Week 5 Respiratory System Flashcards
(43 cards)
What is ventilation?
Increasing contact between air and the respiratory exchange surface.
What is respiratory exchange?
Gas exchange between an organism and its external environment.
What is cellular respiration?
Intracellular catabolism of glucose to yield ATP; requires O2 and produces CO2.
What are the major structures of the upper airway?
External nares, nasal cavity, internal nares, oral cavity, pharynx, epiglottis, glottis, larynx, trachea.
What structures make up the lower respiratory system?
Bronchi (with cartilage), bronchioles (muscular, no cartilage), and alveoli (site of gas exchange).
What are the layers of the respiratory membrane?
Capillary endothelium, basement membrane, and alveolar epithelium.
What are the pleural membranes?
Visceral pleura (on lungs), parietal pleura (on thoracic wall), and the fluid-filled pleural cavity between them.
How does pleural fluid aid ventilation?
Its adhesive and cohesive properties transmit movement of the thoracic wall to the lungs.
What does Boyle’s Law state?
As volume increases, pressure decreases and vice versa.
What muscles are involved in quiet inspiration?
External intercostals and diaphragm.
What causes air to flow into the lungs during inspiration?
Alveolar pressure becomes lower than atmospheric pressure.
Is expiration active or passive?
Quiet expiration is passive due to lung recoil and abdominal organ pressure.
What causes air to exit the lungs during expiration?
Decreased lung volume increases alveolar pressure, pushing air out.
How does gas exchange occur?
By simple diffusion of O2 and CO2 down their concentration gradients.
Where does external respiration occur?
Between alveoli and capillaries.
Where does internal respiration occur?
Between capillaries and body cells.
How is oxygen transported in the blood?
98.5% bound to hemoglobin as oxyhemoglobin; 1.5% dissolved in plasma.
What factors decrease hemoglobin’s affinity for oxygen?
Low O2, high H+ concentration (low pH), and high temperature.
What are the three ways CO2 is transported in the blood?
8% dissolved in plasma, 25% as carbaminohemoglobin, 67% as bicarbonate ion.
How is carbonic acid formed?
CO2 + H2O → H2CO3, catalyzed by carbonic anhydrase in RBCs.
What happens to carbonic acid?
It dissociates into H+ and HCO3- (bicarbonate).
Are gas transport reactions reversible?
Yes; direction depends on surrounding concentrations of O2 and CO2.
What is tidal volume?
Air inhaled or exhaled at rest (~500 mL).
What is inspiratory reserve volume (IRV)?
Extra air inhaled after normal inhalation (~3000 mL).
