Resp part 2 Flashcards
(35 cards)
What are the three major laws that govern gas exchange?
Fick’s Law (surface area & membrane thickness), Dalton’s Law (pressure gradient), Henry’s Law (gas solubility in liquid)
What factors affect the rate of gas diffusion across alveolar membranes?
Surface area, membrane thickness, pressure gradient, molecular weight, and solubility of the gas
Explain Dalton’s Law and its relevance to respiration.
The total pressure of a gas mixture is the sum of the partial pressures of each gas. Gases move from high to low pressure. Drives O2 into and CO2 out of alveoli.
Explain Henry’s Law and its role in gas exchange.
The amount of gas dissolved in a liquid is proportional to its partial pressure. CO2 dissolves more readily than O2 in blood.
How does oxygen bind to haemoglobin?
O2 binds cooperatively to haemoglobin in a transition from tense (T) to relaxed (R) state.
What is the Bohr Effect?
Increased CO2 leads to H+ production, which decreases O2 affinity of Hb, enhancing O2 release to tissues.
What is the role of myoglobin in oxygen transport?
Stores oxygen in muscles and has a higher affinity for O2 than haemoglobin.
What does 2,3-DPG do in red blood cells?
Decreases haemoglobin’s affinity for oxygen, facilitating O2 release during hypoxia or exercise.
How does the respiratory system regulate blood pH?
Alters CO2 levels via ventilation to adjust [H+]: hyperventilation lowers CO2 and raises pH; hypoventilation increases CO2 and lowers pH.
What happens in diabetic ketoacidosis and how does the body compensate?
Metabolic acidosis from ketone production; body hyperventilates to reduce CO2, kidneys excrete H+ and retain HCO3-.
What is the physiological response to severe lactic acidosis from exercise?
Hyperventilation to expel CO2 and renal compensation via H+ excretion and HCO3- retention.
How does vomiting or antacid use affect acid-base balance?
Causes metabolic alkalosis; hypoventilation retains CO2, kidneys reabsorb H+ and excrete HCO3-.
What causes respiratory alkalosis in a panic attack?
Hyperventilation reduces CO2; compensation via hypoventilation and renal HCO3- excretion.
How does opioid overdose affect respiratory pH?
Causes hypoventilation and CO2 retention, leading to respiratory acidosis; compensation via hyperventilation and renal H+ excretion.
What does spirometry measure?
Measures lung volumes and airflow speed to assess pulmonary function.
Define Tidal Volume (TV).
Volume of air during normal, resting breathing.
Define Residual Volume (RV).
Volume of air remaining in lungs after maximal exhalation.
Define Total Lung Capacity (TLC).
Maximum lung volume at full inspiration.
Define Vital Capacity (VC) or Forced Vital Capacity (FVC).
Max air exhaled after full inhalation; forced in FVC. VC measures the maximal volume of air exhaled with a forceful, rapid breath, while VC measures the maximal volume exhaled at a slower, relaxed pace
What is Peak Expiratory Flow (PEF)?
Max airflow achieved during forced expiration after full inspiration.
What spirometry result pattern suggests restrictive lung disease?
FVC and FEV1 reduced, but FEV1/FVC ratio is normal or increased.
What spirometry pattern indicates obstructive lung disease?
FEV1 reduced more than FVC, leading to a reduced FEV1/FVC ratio (<70%).
FEV1 is the amount of air exhaled in the first second of a forceful breath, while FVC is the total amount of air exhaled forcefully and completely
What is a normal FEV1/FVC ratio?
Equal to or greater than 70% in healthy individuals.
Why does oxygen diffuse into the bloodstream more readily despite its low solubility?
Because it has a much larger partial pressure gradient compared to carbon dioxide.
