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chapter 17
martini and roth essentials of anatomy
103
Anatomy
Undergraduate 1
04/22/2012

Additional Anatomy Flashcards

 


 

Cards

Term
Palpebrae (eyelids
Definition

 
Continuation of skin that keeps surface of eye lubricated when blinking
 
Term

Eyelashes

 
Definition

Help prevent foreign matter (insects) from reaching surface of eye

 
Term

Conjunctiva

 
Definition

Epithelium covering inner surfaces of eyelids and outer surface of eye 

 
Term
Conjunctivitis (pinkeye
Definition
inflammation of conjunctiva due to infection or by allergic, chemical or physical irritation
Term
Lacrimal Apparatus
Definition

Group of structures that produces and drains lacrimal fluid or tears

 
Term
Lacrimal glands
Definition
located above the eye; produces and secretes lacrimal fluid
Term
Lacrimal fluid
Definition
watery solution containing salts, mucus, antibodies, and lysozyme (bactericidal enzyme)
Term
Lacrimal fluid
Definition

Spreads over anterior surface of eyeball by blinking

Cleans, lubricates, washes away irritating substances, and kills microbes on eyeball

After passing over eyeball, the tears pass through several structures and eventually drain into the nasal cavity (just inferior to inferior nasal concha) 

Term

Superior, inferior, medial, and lateral rectus muscles

Superior and inferior oblique muscles

 
Definition

6 extrinsic eye muscles attached to each eyeball:

 
Term

1)  Fibrous tunic: outer layer

2)  Vascular tunic or uvea: middle layer

3)  Retina: inner layer

 
Definition
Wall of the eyeball consists of three layers
Term
Sclera
Definition

“White of the eye”: tough outer layer of the eyeball (except for the cornea in front)

Composed of dense fibrous connective tissue

Gives shape to eyeball, protects its inner parts, and serves as site of attachment for extrinsic eye muscles

 
Term

Cornea

 
Definition

Outer layer of eyeball anteriorly

Transparent coat that covers colored iris

Avascular

Curved surface that helps focus light onto the retina

Most sensitive portion of eye due to lots of free nerve endings

 
Term
Corneal Damage/Transplant
Definition

Corneal damage may cause blindness

Cornea has restricted ability to repair itself so injuries to it must be promptly treated to prevent scarring and serious vision loss

Once corneal scarring has occurred, vision can be restored by corneal transplant

Most common form of transplant

Transplants can come from unrelated donors (no blood vessels to carry WBCs to attack foreign cells)

 
Term
Vascular Tunic/Uvea: Middle Layer
Definition

Pigmented layer that contains choroid, ciliary body, and iris

Contains numerous blood and lymphatic vessels, and smooth muscles of eye

Term

Functions:

1)  Provide route for blood and lymphatic vessels to supply tissues of eye

2)  Regulate amount of light that enters eye

3)  Secrete and reabsorb aqueous humor that circulates within chambers of eye

4)  Control shape of lens

Definition

Functions of Vascular Tunic/Uvea: Middle Layer

 
Term

Choroid

 
Definition

Posterior portion of vascular tunic

Lines inner surface of sclera

Highly vascularized – provides nutrients to the retina

Contains melanocytes that produce melanin

Causes this layer to be dark brown

Absorbs stray light rays and thus prevents scattering of light in eyeball – so image sent to retina is clearer and sharper

 
Term

Ciliary body

 
Definition

Anterior portion of vascular tunic – basically where choroid becomes ciliary body

Forms a circular collar around lens

Appears dark brown: contains melanocytes

Contains ciliary processes: secretes aqueous humor

Suspensory ligaments of the lens attaches to the ciliary processes

These ligaments hold the lens behind the iris and centered on the pupil

Contains ciliary muscle: smooth muscle connected to lens

Alters shape of lens adapting it for near or far vision

 
Term
ciliary processes
Definition
secretes aqueous humor
Term
Suspensory ligaments 
Definition

lens attaches to the ciliary processes

These ligaments hold the lens behind the iris and centered on the pupil

 
Term
ciliary muscle
Definition

smooth muscle connected to lens

Alters shape of lens adapting it for near or far vision

 
Term

Iris (“rainbow”)

 
Definition

Colored portion of eyeball

Flattened circular structure between cornea & lens

Contains melanocytes: amount of melanin determines eye color which is genetically determined

Low melanin = blue eyes

 
Term

Iris (“rainbow”)

 
Definition

Main function is to regulate the amount of light entering the eyeball through the pupil (hole in center of iris)

Contains two layers of smooth muscles called pupillary muscles; when they contract, they change the diameter of the pupil

 
Term
Bright light
Definition
parasympathetic fibers of oculomotor (III) cranial nerve stimulate muscles of iris to contract →decrease in pupil diameter (constriction)
Term
Dim light
Definition
sympathetic fibers of oculomotor (III) cranial nerve stimulate muscles of iris to contract →increase in pupil diameter (dilation)
Term

“Red eye” in photographs

 
Definition

If bright light is directed into pupil – the reflected light is red due to blood vessels over surface of retina

 
Term
Retina 
Definition

Lines the posterior ¾ of the eyeball and is the beginning of the visual pathway

Contains optic disc: site where optic (II) nerve exits the eyeball

Central retinal artery and vein are bundled with optic nerve

Blind spot: lacks photoreceptors (rods or cones), so you cannot see an image that strikes this spot; do exercise on page 561 of textbook

 
Term
optic disc
Definition
site where optic (II) nerve exits the eyeball
Term
Blind spot
Definition
lacks photoreceptors (rods or cones), so you cannot see an image that strikes this spot; do exercise on page 561 of textbook
Term
Retina
Definition
consists of pigmented and neural layer
Term

Pigmented layer

 
Definition

Melanin-containing epithelial layer between choroid and neural layer

Absorbs stray light rays; prevents light scattering

 
Term

Neural layer

 
Definition

Multilayered outgrowth of brain that contains retinal neurons that process visual data before sending nerve impulses into axons that form optic nerve

 
Term
Photoreceptor layer
Definition
contains rods and cones
Term
Bipolar cell layer
Definition
contains specialized neurons
Term
Ganglion cell layer
Definition
axons of ganglion cells that comprise optic nerve
Term
Photoreceptors in Retina
Definition
nSpecialized cells that begin process by which light rays are converted to nerve impulses

Two Types: Rods and cones

Term

Rods

 
Definition

Most abundant photoreceptor

Stimulated by low, dim light

No color: can only see black, white and shades of gray

Basis of night vision

Loss of rod vision = difficulty seeing in dim light

 
Term

Cones

 
Definition

Stimulated by brighter light

Produces color vision (blue, red, and green cones)

Gives us sharper, clearer images

Loss of cone vision = legal blindness

 
Term
Macula lutea
Definition

exact center of posterior portion of retina, at the visual axis of the eye

Contains no rods

 
Term
Central fovea (fovea centralis)
Definition

small depression in center of macula

Highest concentration of cones!!!

Area of highest visual acuity (sharpness of vision)

Provides ability to see fine details

Term
Inner Layer: Retina
Definition

Surface of retina is only place in body where blood vessels can be viewed directly and examined for pathological changes that occur in diseases such as:

Hypertension, diabetes mellitus, cataracts

 
Term
ophthalmoscope
Definition

Instrument that shines light into eye and allows observer to see through pupil; provides a magnified image of retina, its blood vessels and optic (II) nerve

 
Term
Detached Retina
Definition

Neural & pigmented layers of retina separate

Due to trauma (blow to head) or various eye disorders 

Fluid accumulates between layers and causes retina to push outward 

Causes distorted vision and blindness

Photoreceptor layer containing rods and cones is dependent on diffusion of oxygen and nutrients from the choroid

If two layers are not reattached, photoreceptors will degenerate and die

Treated by laser surgery which “welds” the two layers together

 
Term
Interior of the Eyeball
Definition

Found behind pupil and iris

Held in place by suspensory ligaments that originate on ciliary body of choroid

Avascular and transparent

Consists of a capsule with proteins (crystallins) in layers

Responsible for the clarity and focusing power of lens

Along with cornea focuses images on retina

 
Term
Lens and Cataracts
Definition

Loss of transparency of lens

Lens becomes cloudy and turns yellowish due to changes in structure of lens proteins

Over time will need brighter light for reading and visual clarity will fade

Common cause of blindness (if lens becomes completely opaque)

Caused by aging, injury, excessive exposure to UV rays, diabetes, smoking, some medications 

Can remove old lens and replace with artificial lens

 
Term

Anterior cavity

 
Definition

Composed of anterior chamber ( between cornea and iris) and posterior chamber (between iris and lens)

Contains aqueous humor: watery fluid that nourishes cornea and lens and maintains eye’s shape

Continuously secreted by ciliary processes and drains out of cavity by scleral venous sinus (canal of Schlemm) into the blood; replaced every 90 minutes

 
Term

Vitreous Chamber (Posterior Cavity)

 
Definition

Much larger than anterior cavity

Lies between lens and retina

Maintains shape of eye

 

 
Term
vitreous body
Definition

Transparent jelly-like substance

Contains collagen fibers and proteoglycans

Holds retina in place against choroid

Does not undergo continuous replacement like aqueous humor

 
Term
Intraocular Pressure
Definition

Pressure in the eye

Produced mainly by aqueous humor and partly by vitreous body

Maintains shape of eyeball and prevents it from collapsing

Stabilizes position of retina by pressing neural part against pigmented part

Pressure can be measured in anterior chamber (fluid pushing against cornea)

Applanation tonography: small, flat disk is placed on anesthetized cornea to measure pressure

 
Term
Glaucoma
Definition

Most common cause of blindness in U.S.

Affects 2% of individuals over age 35

Caused by abnormally high intraocular pressure due to buildup of aqueous humor within anterior cavity

Lens compresses into vitreous body which then puts pressure on retinal neurons (painless)

Leads to visual impairment (tunnel vision), irreversible destruction of retinal neurons, damage to optic nerve, and eventual blindness

Risk factors: race (*African-Americans), age, family history, past eye injuries and disorders

Treatment: topical application of drugs or laser surgery (poke hole in anterior chamber)

 
Term
Image Formation
Definition

Three processes of how the eye forms clear images of objects on the retina:

Refraction or bending of light by the cornea and lens

Accommodation: the change in shape of the lens

Constriction or narrowing of the pupil (diameter of the “hole” gets smaller through which light can enter the eye)

Autonomic reflex that occurs simultaneously with accommodation

 
Term
Refraction 
Definition

is the bending of light rays through transparent substances of different densities

 
Term
Image Formation: Refraction of Light 
Definition

The cornea and lens “bend” or refract light rays entering eye

Most refraction occurs at cornea

The lens then focuses light rays from an object toward a specific point of intersection on retina (focal point)

 
Term
Close vision
Definition

Increase in the curvature of the lens for close or near vision (less than 20 ft.)

Light rays from objects less than 20 ft are more divergent so they must be refracted more by lens to be focused on retina

When you view a close object, the ciliary muscle contracts and the lens becomes more spherical or rounded

Increases its focusing power and causes greater convergence of the light rays 

 
Term
Presbyopia
Definition

With aging, lens loses elasticity and its ability to accommodate e.g. its ability to focus on objects that are close

Older people cannot read print at same close range as younger people – need “reading glasses”

Usually begins in mid-forties

Near point of vision = minimum distance from eye an object can be clearly focused with accommodation

3 - 4 inches in child

6 - 8 inches in young adult

33 inches in 60 year old

 
Term
Image Formation: Image Reversal
Definition

Images focused on the retina are inverted (upside down) and are left-right reversed

Brain “compensates” early in life for this image reversal, and we are unaware of any difference between orientation of image on retina  and that of object.

Term
Normal vision
Definition
eyeball is able to refract light rays from object directly on retina
Term
Nearsightedness (myopia): 
Definition

eyeball is too long or lens is thicker than normal

Image is focused in front of the retina 

Close objects seen clearly; distant objects are blurred

Term
Farsightedness (hyperopia): 
Definition
neyeball is too short or lens is thinner than normal
qImage is focused behind the retina

Distant objects seen clearly; close objects are blurred

Term
Astigmatism
Definition

: cornea or lens has abnormal curvature

Parts of image are out of focus and vision is blurred or distorted

 
Term

Correction of vision

 
Definition

Glasses, contact lenses or LASIK

Nearsightedness: use concave lens

Farsightedness: use convex lens

 
Term

LASIK: laser-assisted in-situ keratomileusis

 
Definition

Doctor uses laser and aid of computer to reshape the curvature of cornea

70% of LASIK patients achieve normal vision

 
Term
Rods and cones 
Definition
are modified retinal neurons that detect photons (basic units of visible light)
Term

Outer segment:

 
Definition

Contains discs which contain visual pigments: colored proteins that undergo structural changes when it absorbs light

Transduction of light energy into receptor potential occurs here!

 
Term
Inner segment
Definition

Contains nucleus, Golgi complex, mitochondria

Releases neurotransmitters

Synapses with a bipolar cell 

Term
Color Blindness
Definition

 Inherited inability to distinguish between certain colors

Results from absence or deficiency of one (or two) of the three types of cones

More likely to occur in males (10% of all males)

Most common type is red-green color blindness, in which red cones are missing

 

 

Term
Night Blindness
Definition

Inability to see well at low light levels

Retinal is a derivative of vitamin A and is the light-absorbing portion of rhodopsin

Results from prolonged vitamin A deficiency

Body has vitamin A reserves for several months, and much is stored in pigmented part of retina

Both day and night vision are affected but the problem first becomes apparent at night

 
Term

1)  External (outer) ear

Collects sound waves and channels them inward

 

2)  Middle ear

Conveys sound vibrations to oval window

 

3)  Internal (inner) ear

Contains receptors for hearing and equilibrium (balance)

 
Definition
Anatomy of the Ear
Term

Auricle

 
Definition

Flap of elastic cartilage shaped like flared end of trumpet and covered with skin

Collects sound waves, channels them into canal

 
Term

External auditory canal

 
Definition

Curved tube about 1 inch long that lies in temporal bone and leads to eardrum

Channels sound waves to eardrum

Contains hairs & ceruminous glands that secrete cerumen (earwax)

Prevents dust and foreign objects from entering ear

 
Term

Eardrum (tympanic membrane)

 
Definition

Thin, semitransparent membrane between external auditory canal and middle ear

Vibrates in response to sound waves

Perforated eardrum: tearing of tympanic membrane from trauma, pressure from cotton swab, or middle ear infection

Takes about a month to heal

Otoscope: an instrument that illuminates and magnifies external auditory canal and tympanic membrane

 
Term
Middle Ear 
Definition

Small air-filled cavity within temporal bone that is lined by epithelium

Contains auditory ossicles

 
Term
auditory ossicles
Definition

Three small bones which bridge the middle ear cavity from eardrum to oval window (entrance to inner ear)

 
Term

Malleus 

hammer

Definition
attached to eardrum and articulates with incus
Term
Incus (“anvil”): 
Definition
in between malleus and stapes
Term
Stapes (“stirrup”): 
Definition
attached to oval window membrane
Term
Function: Ossicles 
Definition

vibrate with the eardrum, amplify (make it stronger), and transfer the vibration to the membrane of the oval window (which creates a pressure wave in the fluid of the inner ear)

 
Term

Middle ear muscles

 
Definition

Tiny skeletal muscles 

Tensor tympani (inserts on malleus)

Stapedius (inserts on stapes)

Contract reflexively to reduce vibrations of the ossicles to very loud sounds to protect inner ear

 
Term

Auditory (Eustachian tube)

 
Definition

Connects middle ear cavity with nasopharynx (superior portion of throat)

Allows equalization of air pressure between middle ear and atmosphere (when you yawn or swallow); “ear popping”

Route for pathogens to travel from nose and throat to middle ear to cause infection – otitis media

 
Term
– otitis media
Definition
Route for pathogens to travel from nose and throat to middle ear to cause infection 
Term
The Internal Ear
Definition

 

Fluid-filled cavity within temporal bone
 
Term
Bony labyrinth
Definition

superficial contours of internal ear formed by layer of dense bone

Continuous with surrounding temporal bone

 
Term
Membranous labyrinth
Definition

delicate interconnected network of fluid-filled tubes

Receptors for internal ear are found here

 
Term
Perilymph:
Definition
liquid similar to CSF that is between bony and membranous labyrinths
Term
Endolymph
Definition
liquid found within membranous labyrinth
Term

1)  Vestibule

2)  Semicircular canals
3)  Cochlea
 
Definition
Three Components of Bony Labyrinth
Term

1)  Vestibule

 
Definition

Oval-shaped; found in central portion 

Contains receptors for equilibrium (balance)

 
Term
Semicircular canals
Definition

Three tubes that project from vestibule and are oriented at right angles to each other

Contain receptors for equilibrium

 
Term
Cochlea
Definition

Bony spiral-shaped canal; looks like snails shell

Contains cochlear duct of membranous labyrinth

Contains auditory (hearing) receptors

Term
Cochlea of Internal Ear
Definition

Contains three channels that are filled with fluid (cochlear duct, scala vestibuli, scala tympani) that are involved in transmission of sound waves

 
Term
Scalae
Definition

are interconnected and form one long and continuous chamber: 

Begin at oval window; go through scala vestibuli; around top of cochlea; go along scala tympani; end at round window (membrane between fluid-filled cochlear chambers and air-filled middle ear)

 
Term
Cochlear duct 
Definition

is an elongated tubelike structure that lies between scala vestibuli and scala tympani

Contains spiral organ or organ of Corti

 
Term
Spiral Organ (Organ of Corti)
Definition

Contains hair cells which are the receptors for hearing

Hair cells are sandwiched between basilar and tectorial membranes of spiral organ

Hair cells change mechanical vibrations (sound waves) into electrical signals!!!!!!

Hair cells synapse with sensory and motor neurons with cochlear branch of vestibulocochlear (VIII) nerve

 
Term
Hearing 
Definition

is the perception of sound, which consists of waves of pressure conducted through air or water

Sound travels in waves from a vibrating object

Think of the ripples that are created when you toss a stone in a pond

 
Term
Pitch and Loudness
Definition

The frequency (or pitch) of a sound vibration is measured in hertz (Hz); 1 Hz = 1 cycle per second

Entire human audible range from 20 to 20,000 Hz

Typically most sounds heard by human ears vibrate at frequencies from 500 – 5000 Hz

The larger the intensity (size or amplitude) of the vibration, the louder the sound

Sound intensity (loudness) measured in decibels (dB)

Normal conversation = 60 dB 

Hair cells in cochlea are damaged to continued exposure to sounds over 90 dB – can lead eventually to deafness

 
Term

Sound waves

 

External ear

Auricle→ external auditory canal→ tympanic membrane 

 

Middle Ear

Auditory ossicles (malleus→ incus→ stapes)→ oval window 

 

Inner Ear

Cochlea: →spiral organ (organ of Corti) → hair cell → receptor potential→ nerve impulse

Definition
Hearing Pathway
Term
Frequency (Pitch) and Loudness 
Definition

Frequency or pitch of a sound will distort the basilar membrane in the spiral organ of cochlea at specific locations.

High pitch sounds (shorter wavelengths) vibrate basilar membrane nearer oval window

Low pitch sounds (longer wavelengths) vibrate basilar membrane nearer round window

Frequency of a sound is translated into information about its position along basilar membrane

Loudness or intensity of a sound will affect amount of force applied to stapes and ultimately how much the basilar membrane moves at a given location

Louder the sound the more forceful the stapes moves and the more the basilar membrane moves

 
Term
High pitch sounds (shorter wavelengths)
Definition
vibrate basilar membrane nearer oval window
Term
Low pitch sounds (longer wavelengths) 
Definition
vibrate basilar membrane nearer round window
Term
Frequency of a sound 
Definition
is translated into information about its position along basilar membrane
Term
Auditory Pathway
Definition

Hair cells of cochlea → cochlear branch of vestibulocochlear (VIII) nerve → brain stem (medulla oblongata and midbrain) → thalamus → primary auditory areas of cerebral cortex in temporal lobe.

Right and left auditory areas in cerebrum receive nerve impulses from both ears. 

Damage to auditory areas: person can respond to sounds and have normal auditory reflexes but difficult or impossible to interpret sounds and recognize a pattern in them

 
Term

 

Sensorineural deafness
Definition

Caused by damage of hair cells in cochlea or damage to cochlear branch of vestibulocochlear (VIII) nerve

Caused by atherosclerosis (reduces blood supply to ears), repeated exposure to loud noise (destroys hair cells) and/or by certain drugs (aspirin, streptomycin)

Term
Conduction deafness
Definition

Caused by impairment of external or middle ear mechanisms for transmitting sounds to the cochlea

Caused by aging (thickening of eardrum and stiffening of joints in auditory ossicles) and impacted earwax 

 
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