FINAL ch 15 Flashcards
Components of the fibrous tunic:
- Sclera (sklee-rah)
2. Cornea
Functions of the sclera:
- Helps maintain the shape of the eyeball.
- Protects the internal structures.
- Provides and attachment site for the muscles that move it.
The avascular, transparent structure that refracts light as it enters the eye is called the?
CORNEA
Components of the (middle) vascular tunic:
- Choroid
- Ciliary body
- Iris
Components of the (inner) nervous tunic:
Retina
This structure is contractile, consisting mainly of smooth muscle surrounding an opening called the pupil:
IRIS
The iris regulates the amount of light by controlling the size of the pupil.
It is the “colored” part of the eye.
This structure is transparent and biconvex, described as an “unusual biological structure”, with its greatest convexity on its posterior side… It focuses light:
LENS
Its anterior surface consists of a layer of cuboidal epithelial cells, its posterior region contains very long columnar epithelial cells called LENS FIBERS.
Converts light into action potentials:
RETINA
What does the term “choroid” mean?
Membrane
What 2 components make up the external ear?
- Auricle (ear)
2. External auditory canal
What is the name for “eardrum”?
TYMPANIC
MEMBRANE
What part of the ear is an air-filled space within the petrous portion of the temporal bone and contains the auditory ossicles (bones)?
MIDDLE
EAR
Begins just inside tympanic membrane.
Separated from the inner ear by the oval and round windows (which are membrane-covered openings).
This canal is lined with hairs and ceruminous glands:
External Auditory Canal
This ends at the tympanic membrane.
These modified eccrine sweat glands are found in the external auditory canal:
CERUMINOUS
GLANDS
What is the proper name for “earwax”?
CERUMEN (seh-roo-min)
What are the 3 ossicles of the ear?
- Malleus (mal-ee-us): hammer.
- Incus (ing-kus): anvil.
- Stapes (stay-peez): stirrup
What transmits vibrations from the tympanic membrane to the oval window?
The OSSICLES (bones).
The handle of the malleus is attached to the tympanic membrane (eardrum) so when the tympanic membrane vibrates, it causes the the hammer to vibrate which causes the incus to vibrate (because the incus is attached by a tiny synovial joint to the head of the malleus) which leads to the stapes to vibrate (again attached by a synovial joint). The foot plate of the stapes rests on the oval window and is held in place by a flexible annular ligament.
What is cerumen made up of?
- Ceruminous secretions
2. Sebaceous secretions
What membrane does the cerumen help protect?
Tympanic membrane.
What thin membrane is composed of 2 layers of epithelium with connective tissue in between?
Tympanic membrane.
What cause the tympanic membrane to vibrate?
Sound waves.
What is the “border” between the external and middle ear?
The tympanic membrane.
Which part of the ear is only used for hearing and ends at the tympanic membrane?
External ear.
Which part of the ear is only used for hearing and contains the auditory ossicles?
Middle ear.
Which part of the ear is used for hearing as well as balance and is composed of interconnected fluid-filled tunnels and chambers within the temporal bone?
Inner ear.