CHAP 15 Flashcards
Special Senses
Olfaction (smell)
Gustation (taste)
Vision (optic)
Auditory (hearing) and balance
CN I
Olfactory Nerve
CN II
Optic Nerve
CN III
Oculomotor Nerve
CN IV
Trochlear Nerve
CN V
Trigeminal Nerve
CN VI
Abducens Nerve
CN VII
Facial Nerve
CN VIII
Vestibularcochlear Nerve
CN IX
Glossopharyngeal Nerve
CN X
Vagus Nerve
CN XI
Accessory Nerve
CN XII
Hypoglosal Nerve
what are Olfactory Hairs
Cilia of olfactory neurons embedded in mucus
Odorants Dissolve in
Mucus
One olfactory receptor may respond to more than one type of
Odor
How often are Olfactory Neurons Replaced?
Olfactory Neurons are replaced by basal cells every two months
Types of Papillae
Filiform, Vallate, fungiform, folate
Filiform
Filament-shaped papillae. Most numerous, contain NO taste buds
Vallate
Largest, but least numerous Papillae. 8-12 in a V shape along the border between the anterior and posterior parts of the tongue. HAS TASTE BUDS
Fungiform
Mushroom-shaped papillae. Scattered irregularly over the superior surface of the tongue. looks like small red dots interspersed among the filiform. have taste buds
Foliate
Leaf-shaped papillae. In folds on the sides of the tongue. contains most sensitive taste buds. Decrease in number with age
Taste Buds
Supporting cells surrounding taste (Gustatory cells)
taste cells have microvilli extending into taste pores.
replaced about every 10 days
Neuronal Pathways for Taste
CN VII - anterior 2/3rds of tongue
CN IX - posterior 1/3rd of tongue
CNX- carry information from base of tongue/epiglottis
A patient presents with involvement to the facial nerve (CNVII), what are their symptoms?
patient will have facial nerve palsy, taste loss to anterior 2/3rds of tongue, weakness to facial muscles, and will have decreased ability to dampen sound
A patient presents with Trigeminal nerve involvement
patient will have sensation loss to the face and difficulty chewing food. CNV provides sensation to the face and innervates the masseter
5 Visual System components
Eyebrow Sclera eyelids (palpebrae) Eyelashes conjunctiva
Sclera
White part of the eye. Extraocular muscles (EOM) attach to the sclera.
Palepral Fissure
the space between the eyelids (where the eyeball is located)
Canthi
Where eye lids meet, laterally and medially.
Medial Canthus has:
Caruncle with modified sweat and sebaceous glands
what is Conjuctiva?
Thin transparent mucous membrane on the eye.
Palpebral Conjuctiva: inner surface of eyelids
Bulbar conjuctiva: anterior surfaces of the eye, except over pupil
Function of the Lacrimal Apparatus
Moisten the nasal cavity
ExtraOcular Muscles of the Eye (EOM) Innervation?
SO4 -superior oblique CNIV
LR6 -Lateral rectus CNVI
AL3 - All the rest are CNIII
EOM attach to the
Sclera
Patient presents with CN VI involvement. what EOM is Involved?
Lateral Rectus. Eye will drift medially
AL3- CN3
Superior rectus
medial rectus
lnferior rectus
inferior oblique muscle
Three Layers (tunic) of the Eye
Fibrous Tunic
Vascular Tunic
Nervous Tunic
Fibrous Tunic contains
Outermost layer - Sclera and cornea
Vascular Tunic
Contains blood vessels. Choroid, ciliary body, iris. (middle.)
Contains IOM to change shape of lens and pupil
Nervous Tunic
Retina. Inner most layer
True or false: the vascular tunic contains the EOM Muscle
False. Vascular tunic contains IOM
What do the EOM muscles do?
Move the Eye
What do IOM Muscles do?
change the shape of the lens and pupil
Corea is __ (lacks blood vessels)
Avascular
Sphincter Pupillae (IOM)
constricts the pupil
Dialator Pupillae (IOM)
Sympathetic. Dilates Pupils
what does the Ciliary Body produce?
Produces aqueous humor that fills the anterior chamber
Ciliary Muscle (IOM) control what?
controls the lens shape (accommodation). smooth muscle.
what is the purpose of changing the shape (accommodation) of the lens?
to change from far vision to close vision
Optic Disk:
“blind spot” of the eye - area through which blood vessels enter eye and nerve processes from sensory retina meet and exit the eye. no photoreceptors are present
Far(distant) point of vision
Greater than 20 feet
shape of the lens is flat
ciliary muscles (IOM) are relaxed
Far, flat relaxed for distant vision
Near point of vision
less than 20 feet
shape of the lens is spherical shaped
ciliary muscles are contracted (shortened)
what is Miosis? (vision)
the changes occurring in size of the pupil
what is Convergence in pupils
changes in distance between pupils
Accomodation
Ciliary muscles contract due to parasympathetic imput via CN III (oculomotor)
pulls choroid toward lens reducing tension on suspensory ligaments
lens becomes more spherical, greater refraction of light
(vision) what is Myopia?
nearsightedness
what is Hyperopia in vision?
farsightedness
what is Presbyopa? (vision)
Degeneration of accommodiation
Astigmatism
cornea and/or lens is not uniform
Cataract
Clouding of lens
Glaucoma
increased intraocular pressure by aqueous humor buildup. HTN (hypertension of the eye)
Retinal Detachment
PVD: posterior vitreous detachment can lead to retrial detachment.
can result in complete blindness
