Task: Physiology of Respiration

Activity 1: Measurements of Lung Function

Measuring the volumes of air that a person can inhale and exhale either normally or forcefully is used to assess pulmonary function (the health of the lungs).Lung function can be measured using a spirometer that provides an expirograph trace.

1. Define the meaning of each in one sentence (0.25 marks each, total 2 marks):
- Tidal volume (VT)

- Inspiratory reserve volume (IRV)

- Expiratory reserve volume (ERV)

- Vital capacity (VC)

- Residual volume (RV)

- Functional residual capacity (FRC)

- Inspiratory capacity (IC)

- Total lung capacity (TLC)

Complete the following using abbreviations for volumes and capacities. For example, Inspiratory Capacity = VT + IRV.(0.25 marks each, total.

- Functional residual capacity =
- Vital capacity =
- Total lung capacity =
- Residual volume =

Activity 2: Further Measurements of Lung Function.

In contrast to the spirometer measurements of tidal volume, inspiratory and expiratory reserve volumes, a vitalograph measures expiratory volumes. These measurements provide information on Forced Vital Capacity (FVC) and the Forced Expiratory Volume in the First Second (FEV1). From these values we determine the FEV1/FVC ratio.

The FEV1/FVC ratio is used to distinguish between restrictive and obstructive lung disorders and helps diagnose the severity of lung disorders. Answer the following questions.

1. What is the definition of an obstructive lung disorder? Give an example (100 words).

2. What is the definition of a restrictive lung disorder? Give an example (100 words).

3. How would the FEV1/FVC ratio be affected in each case (50 words)?

Activity 3: Control of Breathing.

Below is a sample of lung tissue. The tissue has been sectioned, and stained with hematoxylin and eosin (H&E). Haematoxylin has a dark blue-purple colour that stains the nuclei of cells, whereas eosin is pink and stains proteins. The H&E stain is a very commonly used technique to visualise structures within a given tissue sample.

The image below is a high magnification section of lung tissue, which allows us to visualise the alveoli. The alveoli are hollow cavities, which allow the exchange of gasses between the lungs and the bloodstream. The alveoli are made up of thin epithelial cells, and are wrapped with capillaries.

1. Explain why the surface area of the alveoli is so large (0.5 mark), and why the epithelial cells lining the alveoli walls are so thin (100 words).

2. In the tissue section above, you can visualise macrophages in the alveoli. Explain what macrophages are (0.5 mark) and what role they play in the lungs (100 words)

3. Provide a physiological situation in the body when respiratory homeostasis is disturbed (1 mark). State the 3 locations of the central/peripheral chemoreceptors involved in the control of breathing (0.5 marks each), and explain whether they respond more to oxygen or carbon dioxide.

Attachment:- Template.rar