Human Touch and Pain Receptors
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Transcript of Human Touch and Pain Receptors
Human Touch and Pain Receptors
Somatosensory System• Somoesthetic
sensations– Sensations associated
with skin receptors
• Proprioception– Perception and
position of the body including limbs
3 Receptor Types• Mechanoreceptors– Pressure, force,
vibration
• Thermoreceptors– Temperature
• Nociceptors– Tissue damaging stimuli
Definitions
• Modality– Energy form of stimulus
• Sensory neurons convert energy from stimulus into another form of energy.
• Receptor potentials– Graded responses caused by closing and
opening of ion channels. – Number activated and frequency of APs
generated correlated to stronger stimulus intensity perceived.
Mechanoreceptors• Detect stimuli• Two main forms:– Specialized structure
on peripheral end of afferent neuron.
– Separate cell that communicates via chemical synapses with associated afferent neuron.
Thermoreceptors• Respond to surrounding
tissue, not air temp.• Warm receptors– Respond to temps 35-45 °C – Beyond 45 °C APs decrease
rapidly– Above 45 °C nociceptors also.
Thermoreceptors
• Cold receptors– Respond to to temps 20-35 °C– Below 25 °C APs decrease rapidly– Below 10 °C also nociceptors– Also respond to temps above 45 °C
• Paradoxical cold receptors
Nociceptors
• 3 Types–Mechanical – Thermal– Polymodal
Wet Receptors?• Brain integrates info
from different sensory systems.
• Combination of thermoreceptors and mechanoreceptors.
Receptor DensityBody Part
Fingertip, palm surfaceBack of finger
One eye
Receptor Density (cm2)
60 pain, 100 touch100 pain, 9 touch90,000,000!!!!!!!!!
Homework!!!!
• Write a methods, results, and introduction.• Answer ALL questions. • This may be done within the results section or introduction.
Make sure you include a section with answers to questions that you don’t answer within the intro or results sections.
• You do not have to replicate the figures from the pdf for today. Just staple that to your lab report.
Introduction• Successfully establishes the
physiological concepts of the lab.• Effectively presents the objectives and
purpose of the lab.• States hypotheses AND provides
logical reasoning for them.