EXAM III: 6A Respiratory Regulation of pH/ Disturbances Flashcards
What is the basic definition of Bases?
- Bases are H+ acceptors (Soak up H+)
- Similar to acids, bases can also be classified as strong or weak
What is the basic definition of Acids?
- Acids are H+ donors (releases H+)
- Strong acids dissociate completely in solution
- Weak acids do not dissociate completely (reversible)
What is pH?
Measure of H+ concentration
*pH= -log [H+]
-pH of ECF can also be measured by Hasselbach equation
pH=pka+log[HCO3-]/[CO2]
What is the normal range of pH of the ECF?
7.35-7.45
- It is the ratio rather than the absolute values for bicarbonate and dissolved CO2 that determines pH
- Example when ratio is 20:1 pH is 7.4
What is the concentration of H+ in healthy individuals?
50-100 mEq/L of H+ via Metabolic reactions.
What are buffers?
- Substance that prevent changes in pH
- Done by binding H+ (act like bases)
- if pH drops they release H+ (act like acids)
What are the 3 major chemical buffers in the body?
1) Carbonic acid (H2Co3)- Bicarbonate (HCO3-)
2) Phosphate
3) Protein (Hemoglobin and albumins)
How does Carbonic acids and Bicarbonate regulate body?
- If excess H+ is present (acidosis) then the rxn favored to the left. H+ going to to be soaked up
- If shortage (alkalosis), then rxn is favored to the right. H+ is released.
How does Phosphate regulate body?
- If excess H+ is present (Acidosis) then rxn is favored by right and H+ is soaked up
- If shortage, than rxn is favored to the left. H+ released
How do Proteins regulate body?
- If excess H+ is present, the amine portion soaks up H+
- IF shortage H+, carbonyl portion releases H+
How does Respiratory regulation control pH?
-Any increase in conc. of ECF CO2 lowers the pH
-A decrease in the rate and/or depth of breathing increases the retention of CO2 within body
Result–>increase in the amount of H2Co3 formed & consequently the amount of H+ formed
***Hypoventilation decreases the pH of the ECF
How does a decrease in CO2 concentration raise the pH?
By decreasing the level of free H+
What does an increase in the rate and /or depth of breathing do?
Increases the amount of CO2 exhaled, thereby reducing the CO2 level in the blood
Result–> reduces the amount of H2CO3 formed & consequently the amount of H+ formed
***Hyperventilation increases the pH of the ECF
How do the respiratory centers in the brainstem help regulate the H+ concentration?
By controlling the rate & depth of breathing
How do the kidneys regulate the pH?
1) Secreting H+
2) Reabsorbing HCO3
3) Synthesizing HCO3
What does H+ secretion from the kidneys do?
1) causes the urine to become more acidic
2) occurs mainly in the distal convoluted tubule
Where does reabsorbing HCO3- via the kidneys take place?
Occurs mainly in the proximal convoluted tubule
Where does synthesis of HCO3- from the kidneys take place?
Mainly in the cells lining the proximal convoluted tubule
What are the ABG (arterial blood gases) for Respiratory Acidosis?
- Decreased pH
- Elevated PCO2
What are the causes of Respiratory Acidosis?
1) Emphysema
2) Pulmonary edema
3) Chronic bronchitis
4) Opioid overdose
5) Neuromuscular disease (myasthenia gravis, gulline-barre syndrome)
6) injury to brainstem
What is the compensation for Respiratory Acidosis?
1) Buffers act like bases
2) Kidneys increase their secretion of H+, reabsorption of HCO3- & synthesis of HCO3-
What are the ABG (arterial blood gases) for Respiratory Alkalosis?
1) Increased pH
2) Decreased PCO2
What are the cause of Respiratory Alkalosis?
1) Breathing at higher altitudes
2) Anxiety/fear
3) Salicylic acid (Aspirin) overdose
4) Fever
What is the compensation for Respiratory Alkalosis?
1) Buffers act like acids
2) Kidneys decrease their secretions of H+, reabsorption of HCO3- & synthesis of HCO3-
