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SENSORY PERCEPTION

Types of receptors, associated organs

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Functions?

Convert energy into a change in membrane potential of sensory receptors

Four major functions: Sensory transduction – convert stimulus

energy into change in membrane potential Amplification – strengthening stimulus

energy Transmission – carry stimulus to CNS Integration – processing sensory

information

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Types of Sensory Receptors

Mechanoreceptors Chemoreceptors Electromagnetic receptors Thermoreceptors Pain receptors

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Mechanoreceptors

Physical deformation (bending/stretching) Pressure Touch Stretch Motion sound

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Mechanoreceptors in inner ear

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Chemoreceptors

General: (total solute concentration) Osmoreceptors in brain – stimulate thirst

Specific: (individual kinds of molecules) Glucose, oxygen, carbon dioxide, amino

acids

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Taste

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Smell

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Electromagnetic receptors

Detect various forms of electromagnetic energy Visible light: Photoreceptors (Eyes) Electricity (Fish that detect prey that

disturb electric currents) Magnetism (Animals that migrate sense

magnetic fields)

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Thermoreceptors

Respond to heat, cold Signal both surface and body core

temperature Much debate on where these are in

humans… (encapsulated or naked?) Communicate with hypothalamus

(body’s thermostat)

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Pain Receptors

A.k.a. nociceptors Unencapsulated (naked) dendrites Different groups respond to various

stimuli: Excess heat Excess pressure Chemicals released from damaged,

inflamed tissues Certain chemicals raise/lower threshold

of pain receptors