Chapter 10 - Chapter 10 Muscle Tissue and Organization...

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Muscle tissue is responsible for the movement of materials within and throughout the body. All muscle tissue is composed of muscle cells and exhibits specific characteristics: Excitability : muscle cells are very responsive to stimuli Contractility : stimulation of muscle cells generates tension within the cell (contraction) Elasticity : ability to return to its original length when tension is released Extensibility : capable of extending in length in response to the contraction of opposing muscle cells Each skeletal muscle is an organ composed of the four types of tissue: epithelial, connective, muscle, and nervous tissues. A skeletal muscle is striated and usually attached to one or more bones. A single muscle cell may be composed of thousands of cells, and each cell is as long as the muscle itself. –skeletal muscles are often referred to as muscle fibers Skeletal muscles perform the following functions: Body movement Maintenance of posture Temperature regulation –energy is required for muscle tissue contraction, and heat is always produced as a waste product of this energy usage. Most of this heat maintains normal body temperature. Storage and movement of materials –circular muscle bands called sphincters, contract at openings, or orifices, of the gastrointestinal ad urinary tracts. Support Each skeletal muscle is composed of fascicles, which are bundles of muscle fibers. Muscle fibers contain myofibrils, which are composed of myofilaments. Connective Tissue Components Three concentric layers of connective tissue, composed of collagen and elastic fibers, encircle each individual muscle fiber, groups of muscle fibers, and the entire muscle itself. These layers provide protection, sites for distribution of blood vessels and nerves, and a means of attachment to the skeleton. The three connective tissue layers are: Endomysium : innermost connective tissue layer; delicate areolar tissue layer that surrounds each muscle fiber; reticular fibers to help bind together neighboring muscle fibers and support capillaries near these fibers Perimysium : surrounds the bundles of muscle fibers called fascicles; contains extensive arrays of blood vessels and nerves (neurovascular bundles) that branch to supply each individual fascicle Epymysium : layer of dense regular connective tissue that surrounds whole skeletal muscle Deep fascia : ensheaths three connective tissue layers; separates individual muscles, binds muscles with similar functions, forms sheaths to help distribute nerves, blood vessels, and lymphatic vessels, and to fill spaces between muscles. –also called visceral or muscular fascia. Superficial fascia
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This note was uploaded on 05/29/2008 for the course BIOLOGY Anatomy taught by Professor Neff during the Fall '07 term at Temple.

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Chapter 10 - Chapter 10 Muscle Tissue and Organization...

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