B2.3.8 (HL)—Pneumocytes in alveoli
Alveolar pneumocytes are specialized so type I cells support gas exchange while type II cells secrete surfactant to prevent adhesion.
- Syllabus
- First assessment 2025
- Objective
- B2.3.8
- Level
- HL
Exam analysis
Chance of appearing7%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1
Typical marks1
Common command terms
- Identify
- Outline
Scoring notes
- Common mistake
- Reversing the roles of type I and type II pneumocytes.
Recent exam appearances
May 2025Paper1A ["HL"] · TZ115[ 1 ]B2.3.8 (HL)—Pneumocytes in alveoli
May 2024Paper1 ["HL"] · TZ122[ 1 ]B2.3.8 (HL)—Pneumocytes in alveoli
May 2023Paper1 ["HL"] · TZ122[ 1 ]B2.3.8 (HL)—Pneumocytes in alveoli
May 2022Paper1 ["HL"] · TZ123[ 1 ]B2.3.8 (HL)—Pneumocytes in alveoli
May 2019Paper1 ["HL"] · TZ123[ 1 ]B2.3.8 (HL)—Pneumocytes in alveoli
Practice this objective
Coverage 2017–2025 · Updated 15 Jul 2026
Concept essentials
- Type I pneumocytes are thin cells specialized for gas exchange.
- Type II pneumocytes secrete pulmonary surfactant.
- Surfactant helps prevent alveolar walls from sticking together.
- Phagocytes in alveoli ingest pathogens rather than producing antibodies.