Human Touch and Pain Receptors

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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

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

B ody Part

Receptor Density (cm

2

)

Fingertip, palm surface

Back of finger

One eye

60 pain, 100 touch

100 pain, 9 touch

90,000,000!!!!!!!!!

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.

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