Anatomy 224

• a structure specialized to detect a stimulus.
• May be a free nerve ending.

• nerve ending + connective Tissue (C.T.), epithelial T., or muscle T.
• Examples: eye, ear, skin.

converting ENERGY into INFORMATION.

refers to the type of stimulus or the sensation it produces.

Nervous system can distinguish between touch to finger and touch to toe.

body area that a sensory neuron receives input from.

Encoded in three ways: frequency, number of fibers and type of fibers.

Encoded in way nerve fibers change their firing frequencies over time.

burst of electrical activity when stimulus first applied or removed; adapts quickly - stops firing.

(e.g. tactile, smell and hair receptors)

adapt slowly, generate electrical impulses continuously.

(e.g. proprioceptors)

• all receptors adapt eventually, if stimulus is prolonged.
• Firing frequency and conscious perception decline.
• Example: HOT bath.

Chemical receptors

Example: Taste, smell, blood

heat fluxes (loss/gain) receptors

Example: Warm receptors and cold receptors.

• pain receptors; allow awareness of tissue injuries
• found in all tissues except the brain

Example: mechanical pain; chemical pain

Mechanical stimulus

Example: pressure, stretch

Photons (light waves)

Example: rods/cones in retina of eye

internal stimulus, inside body

Example: visceral pain receptors

position of limbs in space

Example: Joints, tendons

external stimulus, outside of body

Example: Skin receptors

An initial response of a receptor cell to a stimulus, consisting of a change in voltage across the receptor membrane proportional to the stimulus strength. The intensity of the receptor potential determines the frequency of action potentials traveling to the nervous system.

have spots on skin that are specifically mediated.