BIOL 1117 Lecture Notes - Lecture 3: Afferent Nerve Fiber, Intrafusal Muscle Fiber, Extrafusal Muscle Fiber
3 Oct 2017
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Document Summary
Carry signals from sensory receptors to the cns: motor (efferent) nerve fiber. Consists of both afferent and efferent fibers. Conduct signals in two directions: ganglion: cluster of neurosomas outside the cns. Enveloped in an epineurium continuous with that of the nerve: among neurosomas are bundles of nerve fibers leading into in and out of the ganglion. Nature of somatic reflexes: pathway of reflex arc. Somatic receptors in skin, muscles, or tendons. Efferent nerve fibers: carry motor impulses to skeletal muscle. Skeletal muscles the somatic effectors which respond to impulse. Primary afferent fibers arise from noncontractile middle; they are fast sensitive to small changes in muscle length and rate of change of muscle length (ex. how fast the muscle is changing) Secondary afferent fibers; arise from adjacent to middle; they are slow: detect muscle length too but do not detect rate of change of muscle length.
