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401 Cards in this Set
- Front
- Back
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Circle of Willis
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blood supply to brain consists of 2 internal carotid and vertebral aa. contributing to basilar a.
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Rete Mirabile
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when the carotid isn't the major blood supply to the brain (cat, cow)
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dura mater
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most external, thickest, well innervated, falx cerebri
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arachnoid
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middle layer, arachnoid trabeculae, arachnoid granulations
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Arachnoid Granulations
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CSF Drainage
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Pia Mater
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innermost, closely adhered to nervous tissue
highly vascular assoc. with denticulate ligament of spinal cord |
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Epidural Space
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mainly potential space in the brain
fall and vessel filled in spinal cord-used for injections |
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subdural space
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potential space in both brain and spinal cord
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subarachnoid space
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interdigitated w/ arachnoid trabeculae
contains CSF sites in brain for tapping and sites on spinal cord |
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cisterns
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specialized enlarged areas around the brain
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Cerebellomedullary cistern
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preferred site for CSF collection in small anima/large under anesthesia
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falx cerebri
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midline of the cerebrum
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filum terminale
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terminus of the spinal cord
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caudal ligament
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attachment of filum terminale to last vertebral foramen
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lumbospinal cistern
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for CSF tap in caudal meninges, in the subarachnoid space around the filum terminale
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what space is used for CSF collection?
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subarachnoid space
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what space is used for injections?
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epidural space (caudal only)
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CSF
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ultrafiltrate of blood
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who produces CSF?
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ependymal cells of choroid plexuses w/in ventricles
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valve less sinus
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dural sinuses
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functions of csf
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water jacket
lymphatics transport hypothalmic hormones in brain CO2 concentration monitoring |
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drains csf?
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arachnoid granulations, ONE WAY valve moves CSF into dural sinuses
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Flow of CSF in ventricles
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Lateral-3rd-4th-arachnoid space (meninges) or central canal
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which neuron regenerate?
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olfactory
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damage to axons of CNS
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minimal regeneration at best
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3 types of injury to an axon
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stretch related
lacerations compression (mechanical or vascular) |
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extent of regeneration depends on...
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number and severity of axons damaged
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which injury has the best chance of regeneration?
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PNS
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cerebrum
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seat of conciousness and cognitive functions
gets all sensory information that reaches concious perception-NOT reflexes! |
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cerebrum divided into __ hemispheres
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2, right and left
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each hemisphere has ____ lobes
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5
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5 lobes of the cerebral cortex
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parietal, occipital, temporal, pyriform, frontal
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parietal lobe
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perception of sensory information to create a 3d map of the world/body in space
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damage to parietal lobe causes?
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hemineglect
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frontal lobe
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contains the sensory and motor cortices, initiations of movement
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damage to frontal lobe causes?
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delay of initiating movement or inappropriate initiation
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frontal lobe lesion?
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is contralateral to side of manifestation
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pyriform lobe
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perception of olfaction, associated with limbic system
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anosmia
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complete loss of smell, complete damage to pyriform lobe
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temporal lobe
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processing of hearing, input from each ear goes down right and left temporal lobe, most is contralateral
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damage to one side of temporal lobe?
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does not result in hearing damage to just one ear
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occipital lobe
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perception of visual stimuli
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damage to occipital lobe
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cortical blindness, reflex arcs are still intact
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somatic sensations
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the senses of touch, pressure, pain, temperature
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limbic system
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collection of cortical and subcortical structures functionally linked by their role in emotion and survival drives
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nuclei involved in limbic system
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hippocampus, cingulate gyrus, hypothalamus, amygdala, parts of the thalamus
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hypothalamus
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regulates autonomic functions and basic survival behaviors
hunger, satiety, thirst, temperature, osmoregulation, circadian rhythms |
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amygdala
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emotional memory formation, shrot term
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hippocampus
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converts short term memory to long term memory
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BAR
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bright alert responsive
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alert
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normal response to environmental stimuli
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obtunded
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withdrawn and unwilling to perform normally
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demented
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animal is responsive but responses are abnormal
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stuporous
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patient unresponsive except to noxious stimuli
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comatose
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patient unresponsive to both environmental and noxious stimuli
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ARAS
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maintains conciousness
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seizure
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cortical event characterized by abnormal neuronal discharge that is both excessive and hypersynchronized
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prodrome
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early indicator of disorder
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aura
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period of altered behavior
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ictus
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synchronized, hyperactive firing of neurons
loss of conciousness, hallucinations, salivation, tachycardia, involuntary movements |
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hallucinations
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alterations of sensation
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post-ictus
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period of confusion and restlessness after seizure
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inter ictus
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periods between seizures
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primary focus
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restricted area of the cortex when the seizure begins
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kindling
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spreading or reinforcement of the tendency to seize
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mirror focus
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seizure spreads to the contralateral side across the corpus callosum by commissural fibers
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focal/partial seizure
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confined to one part of cerebrum, there are no convulsions
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focal motor seizure
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chewing gum fit
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focal seizure with secondary generalization
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neurons outside the focus are recruited, produces behavioral or emotional seizures
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simple partial seizure
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seizure that does not effect conciousness
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generalized seizure
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spreads rapidly to both hemispheres, can have convulsions with loss of conciousness
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petit mal
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no convulsions
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other names for grand mal
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tonic clonic, major motor
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tonic phase
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collapse, extensor rigidity, opisthonons, apnea
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clonic phase
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period of alternation b/t flexion and extension of limbs with violent chewing or vocalization, paddling
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fundus
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area of the retina that we look at
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rods
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cylindrical photoreceptors that are sensitive to low levels of light (nocturnal animals, prey species)
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cones
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tapering photoreceptors that are sensitive to specific wavelengths of light, color (diurnal animals)
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image on retina is?
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inverted and reversed
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ventral visual field hits
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dorsal fundus
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binocular vision
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animals with frontal eyes, predators
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panoramic vision
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laterally placed eyes, prey
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choriod is superficial to
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retina
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what is superficial to choroid?
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schlera
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scotopic vision
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vision in dim light
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tapetal fundus
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rods and cones+unpigmented/pigmented epithelium+tapetal fundus
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nontapetal fundus
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rods and cones +pigmented epithelium + non tapetal fundus
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fovea
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area centralis
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fovea is _____to optic disc
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dorsolateral
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axons ____ cross the fovea
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do not
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fovea is >>>
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avascular
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fovea
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high density cones
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around the fovea
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rods and cones
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periphery of the fundus
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mostly rods
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only cortical visual pathway
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retinogeniculostriate pathway
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retinogeniculostriate pathway
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via LGN, concious perception of vision, menace response, majority of neurons involved
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retinogeniculostriate pathway terminates in
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occipital lobe of cortex
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retinopretectal pathway
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via pretectal nucleii, PLR reflex
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retinotectal pathway
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via rostral colliculi, occular fixation reflex
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retinohypothalmic pathway
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via SCN, circadian rhythms
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miosis
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pupil getting smaller
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mydriasis
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pupil getting larger
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vestibular system
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responsible for maintaining balance
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sensory components of vestibular system
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balance and acceleration
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linear acceleration
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utricle and saccule
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sensory receptors for utricle saccule are in
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maculae
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semiciruclar ducts sense
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pitch, roll, yaw "angular accelerations"
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what is a primary pathway?
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goes to the cortex for concious perception
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maculae
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hair cells covered by gel layer covered by otoconia (rocks)
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what happens to maculae during acceleration?
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heavy stuff lags and bends the hair cells generating action potential
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primary vestibular pathway
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thalamus
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vestibulo-occular reflex
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normally eyes follow head movement, both right and left functioning
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normal nystagmus
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slow movement of the eyes as they are catching up to the movement of the head
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unilateral damage to vestibular system
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resting nystagmus
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resting nystagmus
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head is not moving but eyes still move
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unilateral lesion of vestibular
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fast phase is towards side without lesion
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peripheral vestibular lesion
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up until the vestibular nuclei, associated with vestibular apparatus or Cr N VIII
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central vestibular lesion
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after vestibular nuclei you are in CNS, vertical nystagmus ONLY in central, positional nystagmus ONLY in central
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vestibulocollic reflex
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as body moves/accelerates keeps head straight up
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unilateral lesion of vestibulocollic
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head tilt toward lesion
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vestibulospinal reflex
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makes you extend spine and limbs if head is falling towards one side
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unilateral lesion of vestibulospinal
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circling/falling towards side with lesion
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inner hair cells sense
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pitch
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outer hair cells sense
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loudness
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frequency is
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pitch
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base of cochlea
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shorter inner hairs, stiffer, less discerning, hears higher pitches
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apex of cochlea
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longer inner hair cells, more flexible, super sensitive, hears lower pitches
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amplitude is
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loudness
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primary auditory pathway
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concious percepton of hearing, all the way to cortex
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startle response
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turn your head to see where loud sound comes from, stops at caudal colliculus
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conduction deafness
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problem is somewhere external to vestibular window, due to disease, damage, obstruction
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sensorineural deafness
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problem is somewhere internal to vestibular window, damage to cochlea, cochlear nerves VIII, or central pathway, auditory CTX, inherited deaf
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presbycusis
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deafness of old age, sensoirneural
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meninges
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three connective tissue membranes that surround the brain and spinal cord
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main blood supply to spinal cord
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ventral spinal artery (with some help from dorsal spinal artery)
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functions of meninges
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1.production, circulation, reabsorption CSF
2.divides cranium into smaller compartments 3. arterial into nervous tissues and venous blood return to sinues |
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dura mater also called
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pachymenix
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epidural hematoma
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blood collects b/t skull and dura mater
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subdural hematoma
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blood collects b/t dura mater and arachnoid space
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tentorium cerebelli
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transverse dural reflection b/t cerebrum and cerebellum
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dural reflection
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aids in the reduction of movement of the brain in the braincase during sudden/rapid acceleration or deceleration
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ventricles
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series of fluid filled cavities w/in cerebrum and brainstem
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lateral ventricles
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"c" shaped ventricles w/in each hemisphere
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3rd ventricle communicates w/ 4th via
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mesencephalic aquaduct
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4th ventricles where?
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pons and medulla
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Blood brain barrier
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barrier b/t blood and nervous tissues
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Blood CSF barrier
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b/t capillaries associated with choroid plexus and CSF in ventricles
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cingulate gyrus
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emotion
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thalamus
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emotional behavior
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ARAS stands for
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ascending reticular activating system
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SCN is
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suprachiasmatic clock
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cataplexy
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sudden marked loss of muscle tone
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focus
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abnormal area of the brain where seizure originates
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venous return
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mostly empties into dural sinuses
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dorsal sagittal sinus
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located at the dorsal aspect of the falx cerebri
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transverse sinuses
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bilateral, running laterally from dorsal sagittal sinus along attachment of tentorium cerebella
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ischemic injury
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of spinal cord due to occlusion of vessels
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fibrocartilagenous emboli (FCE)
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fibrocartilagenous material lodged in blood vessels supplying spinal cord, sudden and painful
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ischemic encephalopathy
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cerebral infarction at middle cerebral artery most common, cause unknown could be parasitic migration, possible vasculitis, thrombosis
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lateral ventricle communications w/ third via?
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interventricular foramen
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what diffuses freely across BBB?
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gases (anesthesia), small lipophilic molecules (pharm-antibiotics)
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how does glucose get across BBB?
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molecular transporter
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epidural space in spine?
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b/t dura mater and periosteum of vertebrae
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another name for cerebellomedullary cistern?
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cisterna magna
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facial nerve PS to?
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salivary and lacrimal glands
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occulomotor nerve PS to?
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iris sphincter muscle
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glossopharyngeal nerve PS to?
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parotid and mucosal glands
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vagus nerve PS to
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abdomen
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where do all the cranial nerves come from?
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brain stem
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cerebellar hypoplasia is what disease in cat?
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feline panleukopenia
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cerebellar hypoplasia is what disease in cows?
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bovine viral diarrhea
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what drug is ototoxic?
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aminoglycosides
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animal notices cotton ball but does not have PLR what cr n damaged?
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III
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animal bumps into chair and doesn't have PLR which Cr n?
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II and III
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light shined in O.S. elicits consensual but not direct response? where lesioned?
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L EW nucleus or L Cr N II
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light shined in O.S. elicits direct but not consensual response? where lesioned?
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R EW nucleus or R Cr N II
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begin vision pathway for all
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photoreceptor-optic nerve-optic chiasm-partial decussation-optic tract
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retinopretectal pathway following optic tract
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pretectal nucleii-partial decussation-EW nucleus-motor to ciliary ganglion, PLR
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retinogeniculostriate pathway following optic tract
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LGN of thalamus-Primary visual cortex, concious perception of vision
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retinotectal pathway following optic tract
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tectal region (rostral colliculus)-reflex eye orientation, startle response
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retinohypothalmic pathway following optic tract
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SCN-circadian rhythm
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vestibular pathway for all
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Cr N VIII-vestibular nuclei
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vestibuloccular pathway after nuclei
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via ascending MLR-Cr N III, IV, VI (contra, ipsa, bi)
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vestibular primary pathway after vestibular nuclei
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thalamus-via thalamocortical (bilateral)-cortex
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vestibular (cerebellar pathway) after vestibular nuclei
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cerebellum to either medial vestibulospinal (bilateral) or lateral vestibulospinal (ipsalateral)
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special nervous system
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nerves of special senses (sight, hearing)
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Function for concious perception of surroundings
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GSA
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function of unconcious perception of surroundings
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GSE
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function for ANS
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GVA and GVE
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Function for reflexes
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GSA and GSE
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Dog Vertebral formula
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7-13-7-3-20
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cranial cervical region
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C1-C5
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thoracolumbar region
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T3-L3
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lumbosacral region
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L4-S2
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Caudal region
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Cd 1- Cd5
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sacral region
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S1-3
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cervical intumescence
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C6-T2, Brachial plexus
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lumbar intumescence
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L4-S2, lumbosacral plexus
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GSA stands for
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General Somatic Afferent
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where does GSA go?
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from periphery to CNS
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exteroception
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info about the external environment
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interoception
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info about the internal environment
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proprioception
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info about position and movement of body
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mechanoreceptors
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physical deformation
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thermoreceptors
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heat and cold
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nociceptors
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noxious stimuli
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photoreceptors
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vision
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chemoreceptors
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chemical changes, taste, smell, O2 and CO2
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sensory modality
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type of sense experienced b/c of the input
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where does GSA info for concious awareness go?
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cortex
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where does GSA info for unconcious reflex activity go?
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spinal cord, cerebellum
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where does GSA info for maintaining level of conciousness/alertness go?
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ARAS
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divergence
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same set of sensory info goe to multiple destinations for multiple purposes
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parallel processing
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arrival of this sensory input at multiple places in brain is perceived/evaluated in different parts of the brain in different ways
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3 functions of the cerbellum
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1. regulation of equilibrium
2. maintains posture/muscle tone 3. coordinates voluntary movement |
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where are voluntary movements initiated?
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cortex
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will damage to cerebellum cause paresis/paralysis?
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no
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three main functions of cerebellum require sensory input from?
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vestibular system, proprioceptive pathways
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proprioceptive input in cerebellum is for?
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UNCONCIOUS processing
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cuneospinocerebellar tract
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cranial 1/2 of body and forelimb proprioception, ipsalateral to cerebellum
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trigeminocerebellar tract
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caudal aspects of neck and head, ipsalateral to cerebellum
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rostral spinocerebellar tract
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cranial 1/2 of body and forelimb proprioception, ipsalateral to caudal peduncle, some rostral peduncle
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ventral spinocerebellar tract
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caudal 1/2 of body and hind limbs, crosses in spinal cord then re crosses b/f rostral peduncle, ipsalateral
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dorsal spinocerebellar tract
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caudal 1/2 of body and hind limbs, ipsalateral to enter cerebellum at caudal peduncle
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location of tracts in spinal cord...
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superficial, makes susceptible to compression from disc protrusion
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tract axons are?
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large in diameter, heavily mylenated
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cerebellar tracts for unconcious proprioceptive input (GSA)
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always ipsalateral, unilateral lesion produces dysfunction on ipsalateral side
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motor ataxia
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uncoordinate movements
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hypermetria
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big gait
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tremor
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oscillation of head, trunk, limbs during voluntary movement
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intention tremor
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at the start
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truncal sway
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involves epaxial muscles
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Steps of concious perception in GSA-1st order neuron
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1. 1st order neuron generates action potential
2. enters CNS via DRG and synapses w/ 2nd order neuron in CNS, decussation to contralateral side |
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Concious perception GSA what does 2nd order neuron do?
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enters contralateral primary relay nucleus of thalamus and synapse on 3rd order neuron
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concious perception of GSA, what does 3rd order neuron do?
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synapses on contralateral somatosensory cortex
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cerebral tracts for concious proprioceptive input (GSA) ALWAYS
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contralateral input
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unilateral lesion of cerebral tracts for concious proprioceptive pathway (GSA)
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produce lesion on contralateral side
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cerebral tracts for concious proprioceptive input (GSA) EVERYTHING
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synapses on primary relay nucleus of thalamus
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major pathways for GSA tracks in the spinal cord are
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DCML
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What is DCML?
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dorsal column medial lemniscus
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what does DCML do?
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main pathway that brings different information to cortex
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info from DCML is?
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perceived conciously
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main use of DCML system?
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present afferent info to cortex to guide voluntary behavior
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major afferent receptors of DCML?
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mechanoreceptors, proprioceptors
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DMCL tracts are
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bilateral
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fasciculus gracilis brings info
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brings info caudal to T6
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fasciculus cuneatus brings info
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brings info cranial from T6
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all sensory information synapes
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in the primary relay nucleus of the thalamus
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fasciculous gracilis
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more medial, spinal cord segments caudal to T6
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pathway of fasciculus gracilis
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1st order neuron synapses in nucleus gracilis then 2nd order travel contralaterally to VCL nucleus in thalamus
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fasciculus cuneatus
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more lateral, info cranial to T6
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pathway of fasciculus cuneatus
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1st order neurons synapse in cuneate nucleus, then 2nd order travel contralaterally to VCL nucleus in thalamus
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trigeminal pathway is
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concious proprioception from the face
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fibers in DCML are
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thick, heavily mylenated, superficial
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signs of proprioceptive deficit (concious and unconcious)
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ataxia due to circumduction/hypermetria, delays in initiating protraction of limb, knuckling, dragging toes/scuffing
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fastest conduction of impulse?
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proprioception
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why proprioception fastest?
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pull away before hurt/damage further
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order of conduction speed of impulses (Fast to slow)
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proprioception, mechanorecptors of skin, pain/temperature, temp/pain/itch
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clinical tests for proprioception
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proprioceptive positioning, wheelbarrowing, hopping (3 up, 1 down), hemi standing, hemi walking, placing
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somatotopy
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sensory info traveling to the cortex retains spatial relationships of the receptors in the periphery
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tonotopic
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somatotopy of audition
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retinotopic
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somatotopy of vision
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synonyms for somatic sensory system
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somatotopic, somatotropic
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will damage to cerebellum impair reflexes?
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No, might be hyperreflexive
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DCML is for
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concious proprioception
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how can you differentiate b/t cerebellar and DMCL pathways?
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proprioceptive placement test
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proprioceptive testing
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specific tests for proprioceptive positioning and postural reactions to help identify the reason for ataxia
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sensory ataxia
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inability of motor cortex to make ongoing corrections in the execution of motor command b/c of lack of info about the positioning of limb/body
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motor ataxia
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cerebellar Dz, inability of cerebellum to modify movements
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nociception
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sensations of pain
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nociception mediated by
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thin, slow fibers
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nociceptors are
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free nerve endings in the skin and viscera that respond to stimuli that can damage tissue
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silent nociceptor
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pathological pain
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pain reaction
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you know the animal is aware of it
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algesia
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pain
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hypalgesia
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less pain perception
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analgesia
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no pain perception
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anesthesia
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no sensory input at all
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3 pain pathways
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spino(cervico)thalamic
spinoreticular(thalamic) trigeminal system |
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trigeminal system
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pain pathways from the head
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spinoreticular(thalamic) pain pathway
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deep pain, visceral pain
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spino(cervico)thalamic
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superficial pain and tactile sensations, primary concious pain pathway
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spinocervicothalamic tract functions
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superficial pain perception and tactile sensations
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what kind of tract is spinocervicothalamic?
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ascending
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describe spinocerviocthalamic tract?
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2nd order ipsalateral in lateral funiculus, all synapse lateral cervical nucleus C1/C2, 3rd order decussate to contralateral side and synapse in thalamus
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where is the spinocervicothalamic tract in spinal cord?
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caudal to C2
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spinoreticulothalamic tract is for
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deep pain and visceral sensations
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spinoreticulothalamic tract is
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ascending tract w/ lots of partial and complete decussations
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where do most spinoreticulothalamic terminate?
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ARAS, some go through thalamus to cortex
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can"t....deep pain
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localize
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most ascending fibers are in tracts but...
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some diffuse through spinal cord
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hierarchical order
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proprioceptive to superficial to deep pain (bad)
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deep pain test
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pinch the periosteum under the skin at nail bed
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response to deep pain test
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yelp, look, snap
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deep pain test is testing
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ARAS, cortex
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superficial pain test/withdrawl reflex
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working at the level of spinal cord, reaction if hurts=cortex
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GSA motor pathway involved in
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reflexes, input to cerebellum for coordination, input to cortex for perception
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GSE motor pathway involved in
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reflexes, info from cerebellum for coordination, initiation of movement from the cortex
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upper and lower motor neurons are..
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BOTH GSE
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Two motor pathways for UMN
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dorsolateral system, ventromedial system
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UMN
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initiate voluntary movement, coordinate voluntary/involuntary movement, maintain muscle tone for support/regulation of posture and balance
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LMN
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drones of nervous system-carry out orders
initiate reflexes |
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ventromedial pathway representative tract
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lateral vestibulospinal pathway
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dorsolateral motor pathway representative tract
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rubrospinal pathway
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ventromedial motor pathway controls
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extensors more than flexors
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dorsolateral contrals
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flexors more than extensors, distal muscles
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ventromedial controls
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extensors more than flexors, axial and proximal limb muscles
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ventromedial main use
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posture and balance
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dorsolateral main use
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fine motor skills
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ventromedial system?
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ipsilateral system
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dorsolateral system?
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contralateral pathway
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Equine Vertebral formula
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C7-T18-L6-S5-Cd 15-21
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Damage to White matter affects
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UMN
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UMN Signs
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paresis to paralysis
normal to increased mm. tone normal to increased spinal reflexes disuse atrophy |
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damage to Grey matter
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LMN signs
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LMN Damage Signs
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paresis to paralysis
decrease to absent muscle tone decreased to absent spinal reflexes rapid muscle atrophy=neurogenic atrophy |
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UMN Kinds of Damage
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brain, spinal cord-ruptured disc
damage to white matter upsets descending motor, ascending sensory |
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LMN Kinds of Damage
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disorders w/ nerves coming from spinal cord to mm.
NM junction problems trauma to spinal cord, brain stem damage to grey |
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normal withdrawal reflex
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ipsalateral flexion reflex due to nociceptor/thermoreceptor stimuli
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Loss of withdrawal indicates..
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lesion at level of spinal cord where the arc is/problem w/ peripheral axons/NM junction
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crossed extensor in normal animal
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not present
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crossed extensor lesioned animal will present as
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lateral recumbency will have withdrawal reflex and EXTEND the CONTRALATERAL paw
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crossed extensor lesion is
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in white matter cranial to limb
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normal panniculus
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hemostat pinch of skin lateral to spinal cord elicits bilateral twitch up to T1
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superficial pain perceived b/t T2 and L4 should cause..
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lateral thoracic N (LMN) at T1 to fire
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panniculus lesion
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signal doesn't get up to T1
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why panniculus important?
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for localizing lesions b/t cervical and lumbar intumescences
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perineal reflex
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checks for damage to pudendal nerve, helps assess very caudal trauma
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tonic stretch reflex
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move the limb around while the animal is in lateral recumbency-normal animal has resistance
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phasic stretch reflex
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patellar tap, normal animal kicks
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grading reflexes
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0=absent
1=hyp 2=normal 3=hyper reflexive 4=clonic |
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UMN bladder
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rigid, won't relax to fill, squirts liquid
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LMN bladder
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flabby, leaks out urine as soon as it's produced
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decerebrate rigidity
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neck and all 4 limbs extended, comatose, no PLR/comatose
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tetanus
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neck and limbs extended, sardonic grin
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decerebellate rigidity
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opisthonos, extension of front limbs, flex the back limbs, concious
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schiff sherrington syndrome
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hypertonic front limbs (can be overcome w/ voluntary movement), PLR intact, flaccid hind limbs
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how many pairs of nerve rootlets?
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36
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C1 exits vertebral canal via?
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lateral vertebral foramen of atlas
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C2-7 exit vertebral canal via?
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intervertebral foramina
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dorsal and ventral root join to form
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spinal nerves
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UMN bladder
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rigid, won't relax to fill, squirts liquid
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LMN bladder
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flabby, leaks out urine as soon as it's produced
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decerebrate rigidity
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neck and all 4 limbs extended, comatose, no PLR/comatose
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tetanus
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neck and limbs extended, sardonic grin
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decerebellate rigidity
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opisthonos, extension of front limbs, flex the back limbs, concious
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schiff sherrington syndrome
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hypertonic front limbs (can be overcome w/ voluntary movement), PLR intact, flaccid hind limbs
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how many pairs of nerve rootlets?
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36
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C1 exits vertebral canal via?
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lateral vertebral foramen of atlas
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C2-7 exit vertebral canal via?
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intervertebral foramina
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dorsal and ventral root join to form
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spinal nerves
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menigeal
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largely sensory
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spinal nerve four branches
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meningeal, ventral, dorsal, communicating branches
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dorsal horn
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receive, process, and relay afferent information from dorsal root fibers
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intermediate zone
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network of interneurons, can be recruited for production antigravity support, reflexes, balance and voluntary movement
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ventral horn
|
contains motor neurons that send axons through ventral root to innervate muscle fibers
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lateral horn
|
spinal cord segments T1-L3/4, contains cell bodies of preganglionic SNS
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dorsal funiculi
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position and movement of limbs in space
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lateral funiculi
|
both ascending sensory and descending motor pathways
|
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ventral funiculi
|
both ascending sensory and descending motor pathways
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cranial cervical region innervation to
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axial muscles and skin of cranial cervical region
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cervicothoracic region innervation to
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regional axial muscles and skin, thoracic limb muscles and skin, and preganglionic sympathetic innervation to the eye
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thoracolumbar region innervation to
|
innervation of regional muscles and skin, preganglionic sympathetic neurons
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lumbosacral region innervation to
|
regional axial muscles and skin,muscles and skin of pelvic limb (pelvic plexus), partial supply to bladder/perineum
|
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sacral region innervation to
|
perineum, external anal sphincter, parsympathetic preganglionic to viscera of pelvis and urinary bladder
|
|
|
sciatic nerve receives fibers from
|
S1-2
|
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caudal region innervation to
|
skin and muscles of tail
|
|
|
GVA
|
visceral afferents, sensory from the autonomic NS, includes special senses
|
|
|
GSA
|
somatosensation, sensory from skin and skeletal muscle, pain, temperatures, position of body
|
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|
divergence happens...
|
so parallel processing can occur
|
|
|
sensory tracts with a high degree of somatotopy are..
|
highly discriminative
|
|
|
receptor density in the periphery=
|
amount of space in thalamus/cortex dedicated to it
|
|
|
kinesthesia
|
dynamic sensation-actively moving joints and muscles
|
|
|
two main nerve fibers for pain
|
A delta and C
|
|
|
A delta fibers
|
sharp, pricking pain, fast conducting-myelinated
|
|
|
C fibers
|
dull, throbbing pain, slow conducting-non myelinated
|
|
|
pathologic pain
|
pain from significant tissue inflammation/nervous injury, noxius stimuli in PNS and CNS
|
|
|
physiologic pain
|
pain that occurs w/ noxious stimulus, rarely found w/out pathologic pain, protective/normal body defense
|
|
|
acute pain
|
from trauma/inflammation
|
|
|
primary hyperalgesia
|
injured area
|
|
|
secondary hyperalgesia
|
surrounding tissue
|
|
|
chronic pain
|
persists beyond expected time, usually 3-6 months, maladaptive/not for survival
|
|
|
discriminate
|
location of pain can be determined by the animal
|
|
|
inflammatory mediators
|
released by damaged tissues, prostaglandins and leukotrienes, bradykinin, serotonin, K+
|
|
|
prostaglandins and leukotrienes
|
lower the threshold of nociceptors, perception of pain occurs more easily
|
|
|
bradykinin, serotonin
|
directly stimulate nociceptors
|
|
|
substance P
|
directly associated with nociceptive pathways, degranulation of mast cells, vasodilation-increase sensitization nociceptors, associated w/ allodynia and hyperalgesia
|
|
|
Wide Dynamic Range Neurons (WDR)
|
respond to both noxious/non noxious stimuli, referred pain
|
|
|
wind up
|
spinal fasciculation of pain, associated w/ chronic pain, sustained, amplified depolarization
|
|
|
NMDA receptors
|
permit Ca and N into cell, Ca causes permanent changes
|
|
|
patients w/ chronic pain
|
are more painful overtime if that pain is left untreated
|
|
|
how do you prevent wind up?
|
nerve blocks and aggressive pain management NOT anesthesia
|
|
|
gate control theory
|
non noxious tactile stimulation can help reduce the perception of pain ie grab shin when bump into table
|
|
|
neuropathic pain
|
injury to nervous system
trauma, vascular injury, endocrinopathy, infection |
|
|
dysesthisa
|
tingling, electric pain sensation w/ neuropathic pain
|
|
|
dysethesia in vet med?
|
self mutilation, dentals, tail docking, declaws
|
|
|
reflexes do NOT
|
require participation from the brain, imply conciousness
|
|
|
reactions
|
voluntary behaviors and require cortical perception of noxious stimuli
|
|
|
spinal reflexes
|
a patterned motor response to a sensory stimulus
|
|
|
supratentorial cranial nerves?
|
I and II
|
|
|
infratentorial cranial nerves?
|
III-XII
|
