Senses Somatic Special Types of Sensory Receptors Chemoreceptors

Types of Sensory Receptors Chemoreceptors: sensitive to changes in chemical concentration l Pain receptors:

Terms Sensation: result of brain’s interpretation of a sensory impulse l Projection: process by

Somatic Senses Associated with skin, muscles, joints, and viscera l Touch l Pressure l

Touch and Pressure Receptors: l Sensory nerve fibers—in skin and other epithelial tissues respond

Temperature l Cold receptors l 50 -68° l F (10 -20° C) Heat receptors

Pain l l l Pain receptors are widely distributed throughout skin and internal tissues

Regulation of pain impulses The thalamus creates awareness of pain l Cerebral cortex locates

Slides: 8

Download presentation

Senses Somatic & Special

Types of Sensory Receptors Chemoreceptors: sensitive to changes in chemical concentration l Pain receptors: sensitive to tissue damage l Thermoreceptors: sensitive to changes in temperature l Mechanoreceptors: sensitive to changes in pressure or movement l Photoreceptors: sensitive to changes in light intensity l

Terms Sensation: result of brain’s interpretation of a sensory impulse l Projection: process by which brain causes a sensation to seem to come from region of body being stimulated l Sensory adaptation: sensory receptors become less responsive after repeated stimulation l

Somatic Senses Associated with skin, muscles, joints, and viscera l Touch l Pressure l Temperature l Pain l

Touch and Pressure Receptors: l Sensory nerve fibers—in skin and other epithelial tissues respond to touch and pressure l Meissner’s corpuscles—found in sheaths of connective tissue, found in sensitive areas of skin, respond to light touch l Pacinian corpuscles—found in deeper tissues, joints, ligaments, respond to heavy or deep pressure l

Temperature l Cold receptors l 50 -68° l F (10 -20° C) Heat receptors l 77 -115° l F (25 -45° C) Above or below these temperatures, pain receptors are stimulated

Pain l l l Pain receptors are widely distributed throughout skin and internal tissues (except brain) Visceral pain—pain receptors are the only types of receptors in viscera that create sensations Referred pain—feels as if it is coming from some other part of the body Acute pain fibers: myelinated; associated with sharp pain (no impulse after stimulus is removed Chronic pain fibers: unmyelinated; associated with dull, aching pain that is difficult to pinpoint (will remain active after stimulus is removed)

Regulation of pain impulses The thalamus creates awareness of pain l Cerebral cortex locates and determines intensity l Inhibiting substances in spinal cord/brain l l Enkaphalins (an opiate) l Serotonin (inhibitory neurotransmitter) l Endorphins (mask pain)