Phasic receptors alert us to changes in sensory stimuli and are in part responsible for the fact that we can cease paying attention to constant stimuli The slowly adapting receptors(tonic receptors), such as the pain receptors and the baroreceptors of the arterial tree, are useful in situations requiring maintained information about a stimulus
Phasic receptors alert us to changes in sensory stimuli and are in part responsible for the fact that we can cease paying attention to constant stimuli. The slowly adapting receptors (tonic receptors), such as the pain receptors and the baroreceptors of the arterial tree, are useful in situations requiring maintained information about a stimulus
4. Encoding of Sensory Receptor The quality of the stimulus is encoded in the frequency of the action potentials transmitted down the afferent fibre and the number of sensory receptors activated
4. Encoding of Sensory Receptor The quality of the stimulus is encoded in the frequency of the action potentials transmitted down the afferent fibre and the number of sensory receptors activated
Stretch Frequency Code Receptors Weak stretch Weak trong causes low Stimuli impulse Muscle frequency on C+0 Dendrites neuron leaving Weak Strong receptor. Integrator Receptor potentials Strong stretch causes high Impulse-initiating Graded-to- impulse zone impulse converter fre equency on Weak Strong neuron leaving Impulse receptor embrane 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 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
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
Section 2 Visual Sense organ
Section 2 Visual Sense Organ