McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 7  Introduction to cell physiology

■■ Channels or pores in the cell membrane allow for easier movement of specific substances needed by the cell for normal functioning. ■■ Mitochondria are rod-shaped organelles that produce energy in the form of ATP for use by cells. ■■ Ribosomes are sites of protein production within the cell cytoplasm. The specific proteins produced by a cell are determined by the genetic material within the cell nucleus. ■■ The Golgi apparatus packages particular substances for removal from the cell (e.g. neurotransmitters, hormones). ■■ Lysosomes are packets of digestive enzymes located in the cell cytoplasm. These enzymes are responsible for destroying injured or non-functioning parts of the cell and for promoting cellular disintegration when the cell dies. ■■ Endocytosis is the process of moving substances into a cell by extending the cell membrane around the substance and engulfing it. Pinocytosis refers to the engulfing of necessary materials, and phagocytosis refers to the engulfing and destroying of bacteria or other proteins by white blood cells. ■■ Exocytosis is the process of removing substances from a cell by moving them towards the cell membrane and then changing the cell membrane to allow passage of the substance out of the cell. ■■ Cells maintain homeostasis by regulating the movement of solutes and water into and out of the cell. ■■ Diffusion, which does not require energy, is the movement of solutes from a region of high concentration to a region of lower concentration across a concentration gradient. ■■ Osmosis, which, like diffusion, does not require energy, is the movement of water from an area low in solutes to an area high in solutes. Osmosis exerts a pressure against the cell membrane that is called osmotic pressure. ■■ Active transport, an energy-requiring process, is the movement of particular substances against a concentration gradient. Active transport is important in maintaining cell homeostasis. ■■ Cells replicate at differing rates, depending on the genetic programming of the cell. All cells go through a life cycle consisting of the following phases: G 0 , the resting phase; G 1 , which involves the production of proteins for DNA synthesis; S, which involves the synthesis of DNA; G 2 , which involves the manufacture of the materials needed for mitotic spindle production; and M, the mitotic phase, in which the cell splits to form two identical daughter cells.

■■ Chemotherapeutic drugs act on cells to cause cell death or alteration. All properties of the drug that affect cells should be considered when administering a chemotherapeutic agent.

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ONLINE RESOURCES

An extensive range of additional resources to enhance teaching and learning and to facilitate understanding of this chapter may be found online at the text’s accompanying website, located on thePoint at http://thepoint.lww.com. These include Watch and Learn videos, Concepts in Action animations, journal articles, review questions, case studies, discussion topics and quizzes.

WEB LINKS

Healthcare providers and students may want to consult the following Internet source: www.life.uiuc.edu/plantbio/cell Information on cell structure, properties and division.

BIBLIOGRAPHY

Alberts, B. (2008). Molecular Biology of the Cell (5th edn). New York: Garland Science. Cartwright, K. (2007). Cell markers. Australian Prescriber, 30(5) , 128–129. Cooper, G. & Hausman, R. (2013). The Cell: A Molecular Approach (6th edn). Sunderland MA: Sinauer Associates. Goodman, L. S., Brunton, L. L., Chabner, B. & Knollmann, B. C. (2011). Goodman and Gilman’s Pharmacological Basis of Therapeutics (12th edn). New York: McGraw-Hill. Guyton, A. & Hall, J. (2011). Textbook of Medical Physiology (12th edn) . Philadelphia: Saunders Elsevier. Landowne, D. (2006). Cell Physiology. New York: McGraw-Hill. Lodish, H. F. (2013). Molecular Cell Biology (7th edn). New York: W. H. Freeman. Morgan, D. (2007). The Cell Cycle: Principles of Control . London: New Science Press. Nair, M. & Peate, I. (2013). Fundamentals of Applied Pathophysiology: An Essential Guide for Nursing and Healthcare Students (2nd edn). Ames, Iowa: Wiley-Blackwell. Porth, C. M. (2011). Essentials of Pathophysiology: Concepts of Altered Health States (3rd edn). Philadelphia: Lippincott Williams & Wilkins. Porth, C. M. (2009). Pathophysiology: Concepts of Altered Health States (8th edn). Philadelphia: Lippincott Williams & Wilkins. Sherwood, L. (2013). Human Physiology from Cells to Systems (8th edn) . Belmont CA: Brooks Cole Cengage Learning.