ch03.3 - Cell Physiology

ch03.3 - Cell Physiology - 72 Essentials of Human Anatomy...

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a large Golgi apparatus, to make and secrete the protein building blocks of these Fbers. Erythrocyte (red blood cell) . This cell carries oxygen in the bloodstream. Its concave disk shape provides extra surface area for the uptake of oxygen and streamlines the cell so it ±ows easily through the bloodstream. So much oxygen-carrying pigment is packed in erythrocytes that all other organelles have been shed to make room. 2. Cell that covers and lines body organs: Epithelial cell. The hexagonal shape of this cell is exactly like a “cell” in a honeycomb of a beehive. This shape allows epithelial cells to pack together in sheets. An epithe- lial cell has abundant intermediate Flaments that resist tearing when the epithelium is rubbed or pulled. 3. Cells that move organs and body parts: Skeletal muscle and smooth muscle cells. These cells are elongated and Flled with abundant contractile Flaments, so they can shorten forcefully and move the bones or change the size of internal organs. 4. Cell that stores nutrients: Fat cell. The huge spherical shape of a fat cell is produced by a large lipid droplet in its cytoplasm. 5. Cell that fghts disease: Macrophage (a phagocytic cell). This cell extends long pseudopods (“false feet”) to crawl through tissue to reach infection sites. The many lysosomes within the cell digest the infectious microorganisms it takes up. 6. Cell that gathers inFormation and controls body Functions: Nerve cell (neuron). This cell has long processes for receiving messages and trans- mitting them to other structures in the body. The processes are covered with an extensive plasma membrane, and a plentiful rough ER is present to synthesize membrane components. 7. Cells oF reproduction: Oocyte (female). The largest cell in the body, this egg cell contains many copies of all organelles, for distribution to the daugh- ter cells that arise when the fertilized egg divides to become an embryo. Sperm (male). This cell is long and stream- lined, built for swimming to the egg for fer- tilization. Its ±agellum acts as a motile whip to propel the sperm. Cell Physiology As mentioned earlier, each of the cell’s internal parts is designed to perform a speciFc function for the cell. Most cells have the ability to metabolize (use nutrients to build new cell material, break down substances, and make ATP), digest foods, dispose of wastes, reproduce, grow, move, and respond to a stimulus (irritability). Most of these functions are considered in detail in later chapters. ²or example, metabolism is covered in Chapter 14, and the ability to react to a stimulus is covered in Chapter 7. Here, we will consider only the func- tions of membrane transport (the means by which substances get through plasma membranes), pro- tein synthesis, and cell reproduction (cell division).
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This note was uploaded on 01/31/2011 for the course BIO 210 taught by Professor S during the Spring '10 term at University of Toronto- Toronto.

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ch03.3 - Cell Physiology - 72 Essentials of Human Anatomy...

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