KP161 Lecture Notes - Lecture 8: Reflex Arc, Retina, Sensory Neuron
28 Mar 2016
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Reflex arc: simplest pathway by which a reflex occurs (reflex loop when sensory info comes in and motor movement goes out) Types: monosynaptic (one synapse, the simplest form- e. g. tendon tap in the knee, polysynaptic (more than one synapse- e. g. withdrawal response, if you step on something sharp you must elevate your foot by switching support to opposite leg. Information to one limb for contraction or leg, and information goes to the other to relax) Differences: in polysynaptic reflexes, it takes longer for the reflex to be produced; 30 ms needed for each synapse. More influences from neurons, therefore, the information can be changed. Incomplete: effects of the injury depend on the area of the spinal cord affected. Level of injury: generally, the higher up the spinal cord the injury occurs, the more serious the injury. Stimulate reflexive movement at the spinal cord level.
