Structure & Function
Outline two functions of the trachea.
Supports airway (cartilage rings) and conducts air to bronchi.
State Boyle’s Law
Pressure is inversely proportional to volume.
Define diffusion
Movement of gases from high to low partial pressure
Identify the part of the brain that controls breathing
Medulla oblongata
Define minute ventilation
Total air inhaled/exhaled per minute
Describe the role of goblet cells and ciliated epithelium.
Goblet cells secrete mucus; cilia move mucus to remove particles/pathogens.
Describe inspiration at rest
Diaphragm contracts; external intercostals contract; volume ↑; pressure ↓; air enters.
State Fick’s Law
Rate depends on surface area, gradient, and thickness.
Outline the role of chemoreceptors.
Detect CO2/pH changes; signal medulla to adjust breathing.
Define tidal volume and state its typical value at rest.
Tidal volume is the volume of air inhaled or exhaled in a single breath; approximately 500 mL at rest.
Explain how the structure of alveoli is adapted for gas exchange.
Large surface area, thin walls, rich capillary network, moist surface.
Explain expiration at rest
Muscles relax; volume ↓; pressure ↑; air exits lungs
Explain gas exchange at the alveoli
O2 diffuses into blood; CO2 diffuses into alveoli due to gradients.
Explain why ventilation increases during exercise
↑ CO2→ ↓ pH → chemoreceptors stimulate increased ventilation.
Explain how tidal volume changes during exercise.
Increases to allow more oxygen per breath.
Describe the pathway of air from the external environment to the alveoli.
Nose/mouth → pharynx → larynx → trachea → bronchi → bronchioles → alveoli.
Explain the mechanics of inspiration during exercise
Stronger diaphragm + intercostal contraction; accessory muscles assist; greater volume increase; larger pressure gradient
Explain how partial pressure gradients drive gas exchange
O2 high in alveoli → low in blood; CO2 high in blood → low in alveoli; diffusion occurs accordingly
Explain how the respiratory system regulates blood pH
CO2 removal reduces carbonic acid; maintains pH balance
Explain how respiratory rate changes during high-intensity exercise.
Increases rapidly to meet O2 demand and remove CO2.
Outline three structural components of the trachea and their functions.
Cartilage rings (support), smooth muscle (controls diameter), elastic fibers (recoil/expansion)
Explain expiration during high-intensity exercise
Internal intercostals + abdominals contract; diaphragm pushed upward; volume decreases rapidly; pressure increases; air forced out
Discuss the factors affecting the rate of gas exchange during exercise
↑ ventilation, ↑ cardiac output, large surface area, thin membrane, maintained gradients, ↑ temperature.
Discuss the neural and chemical control of breathing during exercise
Neural input increases rate initially; chemoreceptors respond to CO₂/pH; medulla adjusts ventilation continuously
Discuss the changes in minute ventilation from rest to maximal exercise.
Both TV and RR increase significantly; VE rises greatly; improves O2 delivery and CO2 removal.