Fundamentals of Anatomy and Physiology

416 Chapter 17

Upper lobe

Bronchioles

Middle lobe

Lower lobe

Thyroid cartilage

Trachea

Upper lobe

Primary

bronchus

Lower lobe

Right lung Left lung

(^) ®
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Figure 17- 6 The branching bronchi and the lobes of the lungs.
health Alert
Smoking and the Trachea (^)
(^)
Individuals who smoke or are constantly ex- cilia, the epithelium cannot clear the pas- (^)
posed to secondhand smoke create a con- sageway of mucus and debris. This provides (^)
stant irritation to the trachea. Over time, this an environment ideal for the growth of (^)
irritation from smoke can cause the epithe- microorganisms, leading to respiratory in- (^)
lium of the trachea to change from a pseu- fections. This constant irritation and respira- (^)
dostratified, ciliated columnar epithelium to tory inflammation triggers the cough reflex, (^)
a stratified, squamous epithelium. Without resulting- in what we call a smoker’s cough. (^)
The Anatomy and Function
of The Lungs
The lungs are paired, cone-shaped organs located in and
filling the pleural divisions of the thoracic cavity. Two
layers of serous membrane, known as the pleural (PLOO-
rah) membrane, enclose and protect each lung
(Figure 17-7). The outer layer attaches the lung to the wall of
the thoracic cavity and is called the parietal (pah-RYE-eh-
tal) pleura. The inner layer is called the visceral (VISS-er-
al) pleura and covers the lungs. Between these two layers is a
small space called the pleural cavity, which contains a
lubricating fluid that is secreted by the mem-branes. This
pleural fluid prevents friction between the