Stretch Frequency Code Receptors Weak stretch Weak Strong causes low Stimuli ImI ulse Muscle frequency on Dendrite neuron leaving Weak Strong receptor Integrator Receptor potentials Strong stretch causes Impulse-initiating Graded-to zone impulse impulse converter frequency on Weak Strong neuron leaving Impulse receptor. Membrane conductor potential Impulse frequencies Time
Stretch Receptors: Weak stretch causes low impulse frequency on neuron leaving receptor. Strong stretch causes high impulse frequency on neuron leaving receptor. Time Membrane potential Frequency Code
Summary The external internal environments are monitored y sensory receptors Each type of receptor is excited most effectively by only one modality of stimulus known as the adequate stimulus The stimulus is converted into an electrical potential Stimuli are detected as either static or dynamic events The intensity duration of the stimulus is frequency coded as bursts of action potentials in the priman afferent nerve
Summary • The external & internal environments are monitored by sensory receptors. • Each type of receptor is excited most effectively by only one modality of stimulus known as the adequate stimulus. • The stimulus is converted into an electrical potential. • Stimuli are detected as either static or dynamic events. • The intensity & duration of the stimulus is frequency coded as bursts of action potentials in the primary afferent nerve
Sectⅰon2.Pain
Section 2. Pain
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage” International Association for the Study of pain
“Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage” International Association for the Study of Pain
Why feel pain? Gives conscious awareness of tissue damage Protection Remove body from danger Promote healing by preventing further damage Avoid noxious stimuli Elicits behavioural and emotional responses
Why feel pain? • Gives conscious awareness of tissue damage • Protection: – Remove body from danger – Promote healing by preventing further damage – Avoid noxious stimuli • Elicits behavioural and emotional responses