Unformatted text preview: nd brain stem. • • • • • • • • • • • • • • • Motor output can be voluntary, involuntary. Motor response range from Simple (reflex) Complex (voluntary movement) Receptors Muscle spindle Glogi tendon organ Joint receptors Muscle fiber types (length) Extrafusal (force) Intrafusual (sensory) Consist of collections of specialized muscle fibers known as intrafusal fibers Lie within spindle-shaped connective tissue capsules parallel to extrafusal fibers. Each spindle has its own private efferent and afferent nerve supply. Play a key role in stretch reflex. • • Stretch reflex (monosynaptic) Primary purpose to resist tendency for passive stretch of extensor muscles by gravitational forces when a person is standing upright. • • • • • • • • • Classic examples are patellar tendon, or knee-jerk reflex. Muscle Comprises largest group of tissues in body Produce force, different control mechanisms Similar contractile mechanisms, different morphologies Three types of muscle Skeletal muscle Make up muscular system- voluntary SM- appears throughout the body systems as components of hollow organs and tubes- involuntary, ANS control • • • • • • • • • Cardiac muscle- found only in the heart. Classified in 2 different ways; Striated or unstraited Voluntary or involuntary Controlled muscle contractions allows Purposeful movement of a whole body or parts of the body. Manipulation of external objects Propulsion of contents through various hallow internal organs Emptying of contents of certain organs to external environment. • • Structure of skeletal muscle Muscle consists a number of muscle fibers lying parallel to one another and held together by connective tissue. • • • • • • • • • • • • Single skeletal muscle cell is known as a muscle fiber. Multinucleated Large, elongated, and cylindrically shapd. Fibers usually extend entire length of muscle. Myofibrils- contractile elements of muscle fibers Regular arrangements of thick and thin elements Thick filaments-myosin (protein) Thin filaments- actin (protein) Sacromere- function...
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This note was uploaded on 09/23/2010 for the course NPB 8746546 taught by Professor Goldberg during the Spring '10 term at UC Davis.
- Spring '10