PSIO 201 5th Edition Lecture 30 Outline of Last Lecture Spinal CordOutline of Current Lecture I. Muscle ReflexesII. ClassificationsIII. Flexor ReflexIV. Tendon ReflexV. Stretched Reflex VI. Crossed ReflexCurrent LectureObjectives:1. Define reflex and list the five components of a reflex arc.2. Differentiate between ipsilateral and contralateral, somatic and autonomic, monosynaptic and polysynaptic reflexes.3. Diagram and describe the 4 representative reflex arcs discussed in lecture. Definition:- reflex- a rapid automatic response to a stimulus- reflex arc- the “wiring” of a particular reflex- Innate Reflex- inborn - Learned Reflix- reflex acquired through experienceComponents of a reflex arc:- Sensory receptor- Sensory neuron- Integrating center – with or without interneuron- Motor Neuron- EffectorClassification of Reflexes- Monosynaptic vs. Polysynaptic- Somatic vs. Visceral- Cranial Vs. Spinal- Ipsilateral vs. ContralateralPathways of 4 Reflex Arcs1. Stretch Reflex2. Tendon Reflex3. Flexor Reflex4. Crossed extensor Reflex - They are ALL SOMATIC and SPINALStretch Reflex –- purpose is to prevent injury from over stretching a muscle- Results in contraction of the muscle that was stretched- Stretch sensed by muscle spindle- Monosynaptic, ipsilateral, spinal, somatic reflexAnatomy of Muscle Spindle-- Sensory Nerve- Efferent Nerve Fiber- Muscle Spindle - End plate on extrafusal plate- Intrafusal muscle fiberTendon Reflex:- purpose Is to prevent damage from development of too much tension in a muscle- Result is inhibition of the muscle that is contracting- Tension sensed by Golgi tendon Organ- Polysynaptic, Ipsilateral, Spinal, Somatic ReflexFlexor Reflex:- purpose is to protect body part from further injury- results in flexion of affected limb- pain sensed by nociceptors- polysynaptic, ipsilateral, spinal, somatic reflexCrossed Extensor Reflex:- purpose is to stabilize body position when a painful stimulus results in flexion of opposite limb- Usually paired with flexor reflex- Result is extension of opposite limb- Pain sensed by nociceptors- Polysynaptic, contralateral, spinal, somatic
View Full Document
Unlocking...