Chapter 10 The Sensory System
Terms in this set (155)
Keenness or sharpness of vision.
Blurred vision, resulting from unequal curvatures of the lens or cornea
physician who studies and treats disease of the eye
farsightedness caused by aging
An eye disease in which the intraocular pressure is high enough to cause damage to the optic nerve, resulting in visual loss; caused by impaired drainage of the aqueous fluid out of the eye
an environmental change becomes a ______ when initiates a nerve impulse, which then travels to the central nervous system by way of a sensory neuron
Specialized cells unique to each sense organ that respond to a particular form of sensory stimulation.
receptors can be classified according to the type of ____ to which they respond
Nerve endings in the nose and tongue that are adapted for excitation by chemical substances
The light-sensitive cells in the retina- the rods and cones.
Detect changes in temperature
Found in skin, ears, and throughout the body. Detects pressure, stretch, and motion
Stimulation level that must be exceeded to elicit nerve impulse or muscle contraction
Localized to specific area or structure. vision, hearing, equilibrium, taste, smell
sensations monitored throughout the body by receptors scattered throughout many different tissues. pressure, temperature, pain, touch, sense of position
A state of balance
Diminished sensitivity as a consequence of constant stimulation
receptors for ___ do not adapt
In the embryo, the eye develops at about ___days of development
only about ____ of the eye is visible
____form the walls of the eye orbit protecting the posterior portion of the eye
the skull bones
___ aid in protecting the eye's anterior portion
the muscle that raises the upper eyelid
eyelashes and eyebrows help keep ____ out of the eye
the thin membrane that lines the eyelids and covers the white of the eye
cells within the conjunctiva produce ___ that aids in lubrication
With age, the conjunctiva thins and dries, resulting in inflammation and enlarged _____
Secrete lacrimal fluid (tears) and maintains moisture on the anterior surface of the eyeball. Blinking distributes this lacrimal fluid across the eye.
A duct that carries tears from the lacrimal sac to the nasal cavity
Groups of structures found in the eye to help produce and drain away tears which help flush microbes from the eyes. Tears house lysozymes that kill any microbes that enter the eye.
enzyme in tears and destroy pathogens on the surface of the eye.
Known as the white or white of the eye, is the opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fibre.
Clear membrane at the front of the globe covering the iris, pupil, and anterior chamber. Responsible for 60% of the eyes focusing power. Contains 5 layer
Reddened or bloodshot eyes result from inflammation and swelling of blood vessels in the _______
The sclera contains collagen has no ____ to add color
also known as the choroid coat, is the opaque middle layer of the eyeball that contains many blood vessels and provides the blood supply for the entire eye
part of vascular tunic that alter the shape of the lens
a fibrous membrane that holds the lens of the eye in place
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
Contains sensory receptors that process visual information and sends it to the brain., It's found at the back of your eye and is a thin layer of tissue made up of light receptors and sensory neurons.
rods and cones
three tunics of the eye
fibrous; vascular; nervous
bending or changing the path of light rays
it is nourished by the fluids that constantly bathe it; it has no blood vessels.
a clear, watery fluid that fills the space between the cornea and iris. helps maintainthe cornea's convex curve and refracts light.
____is constantly produced and drained from the eye
Curving or bulging outward
having two sides that are rounded, elevated, and curved evenly like part of a sphere. The lens of the eye is biconvex.
the clear colorless transparent jelly that fills the posterior chamber of the eyeball
gradual improvement in the ability to see in dim light
deepest layer of the retina just anterior to the choroid
rods are highly sensitive to light and thus function best in
rods are more numerous than
cones function best in
cones are sensitive to ___ and give sharp images
cones are localized at the retinal _____
area consisting of a small depression in the retina containing cones and where vision is most acute
A light-sensitive pigment found in the rod cells
cylindrical, toward the anterior of the retina, low acuity, stimulated by dim light, no color perception;shades of gray. 120 million a retina
flask shaped, concentrated at the center of the retina, stimulated by bright light, high acuity, responds to color. about 6 million per retina
general term for a pit or depression
a yellowish central area of the retina that is rich in cones and that mediates clear detailed vision
people who lack cones are _____
people who lack one type of cone are ____ color blind
color blindness occurs more commonly in
vitamin A is needed for the manufacture of _______
instrument used to examine the interior of the eye
voluntary muscles attached to the eyeball's outer surface
involuntary muscles located within the eyeball
the eye muscles are named for their ____ and ____
location and direction
the iris is composed of two sets of
opening in the center of the iris
the iris regulates the amount of ___ entering the eye
in bright light, the iris' circular muscle fibers_____
contract, reducing the size of the pupil
Compression of a part that causes narrowing
in dim light, the iris's radial muscles contract and______
pull the opening outward enlarging it.
the enlargement of the pupil is known as
Ciliary body alters the shape of the crystalline lens during _____, which is the ability to focus
light rays from a close object diverge(separate) more than do the light rays from
a distant object
when we view something close, the lens must become more______ and bend the light rays more to focus them on the retina
Nerves from photoreceptors exit the retina to the optic nerve, absence of photoreceptors, blind spot
opthalmic branch of the trigeminal nerve
cranial nerve that provides sensory information from the eye orbit, nasal cavity and forehead skin
the optic nerve transmits impulses from the retina to the _____ from which they are directed to the occipital cortex
Vision, visual memories
the thalamus is part of the _______
Contains thalamus and hypothalamus
almost all gray matter , located between the midbrain and the cerebrum and consists of the thalamus, hypothalamus, optic chiasma, and pineal body
what it the diencephalon?
these three nerves carry motor impulses to the eyeball muscles
oculomotor, trochlear, abducens
supplies voluntary and involuntary motor impulses to all but two eye muscles
supplies the superior oblique extrinsic eye muscle
supplies the lateral rectus extrinsic eye muscle
events required for proper vision
light refracts through the cornea, the muscles of the iris adjust the pupil, the ciliary muscle adjusts the lens, the extrinsic eye muscles produce convergence, light stimulates retinal receptor cells,, the optic nerve transmits impulses to the brain, the opccipital lobe cortex interprets the impulses
the __ is the sense organ for both hearing and equilibrium
The outer visible portion of the ear that collects and directs sound waves toward the tympanic membrane by way of a canal which extends inward through the temporal bone
The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window
The essential part of the vertebrate organ of hearing and equilibrium that includes the vestibule, the semicircular canals, and the cochlea
visible part of the ear also called the auricle
external auditory canal
Curved tube that extends from the auricle and directs sound waves toward the eardrum, contains a few hairs and earwax
Found only in the external ear canal, where their secretion combines with sebum and dead epidermal cells to form earwax, or cerumen.
A tacky yellow or brown substance secreted by oil glands in the external auditory meatus. This substance is commonly known as ear wax.
The eardrum. A structure that separates the outer ear from the middle ear and vibrates in response to sound waves.
3 tiny bones in the middle ear that amplify sounds
hammer; first of the three auditory ossicles of the middle ear
anvil; middle of the three auditory ossicles of the middle ear
the stirrup-shaped ossicle that transmits sound from the incus to the cochlea; latin for stirrup
A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.
air passage between the middle ear and throat that equalizes air pressure on either side of the eardrum; also called the Eustachian tube
area at back of throat where mouth and nasal cavity meet
channels within temporal bone. 3 regions: vestibule, cochlea, semicircular canals; filled with perilymph
fluid that fills the bony labyrinth of the inner ear
Fluid that bathes the sensory receptors of the inner ear
An organ in the inner ear that works with the semicircular canals to maintain equilibrium
three loops of the fluid-filled tubes that are attached to the cochlea; They help us with our sense of balance
the steps in hearing
sound waves enter the external auditory canal, the tympanic membrane vibrates, the ossicles amplify and transmit vibrations across the middle ear cavity,the stapes transmits the vibrations at the oval window to the inner ear fluid, vibrations travel through the perilymph of the bony labyrinth and start vibrations in the cochlear endolymph, the spiral organ's hair cells vibrate against the tectorial membrane generating nerve impulses, impulses travel via the cochlear nerve to the temporal lobe cortex where they are interpreted, sound waves leave the inner ear through the round window
A membrane located above the basilar membrane; serves as a shelf against which the cilia of the auditory hair cells move
when the stapes vibrate against the oval window, the pressure on the window transfers the waves to cochlear duct, the waves will stimulate the hair cells in the basilar membrane, and then pass on to which duct?
a fluid filled cavity within the cochlea that vibrates when sound waves strike it
Membrane that covers the opening between the middle ear and inner ear
another term for Organ of Corti
organ of corti
Center part of the cochlea, containing hair cells, canals, and membranes
general term that means spot
thick, gelatinous, glycoprotein layer located directly over hair cells of the macula in the saccule and uricle of the internal ear
small christals in FLUID FILLED VESTIBULAR SACS of the INNER EAR that, when shifted by gravity, stimulate nerve cells that inform the brain of the position of the head. gives us VESTIBULAR SENSE.
-change in velocity in a straight line (riding in a car or elevator)
hair cells embedded in a gelatinous material called cupula
A gelatin-like structure containing a tuft of hairlike sensory receptor cells in the semicircular canals.
sense of taste
Sensory Receptors for taste
Bumps on the tongue that contain taste buds, the receptors for taste.
A savory taste due to the presence of glutamic acid, an amino acid that occurs naturally in meats and other protein rich foods.
the nerves of taste include the
facial and glossopharyngeal
sense of smell
the impulses from smell receptors are carried by the _____ nerve which leads to the _____ center in the brainls temporal cortex
we can detect over ____ different smells
the olfactory receptors deteriorate with
Small epidermal structures with nerve endings that are sensitive to touch and pressure
free nerve endings
Class of receptors that respond to temp, pain, itch, and hair follicle movement
there are temperature receptors in the ____that help adjust body temperature according to the temperature of the circulating blood
Sensory receptors, located in the muscles and joints, that provide information about body position and movement.
Awareness of positioning of body parts and body movement.
the most important protective sense
Pain that is felt in a location other than where the pain originates
instrument for examination or observation