ANATOMY OF AIRWAYS - Important Points.pdf

This document describes the antomy of airways.

Airway is divided into upper airway , conducting airway and alveolar airway.

Alveolar airway is also known as lung parenchyma or acinar tissue.

Read this document to learn more.

1. Anatomy of Airways

2. Airflow through the respiratory system can be broken
down into 3 interconnected regions :
●UPPER AIRWAY

●CONDUCTING AIRWAY

●ALVEOLAR AIRWAY ( LUNG PARENCHYMA / ACINAR TISSUE )

3. UPPER AIRWAY
The upper airway consists of the entry systems , the nose /
nasal cavity and mouth that lead into the pharynx .

The larynx extends from the lower part of the pharynx to
complete the upper airway.

5. CONDUCTING AIRWAY
The conducting airway begins at the trachea and branches
dichotomously to greatly expand the surface area of the tissue of
the lung.

The first 16 generations form the conducting zone of the
airways that transports gas from and to the upper airway. These
branches are made up of bronchi , bronchioles and terminal
bronchioles.

7. CROSS SECTION OF AIRWAY

10. MUCOCILIARY ESCALATOR

12. The last seven
generations form
the transitional
and respiratory
zones where gas
exchange occurs
and are made up
of transitional and
respiratory
bronchioles ,
alveolar ducts and
alveoli.

13. The alveoli are lined by two types of epithelial cells -
Type 1 cells ( flat cells , large cytoplasmic extensions , the primary
lining cells of the alveoli , cover ~95% of the alveolar epithelial surface
area )
Type 2 cells ( thicker , contains numerous lamellar inclusion bodies ,
make up only 5% of the surface area but represent ~ 60% of the
surface area of epithelial cells in the alveoli , important in alveolar
repair , produce surfactant )

15. The alveoli also contain
pulmonary alveolar
macrophages.
When the upper and
conducting airway barriers are
overcome or when
microorganisms are small
enough to be inhaled to the
alveolar level, resident alveolar
macrophages are extremely
efficient at clearing and killing
pathogens. .