Question

NATIONAL CENTER FOR CASE STUDY TEACHING IN SCIENCE

Take a Deep Breath:
A Case of Respiratory Illness

by

Brianna S. Nelson, Kelsey N. Aguirre, Alee L. Adams, Emily E. Brodbeck, and Breanna N. Harris Department of Biological Sciences
Texas Tech University, Lubbock, TX

Part I – Symptoms

Callie was 26 years old when she opened a bakery called “Callie’s Cupcakes” in downtown San Francisco with her fiancé, Jeremy. Despite the competitive market, her business was booming; everyone loved the clever recipes and the trendy atmosphere. Between running their fast-growing business and planning for their wedding, Callie hadn’t been able to keep to her usual eight hours of sleep a night. Although she had always lived a very healthy lifestyle, exercising daily and eating healthy, she just hadn’t been feeling herself lately. She was tired all the time, had difficulty breathing, felt stressed, coughed up sputum, consistently ran a low-grade fever, and had lost weight as her appetite decreased. None of these symptoms alone had been particularly alarming so she had put off seeing her physician for a few weeks.

Questions

1. What are Callie’s symptoms? List all that were mentioned.

2. Based on the symptoms presented, what are three possible respiratory infectious diseases Callie could be suffering from? Explain why.

3. Based on Callie’s symptoms and your answers so far, it seems Callie is having trouble with her respiratory system. Several respiratory conditions can impact gas exchange. Describe the process of gas exchange in the lung (alveoli).

Answer 1

Answer 1 - Symptoms of Callie

a. Breathing difficulty

b. Productive cough

c. Low grade fever

d. Weight loss

Ans 2 :-she is a bakery shop owner and without any previous history, hence she is more prone for chronic respiratory fungal infection eg

1. Aspergillosis

2. Histoplasmosis

3. With low grade fever, cough and weight loss, infection with mycobacterium tuberculosis is also a possibility.

Ans 3

Diffusion of Oxygen from Atmospheric Air into Alveoli :-

Partialpressure of oxygen in the atmospheric air is 159 mm Hg and in the alveoli, it is 104 mm Hg. Because of the pressure gradient of 55 mm Hg, oxygen easily enters from atmospheric air into the alveoli

Diffusion of oxygen from Alveoli into Blood :-

When blood passes through pulmonary capillary, RBC is exposed to oxygen only for 0.75 second at rest. So, diffusion of oxygen must be quicker and effective. Fortunately, this is possible because of pressure gradient. Partial pressure of oxygen in the pulmonary capillary is 40 mm Hg and in the alveoli, it is 104 mm Hg. Pressure gradient is 64 mm Hg. It facilitates the diffusion of oxygen from alveoli into the blood.

Diffusion of Carbon Dioxide from Blood into Alveoli--

Pressure of carbon dioxide in alveoli is 40 mm Hg whereas in the blood it is 46 mm Hg. Pressure gradient of 6 mm Hg is responsible for the diffusion of carbon dioxide from blood into the alveoli.

Diffusion of CarbonDioxide from Alveoli into Atmospheric Air:----

In atmospheric air, partial pressure of carbon dioxide is very insignificant and is only about 0.3 mm Hg whereas,in the alveoli, it is 40 mm Hg. So, carbon dioxide enters passes to atmosphere from alveoli easily.