Topic 9: Gas Exchange Flashcards
Definitions I:
(a) Alveoli
(b) Bronchioles
(c) Capillaries
(a) Alveoli: Tiny air sacs for gas exchange. (1 mark)
(b) Bronchioles: Small airways to alveoli. (1 mark)
(c) Capillaries: Thin vessels for blood-gas exchange. (1 mark)
Describe the structure of the human gas exchange system in the chest. [2 Marks]
Lungs contain trachea, bronchi (1 mark); Bronchioles lead to alveoli, capillaries surround (1 mark). (2 marks)
In a lung section, describe the distribution of cartilage and ciliated epithelium. [2 Marks]
Cartilage in trachea/bronchi walls (1 mark); Ciliated epithelium lines airways (1 mark). (2 marks)
Draw and label ciliated epithelium and goblet cells from a trachea photomicrograph. [2 Marks]
Cilia on tall cells, goblet cells round (1 mark); Label: cilia, goblet cell (1 mark). (2 marks)
In a bronchus slide, draw a plan diagram of the transverse section. [2 Marks]
Ring of cartilage, layered wall (1 mark); Label: cartilage, epithelium (1 mark). (2 marks)
Recognise cartilage and smooth muscle in an electron micrograph of a bronchus. [2 Marks]
Cartilage: Rigid rings (1 mark); Smooth muscle: Fibres in wall (1 mark). (2 marks)
In a smoker’s trachea, describe the functions of ciliated cells and goblet cells. [3 Marks]
Cilia sweep mucus up (1 mark); Goblet cells secrete mucus, trap debris (1 mark); Protect lungs (1 mark). (3 marks)
State the role of cartilage and elastic fibres in the gas exchange system. [2 Marks]
Cartilage: Keeps airways open (1 mark); Elastic fibres: Recoil for exhalation (1 mark). (2 marks)
In an alveolus, describe the function of squamous epithelium and capillaries. [2 Marks]
Squamous epithelium: Thin for diffusion (1 mark); Capillaries: Blood close for gas exchange (1 mark). (2 marks)
Explain gas exchange in a runner’s alveoli during exercise. [3 Marks]
O₂ diffuses from alveoli to blood (1 mark); CO₂ from blood to alveoli (1 mark); High demand drives (1 mark). (3 marks)
Draw and label squamous epithelium and capillaries from an alveolus electron micrograph. [2 Marks]
Flat squamous cells, thin capillaries (1 mark); Label: squamous epithelium, capillary (1 mark). (2 marks)
In a child’s lung, explain how smooth muscle and elastic fibres maintain airflow. [3 Marks]
Smooth muscle adjusts airway size (1 mark); Elastic fibres recoil after inhalation (1 mark); Maintains airflow (1 mark). (3 marks)
Analyse the roles of ciliated epithelium and squamous epithelium in gas exchange efficiency. [4 Marks]
Cilia clear mucus, aid breathing (1 mark); Squamous thins barrier (1 mark); Speeds O₂/CO₂ diffusion (1 mark); Efficient exchange (1 mark). (4 marks)
