Demonstration

O bserve the animal lung and the attached trachea. Identify the larynx, major laryngeal cartilages, trachea, and the incomplete cartilaginous rings of the trachea. Open the larynx and locate the vocal folds. Examine the visceral pleura on the surface of a lung, and squeeze a portion of a lung between your fingers. How do you describe the texture of the lung?

columnar epithelium and the deep layer of hyaline cartilage, which represents a portion of an incomplete (C-shaped) tracheal ring (fig. 52.5).

2. Use high-power magnification to observe the cilia on the free surface of the epithelial lining. Locate mucus-secreting goblet cells in the epithelium.

3. Prepare a labeled sketch of a representative portion of the tracheal wall in Part B of the laboratory report.

4. Obtain a prepared microscope slide of a human lung. Examine it using low-power magnification and note the numerous open spaces of the air sacs (alveoli). Look for a bronchiole—a tube with a relatively thick wall and a wavy inner lining. Locate the smooth muscle tissue in the wall of this tube (fig. 52.6). You also may see a section of cartilage as part of the bronchiole wall.

5. Use high-power magnification to examine the alveoli. Note that their walls are composed of simple squamous epithelium. You also may see sections of blood vessels filled with blood cells.

6. Prepare a labeled sketch of a representative portion of the lung in Part B of the laboratory report.

7. Complete Part C of the laboratory report.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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