The Respiratory System Flashcards
20 Exam-Style Flashcards on the Respiratory System (A-Level Biology)
- Structure of the Respiratory System
Q: Name the structures that air passes through from the mouth to the alveoli.
A: Mouth/Nasal cavity → Trachea → Bronchi → Bronchioles → Alveoli
- Function of the Trachea
Q: How is the trachea adapted for its function?
A: Lined with ciliated epithelium to trap mucus and debris; reinforced with C-shaped cartilage rings to keep it open.
- Role of the Alveoli
Q: How are alveoli adapted for efficient gas exchange?
A: Large surface area, thin walls (one cell thick), moist lining, rich blood supply, and ventilation to maintain a concentration gradient.
- Ventilation – Inhalation
Q: Describe the process of inspiration (inhalation).
A: Diaphragm contracts and flattens, external intercostal muscles contract, ribcage moves up and out, thoracic volume increases, pressure decreases, air moves in.
- Ventilation – Exhalation
Q: Explain what happens during expiration (exhalation).
A: Diaphragm relaxes and moves up, external intercostal muscles relax, ribcage moves down and in, thoracic volume decreases, pressure increases, air is forced out.
- Role of the Diaphragm
Q: What is the function of the diaphragm in ventilation?
A: Contracts to increase thoracic volume during inhalation and relaxes to decrease volume during exhalation.
- Role of Intercostal Muscles
Q: What is the difference between external and internal intercostal muscles?
A: External intercostal muscles aid inhalation, internal intercostal muscles aid forced exhalation.
- Gas Exchange in the Alveoli
Q: How does oxygen move from the alveoli into the blood?
A: By diffusion from high concentration in the alveoli to low concentration in capillary blood.
- Gas Exchange of Carbon Dioxide
Q: How is carbon dioxide removed from the body?
A: Diffuses from blood into alveoli due to concentration gradient, then exhaled.
- Factors Affecting Gas Exchange
Q: What factors affect the rate of diffusion in the alveoli?
A: Surface area, diffusion distance, ventilation, and blood circulation.
- Oxygen Transport in Blood
Q: How is oxygen transported in the blood?
A: Bound to hemoglobin in red blood cells as oxyhemoglobin.
- Carbon Dioxide Transport in Blood
Q: Name the three ways CO₂ is transported in the blood.
A: Dissolved in plasma (5-10%), bound to hemoglobin as carbaminohemoglobin (20%), and as bicarbonate ions (70%).
- Control of Breathing
Q: What part of the brain controls breathing?
A: The medulla oblongata.
- Role of Chemoreceptors
Q: How do chemoreceptors regulate breathing?
A: Detect CO₂ levels and pH changes; high CO₂ triggers increased breathing rate.
- Spirometry – Tidal Volume
Q: What is tidal volume?
A: The volume of air breathed in or out in a normal breath (~500 mL in adults).
- Spirometry – Vital Capacity
Q: Define vital capacity.
A: The maximum volume of air a person can exhale after a full inhalation.
- Lung Disease – Asthma
Q: How does asthma affect breathing?
A: Airways become inflamed and constricted, reducing airflow and causing breathing difficulty.
- Lung Disease – Emphysema
Q: How does emphysema reduce gas exchange efficiency?
A: Alveoli walls break down, reducing surface area and elasticity, making gas exchange less efficient.
- Lung Disease – Pulmonary Fibrosis
Q: How does pulmonary fibrosis affect lung function?
A: Thickened alveolar walls increase diffusion distance, reducing oxygen uptake.
- Adaptations of Insects for Gas Exchange
Q: How do insects exchange gases efficiently?
A: Through a tracheal system with spiracles, tracheae, and tracheoles, allowing direct oxygen diffusion into cells.
These flashcards cover key exam-style questions to test your knowledge of the respiratory system at A-Level. Let me know if you need more details!
