Ijmb Model Questions Vol1 2019 Biology Question 4

Practice essay / theory question 4 from the 2019 Ijmb Model Questions Vol1 Biology examination. This question covers respiration .

Ijmb Model Questions Vol1 2019 Biology Essay / Theory
Topic: respiration
Question 4 IJMB_MODEL_QUESTIONS_VOL1 • 2019 • BIOLOGY • essay

The diagram shows the human respiratory system with the labelled structures: A – Nasal cavity, B – Pharynx, C – Larynx, D – Trachea, E – Primary bronchi, F – Bronchioles, G – Alveolar sacs, H – Diaphragm, I – External intercostal muscles.

Question Parts

( a )
Describe the complete pathway that air follows from the external environment to the site of gas exchange, naming each structure it passes through.
( b )
The alveolar wall contains type I and type II pneumocytes. Explain the distinct functions of these two cell types in relation to respiration.
( c )
During vigorous exercise ventilation increases. Using the diagram, explain how the diaphragm (H) and the external intercostal muscles (I) contribute to this increased ventilation. Include the changes in thoracic cavity volume and pressure.
( d )
The partial pressure of oxygen in alveolar air is 100 mmHg and in the pulmonary capillary blood is 40 mmHg. (i) Calculate the diffusion gradient for oxygen. (ii) Discuss how this gradient drives the movement of oxygen into blood. (iii) If pulmonary fibrosis doubles the diffusion distance, qualitatively describe the expected effect on the rate of oxygen diffusion according to Fick’s law.

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About This Question

This is Ijmb Model Questions Vol1 2019 Biology Question 4. It is one of the essay questions from the 2019 Ijmb Model Questions Vol1 Biology examination.

The question covers respiration .

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