Chap 9: Senses WS Flashcards
Anything that causes a response in a tissue.
STIMULUS
Conscious awareness of a stimulus
SENSATION
The perception that a sensation originates from the part of the
body stimulated
PROJECTION
Includes touch, pressure, pain, temperature, vibration, itch, and proprioception
GENERAL SENSES
Includes smell, taste, sight, hearing, and balance.
SPECIAL SENSES
Respond to pain, temperature, and itch
FREE NERVE ENDINGS
Detect light touch and superficial pressure; located in the
epidermis; a capsule surrounding a nerve ending
MERKEL’S DISKS
Respond to fine, discriminative touch; located just deep to the
epidermis
MEISSNER’S CORPUSCLES
Monitor continuous touch or pressure in the skin
Ruffini’s end-organs
Detect deep pressure, vibration, and position (proprioception);
located in tendons and joints.
Pacinian corpuscles
Specialized cells in the epithelium of the nasal cavity; airborne
molecules bind to receptors on these cells, producing action
potentials
Olfactory neurons
Formed by axons from the olfactory neurons; pass through the
cribriform plate
Olfactory nerve
Formed by axons from the olfactory neurons; pass through the
cribriform plate.
Olfactory nerve
Receives the olfactory nerves.
Olfactory bulb
Relays action potentials from the olfactory bulb to the brain
Olfactory tract
Taste buds located on this part of the tongue respond most
strongly to bitter tastes.
Back of tongue
Olfactory cortex
Area of the frontal and temporal lobes that receives the
olfactory tract.
Sensory structure that detects taste stimuli
Taste bud
Enlargements on the surface of the tongue; contain taste buds
Papillae
Makeup a taste bud; each has taste hairs that extend through ataste pore.
Taste cell
Taste sensations from the anterior two thirds of the tongue are
conducted by this nerve
Facial nerve
Taste buds located on this part of the tongue respond most
strongly to sweet and salty tastes
Tip of tongue
Taste buds located on this part of the tongue respond most
strongly to sour tastes
Side of tongue
Prevent perspiration from running down the forehead into the
eye.
Eyebrows
Produces tear
Lacrimal gland
Protect the eye from foreign objects and lubricate the eye by
spreading tear
Eyelids
Thin, transparent membrane that covers the anterior surface of
the eye and the inner surface of the eyelids.
Conjunctiva
Collect excess tears from the medial corner of the eye
Lacrimal canaliculi
Empties excess tears into the nasal cavity
Nasolacrimal duct
Outer layer of the eye, consisting of the sclera and cornea
Fibrous tunic
Move the eyeball
Extrinsic eye muscles
Middle layer of the eye, consisting of choroid, ciliary body, and
iris
Vascular tunic
Firm, opaque, white, outer posterior five sixths of the eye;
maintains the shape of the eye and provides an attachment site
for the extrinsic eye muscles
Sclera
Contains ciliary muscles (smooth muscles) that attach by
suspensory ligaments to the lens.
Ciliary body
Inner layer of the eye, consisting of the retina
Nervous tunic
Avascular, transparent, anterior one sixth of the eye; allows
light to enter the eye and also refracts light.
Cornea
Vascular tunic associated with the scleral portion of the eye;
prevents light reflection.
Choroid
Flexible, biconvex, transparent disc
Lens
Contains smooth muscle that regulates the amount of light
entering the eye
Iris
The opening in the iris through which light passes
Pupil
Photopigment in rods that breaks down when struck by light;
vitamin A is necessary for its manufacture; lack of vitamin A
results in night blindness
Rhodopsin
Outer part of the retina; its black color prevents light reflection
Pigmented retina
Inner part of the retina containing rods and cones
Sensory retina
Photoreceptor cells that are very sensitive to light and function
in dim light.
Cones
Photoreceptor cells responsible for color vision
Rods
Small yellow spot near the center of the posterior retina
Macula lutea
Small pit with the highest concentration of cones and the
greatest ability to most clearly detect images; located in the
macula lutea.
Fovea centralis
Blind spot of the eye; place where blood vessels and the optic
nerve pass through the wall of the eye.
Optic disc
Fills the anterior compartment of the eye; maintains pressure,
refracts light, and provides nutrients to the inner eye surface.
Aqueous humor
Fills the posterior compartment of the eye; helps to maintain
pressure within the eye and holds the lens and retina in place
Vitreous humor
Bending of light rays as they pass from air into some other,
more dense substance.
Refraction
Type of lens that causes light rays to diverge
Concave lens
Type of lens that causes light rays to converge
Convex lens
Where converging light rays cross
Focal point
Act of causing light rays to converge to form an image.
Focusing
Bending of light rays as they pass from air into some other,
more dense substance
Part of the eye that produces the greatest amount of
convergence of light.
Cornea
Part of the eye that accomplishes fine adjustments in focusing
by changing shape
Lens
Process of allowing the lens to assume a more spherical
(convex) shape; enables the eye to focus objects that are closer
than 20 feet
Accommodation
Condition of the ciliary muscles during accommodation
Contracted
Condition of the ciliary muscles for distant vision (greater than
20 feet).
Relaxed
Leaves the eye and passes through the optic foramen
Optic nerve
Image seen by each eye
Visual field
Point where some of the axons in the optic nerves cross to
opposite sides of the brain
Optic chiasma
Part of the occipital lobes of the brain responsible for vision
Visual cortex
Axons between the optic chiasma and the thalamus
Optic tract
Axons extending from the thalamus to the visual cortex
Optic radiations
Passageway that leads to the tympanic membrane
External auditory meatus
Fleshy part of the external ear on the outside of the head.
Auricle
Modified sebum, commonly called earwax, that helps to
prevent foreign objects from reaching the tympanic membrane
Cerumen
Membrane-covered opening between the middle and inner ear
Round window
Thin membrane that separates the external and middle ear;
vibrates in response to sound waves; also called the eardrum
Tympanic membrane
Opening between the middle and inner ear; contains the stapes.
Oval window
Ear bones that transmit and amplify vibrations of the tympanic
membrane to the oval window; the malleus, incus and stapes
Auditory ossicles
Spaces in the temporal bone that are connected to the middle
ear
Mastoid air cells
Structure that enables air pressure to be equalized between the
outside air and the middle ear; the eustachian tube
Auditory tube
interconnecting tunnels and chambers within the temporal
bone.
Osseous labyrinth
Membranes that are found within the osseous labyrinth
Membranous labyrinth
Fluid within the membranous labyrinth
Endolymph
Perilymph
Fluid between the osseous and membranous labyrinth
Part of the inner ear involved with hearing
Cochlea
Two parts of the inner ear involved with balance
- Vestibule
- Semicircular
Membrane separating the scala vestibuli and the cochlear duct
Vestibular membrane
Membrane separating the scala tympani and the cochlear duct
Tectorial membrane
The space that connects to the oval window
Scala vestibuli
The space that connects to the round window
Scala tympani
The space that contains the spiral organ
Cochlear duct
The spiral organ rests on the basilar membrane and its hair cells
extend to this membrane
Tectorial membrane
Type of equilibrium associated with the semicircular canals and
involves evaluating the change in rate of head movements
Kinetic equilibrium
Type of equilibrium associated with the vestibule and involves
evaluating the position of the head relative to gravit
Static equilibrium
The two chambers of the vestibule
- Utricle
- Saccule
Specialized epithelium of the vestibule; consists of hair cells
embedded in a gelatinous mass that contains otoliths
Macula
Specialized epithelium found in the ampulla; consists of hair
cells embedded in a gelatinous mass called the cupula
Crista ampullaris