Final: 24 Apr Acid-Base Balance and Buffer Systems in Physiology Flashcards
What is the acid-base formula?
HA ⇌ H⁺ + A⁻
HA represents the acid, H⁺ is the proton, and A⁻ is the conjugate base.
What is the behavior of a strong acid in solution?
A strong acid readily donates protons.
What is a conjugate base?
The species that remains after an acid donates a proton.
What type of base corresponds to the conjugate base of a strong acid?
Weak base.
What is expected from the conjugate base of a weak acid?
It is likely to be a strong conjugate base.
What happens when a base combines with a proton?
It forms a conjugate acid.
What is the expected property of a conjugate acid formed from a strong base?
It is likely to be a weak conjugate acid.
What is the role of buffers in solution?
Buffers combine with protons to stabilize pH.
What are the three main buffers in the body?
- Bicarbonate
- Phosphate
- Proteins
What is the pK of bicarbonate as a buffer?
6.1
At what pH does bicarbonate function best as a buffer?
Around 6.1
What is the normal blood pH?
7.35 - 7.45
What is the isohydric principle?
Multiple buffers work together on the same pool of protons.
What happens to the buffer line when hemoglobin concentration increases?
The slope of the line becomes steeper.
What indicates a better buffering capacity in blood?
A steeper slope of the buffer line.
What happens to the isobars when the buffer line becomes flatter?
They get further apart.
What does a poor buffer system indicate?
It cannot cope with pH changes effectively.
What is the effect of a strong buffer system on bicarbonate levels during pH changes?
It can adjust bicarbonate levels more effectively.
What is the significance of the concentration of proteins in blood buffering?
Proteins, especially hemoglobin, play a crucial role in buffering capacity.
Fill in the blank: The conjugate base of a weak acid is likely to be a _______.
strong base
Fill in the blank: Buffers work best at their _______ value.
pK
True or False: A higher concentration of hemoglobin improves the buffering capacity of blood.
True
What does a steeper buffer slope indicate about the system’s response to pH changes?
It indicates a greater change in bicarbonate for a given pH change.
What is the role of the bicarbonate buffering system in pH changes?
It helps to manage pH by either removing bicarbonate or adding bicarbonate to the solution
The bicarbonate buffering system is critical for maintaining acid-base balance in the body.
What happens to the slope of the buffer line when the buffering system is weaker?
The slope becomes more horizontal
A horizontal slope indicates that a greater change in pH is expected for a given change in PCO2.
What is a nomogram?
A drawing used to analyze acid-base problems and treatment options
It helps visualize the relationships between different variables in acid-base balance.
What is acute respiratory acidosis?
A condition characterized by a reduction in the drive to breathe, leading to elevated PCO2
This usually occurs rapidly, not allowing the kidneys time to compensate.
How does excess CO2 affect pH?
It leads to a reduction in pH due to increased proton concentration
CO2 in solution can form protons and bicarbonate, affecting acid-base balance.
What is the expected outcome in pH during acute respiratory alkalosis?
An increase in pH due to a deficit of CO2
This condition may occur due to hyperventilation or other factors causing excessive breathing.
How do kidneys compensate for chronic respiratory acidosis?
By increasing bicarbonate levels in the blood
Kidneys play a crucial role in long-term pH regulation.
What response does the respiratory system have to metabolic alkalosis?
It slows down breathing to increase PCO2
This compensatory mechanism helps to restore acid-base balance.
What factors can reduce respiratory drive?
- Opiates
- Sedatives
- Anesthetics
- Neurological injuries
These factors can interfere with the body’s ability to regulate breathing effectively.
What is the impact of phrenic nerve injury on respiration?
It can impair ventilation on the affected side
The phrenic nerve controls diaphragm movement, crucial for breathing.
What are common conditions that can lead to reduced lung function?
- COPD
- Asthma
- Pulmonary fibrosis
- Sarcoidosis
These conditions affect the lungs’ ability to exchange gases effectively.
What is the effect of muscle spasms from tetanus or botulinum on respiration?
They can prevent effective ventilation
Constant contraction of respiratory muscles hinders airflow.
What is the role of the kidneys in acid-base balance?
They regulate bicarbonate levels and secrete protons
The kidneys are critical for long-term acid-base homeostasis.
True or False: The lungs can buffer pH changes in about three minutes.
True
Some evidence suggests that the response may be even faster.
Fill in the blank: Chronic respiratory alkalosis results in a significant reduction in _______.
arterial bicarbonate
This occurs due to the kidneys adjusting bicarbonate reabsorption.
What are the consequences of poor VQ matching?
Ineffective ventilation, reduced oxygen intake, and CO2 retention leading to acidosis
VQ matching refers to the ventilation-perfusion ratio necessary for effective gas exchange in the lungs.
What is a common cause of respiratory acidosis?
Upper airway obstruction
Examples include collapsed vocal cords, scar tissue from tracheostomy, and tumors.
True or False: Respiratory alkalosis is much more common than respiratory acidosis.
False
Respiratory alkalosis is less common.
What might cause the nervous system to go into overdrive, leading to respiratory alkalosis?
Seizures and extreme anxiety
These conditions can cause rapid breathing and CO2 blow-off.
Fill in the blank: _______ can cause respiratory alkalosis due to increased respiratory drive.
Brain tumors
What hormonal changes can lead to respiratory alkalosis in pregnant women?
Increased progesterone levels
This can stimulate increased breathing rates.
What environmental condition can lead to respiratory alkalosis due to hyperventilation?
High altitude
At high altitudes, lower oxygen tension prompts increased ventilation.
What is a potential effect of overventilation with mechanical ventilation?
Blowing off too much CO2
Overventilation can lead to respiratory alkalosis.
What are the two main types of metabolic problems related to acid-base issues?
Metabolic acidosis and metabolic alkalosis
What can cause metabolic acidosis related to bicarbonate loss?
Increased gastric motility and pancreatic fistula
Loss of bicarbonate ions can lead to acidosis.
Name a toxic substance that can result in metabolic acidosis.
Methanol
Methanol is a byproduct of fermentation and can lead to acidification.
What is a common cause of metabolic acidosis linked to renal function?
Renal dysfunction
Impaired kidneys cannot produce bicarbonate, leading to acidosis.
What metabolic shift occurs in the absence of oxygen during ATP production?
Switch to glycolytic metabolism
- Glycolysis is less efficient, producing only 2 ATP per glucose molecule.
- Aerobic respiration is much more efficient, producing 36 ATP per glucose molecule.
What is a potential consequence of hypoxemia on metabolism?
Increased lactate production leading to metabolic acidosis
Lactate is produced when cells switch to anaerobic metabolism due to lack of oxygen.
What can cause pain in skeletal muscles after intense exercise?
High levels of lactate
Lactate accumulation occurs when muscles are overworked or unconditioned.
What condition can result from lung problems affecting oxygen levels?
Acute respiratory distress syndrome (ARDS)
ARDS leads to a switch in metabolism, increasing acid production.
What is ketoacidosis associated with?
Uncontrolled diabetes
This condition is characterized by the production of non-volatile acids.
What happens when lung function is compromised regarding oxygen levels?
The tissue switches to alternative forms of metabolism, producing more acid than normal.
This can lead to conditions such as ketoacidosis.
What is ketoacidosis?
A metabolic condition characterized by the production of ketones, resulting from inadequate glucose intake.
It is a common issue in uncontrolled diabetes.
How does alcoholism affect metabolic pathways?
It limits the liver’s ability to regulate blood sugar and can lead to the production of ketone acids.
The liver stores sugar in the form of glycogen, and its dysfunction interferes with normal metabolism.
What metabolic condition arises from starvation?
Metabolic acidosis due to the body scrambling for energy.
The lack of energy sources leads to the production of acids.
What happens in renal dysfunction regarding acid-base balance?
Inability to excrete protons leads to acid accumulation and metabolic acidosis.
This is due to the kidneys’ failure to remove excess protons.
What condition can result from repeated vomiting?
Metabolic alkalosis due to loss of gastric acid.
This results in a higher pH level in the body.
What is the effect of gastric fistulas on acid-base balance?
They can lead to metabolic alkalosis by expelling gastric acid from the body.
This alters the body’s acid levels and raises pH.
How do potassium-wasting diuretics affect acid-base balance?
They can lead to metabolic alkalosis by removing potassium and protons.
Potassium and protons typically balance each other in the body.
What is the role of aldosterone in acid-base balance?
Aldosterone promotes potassium excretion, which can also affect proton levels.
An increase in aldosterone can lead to metabolic alkalosis.
What can excessive intake of alkaline compounds cause?
Metabolic alkalosis.
This includes consuming large amounts of antacids or bicarbonate.
What characterizes uncompensated respiratory acidosis?
A decrease in pH due to excess CO2 with minimal bicarbonate adjustment.
This condition reflects a failure to buffer the excess protons.
What occurs during uncompensated respiratory alkalosis?
An increase in pH due to low CO2 levels and a slight decrease in bicarbonate.
This reflects a lack of compensation from the respiratory system.
What defines uncompensated metabolic acidosis?
Low pH due to high proton levels and low bicarbonate.
This occurs when the body cannot compensate for the acid load.
What is the respiratory response to metabolic alkalosis?
Reduced ventilation to increase CO2 levels and help lower pH.
This is a limited compensation method due to the risk of hypoxemia.
What is the anion gap?
A diagnostic measure assessing the balance of cations and anions in blood.
It is used to evaluate acid-base disorders.
What cation is primarily measured in the anion gap calculation?
Sodium.
It is balanced by anions like chloride and bicarbonate for electrical neutrality.
What is the relationship between cations and anions in blood?
Cations must equal anions to maintain electrical neutrality.
This balance prevents the blood from having an overall charge.
What is the effect of too much CO2 in respiratory acidosis?
It leads to a decrease in pH and potential bicarbonate elevation.
This occurs as the body attempts to buffer the acid load.
What happens in partially compensated respiratory alkalosis?
A reduction in bicarbonate levels as the kidneys respond to low CO2.
This adjustment helps to normalize pH.
What occurs when both respiratory and renal systems are compromised?
Severe acidosis or alkalosis due to inadequate compensation by either system.
This often requires medical intervention.
What is the main cation measured in body fluids?
Sodium
What are the main anions measured in body fluids?
Chloride and bicarbonate
What is the typical sodium concentration in milliequivalents per liter?
142
What is the typical chloride concentration in milliequivalents per liter?
106
What is the typical bicarbonate concentration in milliequivalents per liter?
24
What is the normal anion gap value in milliequivalents per liter?
12, plus or minus 4
True or False: The anion gap can be affected by unmeasured ions.
True
What is the relationship between cations and anions in body fluids?
Total cations must equal total anions
Fill in the blank: The anion gap can be calculated as the difference between total _______ and total measured anions.
Cations
What happens to sodium concentration if unmeasured cations increase?
Sodium concentration decreases
What are some common causes of increased anion gap metabolic acidosis?
- Ketoacidosis
- Lactic acidosis
- Renal insufficiency
- Toxic substances like alcohol and salicylates
What is a common cause of normal anion gap metabolic acidosis?
- Diarrhea
- Pancreatic fluid loss
- Chloride retention
Fill in the blank: Non-volatile acids are harder for the _______ to deal with.
Lungs
What is the effect of a decrease in bicarbonate on chloride levels in a balanced system?
Chloride levels should increase
What typically results from the presence of unmeasured anions in body fluids?
Increased anion gap
True or False: A healthy kidney can usually correct chloride retention when experiencing acidosis.
True
What is the significance of proteins in relation to the anion gap?
Proteins have a net negative charge and can contribute to unmeasured anions.
What happens to chloride levels if bicarbonate levels increase significantly?
Chloride levels should decrease
What is the effect of poisons or abnormal acids on the anion gap?
They generally result in an increase in the anion gap
This indicates that the body is dealing with significant disturbances in its acid-base balance.
How does the body typically handle common problems affecting the anion gap?
The body usually keeps the anion gap relatively normal
This is due to its ability to manage less severe changes effectively.
What is the significance of bicarb loss in diarrhea and pancreatic fluid loss for adults?
It’s usually not a big deal for adults
Even severe intestinal bugs typically do not require emergency care.
Why is diarrhea more dangerous for children compared to adults?
Children do not have the same ability as adults to manage changes
This is likely due to their not fully developed kidneys.
What must neonates be given shortly after birth?
A very specific formula, either breast milk or a carefully controlled solution
This is crucial for their health and development.
What happens if a caregiver dilutes neonate formula?
It can lead to volume overload
Neonates cannot eliminate the extra water, which can be dangerous.
Why is volume overload dangerous for a pediatric heart?
The pediatric heart cannot stretch out as easily
This makes it less adaptable to changes in volume.
What is the risk associated with diarrhea in children?
Children struggle to cope with changes in pH and bicarbonate loss
This can result in significant health issues.
How do adults typically respond to severe diarrhea?
It’s not as dangerous for adults unless accompanied by blood loss
Severe cases can still pose risks, but children are more affected.
What common over-the-counter medications are mentioned for diarrhea relief?
Pepto-Bismol and other stomach aids
These may help alleviate symptoms but do not fix the underlying issue.
Fill in the blank: Kids are much more prone to problems with _______ than adults.
diarrhea
