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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
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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 Density Body Part Receptor Density (cm2) 60 pain, 100 touch 100 pain, 9 touch 90,000,000!!!!!!!!! Fingertip, palm surface Back of finger One eye
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.