Post on 24-May-2015
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General Senses
Human Anatomy and Physiology
L|E|C|O|M Mathew J. Bateman, Ph.D., D.H.Ed.
Properties of Receptors
What is a receptor?
What is a sense organ?
Receptors Transmit Information
Modality
Location
– sensory projection
Intensity
Duration
– Phasic receptors
– Tonic receptors
Receptive Fields
Tonic -vs- Phasic Receptors
Classification of Receptors
By modality:– chemo-, thermo-, mechano-, photo-
receptors and nociceptorsBy origin of stimuli
– interoceptors– proprioceptors– exteroceptors
By distribution– general senses – special senses
Unencapsulated Nerve Endings
Encapsulated Nerve Endings
Somesthetic Projection Pathways
1st order neuron 2nd order neuron3rd order neuron
Pain Signal Destinations
Referred Pain
Spinal Gating of Pain Signals
Pharmacology of Pain Management
• Receptor – Anti-inflammatory agents reduce pain stimuli
• Nociceptor transmitter of first order neuron– Substance P stimulates ascending pain neuron– Substance P inhibits inhibitory interneuron– Looking for antagonists now
• Presynaptic inhibition of first order neurons– Normal function of reticulospinal tract– Opiate peptides: enkephalins, endorphins, dynorphins
• Morphine, opium, etc mimic their effects • Sensory transmitter of first order neuron
– Stimulation of inhibitory interneuron– Inhibition (usually) of ascending pain neuron– Site of action of acupuncture, etc.