A flagellum13 (fla-JEL-um) is a whiplike structure much longer than a cilium, but with an identical axoneme. The only functional flagellum in humans is the tail of a sperm cell.

Figure 3.12 Cilia of the Trachea. Several nonciliated, mucus-secreting goblet cells are visible among the ciliated cells. The goblet cells have short microvilli on their surface.

" axo = axis + neme = thread l2dyn = power, energy + in = protein l3flagellum = whip

Mucus And Cilia
Figure 3.13 Ciliary Action. (a) Cilia of an epithelium moving mucus along a surface layer of saline. (b) Power and recovery strokes of a cilium.

Saladin: Anatomy & I 3. Cellular Form and I Text I © The McGraw-Hill

Physiology: The Unity of Function Companies, 2003 Form and Function, Third Edition

106 Part One Organization of the Body

Before You Go On

Answer the following questions to test your understanding of the preceding section:

  1. How does the structure of a plasma membrane depend on the amphiphilic nature of phospholipids?
  2. Distinguish between integral and peripheral proteins.
  3. Explain the differences between a receptor, pump, and cell-adhesion molecule.
  4. How does a gate differ from other channel proteins? What three factors open and close membrane gates?
  5. What roles do cAMP, adenylate cyclase, and kinases play in cellular function?
  6. Identify several reasons why the glycocalyx is important to human survival.
  7. How do microvilli and cilia differ in structure and function?

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Essentials of Human Physiology

Essentials of Human Physiology

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