PS261 Chapter Notes - Chapter 2: Startle Response, Efferent Nerve Fiber, Reflex Arc
Document Summary
Irritation of respiratory passages causes sneezing and coughing: behaviour occurs in response to stimuli elicited. Elicited behaviour = reflexive behaviour: concept of the reflex. Eliciting stimulus and corresponding response: stimulus and response are linked specificity of relation between stimulus and accompanying reflex response is consequence of nervous system organization. Environmental stimulus for reflex activates sensory organ (afferent neuron) transmits sensory message to spinal cord: neural impulses related to motor neuron (efferent neuron) Activates muscles involved in reflex response sensory and motor neurons rarely communicate directly impulses from one to other are relayed through at least one interneuron. Neural circuitry ensures that particular sensory neurons are connected to corresponding set of motor neurons restricted wiring restricted set of stimuli elicits particular reflex response reflex arc. Pull head back face-wiping motion crying involves vigorous expulsion of air. Essential for survival: modal action patterns. Simple reflex responses are evident in many species. Mammalian infants suck in response to object being placed near mouth.
