Histology Guide

virtual microscopy laboratory

Chapter 17 - Respiratory System

The respiratory system is responsible for taking in oxygen and expelling carbon dioxide. It can be divided functionally into two regions:

Respiratory Epithelium

Respiratory epithelium is a pseudostratified ciliated columnar epithelium with goblet cells that covers most regions of the conducting portion of the airways.

LUNG

The adult lungs are sponge-like organs whose main function is to provide oxygen and remove carbon dioxide from blood.

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Pleural Surface
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Respiratory Bronchiole

Respiratory bronchioles are the beginning of the airways involved in the exchange of gases.

Alveoli

Alveoli are sac-like evaginations from respiratory bronchioles alveolar ducts, and alveolar sacs. Between neighboring alveoli lie thin interalveolar septa containing capillaries.

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Alveoli
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Alveoli
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The alveolar epithelium comprises two main cell types:

Type I cells are large flat cells that comprise 95% of the alveolar surface. Type II cells are small cuboidal cells that cover the rest of the alveolar surface.

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Type I Alveolar Cell
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Type I Alveolar Cell
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Type II Alveolar Cell
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