SENSES Flashcards
means by which the brain receives information about the environment and body
senses
process initiated by stimulating sensory receptors
sensation
conscious awareness of those stimuli
perception
what are the five senses
smell, touch, taste, vision, and hearing
two basic groups of senses
general senses and special senses
have receptors distributed over a large part of the body
general senses
divisions of general senses
somatic and visceral senses
provide sensory information about the body and environment
somatic senses
provide information about various internal organs primarily involving pain and pressure
visceral senses
the receptors of these senses are more specialized in structure and are localized to specific parts of the body
special senses
what are the special senses
touch, taste, smell, vision, and balance
are sensory nerve endings or specialized cells capable of responding to stimuli by developing action potentials
sensory receptors
respond to mechanical stimuli such as bending or stretching
mechanoreceptors
respond to chemicals such as odor molecules that allow us to perceive smell
chemoreceptors
respond to light
photoreceptors
respond to temperature changes
thermoreceptors
respond to stimuli that result in the sensation of pain
nociceptors
what are the general senses
touch, pressure, pain, temperature, vibration, itch, and proprioception
sense of movement and position of the body and limbs
proprioception
the simplest and most common types of sensory receptors are
free nerve endings
what are the receptors for temperature
cold or warm receptors
respond to decreasing temperatures but stop responding at temperatures below 12C or 54F
cold receptors
respond to increasing temperatures but stop responding at temperatures above 47C or 117F
warm receptors
structurally more complex than free nerve endings
touch receptors
are small superficial nerve endings involved in detecting light touch and superficial pressure
merkel disks
associated with hairs ; also involved in detecting light touch
hair follicle receptors
receptors for fine, discriminative touch and are located just deep to the epidermis
meissner corpuscles
deeper tactile receptors and play an important role in detecting continuous pressure in the skin
ruffini corpuscles
deepest receptors and are associated with tendons and joints (proprioception)
pacinian corpuscles
enables us to maintain an upright position even if our body is on uneven ground
righting reflex
is characterized by a group of unpleasant perceptual and emotional experiences
pain
two types of pain sensation
- localized, sharp, pricking, or cutting pain resulting from rapidly conducted action potentials
- diffuse, burning, or aching pain resulting from action potentials propagated slowly
it suppresses action potentials from pain receptors in local areas of the body through the injection of chemical anesthetics near a sensory receptor or nerve
local anesthesia
pain sensation suppressed by loss of consciousness ; treatment where chemical anesthetics that affect the reticular activating system are administered
general anesthesia
perceived to originate in a region of body that is not the source of the pain stimulus
referred pain
sense of smell is also called
olfaction
olfaction occurs in response to airborne molecules called
odorants
these are bipolar neurons within the olfactory epithelium
olfactory neurons
it lines the superior part of the nasal cavity
olfactory epithelium
axons from olfactory neurons form olfactory nerves which pass through foramina of the cribriform plate and enter the _
olfactory bulb
there the olfactory neurons synapse with interneurons that relay action potentials to the brain through the _
olfactory tracts
each olfactory tracts terminate an area of the brain called the _ ; located within the temporal and frontal lobes
olfactory cortex
feedback loop plus temporary decreased sensitivity at the level of the receptors results in an
adaptation
the sensory structures that detect stimuli are called
taste buds
taste buds are oval structures located on the surface of certain _ which are enlargements on the surface of the tongue
papillae
how many taste cells
40
each taste cell contains hairlike processes called _ that extend through a tiny opening in the surrounding stratified epithelium
taste hairs
the surrounding stratified epithelium is called
taste pore
what are the five taste sensations
sour
salty
bitter
sweet
umami
taste sensations are carried to the brain by three cranial nerves which are
the facial nerve
the glossopharyngeal nerve
the vagus nerve
transmits taste sensations from the anterior two-thirds of the tongue
facial nerves
carries taste sensations from the posterior one-third
glossopharyngeal nerve
carries some taste sensations from the root of the tongue
vagus nerve
the visual system includes the _
eyes, accessory neurons and sensory neurons
housed within bony cavities called orbits
eyes
what are the accessory structures of the eye
eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
protect the eyes by preventing perspiration from running down the forehead and into the eyes causing irritation
eyebrows
protect the eyes from foreign objects
eyelids
is a thin, transparent mucous membrane covering the inner surface of the eyelids and the anterior surface of the eye
conjunctiva
consists of lacrimal gland situated in the superior lateral corner of the orbit and a nasolacrimal duct and associated structure in the inferior medial corner
lacrimal apparatus
produces a fluid we call tears which pass over the anterior surface of the eye
lacrimal gland
excess tears are collected in the medial angle of the eyes by small ducts called
lacrimal canaliculi
canaliculi open into a _
lacrimal sac
lacrimal sac is an enlargement of the
nasolacrimal duct
how many extrinsic eye muscles are attached
6