Exam 3 Chapter 16 Flashcards
What type of tissue forms the receptor cells for taste?
epithelial cells
What type of cell are the olfactory receptors?
bipolar neurons
What happens when bipolar neurons are damaged?
they are replaced
What is conjunctiva and where is it located?
transparent mucous membrane that covers the inner surfaces of the eyelids and the anterior surface of the eye
What muscle is not functioning in a person whose eye turns medially?
lateral rectus
What nerve innervates lateral rectus?
abducens (VI)
Differentiate the cornea from the choroid with reference to the location, structure, and function of each.
Corea: fibrous layer of the eye
- composed of dense connective tissue sandwiched between two layers of epithelium
Choroid: middle vascular layer of the eye
- blood vessels nourish the eye and its pigment absorb light
What portion of the visual field is lost in a person with degeneration of the macula lutea?
straight ahead
What is the aqueous humor? Where is it located? What are its functions?
Clear watery fluid that fills the anterior segment
- supplies nutrients and oxygen to the avascular lens and cornea
- maintains constant intraocular pressure
In a normal eye, when the lens accommodates for viewing close objects, does it become rounder or more oval in shape?
rounder
Why do middle-aged to older adults develop difficulty focusing on close objects?
Lens become less elastic as we age.
- accommodation for viewing close objects requires elasticity of the lens
Trace the visual pathway from the medial half of the retina of the right eye to the cerebral cortex.
1) Axons from ganglion cells from the medial half of the retina extend through the right optic nerve.
2) Passes through the optic chiasma to the left optic tract
3) Synapse in the left lateral geniculate nucleus of the thalamus with neurons that extend via the optic radiation to the left primary visual cortex
What structure separates the external acoustic meatus from the middle ear cavity?
tympanic membrane (ear drum)
Name the four openings or holes into the middle ear cavity.
- pharyngotympanic tube
- round window
- oval window
- mastoid antrum
Which auditory ossicle abuts the tympanic membrane?
malleus
What is the difference between the membranous labyrinth and the bony labyrinth of the internal ear?
membranous: continuous series of membranous sacs and ducts filled with endolymph (contains sensory receptors for hearing and equilibrium)
bony: cavity within petrous portion of the temporal bone that surrounds the membranous labyrinth
Where is perilymph located within the cochlea?
fills the cavity of the bony labyrinth or the cochlea, scala vestibuli, and scala tympani
Where in the cochlear duct is the vestibular membrane located?
roof of the cochlear duct
Where in the cochlear duct is the basilar membrane located?
forms the floor
Where in the cochlear duct is the tectorial membrane located?
sits atop the sensory hair cells
Vibrations in which membrane stimulate the hair cells of the spiral organ?
tectorial membrane
Which sensory receptors monitor stationary head position and linear movements of the head? Where are these receptors located?
maculae of the utricle and saccule
What type of deafness results from damage to the cells of the spiral ganglion?
sensorineural deafness
What brain regions receive input from the vestibular nerves and process information on equilibrium?
vestibular nuclei of the medulla and cerebellum
What sense is involved in sensory impulses transmitted over the facial, glossopharyngeal, and vagus nerves?
taste
What part of the eye is white, tough, and opague?
sclera
Where does the transmission of sound vibrations through the internal ear occur?
fluid
Of the neurons in the retina, which form the optic nerve?
ganglion neurons
In the brain, where is taste information transmitted through?
insula lobe, solitary nucleus, thalamus
Where does conduction of sound from the middle ear to the internal ear occur?
Vibration of stapes in the oval window
Where are the receptors for static equilibrium that report the position of the head in space relative to the pull of gravity located?
maculae
What is part of the spiral organ?
tectorial membrane, inner hair cells, outer hair cells
What would be affected from the paralysis of a medial rectus muscle?
refraction
What’s the order that a light ray passes through the refractory structures of the eye?
cornea, aqueous humor, lens, vitreous humor
What extrinsic eye muscles originate from the common tendinous ring?
superior oblique, superior rectus, inferior rectus
What are some basic taste sensation?
bitter, sour, sweet
What and where is the optic disc and why is it important?
Where optic nerve fibers exit the eye (blind spot because lack of photoreceptors)
- on the retina
- understanding visual field deficits and diagnosing conditions (can indicate damage or pressure in the eye)
Name two special senses whose receptor cells are replaced throughout life, and two special senses whose receptor cells are replaced so slowly that there can be no functional regeneration.
Can be replaced: Taste and smell
Can’t be replaced: Hearing and vision
Describe the function and the innervation of both the sphincter and dilator muscles of the pupil.
Sphincter function: constricts pupil to regulate light entry
Sphincter innervation: parasympathetic fibers of the oculomotor nerve (III)
Dilator muscle function: dilates the pupil to allow more light in
Dilator muscle innervation: sympathetic nervous system
