6.4: Gas exchange
Teaching time: 3 hours Practical time: 0.5 hours for a pluck (lungs and heart dissection)
1 hour for required practical 6.
key vocabulary
Exercise 1: Use the quizlet learn function to study these terms
Review 6.2 the blood system
Review 2.8 cell respiration
Structure & Function of the ventilation system
Essential idea: The lungs are actively ventilated to ensure that gas exchange can occur passively.
Exercise 2: Watch this video and connect-extend-challenge
U1: Ventilation maintains concentration gradients of oxygen and carbon dioxide between air in alveoli and blood flowing in adjacent capillaries.
Exercise 3: Outline the difference between ventilation, gas exchange and respiration.
Exercise 4: Use moylmods and your phone to make a short video explaining why it is important for concentration gradients of oxygen to be maintained.
U4: Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles.
U5: Muscle contractions cause the pressure changes inside the thorax that force air in and out of the lungs to ventilate them.
U6: Different muscles are required for inspiration and expiration because muscles only do work when they contract.
A3: External and internal intercostal muscles, and diaphragm and abdominal muscles as examples of antagonistic muscle action.
Exercise 5: Describe the process of ventilation with reference to antagonistic muscle action.
Exercise 6: Study this diagram of the ventilation system using "learn"
Adaptations of the Ventilation system
U2: Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange.
U3: Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension.
Exercise 7: Study this diagram using "learn"
Guidance from the syllabus: Students should be able to draw a diagram to show the structure of an alveolus and an adjacent capillary.
Lung disease
NoS: Obtain evidence for theories—epidemiological studies have contributed to our understanding of the causes of lung cancer. (1.8)
A1: Causes and consequences of lung cancer.
A2: Causes and consequences of emphysema.
Exercise 8: create a presentation on the causes and consequences of lung cancer and emphysema
Practical 6: Monitoring ventilation
S1: Monitoring of ventilation in humans at rest and after mild and vigorous exercise. (Practical 6)
