Sensory System Flashcards
What are the 5 general senses
1) Pain 2) Touch 3) Temperature (hot and cold) 4) Pressure 5) Position
What are 5 special senses
1) Vision 2) Hearing 3) Equilibrium 4) Taste 5) Smell
Accommodation
Alterations in the lens’ shape to allow for near or far vision.
Adaptation
Adaptation is the decline of the electric responses of a receptor neuron over time in spite of the continued presence of an appropriated stimulus of constant strength.
Anterior and posterior cavities
First division of the eyeball, separated by the crystalline lens.
Anterior and posterior chambers
Second division of the eyeball, separated by the iris.
Anosmia
The loss of the sense of smell, either total or partial. It may be caused by head injury, infection, or blockage of the nose.
Astigmatism
The visual defect caused by a irregularity in the curvature of the lens or cornea.
Auditory Tube
Eustachian tube- connects the middle ear with the nasopharnyx
Aqueous humor
The watery fluid that fills much of the eyeball in front of the crystalline lens.
Cataract
A loss of lens transparency.
Choroid layer
The vascular, dark brown or black pigmented which absorbs excess light and keeps the eye dark inside by preventing reflection. The middle layer of the eye.
Cornea
The part of the eye that light rays pass through first as they enter the eye. The transparent portion of the sclera.
Conjunctiva
The membrane that lines the inside of the eyelids and is a thin transparent layer of mucous membrane that covers the exposed eyeball.
Cone
A vision receptor that is sensitive to color
Ciliary muscle or body
The structure that alters the shape of the lens for accommodation
Conclear branch
The branch of the vestibulocochlear nerve that carries hearing impulses.
Cochlea
A spiral tube shaped like a snail shell. Inside is the organ of Corti that translates sound vibrations into nerve impulses.
Color blindness
A condition in a person who lacks cones in the retina.
Cerumen
Ear wax
Ceruminous gland
The glands that secrete cerumin.
Crystalline lens
A circular structure that consists of a jelly-like material, Its function is to accommodate or make adjustments for viewing near and far objects.
Dark adaptation
The interval needed for rods to adjust from light to dark stimuli.
Eyelids
Protects the anterior eye from dust, intense light and impact.
Eyelashes
Hair growing on the edge of an eyelid; aid in protecting the anterior (front) of the eye.
Eustachian tube
The channel connecting the middle ear cavity with the pharynx.
Glaucoma
A condition caused by continued high pressure of the aqueous humor, which may result in the destruction of the optic nerve.
Gustation
Scientific name for the sense of taste.
Hearing
The faculty of perceiving sounds.
Hyperopia
The scientific name for farsightedness, in which light rays are not bent sharply enough to focus on the retina when viewing close objects.
Incus
Anvil shaped middle bone of the ear.
Iris
The muscle that regulates the amount of light entering the eye.
Lacrimal Apparatus
A mechanism (structure) that cleanses and lubricates (kept moist) the eye. Consists of
1) Lacrimal gland-located superiorly and laterally over each eye.
2) Lacrimal ducts- two short ducts in the medial corner of each eye
3) Lacrimal sac- an enlarged sac that leads to the…
4) Nasolacrimal duct- conveys the tear fluid from the sac into the nasal cavity through the lacrimal bone.
Lymph
Fluid contained within the inner ear.
Lens (crystalline lens)
Located posterior to the iris and is suspended by thin zonular fibers near the ciliary body.
Macula
An oval yellowish area surrounding the fovea near the center of the retina in the eye, which is the region of keenest vision.
Malleus
Hammer shaped middle bone of the ear.
Myopia
The scientific name for nearsightedness, in which the focal point is in front of the retina and distant objects appear blurred.
Olfaction
The sense of smell. Receptors are located in the epithelium of the nasal cavity and supplied by the Olfactory nerve (CN I).
Ophthalmia neonatorum
Eye infection of newborns
Pinna or auricle
Another name for the projecting part, or auricle of the ear.
Orbital cavity
A bony, cone-shaped socket in front of the skull lined with fatty tissue to protect the eyeball. Bones of the orbital cavity are: FRONTAL, SPHENOID, ETHMOID, MAXILLA, ZYGOMATIC and LACRIMAL.
Optic nerve
The nerve that carries visual impulses from the retina to the brain.
Origin of the Corti
of hearing.The structure that contains specialized receptor cells that detect sound waves or for hearing. Known as the organ
Ossicles
Little bones of the ear; malleus (hammer), incus (anvil) and the stapes (stirrup). These extend across the chamber of the tympanum to the oval window and transmit sound waves through the middle ear.
Otitis media
Infection and inflammation of the middle ear.
Perilymph
Fluid of the inner ear.
Pupil
The central opening of the iris.
Proprioceptor
A sensory receptor which receives stimuli from within the body, especially one that responds to position and movement.
Refraction
The bending of light rays as they pass through the structures of the eye.
Rod
A vision receptor that functions well in dim light.
Retina
The innermost layer or nervous layer of the eyeball that includes the receptors for the sense of vision.
Sclera
The outermost layer composed of dense white fibrous tissue which becomes modified in the front of the eyeball into the delicate structure called the cornea.
Semicircular glands
The sense of position is partially governed by equilibrium receptors in the internal ear, including chambers in the vestibule and the three semicircular glands.
Semicircular canal
Passages in the inner ear which control the sense of balance.
Sensory adaptation
Sensory adaptation is a reduction in sensitivity to a stimulus after constant exposure to it.
Sensory receptor
Sensory receptors occur in specialized organs such as the eyes, ears, nose, and mouth, as well as internal organs.
Spiral organ
The organ of Corti, also known as the spiral organ, is the receptor organ for hearing, located in the cochlea.
Stapes
Stirrup shaped middle bone of the ear.
Strabismus
Abnormal alignment of the eyes; the condition of having a squint.
Trachoma
Infection of the eye caused by Chlamydia trachomatis
Lacrimation
The production of tears.
Tympanic membrane
The tympanic membrane is also called the eardrum. It separates the outer ear from the middle ear.
Vestibule
An oval cavity located in the center of the inner ear next to the oval window. Contains receptors for equilibrium which control the sense of balance.
Vitreous body
The jelly-like material located behind the crystalline lens that maintains the shape of the eye.
Conjunctivitis
Inflammation of the membrane lining the eyelid.
Lysozyme
A bacteriocidal (kills bacteria) enzyme in tears.
Extrinsic muscles of the eye
Muscles that attach to the bones of the eye orbit and sclera- There are six muscles located outside the eyeball.
Intrinsic muscles of the eye
Muscles inside the eyeball.
Nerves of the eye
1) Optic nerve (CN II)- carries impulses from the retina to the brain, involved in vision
2) Oculomotor nerve (CN III)- Pupillary reflex, focusing lens, movement of the upper eyelid and supply four of the extrinsic muscles of the eye
3) Trochlear nerve (CN IV)- Supply the superior oblique muscle
4) Trigeminal nerve (CN V)- Sensory fibers from the eyes, tear glands, and upper eyelids
5) Abducens (CN VI)- Supply the lateral rectus muscle
2 Functions of the Ear
1) Hearing 2) Maintaining equilibrium
Function of external ear
To pick up sound waves
Function of Middle ear
To amplify sound waves
Function of Inner Ear
To convert sound waves into nerve impulses that can be interrupted by the brain and maintain equilibrium.
Vestibulocochlear Nerve (CN VIII)
Also known as the acoustic and/or auditory nerve. Serves the vestiblule of the ear and the semicircular canals carrying impulses for equilibrium.
Taste buds
Located on the tongue are the receptors for taste. Different types are for sweet, sour, salty, bitter and umami.
The two nerves for Gustation
Facial nerve (CN VII) and Glossopharyngeal nerve (CN IX)
