tOSU CVM Block 2 "Learning Objectives"

levator palpebrae superioris

elevate upper eyelid; CN3

obicularis oculi

closes upper and lower lip and surrounding margin: CN7

Malaris muscle

lowers inferior eyelid: CN7

Mueller's muscle

smooth muscle/tone tarsus; sympathetic nerve

Dorsal Rectus Muscle

eye elevation; CN3

Ventral Rectus Muscle

eye depression (pulls the eyeball downward); CN3

Lateral Rectus Muscle

abduct eye (move outward/away from midline); CN6

Medial Rectus Muscle

adduct eye (move inward/toward midline); CN3

Dorsal/Superior oblique muscle

internal rotation, downward movement, outward movement (down and out); CN4

Ventral/Inferior oblique muscle

external rotation, upward movement (up and in); CN3

retractor bulbi

pulls globe back in orbit; CN3

What structure gives rigidity to eyelids?

tarsus

Meibomian Glands: where and produce what

where: row of sebaceous gland that lie along eyelid margin

Produce: lipid layer of tear film

Goblet cells: where and produce what

where: between epithelial cells

produce: secret mucous; produce mucus layer of tear film

Conjunctiva: where and function

where: cover ocular surfaces

function: allows smooth gliding of nictitans and eyelids over globe

type of epithelium that covers cornea and conjunctiva

nonkeratinized stratified squamous

Nictitans: function and what gives support

supported by T-shaped cartilage

function: spread tear film, protect globe, remove particulate matter from surface

components of aqueous tear film and its respective production

1. Lipid layer; outermost; Meibomian gland

2. Aqueous layer; middle, thickest; lacrimal gland

3. Mucin layer; innermost; goblet cells

Path of lacrimal outflow

ocular puncta -> canaliculi -> lacrimal sac -> nasolacrimal duct -> nasal puncta

3 tunics of globe

Fibrous, Vascular, and Nervous

Fibrous tunic components and function

sclera and cornea (shape)

Vascular tunic components and function

ciliary body, choroid, and iris (homeostasis/control)

nervous tunic components and function

retina and optic nerve (light to electricity)

function of cornea

transmit light, refract light, and protect

Layers of cornea

(OUT) epithelium, stroma, descemnt's membrane, and endothelium (IN)

corneal epithelium function

barrier, prevent pathogen, excess floud

stroma of cornea function

90% of corneal thickness, 78% water composition, regularly arranged collagen

Descement's Membrane of Cornea function

basement membrane to endothelium

Corneal endothelium function

actively pump fluid out of cornea; mechanical barrier to stroma

how fast can corneal epithelium turnover

7 days

cause of focal corneal edema

ulceration of corneal epithelium; broken barrier -> fluid influx from tear film -> corneal hypoxia

cause of diffuse corneal edema

damage to corneal endothelium; broken barrier -> fluid accumulation in stroma

how does corneal endothelium respond to injury

endothelium cells heal by cellular enlargement and migration (NOT mitosis)

sclera vs cornea collage and epithelium

sclera = irregular dense collage fibrils, vascularized, opaque

cornea = regular collage w/straight basement membrane

components and functions of Uvea

iris = most anterior; regulate amount o light enter posterior eye; blood aqueous barrier

ciliary body = accommodation (fine focus); posterior to iris

choroid = vascular support to retina; cools blood flow

muscle that constrict pupil

sphincter muscle (encircles pupil margin)

muscle that dilate pupil

dilator muscle (lines posterior iris)

Path of aqueous humor outflow

ciliary epithelium -> between iris and pupil -> pupil -> anterior chamber ->iridocorneal angle -> trabecular meshwork -> scleral venous plexus

where is aqueous humor produced

produced in non-pigmented epithelium of posterior chamber (drain out thru iridocorneal angle through trabecular meshwork)

components and function of iridocorneal angle

site of aqueous drainage

junction of iris base to inside of cornea (attached via pectinate ligament)

obstruction of aqueous humor results in

glaucoma; obstruction of aqueous humor through iridocorneal angle = increased intraocular pressure

function of lens

accommodation to focus light onto retina

lens fibers: where formed, how formed, where meet

where form: epithelial cells at equator

how form: elongate, and move internally by subsequent lens fibers

where meet: anterior and posterior sutures

what causes nuclear sclerosis

increased central density of lens

components and function of vitreous humor

99% water, optically transparent, collagen fiber matrix

primary VH = vascular support to lens

secondary VH = becomes main vitreous body

tertiary VH = lenticular zonules; suspend the lens

choroid funtion

vacular support to retina

made of pigmented, vascularized connective tissue

location and function of tapetum

where: part of choroid in dorsal retina

what: increase vision in dim light (reflective)

retinal photoreceptor function

send electrical signal to retinal ganglion cells (convert light to electrical signal); rods and cones

retinal ganglion cell function

Transmit visual information from the retina to the brain via axons

composition and function of optic nerve

collection of axons and retinal ganglion cells

transmit image to brain

mesial

toward midline

distal

away from midline

buccal

cheek

labial

lip

palatal

inner surface of top jaw (maxilla)

lingual

inner surface of bottom jaw (mandible)

upper right quadrant of mouth

100s adult; 500s deciduous

upper left quadrant of mouth

200s adult; 600s deciduous

lower left quadrant of mouth

300s adult; 700s deciduous

lower right quadrant of mouth

400s adult; 800s deciduous

Canine dental formula

2 (I 3/3 + C 1/1 + P 4/4 + M 2/3) = 42

Feline dental formula

2 (I 3/3 + C 1/1 + P 3/2 + M 1/1) = 30

class 1 malocclusion

malposition of 1+ individual teeth

class 2 malocclusion

overbite

class 3 malocclusion

underbite

Class 4 malocclusion

Maxillomandibular asymmetry

periodontal disease progression

plaque -> tartar -> gingivitis -> periodontitis

pulp relation with age

increase age = decrease pulp thickness

stage 1 periodontal disease

gingivitis only, no attachment loss, reversible

stage 2 periodontal disease

<25% attachment loss, pockets form between tooth and gum

stage 3 periodontal disease

25-50% attachment loss, often extractions

Stage 4 periodontal disease

>50% attachment loss, required extractions

what tooth is #4

#4 always is canine

what tooth is #9

#9 is always 1st molar

what teeth are cats "missing"

2 maxillary and 4 mandibular

parts of the upper motor neuron (control)

pyramidal (high skill, fine motor) + extrapyramidal (muscle tone, stereotype movement)

parts of the lower motor neuron (activate)

GSE, GVE, SVE

Pyramidal pathway

1. motor cortex pf cerebrum (orgin)

2. corona radiata

3. internal capsule

4. crus cerebri

5. transverse & longitudinal fibers of pons

6. pyramids

7. corticonuclear tract

8. corticospinal tract (lateral & ventral)

9. corticopontocerebellar tract

extrapyramidal tract pathway

1. rubrospinal tract (MOST IMPORTANT; mesenceph)

2. metencephalic/pontine reticulospinal tract (mete)

3. medullary reticulospinal tract (myel)

4. olivocerebellar tract (myel)

extrapyramidal nuclei

1. corpus striatum (tel)

2. many (die)

3. red nucleus (mes)

4. metencephalic reticular formation - pontine (met)

5. medullary reticular formation (myel)

GSE (lower motor neuron) target

skeletal muscle

spinal nerves of ventral horn

cranial nerves: 3+4+6 (extraocular), 12 (tongue)

SVE (lower motor neuron) target

branchial arch

cranial nerves: 5 (mastication), 7 (facial express), 9+10 (larynx, pharynx, esophagus), 11 (neck/trapezius)

GVE (lower motor neuron) target

cardiac muscle, smooth muscle, and glands

cranial nerves: 3, 7, 9, 10 (parasympathetic NS)

Ew Looks Really Can Vary -> Counts Per Million Over the Top

cerebrum - groves

1. longitudinal (left and right halves)

2. transverse (separate cerebellum from cerebrum)

3. cruciate (area of motor cortex)

4. lateral rhinal sulcus (olfactory section)

cerebrum - white matter divisions

1. projection fibers

2. association fibers (short = btw gyri; long = across lobes)

3. commissural (left and right halves)

cerebrum - grey matter divisions

1. cortical

2. subcortical

Ew Looks Really Can Vary --synapse--> Counts Per Million Over the Top

Ew = CN3; Ednger Westphal -> Counts = ciliary

Looks = CN7; Lacrimal -> Per = Pterygopalatine

Really = CN7; Rostral Salivatory -> Million = mandibular

Can = CN9; Caudal Salivatory -> Over = Otic

Vary = CN10; Vagal -> Top = Terminal

hyper =

upper motor

slow atrophy

static paralysis

hypo =

lower motor

quick atrophy

flaccid paralysis

Rotary/Dynamic equilibrium =

ampulla of semicircular duct -> crista ampullaris

Linear/Static equilibrium =

utricle/sacule -> macula

formation and function of CSF

form: active secretion by choroid plexus epithelial cells

funct: protect brain, absorb shock, transport nutrients/hormones/metabolites

indicators for CSF analysis

abnormal neurologic exam, neck/limb pain, fever of unknown orgin, infectious disease

contraindications for CSF analysis

rabies, anesthesia risk, post trauma, high cranial pressure, non-responsive pupils

collection and handling of CSF samples

Collection location: c1-c2, lumbar-sacral cistern, atlantooccipital cistern

collection method: 0.5-8mL in lavender top tube, process within 30min or store in 4C up to 24hours, normal CSF will NOT clot

CSF characteristics (norm and disease)

normal = colorless and clear

hemorrhage = blood contamination = pink/bright red

xanthochromia = prior to hemorrhage = dull red, brown, yellow

Jugular Groove Borders

Dorsal Border = cleidomastoideus

Ventral = sternocephalicus

Deep = omohyoideus

Median Pectoral Groove Borders

dorsal border = left and right descending pectoral

Lateral Pectoral Groove Borders

dorsal border = descending pectoral

ventral border = cleidobrachialis

components of carotid sheath

1. common carotid

2. vagosympathetic trunk

3. recurrent laryngeal nerve

4. internal jugular vein (+/-)