Exam 3 Flashcards
what cranial nerves arise from the diencephalon
II
what cranial nerves arise from the mesencephalon (midbrain)
III, IV
what cranial nerves arise from the pontomedullary junction
V, VI
what cranial nerves arise from the medulla
VII, VIII, IX, X, XI, XII
what cranial nerves exit from the foramina of ethmoid bone
I
what cranial nerves exit from the optic canal
II
what cranial nerves exit from the orbital fissure
III, IV, ophthalmic, VI
what cranial nerves exit from the round foramen
maxillary br of V
what cranial nerves exit from the oval foramen
mandibular br of V
what cranial nerves exit from the internal acoustic meatus
VII, VIII
what cranial nerves exit from the jugular foramen
IX, X, XI
what cranial nerves exit from the hypoglossal canal
XII
carnivores bony orbit
incomplete bony orbit
horses and ruminants bony orbit
complete bony orbit
optic canal has what vessels and nerves in carnivores, horses and ruminants
optic n.
internal ophthalmic a.
orbital fissure has what vessels and nerves in carnivores
cr.n. III, IV, ophthalmic, VI
anastomotic a.
orbital fissure has what nerves in horses
cr.n. III, IV, ophthalmic, VI
IV sometimes has its own foramen
foramen orbitorotundum has what vessels and nerves and in what species
ruminants only
orbital fissure + round foramen
cr.n. III, IV, VI, ophthalmic and maxillary
maxillary a.
supraorbital foramen is in what species and has what nerves and vessels
horses and ruminants
supraorbital n.
supraorbital a. & v.
blood supply to the eye arises from branches of ________
internal & external ophthalmic aa.
external ophthalmic aa. supplies ______
eyeball, extraocular eye muscles and adjacent structures
long posterior ciliary aa. run along ________
optic n.
short posterior ciliary aa. supply ________
vascular coat of the eye & uvea
anterior ciliary aa. supply ______
iris, limbic region of the eye
anastomosis with long posterior ciliary aa.
what is the major arterial circle
the aa entering the iris from the margins
animal eye much more vascular
three routes that venous blood leaves the orbit
- angular v. of the eye
- ophthalmic plexus
- ventral external ophthalmic v.
angular v. of the eye drains –>
facial v.
ophthalmic plexus drains –>
cavernous sinus
ventral external ophthalmic v. drains –>
deep facial v.
how can infection of the face migrate inside the braincase
through the venous system because these valves are valveless
why do albino/subalbino animals have “red eyes”
non-tapetal region have decreased/no melanin (pigment epithelium unpigmented) so blood vessels of choroid coat are prominent
parasympathetics and sympathetics innervation of the eye
parasympathetics: parasymp. nucleus of III, oculomotor n., ciliary ganglion
sympathetics: spinal cord segments T1-2, cranial cervical ganglion
three layers of the precorneal tear film and their respective glands
oil layer - meibomian glands
aqueous layer - lacrimal gland & gland of third eyelid
mucoid layer - mucous glands of conjunctiva (goblet cells)
functions of the precorneal tear film (5)
rinses foreign debris
lubricates
medium for diffusion
migration of inflam cells
smooth surface to cornea
innervation of levator palpebrae superoris m.
oculomotor n.
innervation of m. rectus dorsalis
oculomotor n.
innervation of m. rectus ventralis
oculomotor n.
innervation of m. rectus lateralis
abducent n.
innervation of m. rectus medialis
oculomotor n.
innervation of m. obliquus dorsalis
trochlear n.
innervation of m. obliquus ventralis
oculomotor n.
path of light
cornea
aqueous humor
lens
vitreous body
retina
unpigmented pigment epithelium
tapetum
choroid
anatomy of the cornea
precorneal tear film
anterior epithelium
stroma
descemete’s membrane
endothelium
corneal transparency function of ______
avascular tissue
unpigmented
dehydration of tissue
smooth optic surface from tear film
regular, laminar collagen
glaucoma
obstruction of filtration angle that prevents outflow of aqueous humor increasing intraocular pressure –> blindness
retina develops from what embryonic structure
optic cup
lens develops from what embryonic structure
optic vesicle + ectoderm = lens placode = lens
optic n. develops from what embryonic structure
diencephalon connection = optic stalk = optic n.
define coloboma
failure of choroid fissure to close completely during development
parts of the limbic system
hippocampus
cingulate gyrus
hypothalamus
amygdala
fornix
limbic system creates complex behaviors with what structures? their function?
neocortex: consciousness, perception
hypothalamus: drives and physiological change
amygdala: emotional memory
ARAS role in consciousness
ascending reticular activating system: nuclei in brainstem that receive collaterals from all sensory projection pathways and use this neuronal activity to increase diffusely the level of arousal in cerebral cortex
consciousness components
cortex + ARAS
levels of consciousness
alert
obtunded
stuporous
comatose
delirious
define alert
normally responsive to environment
define obtunded
withdrawn but still responsive
define stuporous
unresponsive except to painful stimuli
define comatose
non-responsive to all stimuli except reflex
define delirious
responds abnormally
list behaviors/postures associated with dementia or other derangement of consciousness
compulsive wandering
head pressing
somnolence
abnormal vocalization
circling
three parts of any seizure
aura (altered behavior, sec-min, alteration sensation/emotion)
ictus (max activity, 1+ changes, 1-2min)
post-ictus (confusion, disoriented, cortical blindness, wandering, min-hrs)
simple partial seizure
focal/partial seizure
no loss of consciousness
complex partial seizure
focal/partial seizure
altered consciousness - limbic focus - psychomotor seizure
convulsive seizure
generalized seizure
most common in vetmed
“grand mal seizure”
consciousness altered, lost bilateral motor activity, tonic (hyperextension), clonic (paddling, chewing), ANS activity
non-convulsive seizure
generalized seizure
rarely in animals
consciousness altered, no collapse “petit mal”
main strategies for seizure control
decrease glutamate
increase GABA
what cells of the retina whose axons become the optic nerve
ganglion cell axons
four different targets of axons within the optic n.
lateral geniculate nucleus
rostral colliculus
pretectal nucleus
suprachiasmatic nucleus
LGN purpose of retinal information
relays to primary visual cortex in occipital lobes
rostral colliculus purpose of retinal information
visual grasp reflex (head moves in response to visual, auditory or somatosensory input)
pretectal nucleus purpose of retinal information
PLR
suprachiasmatic nucleus purpose of retinal information
circadian and seasonal rhythms
conscious visual pathway
nasal hemiretina (contralaterla)
temporal hemiretina (ipsilateral)
optic n.
optic chiasm
optic tract
LGN
pretectal nuclei
parasympathetic nucleus of III
oculomotor n.
ciliary ganglion
pupillary constrictor mm.
unilateral injury to one visual cortex or optic tract or LGN will produce deficits in the _______ half of the visual filed in _____ eye(s)
contralateral
both
fibrous tunic components
sclera + cornea
vascular tunic components
“uvea”
anterior uvea = iris + ciliary body
posterior uvea = choroid
nervous tunic
retina
the lens _______ throughout life
what is the term for compression of the center of the lens
what is the term for opacity of lens or capsule
continues to grow throughout life - more fibers added to cortex
lenticular (nuclear) sclerosis
cataract
conscious processes are in the _____ hemisphere
contralateral
