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VetMed Year 1 > NEU 4 > Flashcards

NEU 4 Flashcards

1
Q

Outline what is meant by a spinal segment and how this can be used to localise a lesion.

A
  • Spinal cord segments do not line up with the segments of the vertebrae
  • The nerve apears caudal to segment, as has to get through the intervertebral foramen
  • e.g. L7 is attached to the L7 segment of SC
  • This can be used to localise a lesion as there will usually be pain over lesion
  • Can work out which muscles have atrophied and what their roots are, this can then show the approximate location of the lesion
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2
Q

Which spinal nerves supply the forelimb?

A

C6 - T2

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3
Q

Which spinal nerves supply the hindlimb?

A

L4 - S3

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4
Q

What clinical signs will be seen if there is damage in the T3 - L3 region in the grey matter?

A
  • UMN symptoms only in the hindlimb
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5
Q

Describe the structure and function of the cranial cavity.

A
  • Lined by periosteum and dura mater (fused in cranial cavity)
  • Cranial vault separated into 3 compartments by dura fold: falx cerebri, tenorium cerebelli, diaphragmasellae
  • 9 main foramina - all bar one are for nerves (carotid canal is for carotid artery)
  • Tentorium cerebelli separates cranial and caudal fossa
  • Hypophyseal fossa for pituitary gland
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6
Q

Describe the strcutre of the wall of the skull

A
  • Outer and inner cortical layer of bone
  • Middle layer has reduced spongiosa
  • Called diploe (weight saving)
  • Surface covered by periosteum
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7
Q

List the foramina of the skull in order, rostral to caudal

A
  • Cribriform plate
  • Optic canal
  • Orbital fissure
  • Foramen rotundum
  • Oval foramen
  • Carotid canal
  • Internal acoustic meatus
  • Jugular foramen
  • Hypoglossal canal
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8
Q

Explain the difference between vomiting and regurgitation.

A
  • Regurgitation: food has never reached stomach

- Vomiting: forceful expulsion of the stomach contents through the oesophagus and through the mouth

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9
Q

Explain the clinical signs associated with feline dysautonomia with reference to the ANS

A
  • Key-Gaskell syndrome
  • Raised temperature, low heart rate, dry crusty nose, no PLR, dry mucous membranes, normal CRT, hard faeces in colon, full distended bladder
  • Marked reduction in number of neurones in autonomic ganglia, brainstem and cranial nerves
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10
Q

Describe ways of treating cats with feline dysautonomia

A
  • IV fluids
  • Antibiotics
  • Paraffin enemas to releive consipaation
  • Empty bladder (cystocentesis)
  • Metoclopramide (improve gastric motility)
  • Pilocarpine for eyes
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11
Q

Describe ways in which the autonomic nervous system can be manipulated pharmacologically and the physiological consequences of these manipulations

A
  • Administration of epinephrine - agonsit to alpha and beta receptors so increases heart rate, contractility and vasoconstriction
  • Parasympathetic agonsits to inrease gut motility, watery secretions, decrease heart rate, stimulate vasodilation
  • Anticholinesterases: increase ACh levels in a synapse which then compete with a blocker (e.g. neostigmine)
  • Parasympathetic antagonist (atropine) acts to increase heart rate by reversing heart blodk caused by increased tone in the vagus nerve
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12
Q

At what points may the ANS be manipulated by the use of drugs?

A
  • Synaptically: prevent break down and reuptake of NT or increase the break down and reuptake of an NT before can reach the other side
  • Postsynaptic membrane: prevent binding with receptors by using a blocker, or increase binding by increasing NT available, or blocking enzymes that break down NT to maintain action potential propagation for longer
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13
Q

Give examples of TSEs

A
  • Scrapie: sheep
  • BSE: bovine spongiform encephalitis
  • Kreutzfeld-Jakob syndrome: humans
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14
Q

Discuss the role of prions in the development of TSEs.

A
  • Prions are derived from normal, native glycoproteins = PrPc
  • PrPSc = the abnormal scrapie prion protein
  • The PrPc is required for the development of TSEs
  • There are species barriers because of this - different species do not always share the same glycoproteins
  • Different strains can develop
  • The species barrier can be overcome
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15
Q

Describe the clinical signs caused by TSEs

A
  • Abnormal behaviour
  • Aggression
  • Hypersensitivity to touch, sound, visual stimulation
  • Abnormal locomotion (ataxia)
  • BSE specific: high stepping, excessive nose licking, reduced milk yield, weight loss, downer cow
  • Scratching in scrapie
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16
Q

Describe the pathology of TSE and the current diagnostic procedures

A
  • Primary site for pathogenic prions is in the obex
  • Vacuolarisation in infected brain tissue (white gaps where there shouldn’t be any)
  • Definitive diagnosis can only be made by demonstrating the presence of prion protein
  • Can be done by transfer of brain extract to permissive experimental animal (ethical issue, long incubation period before diagnosis, costly)
  • Specific identification of the PrPSc (disease specific protein)
  • Rapid screening test: protease treatment prior to tests and then PrPSc purified and detected by ELISA
  • Western blotting: detect PrPSc protein by molecular weight and rection to antibodies
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17
Q

Explain the economic impact of TSEs in the UK

A
  • Stock restrictions if TSE detected. Suscpetible stock must be culled (all goats, sheep with susceptible genotype)
  • Slaughtered stock may or may not be able to enter the food chain depending on genotype
  • Tests can be costly
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18
Q

Explain how TSEs can be transmitted

A
  • Ingestion of PrPSc contaminated feeds (previously meat and bone meal prepared from slaugher offal - now banned)
  • Horizontal transmission during perinatal period (milk has high level of infectivity, placental material from scrapie infected ewes may play important role, not seen musch in cattle)
  • Superficial abrasions
  • Environmental factors (last a long time in the environment, but not a prathway for infection in cattle)
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19
Q

Explain how PrPScs may get to the brain

A
  • 3 proposed pathways (but pooly understood)
  • Parasympathetic fibres of the vagus: bypasses spinal cord, innervates viscera of head, neck, thorac, abdomen, originates in medulla oblongata
  • Splanchnic nerve sympathetic trunk: enteric plexus -> prevertebral ganglia -> splanchnic nerves -> sympathetic trunk -> spinal cord -> brain
  • Sympathetic and vagosympathetic trunk: sympathetic trunk -> cervicothoracic ganglion -> ansa subclavia -> vagosympathetic trunk -> brain
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20
Q

Discuss the transmission risk of TSE in the context of public health

A
  • Can be spread by puncture contact or ingestion
  • Long survival time in soil
  • Ban on feeding mammalian meat and bone meal
  • Prevent risk of material entering food chain (suspect animals and their products
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21
Q

Describe the pattern of the development of the cerebellum

A
  • Upward growth of alar lamina of hindbrain
  • All neurones association in type - no efferent motor neurones
  • Initllay has the mantle zone (cellular) which is deep and grey matter and the marginal zone fibrous) which is superficial and white matter
  • Later some mantle zone migrates to surface becoming cerebellar cortex - becomes white matter
  • Remainder stays deep forming cerebellar nuclei
  • Paired upgrowth from the future pons part of the hindbrain
  • fuses into single cerebellum
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22
Q

Describe the general anatomy of the cerebellum

A
  • Cerebellar cortex: fissures on surface divide into lobules and further subdivison into folia
  • White matter: fibres running to/from cortex (arbor vitae)
  • Cerebellar nuclei: 3 on each side, from lateral to medial: dentate, interpositus and fastigial
  • All of it is grey matter except the arbor vitae
  • Rostal, caudal and flocculonodular lobes
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23
Q

Describe the relations of the cerebellum to other parts of the brain

A
  • Sits dorsal to pons, medulla oblongata and 4th ventricle
  • Attached to the brainstem by peduncles
  • 3 pairs: rostral (to midbrain), middle (to pons) and caudal (to medulla oblongata)
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24
Q

Describe the afferent fibres found in the cerebellar cortex

A
  • Mossy and Climbing
  • Mossy synapse to granular cells and on way to crotex synapse with deep cerebellar nuclei
  • Climbing connect to Purkinje cells in molecular layer and also connect to deep cerebellar nuclei (output)
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25
Q

Describe the location function of the Purkinje cells in terms of the cerebellum

A
  • Are the only efferent cells of the cerebellum
  • Project to the deep cerebellar nuclei and from there to other parts of the CNS as final target outside teh cerebellum
  • Are inhibitory
  • EXCEPTION: connection from cerebellum to vestibular system is a direct connection, does not require nuclei
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26
Q

Describe the topography and main subdivisions of the diencephalon

A
  • Midline part of forebrain
  • Rostral to midbrain
  • Medial to cerebal hemispheres
  • Subdivisons: epithalamus, thalamus and hypothalamus
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27
Q

Describe the structure and function of the epithalamus

A
  • Most dorsal portion of diencephalon
  • Contains some small nuclei and their connections
  • Contains the pineal gland - endocrine function
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28
Q

Describe the structure and function of the thalamus

A
  • Largest part of diencephalon
  • Wakefulness
  • Right and left thalami project medially to come together and form the interthalamic adhesion
  • General and special sensory information relays through appropriate groups of thalamic nuclei
  • Special through geniculate nuclei
  • Feedback from cortex to the rest of the brain
  • Have specific and non-specific nuclei
  • Specific: well defined sensory and motor functions, highly organised point-to-point connection with sensory and motor regions of cerebral cortex
  • Non-specific: receive less functionally distinct afferent input, connect with wider area of cortex, including associative and limbic regions
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29
Q

List the specific nuclei of the thalamus and where they go

A
  • Lateral geniculate nucleus: from eye to primary visual cortex
  • Medial geniculate nucleus: from inner ear to primary auditory cortex
  • Ventrolateral: from cerebellum to primary motor cortex
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30
Q

List the non-specific nuclei of the thalamus and where they go

A
  • Intralaminar: diffuse projections to much of the cortex

- Midline

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31
Q

Describe the structure and function of the hypothalamus

A
  • Lies below thalamus and forms ventral part of diencephalon
  • Exposed on ventral surface of brain
  • Largely used for survival
  • Optic chiasm gives attachment to optic nerve
  • Tuber cinereum gives attachment to infundibulum of the pituitary gland
  • Mamillary bodies receive inputs from hippocampus via fornix, relay via mammillothalamic tract to thalamus, function uncertain but usually grouped within limbic system
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32
Q

Describe the location and general function of the pineal gland

A
  • In epithalamus
  • Just above the interthalamic adhesion and behind the third ventricle
  • Endocrine gland
  • Produces melatonin and plays a role in circadian and seasonal rhythms
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33
Q

Describe the location and main parts of the pituitary gland and their main functions

A
  • Just under the hypothalamus in the pituitary fossa
  • Has an anterior, posterior and intermediate section
  • The posterior lobe: ADH, oxytocin, uterine smooth muscle, mammary gland smooth muscle
  • Intermediate lobe: melanocyte stimulating hormone
  • Anterior: FSH, LH, ACTH, TSH, GH, prolactin
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34
Q

Give the hypothalamic nuclei.

A

Paraventricular, supraoptic, suprachiasmatic, lateral, ventromedial, arcuate, mammillary

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35
Q

What is the function of the paraventricular and supraoptic nuclei?

A

Control oxytocin and ADH production and secretion

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36
Q

What is the function of the suprachiasmatic nucleus?

A
  • Biological clock

- Circadian rhythm

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37
Q

What is the function of the lateral nucleus?

A
  • Arousal/feeding (excitatory, stimulates feeding)
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38
Q

What is the function of the ventromedial nucleus?

A
  • Feeding (inhibitory, reduces feeding)
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39
Q

What is the function of the arcuate nucleus?

A

Controls energy homeostasis (insulin)

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40
Q

What is the function of the mammillary nucleus?

A

Wakefulness via histamine

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41
Q

Explain the law of specific nerve energies

A
  • Brain assumes a set of connections with outside world
  • Stimulation arriving at the brain si referenced to an internal group
  • Accidental stimulation of anerve is interpreted as being due to an external event
  • e.g. pressing eyeball to distort retina produces visual flash as brain assumes information in the optic nerve is due to light hitting the retina
42
Q

Describe the skin mechanoreceptors and their different functions

A
  • Use A-beta nerve fibres
  • Ruffini’s end organs detect tension deep in skin
  • Meissner’s corpuscles detect changes in texture
  • Pacinian corpuscles detect rapid vibrations
  • Merkel’s discs detect sustained touch and pressure
  • End bulbs of Krause detect slow movement
  • Hair follicle receptors detect movement but not sustained pressure
  • Each receptor connect to one axon
  • Axons are fixed type (A-beta)
  • Intensity transmitted by frequency of action potentials
43
Q

Describe how proprioception is detected

A
  • Use A-alpha nerve fibres
  • Joint position - stretch receptors within joint capsule and ligaments
  • Tendon tension - golgi tendon organs, stretch receptors
  • Muscle tension - muscle spindles, sense rate of change and length, use A-alpha and A-beta
  • Feed forward - awareness of where a joint will or should be in advnce of actually attaining the position
44
Q

Describe pain receptor density

A
  • Specialised nociceptors - not just over stimulation of touch
  • Superficial somatic: skin, high density of pain receptors, well localised, rapid sensation
  • Deep somatic: tendon, ligament, bone, fascia, low density, dull, poorly localised
  • Visceral: guts, can be sharp, tends to be dull, cramping, referral of pain to an area of skin is common
45
Q

Describe pain transmission

A
  • Fast and slow pain nerve fibres
  • A-detla = sharp initial pain
  • C fibres = slow, delayed burning sensation (after-pain)
46
Q

Describe the general pathway of neurones for general somatic afferent information

A
  • Sensory neuron from receptor to CNS. Cell body in dorsal root ganglion
  • Neuron inside CNS (SC or MO) transmits information to thalamus
  • Neuron in thalamus trnamsits information to somatosensory cortex in telencephalon
47
Q

Describe the functions of the 3 funiculi in the spinal cord

A
  • Project afferent fibres centrally
  • Dorsal: primary afferent axons
  • Lateral and ventral: secondary axons from neurons in spinal grey matter
48
Q

Describe the 3 funiculus options available to afferent fibres

A
  • Primary afferent to dorsal funiculus and out
  • Primary afferent synapsing with secondary afferent to lateral funiculus
  • Primary afferent synapsing with secondary afferent to ventral funiculus
49
Q

Describe the function of teh trigeminothalamic tract

A
  • 3 nerves enter brain directly as a single root
  • Sensory for head region
  • GSA and GPA
  • Ophthalmic, maxillary and mandibular divisions
50
Q

Which tracts are present in the dorsal funiculus?

A
  • Cuneat

- Gracile

51
Q

Describe the function and position of the cuneate tract inrelative detail

A
  • Sits most laterally in the dorsal funiculus
  • Transmits touch and kinaesthetic information from forelimb
  • Contains axons which make up spinocuneocerebellar tract
52
Q

Describe the function and position of the gracile tract in relative detail

A
  • Most medial tract in the forsal funiculus

- Touch and some kinaesthetic information from hindlimb

53
Q

List the tracts present in teh lateral funiculus and give their function

A
  • Spinothalamic: touch, nociception, temperature
  • Spinocervicothalamic: dominant nociceptive tract in carnivores
  • Dorsal spinocerebellar: muscle spindles, tendon organs, joint receptors, skin
  • Spinomedullary: muscle spindles, tendon organs, joints caudal o thoracic limb, axons go to nucleus Z
  • Ventral spinocerebellar: conveys information about motor neuron state directly to cerebellum
54
Q

List the tracts inteh ventral funiculus and give their functions

A
  • Spinoreticular: nociception, mechanoreception, involved in motivation and awareness
  • Spinovestibular: proprioception from cervical region
  • Spinomesencephalic: nociception, mechanoreception projection to midbrain
  • Spinoolivary axons: sensory feedback from olivary nucleus to cerebellum, fibres travel in several other tracts
55
Q

Describe the role and location of the somatosensory cortex.

A
  • Site of perception of the general senses
  • Parietal lobe, caudoventral to coronal sulcus
  • Information relayed contralaterally
  • Arrangement within general sensory cortex is highly organised
56
Q

Outline how conscious sensation occurs and is transmitted.

A
  • Projections from thalamus to telencephalon for awareness of various sensations
  • Also fibres from cerebellum to thalamus to coordinate motor responses to sensory input
  • Cerebellum takes over to control repetitive motor tasks
57
Q

Describe the structure of motivated behaviour

A
  • 3 phases
  • Orientation, oriented, consumption
  • Is a feedback loop (positive or negative depending on stimulus)
  • e.g. if an animal is looking for food and continues to find low quality food, the motivation to look for better food will increase
58
Q

Describe the state-space concept of motivation

A
  • Combined physiological and perceptual state as represented in the brain
  • Called motivational state of animal
  • Relationship between motivational state and behaviour is not direct as in traditional view
  • Combine assumptions of homeostatic models with an explicitly functional approach to mechanisms
59
Q

Describe the 4 phases of appetitive behaviour

A
  • Phase I: no evidence of stimulus e.g. prey, food (non directed)
  • Phase II: stimulus detected (e.g. smell, sight of prey, food) eventually chasing and capturing prey/finding food (directed)
  • Phase III: sonsummatory (killing pre, eating)
  • Phase IV: satiation
60
Q

Describe ingestive behaviour in terms of glucostatic and lipostatic theories.

A
  • Homesostatic, negative feedback system regulating feeding
  • 2 set points being regulated: blood glucose (short term regulation) and body fat (long term regulation)
  • Settling point is a stable state caused by a balance of opposing forces
  • ## feeding centre and satiety centre
61
Q

What are the feeding and satiety centres of the brain, and what happens if there is a lesion in these areas?

A
  • Feeding centre is lateral hypothalamus, lesion leads to starvation
  • Satiety centre if in ventromedial hypothalamus, lesion leads to obesity
62
Q

Where can rete mirabile be found in the blood supply to the brain, what is their function and what are species differences?

A
  • Is an anastomosing ramus
  • In sheep and cats - pair of maxillary rete mirabile
  • In cattle - maxillary and ventral pairs
  • None in dogs and humans
  • Cool blood and reduce fluctuations due to pulsatile flow
63
Q

Where are the ventricles of the brain located

A
  • Lateral: cerebral hemispheres
  • 3rd: around interthalamic adhesion
  • 4th: in metencephalon under medulla
64
Q

Between which structures is the interventricular foramen?

A

3rd and lateral ventricles

65
Q

What are the functions of CSF?

A
  • Nutrition
  • Support
  • Protection
  • Removing waste
  • Preventing ischaemia
66
Q

What are the modes of cell communication?

A
  • Contact dependent (touching)
  • Synaptic (close)
  • Autocrine, paracrine, endocrine (widespread/far away)
67
Q

Briefly outline contact dependent cell signalling.

A
  • Communicate via cytoplasmic bridges
  • Allow signalling molecules to pass between cells
  • If something is wrong with one cell, will be passed onto another
  • Known as gap junctions
  • Ions, metabolites and more complex molecules (cAMP)
  • Slow transmission across an organ (can only communicate with adjacent cells)
68
Q

Briefly outline synaptic transmission, including the advantages and disadvantages

A
  • Communication between neurons involving a chemical messenger across a short synaptic cleft
  • No dilution in general circulation, system can be reactivated very quickly
  • Specific, hardwiring is expensive, possibly vulnerable
69
Q

What is meant by autocrine, paracrine and endocrine cell signalling?

A

Autocrine: self signalling
Paracrine: signalling to cell nearby
Endocrine: signalling to a distant cell

70
Q

Describe the difference between endocrine and exocrine secretion

A
  • Endocrine is into the body interior (directly into blood or tissues)
  • Exocrine is into exterior or gut (via a duct)
71
Q

Describe the regulation of the pineal gland

A
  • Regulated by circadian and seasonal cycle
  • Activity inhibited by light
  • Activity stimulated by darkness - melatonin release, inhibited gonads and other endorcrine functions
72
Q

Describe the location of the pituitary gland in relation to the hypothalamus

A
  • From median eminence
  • Ventral aspect of hypothalamus from which portal vessels arise
  • Is outside BBB
73
Q

Describe the general structure of the pituitary gland

A
  • Anterior, intermediate and posterior lobe
  • Intermediate lobe is made from oral ectoderm derivatives
  • Anterior pituitary has few nerves, mainly portal system
  • Network of vessels in plexuses increases surgace area increasing transport of hormones
74
Q

Where are ADH and oxytocin produced?

A

Produced in hypothalamus (hypothalamus also produces other peptide hormones)

75
Q

Describe the production and secretion of hormons produced in the hypothalamus (e.g. ADH)

A
  • Peptides synthesised in nerve cell bodies
  • Prohormones
  • In supraoptic and paraventricular nuclei
  • Via axons into posterior lobe (using neurophysins as carrier proteins)
  • Stored in nerve endings in the posterior lobe (Herring bodies)
  • Action P induce hormone release
  • Exocytosed into the blood
76
Q

Describe the development, structure and function of the posterior pituitary lobe

A
  • Neuroectoderm derivative, downward growth of diencephalon (infundibulum)
  • Is part of nervous system and has a neural connection to the hypothalamus
  • No hormone producing cells - stores and secretes the hormones produced by the hypothalamus
  • Mainly ADH and oxytocin secretion
77
Q

What is the function of ADH?

A
  • Used in the control of fluid balance
  • Increases water retention
  • It is released in increased osmolarity of ECF and a fall in ECF volume
  • Increases water absoption from the distal tubule and the collecting duct in the kidneys
  • Reduces volume and increases concentration of urine
  • Interference leads to pooly constituted urine
  • If high blood loss, ADH released, retains water, dilutes blood but volume increases
78
Q

Describe the function of oxytocin

A
  • Important in contraction of uterine smooth muscle (parturition)
  • Stimulates mammary gland smooth muscle (milk let down)
79
Q

Describe the development, structure and function of the anterior pituitary gland

A
  • Develops from anterior wall of Rathke’s pouch
  • Has vascular connection to hypothalamus
  • Hormones produced in anterior pituitary
  • Under hypothalamic control, secreted into portal circulation
  • Releasing and inhibitory factors
  • Produces: FSH, LH, ACTH, TSH, GH, prolactin
80
Q

Describe the gross anatomical strucures of the eye of dogs, cats, horses, sheep, snakes and birds

A
  • Dogs: round pupil, upper eyelashes only
  • Cats: no lashes, modified guard hairs, vertical slit pupil
  • Horse: upper eyelashes, prominent vibrissae, horizontal oval pupil
  • Sheep: upper lashes, horizontal oval pupil
  • Snake: fused eyelids (spectacle), vertical slit pupil/variable
  • Birds: filoplumes (modified feathers as eyelashes), round pupil
81
Q

Describe the 3 ocular layers of the eye

A
  • Outer: fibrous, provides protection and imparts rigidity to eye, white of eye (sclera) and cornea, cornea is a continuation of the sclera
  • Middle layer: vascular, nutrition, uveal tract, choroid, ciliary body, iris
  • Inner layer: neural, allows vision, retina and optic nerve
82
Q

What is the limbus?

A

The junction between cornea and sclera/conjunctiva

83
Q

Briefly outline the embyrology of the eye

A
  • Develops from the forebrain
  • Develops from 3 tissue types: neuroectoderm, surface ectoderm (becomes internalised in the eye as the lens) and mesoderm
84
Q

Describe the orbit of the eye

A
  • The cavity within the skull that encloses the eye
  • Protection and separating the eye from the cranial cavity
  • Foramina within walls of orbit are pathways for blood vessels and nerves to reach the eye
85
Q

What are the 2 types of orbit present in domestic species

A
  • Open/incomplete

- Closes/complete

86
Q

Describe open/incomplete orbits and what species they are found in

A
  • Lateral wall is soft tissue not bone
  • Facilitates wide opening of the jaw (to catch prey)
  • Carnivores (dog, cat) and pigs
87
Q

Describe complete/closed orbits and what species they are found in

A
  • Lateral wall is bony
  • Protection for fighting
  • Herbivores (horse, cow, sheep, goat)
88
Q

Describe the difference in visual fields of predators vs prey

A
  • Predators have frontal orbits - smaller field of vision but more accurate at gauging depth
  • Prey have lateral orbits - larger field of vision so can see predators approaching. Almost 360 degree vision
89
Q

Describe the walls of the orbit

A
  • Medial wall: very thin, underlying ethmoturbinates
  • Floor: part bone, part soft tissue, masticatory muscles
  • Rostral margin/orbital rim: made up of frontal, lacrimal and zygomatic bones
  • Lateral wall in closed: fusion of zygomatic and frontal bones
  • Lateral wall in open: lateralorbital ligament - palpate as taut band in live animal
90
Q

Describe the relationship between the ramus of the mandible and the eye

A
  • When jaw is open, back of jaw can press on the eye

- If have a problem (e.g. tumour) in this area then will be very painful

91
Q

Describe the foramina of the orbit

A
  • Pathways for nerves and blood vessels to reach orbit from cranial cavity
  • 8 different foramina
  • Interspecies variation
92
Q

Name the important orbital foramina

A
  • Optic foramen (CN II and internal ophthalmic artery)
  • Orbital fissure (CN III, IV, VI, V ophthalmic branch)
  • Round foramen (V maxillary)
  • Supraorbital (supraorbital vessels and nerve)
  • Ethmodal foramina (ehtmoidal vessels and nerve)
  • Rostral alar foramen (V maxillary and maxillary artery)
93
Q

Describe the arterial supply to the eye

A
  • Main supply for eye is external ophthalmic artery
  • External ophth artery arises from internal maxillary artery and external carotid artery
  • Optic nerve and retina are supplied from internal ophthalmic artery
  • Arises from internal carotid
94
Q

Describe the venous drainage of the eye

A
  • 2 routes from orbit into orbital plexus: dorsomedial region of eye and ventrolateral region of eye
  • 2 routes from orbital plexus: intracranial route and extracranial route
95
Q

Describe the intracranial route of venous drainage from the eye

A
  • Orbital vein via orbital fissure

- Into cavernous sinus on base of skull

96
Q

Describe the extracranial route of venous drainage from the eye

A
  • Internal maxillary vein and external jugular vein via facial vein
97
Q

List the ocular muscles

A
  • Dorsal rectus
  • Ventral rectus
  • Medial rectus
  • Lateral rectus
  • Dorsal oblique
  • Ventral oblique
  • Retractor bulbi
98
Q

Which extraocular muscles are innervated by cranial nerve III

A
  • Dorsal, medial and ventral rectus and ventral oblique
99
Q

Which extraocular muscle is innervated by cranial nerve IV

A

Dorsal oblique

100
Q

Which extraocular muscles are innervated by cranial nerve VI

A
  • Lateral rectus

- Retractor bulbi

VetMed Year 1 (13 decks)

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