Senses

Sensation

Sensation

the conscious of unconscious awareness of external or internal stimuli

Perception

conscious awareness AND interpretation of (a) sensation(s).

Sensory Receptors

specialized structures at the end of peripheral nerves that respond to location stimulus type and structure

Mechanoreceptors

respond to changes in pressure (touch, vibrations, etc.)

Thermoreceptors

respond to changes in temperature

Photoreceptors

respond to light

Chemoreceptors

respond to changes in chemical concentration

Nociceptors

respond to extreme (harmful) stimuli by producing the sensation of pain

Sensory Adaptation

process in which sensory receptor is less stimulated due to continuous stimuli (getting used to a sensation)

What kind of sensory receptors do no undergo sensory adaptation?

Nociceptors

What do receptors associated with skin, muscles, joints, and viscera provide?

Somatic Senses

Exteroceptors

respond to direct changes in body’s surface (touch, pressure, temperature)

Proprioceptors

detect changes in muscles, tendons, and body position

Visceroceptors

detect changes in viscera

free nerve endings, Meissner’s corpuscles, Pacinian corpuscles

name the three types of touch and pressure receptors

Location of free nerve endings

epithelium, connective tissue

Meissner’s Corpuscle

encapsulated dendrite endings that detect light touch

Pacinian Corpuscle

encapsulated dendrite endings that detect heavy pressure

Meissner’s Corpuscles

abundant in hairless portions of skin

Pacinian Corpuscles

abundant deep in subcutaneous tissues of hands, feet, penis, clitoris, urethra, and breasts

75 degrees Fahrenheit (25C)

minimum temperature that heat receptors respond at

113 degrees Fahrenheit (45C)

maximum temperature that heat receptors respond at

Nociceptors

What responds to temperatures that are too extreme for heat or cold receptors to respond to?

50 degrees Fahrenheit (10C)

Minimum temperature that cold receptors respond at

68 degrees Fahrenheit (20C)

Maximum temperature that cold receptors respond at

Free Nerve Endings

receptors that detect pain; widely distributed but not in brain

Nocireceptors

Protect against tissue damage

Visceral Receptors

only produced by visceral receptors

stretch receptors

Stimulated by pressure and/or a decrease O2 levels

referred pain

pain may feel as if it is coming from another area of the body

General Senses Distribution

Distribute over entire body

organ of Corti

Organ of hearing

cochlea of inner ear

location of organ of corti

mechanoreceptors

sensory receptors for hearing

Auricle

outer ear (cartilage)

collection of sound waves

Function of Auricle

External Auditory Meatus

ear canal

starts vibrations of sound waves and directs them toward tympanic membrane

Function of External Auditory Meatus

tympanic membrane

ear drum

tympanic cavity

air-filled space behind ear drum

Auditory Ossicles

3 tiny bones in ear

Malleus (hammer)

Bone that is connected to tympanic membrane