sense Flashcards
results only from those stimuli that reach the cerebral cortex and are consciously perceived. Can be defined as general or special.
sensation
are sensory nerve endings or specialized cells capable of responding to stimuli by developing action potentials.
sensory receptors
general senses, such as pain, temperature, touch, pressure, and proprioception, are scattered throughout the body.
receptors
an unpleasant sensation that may be either localized or diffuse.
can be reduced or controlled by stimulation of tactile receptors as well as increased motor activity.
from deeper structures may be referred to more superficial structures, such as the skin.
pain
respond to chemical stimulation, vision to light stimulation, and hearing and balance to mechanical stimulation.
smell and taste
have enlarged distal ends with long cilia. The cilia have
olfactory neurons
The wide range of detectable odors results from
combinations of receptors responses
of the olfactory neurons form the olfactory nerves, which enter the olfactory bulb.
the vestibular portion of the vestibulocochlear nerve project to the vestibular nucleus and on to the cerebral cortex.
axons
carry action potentials from the olfactory bulbs to the olfactory cortex of the brain.
olfactory tract
contain taste cells with hairs that extend into taste pores.
Receptors on the hairs detect dissolved substances.
taste buds
carries taste from the anterior two-thirds of the tongue;
facial nerve
carries taste from the posterior one-third of the tongue
glossopharyngeal nerve
carries taste from the root of the tongue
vagus nerve
prevent perspiration from entering the eyes.
eyebrows
protect the eyes from foreign objects.
eyelids
covers the inner eyelids and the anterior surface of an eye
conjunctiva
produce tears that flow across the eye surface to lubricate and protect the eye. Excess tears pass through the nasolacrimal duct into the nasal cavity.
lacrimal glands
move the eyeball.
extrinsic eye muscles
the outer layer of the eye. It consists of the sclera and cornea.
fibrous tunic
the middle layer of the eye. It consists of the choroid, ciliary body, and iris.
vascular tonic
held in place by the suspensory ligaments, which are attached to the smooth muscles of the ciliary body.
lens
the inner layer of the eye and contains neurons sensitive to light.
nervous tunic
responsible for vision in low illumination (night vision).
rods
responsible for color vision.
cones
the center of the macula has the highest concentration of cones and is the area where images are detected most clearly.
fovea centralis
where the optic nerve exits the eye and blood vessels enter.
optic disc, or blind spot,
The anterior and posterior chambers of the eye are anterior to the lens and are filled with
aqueous humor
filled with vitreous humor.
vitreous
keep the eye inflated, refract light, and provide nutrients to the inner surface of the eye.
humors
passing through a concave surface diverges. Light passing through a convex surface converges.
causes retinal to change shape, which causes opsin to change shape, leading eventually to cellular changes that result in an action potential at the retina.
light
cross at the focal point and are said to be focused.
converging light rays
responsible for most of the convergence, whereas the lens can adjust the focus by changing shape (accommodation).
cornea
conducted along the optic nerve.
action potential
pass through the optic nerves to the optic chiasm, where some cross.
from the nasal retina cross, and those from the temporal retina do not.
axons
from the chiasm lead to the thalamus.
optic tract
extend from the thalamus to the visual cortex in the occipital lobe.
optic radiation
consists of the auricle and the external auditory canal.
external ear
contains the three auditory ossicles.
also connected to the mastoid air cells.
middle ear
(eardrum) is stretched across the external auditory canal.
tympanic membrane
tube connects the middle ear to the pharynx and equalizes pressure.
auditory or eustachian
has three parts: the semicircular canals, the vestibule, and the cochlea.
inner ear
a canal shaped like a snail’s shell.
divided into three compartments by the vestibular and basilar membranes.
cochlea
consists of hair cells that attach to the basilar and tectorial membranes.
spiral organ
are funneled through the auricle down the external auditory canal, causing the tympanic membrane to vibrate.
sound waves
are passed along the ossicles to the oval window of the inner ear.
tympanic membrane vibrations
action potentials travel to the cochlear nucleus and on to the cerebral cortex.
vestibulocochlear nerve,
evaluates the position of the head relative to gravity.
static equilibrium
located in the vestibule, consist of hair cells with the microvilli embedded in a gelatinous mass that contains otoliths.
maculae
evaluates movements of the head
dynamic equilibrium
each semicircular canal contains a crista ampullaris, which has hair cells with microvilli embedded in a gelatinous mass, the cupula.
ampulla
