Sensation:• The conscious or subconscious

awareness of external or internal stimuli.

Perception:• The conscious awareness and the

interpretation of meaning of sensations.

PainTemperatureLight touchPressureSense of body and limb position

TasteSmellVisionHearingBalance

General SensesGeneral Senses vs. vs. Special Special SensesSenses

• Mechanoreceptors

• Thermoreceptors

• Photoreceptors

• Chemoreceptors

• Nociceptors

skin, bones, internal organs, joints

Naked nerve endings surrounded by one or more layers

Pacinian corpuscle

Free nerve endings

Encapsulated Nerve Encapsulated Nerve

EndingsEndingsvs

Unencapsulated Unencapsulated

Nerve EndingsNerve Endings

Deeper tissue, muscles

Free Nerve Endings - Pain & Temperature

Merkel’s Discs - Light Touch & Pressure

Root Hair Plexuses - Light Touch

pain, light touch, and temperature

Pacinian Corpuscles - Deep Pressure

Meissner’s Corpuscles - Discriminative Touch in Hairless Skin Areas

Krause’s End-Bulbs - Discriminative Touch in Mucous Membranes

Ruffini’s Corpuscles - Deep Pressure & Stretch (Proprioception)

Muscle Spindles - Skeletal Muscle Stretching (Proprioception)

Golgi Tendon Organs - Tendon Stretching (Proprioception)

Somatic Pain-results from injuries to skin, muscle, joints, tendon vs.Visceral Pain- pain in body organs

Referred Pain-felt on the body surface

epidermis

dermis

subcutaneous fat

hair follicle

hair shaft

free nerve endings

root hair plexus

Meissner’s corpuscles

Pacinian corpuscles

nerve

Krause’s End-Bulb

Somatic Sensory Pathway

Ascending Spinal Cord Tract

Descending Spinal Cord Tract

Primary Somatosensory Cortex & Primary Motor Area

Primary Sensory Cortex

Primary Sensory Cortex

Primary Motor Cortex

Primary Motor Cortex