Physiology of Sensations

structures that transmit information about changes in the external and internal environment of the animal

located at or near the surface of the body and are sensitive to stimuli outside the body

transmit sensations of pressure, pain, fatigue, hunger, thrist, and nausea

detect mechanical or physical deformation of the receptor itself or adjacent cells

detect changes in temperature

detect pain, usually as a result of physical or chemical damage to tissues

detect light on the retina of the eye

detect taste in the mouth, smell in the nose, and chemicals in body fluids such as oxygen, CO2, water, and glucose

typically modified dendritic endings of sensory neurons and are found in the skin, mucous membranes, muscles, and connective tissues

detect tactile sensations (such as pressure, stretch, touch, vibration), pain, hear, cold, and proprioception

sense organs comprised of a variety of cells that work together to accomplish specific receptive processes

equilibrium, hearing, sight, smell, taste; confined to the head and are highly localized, either housed within complex sensory organs or within distinct epithelial structures

include tactile sensations (pressure, stretch, touch, vibrations), thermoreceptive sensations, and pain

unequal distribution of receptors

largest of the corpuscular receptors and are found deep in the dermis and respong to strong deep pressure when it is first applied and then adapt rapidly

consist of free dendritic endings associated with enlarged. disc-shaped epidermal cells

free dendritic endings that entwine hair follicles like a basket and detect the bending of hairs and adapt rapidly

small receptors consisting of a few spiraling dendrites wrapped in Schwann cells and CT

mechanoreceptor found in the CT of the mucosae (mouth and conjunctiva of the eye) and in the hairless skin near body openings (lips)

consist of numerous dendritic endings enclosed in a flattened capsule; located in the dermis, subcutaneous tissue, and joint capsules and respond to deel and continuous pressure and adapt slowly

naked or bare dendritic endings that detect pain

receptors are most sensitive to temperatures above 25C and become unresponsive at temperatures above 45C; if temp goes above 45, pain kicks in

receptors that are most sensitive to temperatures between 10C and 20C; if temp drops below 10C, pain kicks in

taste

smell

about 10,000

olfactory receptor cells line the roof of the nasal cavity forming a yellow-tinged patch of pseudostratified epithelium

absence or deficiency of one or more of the cone pigments results in the inability to perceive that color