False:
Nonvolatile acids produced during metabolism do not circulate as free acids, but are immediately buffered. |
True!
|
|
Where are nonvolatile acids used in buffering excreted?
|
In the kidneys.
|
|
In order to maintain acid-base balance, the kidney must excrete ____ salts and replenish lost ____.
|
Excrete Na+ salts and replenish lost HCO3-.
|
|
How is the reabsorption of filtered HCO3- and excretion of acid accomplished?
|
Through H+ secretion by the nephrons.
PT secretes the bulk of the acid, and CD controls net acid excretion and final urine pH. |
|
What must net acid excretion equal?
|
Nonvolatile acid production.
|
|
What three transporters provide the majority of acid excretion in the renal tubules?
|
Na+/H+ antiporter. (PT)
H+ ATPase (CD) H+/K+ ATPase (CD) PT=Proximal Tubule CD=Collecting Duct |
|
What are the three most important buffers in the tubular fluid that accept secreted H+?
|
HCO3- (Predominates because of its high concentration)
Ammonia Phosphate |
|
How is NH3 produced in the kidneys?
|
Via hydrolysis of the amino acid glutamine.
Glutamine --> NH4+ + HCO3- |
|
How does Plasma K+ concentrations alter NH4+ production?
|
Hyperkalemia inhibits NH4+ production and hypokalemia stimulates production.
|
|
Why is Ammonia an important urinary buffer?
|
It is produced by the kidney and its synthesis and excretion can be regulated in response to the acid-base requirements of the body.
|
|
The proximal tubule has a high capacity for ___ secretion and ___ resorption.
|
H+ secretion
HCO3- resorption. |
|
How much of filtered HCO3- is reabsorbed by the Proximal Tubule
|
80-90%
|
|
True or False:
Since the PT has a high capacity for H+ secretion and HCO3- reabsorption it is able to maintain a large pH gradient across the apical plasma membrane. |
False.
It can't maintain a large pH gradient, so the pH of tubular fluid as it leaves the proximal tubule will be similar to that of the glomerular filtrate. |
|
What part of the nephron determines the final urine pH?
|
The collecting ducts.
|
|
What is the normal range of urine pH in carnivores? In Ruminants?
|
Carnivores: 5.5-7.7
Ruminants: 6-9 |
|
How does the collecting duct generate an acidic urine?
|
By secreting protons.
|
|
What does the rate of H+ secretion depend on?
|
The number of proton pumps in the apical plasma membrane.
|
|
What are some primary factors that regulate H+ secretion in the nephron?
|
INC H+ secretion.
Decreased plasma HCO3- concentration. Increase in partial pressure of arterial carbon dioxide DEC H+ secretion Increase in plasma HCO3- concentration Decrease in partial pressure of arterial carbon dioxide. |
|
What are some secoondary factors that regulate H+ secretion in the nephron?
|
INC H+ secretion
Increase in filtered load of HCO3- Decrease in ECF volume Increase in An II Increase in ADS Hypokalemia Decreased H+ secretion Decrease in Filtered load of HCO3- Increase ECF volume Decrease in ADS Hyperkalemia |
|
___ is thought to increase the number of proton transporters in the apical plasma membrane. It increases the reabsorption of NA+ and increases the secretion of H+ and K+
|
ADS (Aldosterone)
|
|
What cells in the Collecting Duct are responsible for HCO3- secretion?
|
Type B intercalated cells.
(They do the reverse of the acid secreting cells) |