Nervous System Flashcards
What are the 3 basic fucntions of the nervous system
Sensory
Motor
Integration
What is the sensory function of the nervous system
Sensing changes from the internal or external environment and sending it to the spinal cord or brain
What is the integration function if the nervous system
Reviewing , analysing, and storing signals to integrate into a response
What is the motor function of the nervous system
The integrated response sent out to the body
What are neurons?
Aka nerve cells
The functional unit of nervous tissue
Transmits information throughout the nervous system
Monitors for changes, converts signals to impulses, send impulses to other neurons
What are neuroglia
Aka glia
Means “nerve glue”
Special nervous tissue that do not have axons
Substances that influence neuronal function are exchanged between extracellular space and neuroglial cells
Insulate, nourish, support and protects neurons
What are ganglion
Dense group of nerve-cell bodies in the PNS
What are the 3 basic parts of the neuron
Cell body
Dendrites
Axon
What is the cell body of a neuron
Inclused nucleus and cytoplasm and organelles
What are dendrites
Short, numerous highly branched processes that extend out from the cell body
What do dendrites do
Recieve impusles from other neurons or receptors that are stimulated by internal or external changes in the environment
Carry impulses TOWARDS the cell body
What are axons
A single process extending from the cell body
May be called a nerve fiber
What do axons do
Conduct impulses AWAY from the cell body to other cells
What are bundles of axons called in the CNS and outside of the CNS
Inside: Tracts
Outside: nerves
Axons are often myelinated, what are the myelinated cells called in the CNS and the PNS
CNS: oligodendrocytes
PNS: Schwann cells
What is myelin
An insulator that speeds the conduction of impusles along axons (white)
Nervous tissue that is myelinated is called
White matter
Nervous tissue that is not myelinated is called
Gray matter
Gray matter often contains
Cell bodies
White matter often contains
Myelinated axons
Sensory or afferent nerves
These affect the brain
These nerves conduct impulses from sensory receptors in the body TOWARDS the CNS
Motor or afferent nerves
Conduct nerve impusles AWAY from the CNS
these effect the body: control responses or skeletal maucle contraction
True or false
A nerve can be sensory, motor or both
True
What is the motor function of the somatic nervous system
Voluntary control of skeletal muscles (conscious movement)
What is the sensory fucntion of the somatic nervous system
Information that is consciously percieved (muscles, skin, eye, ear)
What is the function of the autonomic nervous system
Coordination of automatic (unconscious) body functions
Smooth and cardiac mucles, endocrine glands, heart rate, GI motility, homeostasis
True or false
Many fibers in the somatice nervous system are unmyelinated
FALSE
they are normally myelinated (rapid conduction)
True or false
Many fibers in the autonomic nervous system are unmulinated
TRUE
What is the autonomic nervous system divided into
Parasympathetic and sympathetic nervous system
The sodium potassium pump maintains a higher concentration of sodium ions ____ the membrane and a higher concentration of potassium ion ____ the membrane
Outside
Inside
True or false
The sodium potassium pump moves more sodium out than potassium enters
True
True or false
There is a negative charge on the outside of the cell
FLASE
There is a negative charge on the INSIDE of the cell
Why is the cell considered polarized
Because of the difference in charges across the membrane
The difference in electrical charge across the membrane is called the
Resting membrane potential
True or flase
The sodium potassium pump is closed at rest
True
What happens during depolarization
Upon stimulation, sodium channels open allowing sodium to diffuse into the cell, and the influx of positive ions changes the charge inside the cell from negative to positive
What happens during repolarization
Rapidly after depolarization, the sodium channels close and potassium channels open, potassium moves OUT of the cell to reestablish a positive charge outside the cell and a negative charge inside the cell which restores resting membrane potential
The whole process in changes of charge is called an
Action potential
What is the difference between repolarization and resting state of a cell
Sodium ion concentration are now higher inside the cell and potassium ion concentration are higher outside the cell
What restores a normal resting state of a cell after repolarization
Active transport by the sodium potassium pump
What is absolute refractory period
Time when the neuron will NOT respond to a stimuli no matter what
What is relative refractory period
At the end of repolarization (neuron is almost back to resting) when the neuron WILL respond to a stimuli that is stronger than normal
Why can nerve impulses not be conducted backwards
Because of the refractory period
What is threshold
The change in membrane potential required to cause adjacent membrane to depolarize
What is the all or nothing principle
Either the neuron depolarizes significantly enough to depolarize the adjacent neuron or it is not sufficeint enough to carry on the impulse and the signal dies out
If the stimulus is too weak to cause a wave of depolarization, what may you see
A localized contraction or response but will not spread
How does the body speed up transmission of impulses
Myelinated axons
How does myelin speed up transmission of impulses
Myelin insulates the axons and prevents sodium movement in the areas covered
Depolarization only occurs at the gaps between the myeline
What is the rapid conduction of impulses in myelinated axons called
Saltatory conduction
What are the gaps in the myelin called
Nodes of ranvier
What is multiple sclerosis
Disease caused by degeneration of myelin sheaths, inhibiting conduction of nerve impulses
Affects the ability to see and coordinate movement
Vitamin D helps prevent this
What is an electroencephalogram (EEG)
A recording device that measures and records brain waves, helps diagnose some disorders
How do Local anesthetics like lidocaine work
The block sodium channels of the neuron and prevent depolarization. Impulses cannot be sent to the brain and therefore give no pain signal
What are synapses
The junction between two neurons (or a neuron and a target cell) because they do not touch
The gap between two neurons is called the
Synaptic cleft
True or false
Neurons can have up to thousands of synapses
True
The presynaptic neuron releases a neurotransmitter that is recieved by the
Postsynaptic neuron
The synaptic bulb is the end of the
Presynaptic axon/neuron
The synaptic bulb contains
Mitochondria
Neurotransmitters in vesicles
What causes the synaptic bulb on the presynaptic neuron to release neurotransmitter vesicles into the synaptic cleft
When depolarization causes calcium channels to open
What are the two types of neurotransmitters and what do they do
Inhibitory: increases polarization (hyperpolarize) and makes it less likely to depolarize (prevents the sodium channels from opening)
Excitatory: causes depolarization
What is summation
The process of adding up the effect of multiple stimuli that are individually sub-threshold in order to reach threshold
The relative balance of excitatory and inhibitory neurotransmitters determines the overall effect on the
Postsynaptic membrane
What is a acetylcholine
Very common neurotransmitter
Can be excitatory (neuromuscular junctions)
Can be inhibitory (heart)
What are the 3 Catecholamine neurotransmitters
Norepinephrine
Epinephrine
Dopamine
Associated with arousal and fight or flight reactions in the sympathetic NS. Stress hormones
Norepinephrine
Fight or flight response
Epinephrine
Fight or flight response
Is also secreted by adrenal medulla as a hormone
Dopamine
In the brain, important for autonomic functions and muscular control
What is Gamma-aminobutyric acid
GABBA
inhibitory neurotransmitter in the brain
What is glycine
Inhibitory neurotransmitter in the spinal cord
Some tranquilizers affect GABBA receptors to increase its ____ effect in the brain
Inhibitory
How do amphetamines affect neurotransmitters
Increases catecholamine release like dopamine
Stimulant
Causes schizophrenic episodes
Methamphetamine
What do antipsychotic drugs do
Block dopamine
What does cocaine do to neurotransmitters
Prevents normal reuptake of norepinephrine at synaptic bulb end
Stimulant
What does lithium carbonate do to neurotransmitters
Decreases norepinephrine release
Used to treat mania: slows processes, stabilizes mood and depression and anxiety disorder in pets
What do opiates do to neurotransmitters (heroine)
Binds receptors normally used by endorphins
Provides analgesia, improves mood/emotions
Euphoric (high)
What does alcohol, barbituates, benzodiazepines do to neurotransmitters
All effect GABBA: either promoting or imitating its effects
Therefore it is inhibitory (because GABBA is inhibitory)
How do toxins affect neurotransmitters
Different toxins either mimic excitatory receptors and cause over stimulation or blocking receptors and preventing stimulation or normal function
What does strychnine (poison) do to neurotransmitters
Binds irreversibly to inhibitory receptors (inactivates them)
Blocks GABBA
Overstimulation of CNS motor fibers
See convulsions
How are neurotransmitters recycled and reused
After release from the presynaptic membrane and binding with postsynaptic receptors, enzymes break down the neurotransmitters to remove it from the receptor to end the stimulus
The break down products are reabsorbed by the presynaptic membrane and reassembled to be used again
What is acetycholine broken down by
Acetylcholinesterase
Monoamine oxidase (MAO) breaks down norepinephrine. Many antidepressents inhibit MAO, why?
By inhibiting MAO, they prolong the excitatory action of norepinephrine, relieving anxiety
By knowing the areas of the brain, what does this help you do
Understand neurological diseases and medications that affect the CNS
What is the cerebrum
The largest part of the brain responsible for “higher order” behaviour such as learning, intelligence and awareness, thought and perception of sensation
What does the cerebrum do
Recieves and interprets info
Initiates skeletal muscle movement
In charge of emotions, learning, memory and recall
What is the cerebrum divided by
The median fissure or groove
Into two hemispheres
True or false
Each hemisphere of the cerebrum is connected to the same side of the body
FALSE
they are connected to the contralateral or opposite side if the body
The outer part or the cerebral cortext is ___ matter containing ____
Gray
Cell bodies
The inner part of the cerebrum is ____ matter and contains ___
White
Myelinated axons
Folds in the cerebrum (raised part) are called
Gyri
The grooves in the cerebrum separating the gyri are called
Sulci (shallow)
Fissures (deeper)
What are the lobes the cerebrum is divided in to? (5)
Frontal
Occipital
Temporal
Parietal
Ventral cerebrum
What is the frontal lobe of the cerebrum
Rostral part of the hemispheres
Motor area
What is the occipital lobe of the cerebrum
Caudal area of the hemispheres
Centers for vision
What is the temporal lobe of the cerebrum
At the side near the base if the ear
Hearing center
What is the parietal lobe of the cerebrum
Between the frontal and occipital lobes
Area of temperature, pressure, touch and pain perception
What is the ventral cerebrum
The olfactory bulb and tract
Centers for smell
What is the result of drugs/cell damage/ NT imbalance causing sponanteous firing of the cerebrum
Spontaneous movements, seizures, abnormal behaviour, or hallucinations
If the cerebrum becomes damaged from lack of oxygen, poison or bloot clots (stroke) the animal may lose what
Perception of sensations
voluntary movement
Ability to learn (retain and recall info)
What is the cerebral cortex
A sheet if neural tissue that is the outermost layer of the brain
Associated with conciousness, thought, emotion, reasoning, language and memory
What is the cerebellum
Second largest part of the brain
Allows coordination of movement, balance, posture, and complex reflexes
What controls Proprioception
Controlled by the cerebellum
It compares the intended movement of the brain with the actual position of the muscles, determines if the intensions of cerebral cortex is being cardied out
What is proprioception
The sense of knowing your own body’s position
If the cerebellum determines the movements of the cerebral cortex are not being carried out what does it do?
The cerebellum stimulates or inhibits the muscles to fine tune the movement
Damage or disease to the cerebellum results in
Hypermetria (movements become exaggerated and jerky)
What is a common example of hypermetria
Kittens have it if their mother was infected with feline panleukopenia during gestation
What structures make the diencephalon
Thalamus
Hypothalamus
Pituitary gland
What does the thalamus do
Central relay center for sensory impulses to the cerebral cortex and all senses except smell come to the to the thalamus and gets sent to the appropriate lobe
Also interprets pain, touch, temperature
What is the hypothalamus
Interface between nervous and endocrine system (communicates between pituitary gland and brain centers) controls and regulates the autonomic system
Single most important area controlling the internal environment
Diseases and drugs that affect the hypothalamus may result in
Fever or compulsive eating/drinking
What is the pituitary gland
The endocrine “master gland” that controls hormone regulation throughout the body
What is the brainstem and what structures make it
The connection between the brain and spinal cord
Made of the midbrain, pons and medulla oblongata
What is the brain stem responsible for
Responsible for maitenance of basic support functions of life in the body
Operates subconsciously
What are the 3 vital reflexes controlled by the brain stem
Cardiac center: rate and contractility
Vasomotor center: diameter of blood vessels (blood pressure)
Respiratory center: rhythm of breathing
What are the non-vital reflexes controlled in the brain stem
Cough
Sneeze
Swallowing
Vomiting
True or false
Many cranial nerves originate from the brain stem
True
Why is it important to not go too deep with anesthesia
Dont want to go too deep to affect the brainstem and inhibit essential functions /reflexes
What are the meninges, what are the 3 layers
Connective tissue membranes that surround, support and protect the brain and spinal cord
Dura mater, arachnoid mater, pia mater
In what order are the 3 layers of meninges
Dura mater is the tough outer membrane (separated from the arachnoid mater by the subdural space)
Arachnoid mater: second later that has a web like structure (cavities in the arachnoid layer hold CSF)
The have a subarachnoid space
Pia mater: inner most layer, tight to the surface if the CNS only separated by a thin layer of neuroglial
The meninges carry a complex network of blood vessels and supply
Nutrients and oxygen to superficial tissues of the brain and spinal cord
Meningitis
Inflammation of the meningeal membranes from a virus or bacterial infection
In the distal spinal cord, dura mater is separated from the vertebrae, what does this allow
Epidurals are given in the space between the dura and vertebrae to block sensation on the spinal cord
What is cerebrospinal fluid
Fluid that bathes and protects the brain and spinal cord
Formed by filtration and secretion from capillary networks called the choroid plexus in the ventricles of the brain
True or false
Epidural space have NO cerebrospinal fluid and subarachnoid space has LOTS
True
Cerebrospinal fluid circulates through
Cavities in the brain and spinal cord to enter pores to the subarachnoid space
What does collection of cerebrospinal fluid sample help diagnose
Changes in cell composition to detect disease
You can inject contrast media into the spinal canal to look for
Spinal cord compression (ex. Intervertebral disc disease)
What is intervertebral disc disease
Prolapse of disk material into the vertebral canal and causes compression of the spinal cord
Most common in chondrodystrophic breeds (short legs)
Signs: lumbar pain and hind limb ataxia
What is hydrocephalus
Excess accumulation of CSF
Causes expansion of ventricles and bulging of the brain
Signs: seizures, dome shaped skulls, lateral deviation of the eyes
Common in dome-skulled dogs like chihuahuas
What is the blood brain barrier
A functional barrier separating the capillaries in the brain from the nervous tissue
Capillary walls are relatively impermeable (tightly aligned with brain and covered in neuroglia)
What is the point of the blood brain barrier
To prevent drugs, proteins, ions and other molecules from passing into the brain from blood
How does ivermectin work and why is it used in heartworm prevention
Ivermectin attacks receptors in the brain, worms dont have a blood brain barrier so easily kills the worms but has no effect on the aimal at therapeutic doses
Why is difficult to treat meningitis it meningoencephalitis
Because the blood brain barrier makes it difficult for antibiotics and anti inflammatories to penetrate the brain
What is the mnemonic for remembering the 12 pairs of cranial nerves that originate from the brain
On On On They Travelled And Found Voldemort Guarding Very Ancient Horcruxes
What is the first cranial nerve and what is is responsible for
Olfactory : smell (sensory)
What is the second cranial nerve and what is is responsible for
Optic : vision (sensory)
What is the third cranial nerve and what is is responsible for
Oculomotor : eye movements, pupil size, focusing lens (motor)
What is the fourth cranial nerve and what is is responsible for
Trochlear : eye movement (motor)
What is the fifth cranial nerve and what is is responsible for
Trigeminal : sensations from the head/teeth, motor chewing (both)
What is the sixth cranial nerve and what is is responsible for
Abducens: eye movement (motor)
What is the seventh cranial nerve and what is is responsible for
Facial: muscles of facial expression, salivation and tears (motor)
What is the eighth cranial nerve and what is is responsible for
Vestibulocochlear: hearing and balance (sensory)
What is the ninth cranial nerve and what is is responsible for
Glossophartngeal: tongue movement, swallowing, taste, salivation (both)
What is the tenth cranial nerve and what is is responsible for
Vagus: sensory from gastrointestinal, respiratory system, motor to larynx/pharynx, parasympathetic (motor to abdominal and thoracic organs)runs next to the jugular vein and carotid artery (both)
What is the eleventh cranial nerve and what is is responsible for
Accessory: head movement (motor)
What is the twelfth cranial nerve and what is is responsible for
Hypoglossal: tongue movement (motor)
Why are there areas of enlargement at the caudal cervical and midlumbar regions
Accomodation for the nerve of the limbs
True or false
White and gray matter of the spinal cord are the same as in the brain
FALSE
The spinal cord is gray matter surrounded by white matter (the brain is white matter surround by gray matter)
Spinal nerves emerge from
The intervertebral foramen between adjacent vertebrae of the spine
What is the dorsal root of spinal nerves
Carries sensory info from the body to the spinal cord
What is the ventral root of the spinal nerve
Cardies motor information from the spinal cord to the body
How are spinal nerves names
Named and numbered the same as the vertebrae they emerged from (thoracic, lumbar and sacrum)
In the cervical region there are ___ nerves
8 (one extra than the vertebrae)
True or false
There are fewer coccygeal spinal nerves than coccygeal vertebrae
True
Spinal nerves that emerge from the spinal cord go to ___ structures
Somatic
Spinal nerves that go to appendages initially form braid like arrangements known as
Plexuses
The brachial plexus
Innervates the thoracic limbs from last 3-4 C and 1-2 T spinal nerves
Radial nerve: most cranial (damage causes paw to drag)
Median nerve: middle nerve
Ulnar nerve: most caudal (funny bone)
What is the lumbosacral plexus
Innervates the pelvic limbs from last 3-5 L and first 1-3 S spinal nerves
What happens with injury ti the facial nerve
Halter or lateral recumbency on the facial nerve causes dropping of the lip, ear, and nostril on that side of the face (common in horses)
What happens with damage to the vagal nerve
Laryngeal paresis: muscular weakness caused by nerve damage (in horses)
Femoral nerve
On medial surface of the thigh next to femoral artery and vein
Motor to muscles of the thigh and sensory to skin
What can be damaged during birth if hind limbs are under strong traction (foals and calves)
The femoral nerve
Sciatic nerve
On lateral thigh between bicep femoris muscle
Motor to flexors of stifle and digits
How can the sciatic nerve be damaged
Pelvic or femur fractures or improper IM injections
What is the autonomic nervous system divided into
The sympathetic and parasympathetic nervous systems
Sympathetic nerves come off the spinal cord in the thoracic and lumbar regions, so it is called the
Thoracolumbar system
parasympathetic nerves come off the brain and sacral regions of the spinal cord so it is called the
Craniosacral system
The first neuron in sequence is called the ____ and the second neuron in sequence is called the ___
Preganglionic neuron and the postganglionic neuron
In the sympathetic nervous system, preganglionic neurons are ___ and post ganglionic neurons are ____
SHORT
LONG
What is the sympathetic ganglion chain
Preganglionic neurons synapse with many other neurons (to have generalized effects) in a chain of ganglia
Found in a line near the spinal cord on either side of the vertebral column
Changes in the sympathetic nervous system often affect
Many organs at the same time
In the parasympathetic nervous system preganglionic neurons are ___ and they synapse with ___ postganglionic neurons
LONG
Very short
General functions of the sympathetic nervous system (fight or flight)
Bronchodilatiom Increased HR and strength Vasodilation to muscles Vasoconstriction to skin, GI tract, kidneys Pupil dilation
These organs can die in shock due ti no stimulation
General functions of the parasympathetic nervous system (rest and restore)
Decrease bronchodilatoon Decreases HR and strength Decreases vascular changes Increase GI activity Pupil constriction
True or false
ALL preganglionic nerve fibers use acetylcholine as the neurotransmitter
True
In the sympathetic NS, the primary neurotransmitter used in postganglionic neurons is
Norepinephrine
Releases neurons called adrenergic neurons
The adrenal medulla act like a cluster if adrenergic neurons (epinephrine and norepinephrine)
What are the adrenergic receptors in The sympathetic NS
Alpha 1: in blood vessels
Beta 1: in heart
Beta 2: in bronchi
(Respond to adrenergic neurons and had sympathetic NS responses depending on which one is stimulated)
True or false
The ultimate effect of sympathetic and parasympathetic systems is determined by their postganglionic neurons
True
True or false
The parasympathetic NS uses acetylcholine at the NT at both the pre and postganglionic neurons
True
What receptors does the parasympathtic NS have
Muscarinic (on target organs)
nicotinic (on postganglionic neurons of both the parasympathetic and sympathetic NS) (and voluntary muscle motor neurons)
What happens with stimulation of muscarinic receptors
Increases salivation, increased GI motility, decrease HR and constrict pupils
Why is stimulation of the muscarinic undesirable during surgery
Because we dont wanr a decrease in HR or increase in GI motility
What does atropine do
Blocks muscarinic receptors (antagonist)
To reduce salivation and GI motility during surgery
Ocular use: to dilate pupils
What does stimulation of nicotinic receptors do
Stimulated by nicotine, stimulates parasympathetic activy and the brain
Used to be used at a dewormer in horses vecause it stimulates GI motility and make them defecate
Reflexes
Rapid automatic responses meant to protect the body
Basic reflexes
Unlearned and involintary “built in”
Example: patellar reflex
Learned reflexes
Appear to be innate but occur only because a great deal of concious effort is put into them
(Reflex to catch a ball)
Reflexes can be somatic or autonomic
Somatic: skeletal msucle contraction
Autonomic: smooth, cardia muscles and endocrine glands
Explain the reflex arc
Sensory receptor detects a change
Sends signal along sensory neuron to gray matter of spinal cord or brainstem
Synapses with interneuron
Integrate info with ither sensory neurons
Reflex response sent out by motor neuron
Effect caused by the effector organ
What can tiu use skeletal msucle reflexes to help
Identify, diagnose, locate and measure severity of spinal cord damage, nerve damage or muscle disease
Stretch reflex (patellar reflex)
Stretch receptors in maucle detect change, sends signal to soinal cord and causes contraction
Another branch stinukate inhibitory motor neurons to the opposing muscle (to relax it)
Another branch tells the brain what happened and helps cerevellum coordinate the movement
What is the withdrawal reflex
Ex. Flexor reflex
Strong stimulus (pain) causes ralid withdrawal of the limb Stinulates withdrawal muscles and inhibits opposing msucles
Limb is withdrawn BEFORE the brain receives the message of pain
What is the crossed extensor reflex
Goes hand in hand with the wthdrawal reflex
Extension of contralateral leg ti the one that is witndrawn
Ex. Stepping on a taxk, withdrawing that limb and shifting weight ti the opposite limb
True or false
Spinak reflexes dint require input from the brain
True
True or false
Damage to the spinal cord at L1 or L2 would allow reflxes that are controlled at L3 or lower to happen
True
The brainwould just not recieve the sensory info through the damaged area
What happens if the damagae ti the spinal cord is to T11 or 12
The reflexes would occur but response would become exaggerated (still would not feel it because of loss of signal transmission to the brain)
Hyperreflexia
Occurs because normally the upper CNS would have inhibitory effect to modify the reflex, but modification cant occur with spinal cord damage
Hyporeflexia
Can occur is the trauama ocxurs anywhere in the actual reflex arc (where it is mediated) including thenpart of the spinal cord involved
Can use changes in intensity of reflexes to help
Localize lesions
Babinski reflex
Scrape the pointy end of an instrument up the metacarpus/metatarsus
An abnormal response is if there is extension of the digits (damage to the spinal cord)
Menace reflex
Move fingers toward patients eye: eye should blink
Involves optic and facial nerves
May nor be present in neonates
Pupillary light reflex
Optic and oculomotor nerve
Must have direct and concensual response (construction in both eyes)
If they constrict, it does NOT mean the animal can see
Should NOT be present during surgery
Palpebral reflex
When the median canthus of the eye is touched, the eye should close
Trigeminal and facial nerves
Monitors depth of anesthesia (if present they can stikl feel the surgery)!
Corneal reflex
Trigeminal and facial nerve
Touch the cornea to result in blink
Reflex dimishes with anesthesia (danger of corneal damage) and used to help pronounce death
Neurons are ___ of mitosis and therefore the body ___ replace nerve cells lost to injury/disease
Incapable
Cant
If the cell body survives injury/disease then the axons
Can regenerate
Usually does not result in full recovery of function
Whether a nerve recovers from damage depends on
How close the i jury is to the cell body
Whether the nerve sheath is damaged
Minor injuries to nerves can regenerate
2-4 mm per day
The neurological exam
History Observation Palpation Postural reactions and reflexes Localize the lesion Determine cause
Epilepsy has a higher frequency in
Beagles German Shepards and cockers
Kind charles spaniels are know for syringimyelia
“Fly biting”
Fluid containing cavities in the soinal cord and cerebelluk pished out foramen magnum due to flat head (herniation)
Causes hallucinations
Wobbler syndrome seen in
Compression of the spinal cord in the neck
Dobermans, great danes and thoroughbred horses
Congentital and hereditary disease are iften odserved in animals before 2 years of age
Behavioural abnormalities are often due to
Lesions of the cerebrum, thalamus or hypothalamus
Involuntary head tilt due to
Vestibular disease
Head tilt or compulsive rolling/curcling without head tilt are often because of
Lesions if the cerebrum thalamus or hypothalamus
Ataxia bobbing and tremors result frim
Cerebellar dysfunction
Cerebellar abiotrophy
Failure to form the cerebellum
Nystagmus
Rhythmic predictable movements of the eye at rest witha fast and slow ohase usualky in the horizontal plane
Spinal accessory nerve test
Atrophy of the sternocephalicus muscle
Hypoglossal nerve test
Atrophy if the tongue
Testing for proprioception
Knucking (paw is set on dorsal surface, should immediately be corrected)
Hopping (held on 1 limb and moved laterally)
Extensor postral thurst (lowered to rhe ground, hind limbs should extend)
Perineal/anal reflex
Touch the perineum and the anus should wink
Cutaneous trunci reflex
Blunt object run along the skin lateral to the spinous process and thw skin should contract
Rabies
Virus that affects the CNS
signs: behavioural changes, tremors, hyperesthesia (excessive response), loval area of paralysis (face/limb)
Dead in 10 days of start if signs
Always consider in causes of progressing CNS disease
Epilepsy
Functional disease if the brain
May have hereditary factor or be idiopathic
Seizures are often seen for the first time when you ger than 2 years
Seizures are 1-2 minutes
Starts with a “gaze”, lateral recumbency, rapid convulsions, urinate and defecate, returns to consciousness but may he disoriented
Seen in older dogs and often with neoplasia
Facial paralysis
Nerve damage to the facial nerve
Signs: No palpebral reflex Immobility of ear Facial deviation Eyelid may droop (bovine/equine) Menance test: 3rd eyelid with flick and eye retract instead of a blink (dogs/cats) Pendulous lip
Horner’s syndrome
Neurological disorder of the eye and facial msucles caused by dusfunction of the sympathetic NS
“Tree falling syndrome” in cats
Can because by ear infections in dogs
Signs: retraction of eye and protrusion of 3rd eyelid Ptosis (dropping) of eye Constructed pupil Unequal eye sizes Sweating in horses
Called tequila sunrise syndrome
Guttural pouch mycosis in horses
Fungal infection in the guttural pouch of horses (in eustachian tube)
The fungal infection affects the internal carotid artery, and adjacent nerves (causes laryngeal and pharyngeal paralysis)
Major signs: dysphagia (difficulty swallowing) and aspiration pneumonia
Intervertebral disc disease
Most common neurological disorder of dogs
Prolapse of disc material into vertebral canal which compresses the soinal cord
Common in chondrodystrophic breeds (short legs) and obese dogs
Signs: tetraplegia (paralysis of all 4 limbs), reluctance to moce and pain
