Unit 9.2: Diseases of the Respiratory system
Outline
Part 1: Anatomy and Normal Microbiota of the Respiratory Tract
- Anatomy of the Upper Respiratory System
- Anatomy of the Lower Respiratory System
- Defenses of the Respiratory System
- Normal Microbiota of the Respiratory System
- Signs and Symptoms of Respiratory Infection
Learning Objectives
After reading the following, you should be able to:
- Describe the basic structure of the respiratory system, including protective features and defenses.
- Describe any features that promote microbial growth and give one example of a bacterial species that is part of the normal flora.
- Describe any general features of infections of the respiratory system.
- Describe strep throat, including its causative organism and possible complications.
- Describe bacterial pneumonia and compare and contrast its three main causative species.
- Describe tuberculosis, including its causative organism and possible complications.
- Describe whooping cough, including its causative organism and possible complications.
- Describe the common cold, including its causative organism and possible complications.
- Describe influenza, including its causative organism and possible complications.
- Explain the difference between antigenic shift and antigenic drift
- Describe measles, including its causative organism and possible complications.
- Describe chicken pox, including its causative organism and possible complications.
- Explain the connection between chicken pox and shingles
- For all the diseases in this section, describe mode of transmission, portal of entry, modes of detection (where discussed) and treatments (in general, e.g. antiviral medication, vaccine, etc)
The respiratory tract is one of the main portals of entry into the human body for microbial pathogens. On average, a human takes about 20,000 breaths each day. This roughly corresponds to 10,000 liters, or 10 cubic meters, of air. Suspended within this volume of air are millions of microbes of terrestrial, animal, and human origin—including many potential pathogens. A few of these pathogens will cause relatively mild infections like sore throats and colds. Others, however, are less benign. According to the World Health Organization, respiratory tract infections such as tuberculosis, influenza, and pneumonia were responsible for more than 4 million deaths worldwide in 2012.
At one time, it was thought that antimicrobial drugs and preventive vaccines might hold respiratory infections in check in the developed world, but recent developments suggest otherwise. The rise of multiple-antibiotic resistance in organisms like Mycobacterium tuberculosis has rendered many of our modern drugs ineffective. In addition, there has been a recent resurgence in diseases like whooping cough and measles, once-common childhood illnesses made rare by effective vaccines. Despite advances in medicine and public health programs, it is likely that respiratory pathogens will remain formidab