Exam 3 Flashcards
(164 cards)
1
Q
What is the functional unit of the nervous unit of the nervous system
A
The neuron
2
Q
What are the parts of the neuron
A
The perikaryon (soma/body), dendrites, axon, and the axon terminal
3
Q
What is the function of the dendrites
A
The afferent process that receives signals from other neurons
4
Q
What is the function of the axon
A
The efferent process that synapses w/ another neuron or effector cell
5
Q
What is synapse
A
The small gap btw 2 neuron cells where electrical or chemical reaction occurs
6
Q
What is the pre synaptic cell
A
The cell prior to the synapse
7
Q
What is the post synaptic cell
A
Cell after the synapse
8
Q
What are characteristics of neurons
A
High O requirement, only uses glucose for energy, lack repro ability, can regenerate if the cell body is intact, and supported by glial cells
9
Q
What are astrocytes
A
Glial cells that maintain the blood brain barrier, levels of neurotransmitter around synapses, regulates ions, and provides metabolic support
10
Q
What are ependymal cells
A
Glial cells that line spinal cord and ventricles of the brain and produce CSF
11
Q
What are oligodendrocytes
A
Glial cells that myelinate CNS axons and provide structural framework
12
Q
What are microglia
A
Glial cells that form the brains immune cells removing dead cells and pathogens via phagocytosis
13
Q
What are satellite cells
A
Glial cells that surround neuron cell bodies in ganglia of PNS regulating neurotransmitter levels
14
Q
What are schwann cells
A
Glial cells that myelinate neurons in PNS, maintain, and regenerate neurons after injury
15
Q
What is white brain matter
A
Lots of myelinated fibers
16
Q
What is grey brain matter
A
Lots of neuron cell bodies
17
Q
What are nodes of ranvier
A
Gaps in myeline sheath that is vital for accomplishing action potentials by enhancing conduction of nerve impulses
18
Q
What are afferent nerve fibers
A
Sensory nerves fibers that send impulses from periphery to CNS
19
Q
What are efferent nerve fibers
A
Motor nerve fibers that send impulses from CNS to periphery
20
Q
What are mixed nerves
A
Nerves that have both sensory and motor functions primarily found in PNS
21
Q
What is the autonomic nervous system
A
Automatic control of smooth muscle, cardiac muscle, and glands allowing afferent activity in terms of autonomic sensory function and efferent activity in terms of autonomic motor function
22
Q
What is the somatic nervous system
A
Conscious control of skeletal muscle w/ afferent activities such as somatic sensory function such as muscles, skin, eyes, and ears and efferent w/ somatic motor function
23
Q
What are the 3 states of a neuron
A
Resting, depolarization, and repolarization
24
Q
What is the resting state
A
The cell membrane working to maintain electrical polarization using the sodium potassium pump and concentration gradients making it more negatively charged inside the cell
25
What is depolarization
When an action potential causes a sudden influx of Na where the stimulus occurs causing loss of membrane potential this occurs via passive diffusion
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What is repolarization
When the Na channels shut, K channels open, passive diffusion occurs, the membrane potential shifs back toward the negative polarized state, and the sodium potassium pump takes over placing the K and Na back on the right side of the membrane
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What is the depolarization threshold
The membrane potential that must be reached in order for an action potential to occur
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What is an action potential
Wave of depolarization down the cell membrane
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What is the all or nothing principle
Neuron completely depolarizes or not at all
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What is the refractory period
Insensitive to new stimuli and can be absolute or relative
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What is the absolute refractory period
Period of sodium influx and early potassium outflux keeping the cell cannot respond at all no matter how strong the stimulus is
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What is relative refractory period
A strong stimulus at the end of repolarization may result in a new action potential
33
How do myelin sheaths cause conduction
The myelin sheath prevents sodium from crossing the cell membrane allowing the rapid conduction of the action potential to leap down the axon
34
What is the flow of the synapse down a pre synaptic neuron action potential
Axon, telodendron, and synaptic knob
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What happens once the action potential hits the synaptic knob
Ca influxes, a neurotransmitter releases, they bind to receptors on the post synaptic neuron, and the synaptic transmission occurs
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What are excitatory neurotransmitters
They open Na channels to depolarize the post-synaptic membrane causing an action potential
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What are inhibitory neurotransmitters
Open Cl or K channels that hyperpolarize postsynaptic membrane preventing an action potential
38
What type of neurotransmitter is acetylcholine
Excitatory by stimulating skeletal and smooth muscle contraction and inhibitory by inhibiting cardiac muscle via parasympathetic nerves slowing HR
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What type of neurotransmitter is epinephrine
Excitatory causing the fight or flight response in the sympathetic nervous system
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How is epinephrine a hormone and neurotransmitter
Because it is also produced by the adrenal medulla as adrenaline along w/ the sympathetic nervous system
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What type of neurotransmitter is norepinephrine
Excitatory as it is an arousal fight or flight response in the sympathetic nervous system
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What type of neurotransmitter is dopamine
Excitatory as it stimulates the secretion of GH and inhibitory as it inhibits unnecessary movements and certain hormone secretion from the pituitary gland
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What disease is associated w/ a decrease in dopamine neurons
Parkinson's
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What type of neurotransmitter is Gamma Aminobutyric Acid (GABA)
Inhibitory as it reduces neuronal excitability such as seizures
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What type of neurotransmitter is glycine
Inhibitory by reducing neuronal excitability
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What stops the acetylcholine signal
Acetylcholinesterase breaks down acetylcholine the products are reabsorbed by synaptic knob are reassembled and wait for next action potential in vesicles
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What happens if acetylcholinesterase is inhibited
There will be a persistent stimulation of receptors causing salivation, diarrhea, vomiting, dyspnea, miosis, muscle fasciculations, and seizures
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How is the norepinephrine signal stopped
At a slower process than stopping acetylcholine and occurs after the release into synaptic cleft and is reabsorbed by synaptic knob broken down by monoamine oxidase (MAO) if any is not reabsorbed in the synaptic knob it is broken down by catchol-O-methyl transferase (COMT)
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What is contained in the CNS
Neuron cell bodies, myelinated, unmyelinated nerve fibers, and glial cells
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What are the parts of the brain
Cerebrum, cerebellum, diencephalon, brainstem, meninges, cerebrospinal fluid, blood brain barrier, and cranial nerves
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What is the cerebrum
The largest part of the brain in domestic animals, area of learning and intelligence, the gyri is separated by fissues and sulci, where sensory info is received and interpreted, voluntary motor control is initiated here, and integration of neuron info such as emotional response, learning, memory, and recall
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What divides the cerebrum into 2 hemipheres
The longitudinal fissure
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What is the function of the corpus callosum in the cerebrum
Allows for communication btw the left and right hemipheres
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What does the sulci do
Divides the hemispheres into lobes superficially
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What are the different lobes of the brain
Frontal, parietal, occipital, and temporal
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What is the cerebellum
Second largest part, contains grey matter cortex w/ white matter underneath, coordinates movement, balance, posture, and complex reflexes, and results in hypermetria if damage/disease which is exaggerated movements
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What is the diencephalon
Passageway btw cerebrum and brainstem and contains the thalamus, hypothalamus, and pituitary
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What is the function of the thalmus
Regulates the sensory input to the cerebrum
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What is the function of the hypothalamus
Nervous system-endocrine system interface w/ temperature control, thirst, hunger, and anger response
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What is the pituitary
Master gland of the endocrine system
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What is the brainstem
The connection btw the spinal cord and the rest of the brain, it is the most primitive part for autonomic control of the cardiovascular system, respiration, swallowing, and vomiting, and contains the medulla oblongota, pons, and midbrain
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What are the meninges
Connective tissue layers surrounding the brain/spinal cord supplying nutrient, oxygen, and cushioning, the layers are the dura mater, arachnod, and pia mater
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What is dura mater
Tough and fibrous superficial layer of the meninges
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What is the arachnoid
Delicate spider web looking layer that contains CSF
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What is the pia mater
Thin layer that lies on the brain/spinal cord
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What is the cerebrospinal fluid
Fluid btw layers of meninges, in canals/ventricles of the brain, and spinal cord that influences autonomic functions
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What is the blood brain barrier
Tightly constructed capillary wall w/ no fenestrations, astrocytes add additional support, and prevents drugs, proteins, and ions from passing from the blood to the brain
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How many cranial nerves are there
12 pairs in the pNS that originate directly from the brain
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What is the mnemonic for remembering the cranial nerves
On (olfactory) old (optic), Olympus' (oculomotor) towering (trochlear) tops (trigeminal) a (abducent) friendly (facial) viking (vestibulocochlear) grows (glossopharyngeal) vines (vagus) and (accessory) hops (hypoglossal)
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What is the mnemonic for remembering the type of axon each cranial nerve has
Some (sensory) say (sensory) marry (motor) money (motor) but (both) my (motor) brother (both) says (sensory) big (both) brains (both) matter (motor) more (motor)
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What is the function of the olfactory nerve
Sense of smell
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What is the function of the optic nerve
Sences of vision
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What is the spinal cord
Caudal continuation of the brainstem outside of the skull conducting sensory and motor info, contains neuron cell bodies and synapses, and nerve roots emerge btw adjacent vertebrae dorsal nerve roots being sensory afferent and ventral nerve roots being motor efferent
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What does the left hemisphere do signal wise
Receives sensory info from the right side of the body and provides motor control to the right side of the body
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What does the right hemisphere do signal wise
Recieves sensory info from the left side of the body and provides motor control to the left side of the body
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What are the 2 parts of the ANS
Sympathetic and parasympathetic
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What is the sympathetic nervous system
The thoracolumbar system that develops the fight or flight response and the body's way of coping in emergency situations
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What are is the parasympathetic nervous system
The cranial sacral system, that rest and restores the body to bring it back to a resting state replacing the resources used during an emergency
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What is an efferent motor nerve composed of
2 neurons and a ganglion
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What are preganglionic neuron
Cell body in brain or spinal cord that sends a signal
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What is a ganglion
Cluster of neuron cell bodies such as a collection of synapses outside the CNS
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What is the postganglionic neuron
Carries the impulse to the target organ
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What is the description of sympathetic nervous system motor nerve
The postganglionic neuron is much longer than its preganglionic neuron
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What is the impulse flow of a neuron w/ the sympathetic nervous system
The signal exits the thoracolumbar spine and terminates near the spinal cord and may synapse w/ a neuron w/in the ganglion chain or pass thru the ganglionic chain and synapse w/ neuron located beyond the sympthetic chain
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How many postganglionic neurons are there for one preganglionic neurons in the SNS
Multiple
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Where is the sympathetic ganglion chain
Connected by the sympathetic trunk
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What is the description of parasympathetic nervous system motor neuron
The postganglionic neuron is much shorter than its preganglionic neuron
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What is the impulse flow of a neuron in parasympathetic nervous system
Preganglionic neuron originates from the nuclei or from the sacral spine and travels to its target organ
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What is the primary neurotransmitter in the SNS
Norepinephrine which is released by adrenergic neurons
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What are the adrenergic receptors for norepinephrine in the SNS
Alpha 1-adrenergic receptors, beta 1-adrenergic receptors, and beta 2 adrenergic receptors
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What do alpha 1 adrenergic receptors do in the SNS
Vasoconstrictions of skin, GIT, and kidney
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What do beta 1-adrenergic receptors in the SNS
Increases HR and force of cardiac contraction
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What does beta 2-adrenergic receptors do in the SNS
Bronchodilation
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What is the primary neurotransmitter for the parasympathetic nervous system
Acetylcholine
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What type of neurons release acetylcholine
Cholinergic in the pre and post ganglions in the parasympathetic and preganglion in sympathetic
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What are the cholinergic receptors for acetylcholine
Nicotinic and muscarinic
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Where are the nicotinic receptors
Found on the postganglionic neurons of both the sympathetic and parasympathetic nervous system btw motor neurons and muscle
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Where are the muscarinic receptors
Found on target organs and tissues supplied by postganglionic neuron of the PNS
99
What are reflexes
Rapid autonomic responses to stimuli that protects the body and maintain homeostasis
100
What are the two types of autonomic reflexes
Contralateral and ipsilateral
101
What are contralateral reflexes
Reflexes on the other half of the body from the stimuli
102
What are ipsilateral
Reflexes on the same side of the body from the stimuli
103
What is the reflex arc
The sensory receptor detects a change, the sensory receptor fires an action potential along the sensory neuron to gray matter of the spinal cord or brain stem, sensory neuron synapses w/ interneurons, the integrated response of the reflex is sent out from the spinal cord or brainstem by the motor neuron leading to contraction inhibition of muscle or gland
104
What is the stretch reflex
Ipsilateral reflex occurs w/ a simple monosynaptic arc the muscle spindle senses a stretch sending an impulse to the sensory neuron of the spinal cord, synapse occurs w/ the motor neuron to the same muscle, contraction of the same muscle occurs inhibiting the opposing muscle, and sends a sensory signal to the brain
105
What does the stretch reflex maintain and prevent in muscles
Maintains tension and muscle tone and prevents overstretching
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What is the withdrawal reflex
Ipsilateral reflex of several interneuron synapses that results in muscle contraction/flexion while relaxing opposing muscle this reflex occurs before the brain is aware of the painful stimulus
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What is crossed extensor reflex
A contralateral reflex where sensory neuron synapses w/ interneurons, the flexor muscles in ipsilateral limb contract while opposing muscle groups are inhibited and the extensor muscle in contralateral limb contract so that limb can support your full weight
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Where is the inhibitory effect on the reflex arc
The CNS cranial to the site where the sensory neuron enters the spinal cord/brain stem
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What is a hyperreflexive
Lack of inhibition to reflexes causing them to be more exaggerated than normal
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What is a hyporeflexive
Lack of reflex present
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What causes a hyperreflexive
If an injury occurs in the cranial aspect of the CNS and reflex arcs are intact caudal to the trauma
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What causes hyporeflexive
If injury occurs where the reflex arc enters or leaves the spinal cord
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What is the palpebral reflex
Sensory receptors on skin of the eyes send a signal to cranial nerve 5 in the pons and sends a signal to cranial nerve 7 to stimulate a blink
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What happens to the interneurons in the pons while under anesthesia
They are depressed resulting in a loss of palpebral reflex
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What is the pupillary light reflex
Retina senses the light, a signal to cranial nerve 2 that is transmitted to the optic chiasm then to the diencephalon which sends a response signal to cranial nerve 3 resulting in an ipsilateral pupil constricts in a strong and a weak contralateral pupil constriction
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What does a neurologic exam include
Testing reflexes both for withdrawal and patellar, palpate along the spine looking for signs of pains, movement of neck, cranial nerve exam, and evaluate gait
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What are the 3 types of ataxia
Proprioceptive, cerebellar, and vestibular
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What is proprioceptive ataxia and what are common tests for it
Unawareness of limbs and the space around them this can be identified by listening for shuffling of the dogs feet and placing their foot dorsal side down
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What is cerebellar ataxia
Lack of fine motor control and can be diagnosed w/ a hypermetric gait
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What is vestibular ataxia
Inner ear issue that causes uncordination typically the animal stumbles or tilts its head in the direction of the issue
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What are diagnostics for neurologic issues
PE, neurolocalization via neuro exam, minimum databases such as CBC, chem, and UA, rads of spine or skull, MRI, CT, myelograms, CSF tap/analysis, electromyograph, and electroencephalograph
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What is the downfall to using a radiograph as a diagnostic for neuro issues
The radiograph does not show any soft tissue such as the spinal cord itself
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What diagnostic shows soft tissue
MRI
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Where do we tap for CSF fluid
At the base of the skull or right behind the lumbar vertebrae
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How do we handle large animals and small animals differently w/ CSF taps
Large animals we sedate while small animals are anesthetize
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What is an electromyograph
An EMG asses the electrical activity of the muscle to identify nerve disease
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What is an electroencephalograph
An EEG assess the electrical activity of the brain
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What is the BAER hearing test
The brainstem auditory evoked response test establishes if the animal or not by administering auditory stimuli to watch for a reaction
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Why do dogs w/ brain tumors have different neurologic symptoms
Tumors in different locations will cause different symptoms
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What is wobblers caused by
Compression of the cervical vertebrae typically appears in younger large dogs such as great danes
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What is intervertebral disc disease
When the soft tissue disk becomes compressed by the vertebral bone
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What part of the nervous system does tetanus affect
The PNS
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What are common symptoms of distemper
Twitches in the neck and face, respiratory symptoms, diarrhea, vomiting, teeth abnormalities, and hyperkeratosis
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What is DAMN IT-V
Reasons why different neurological issues occur such as degenerative or developmental, anomalous or autoimmune, metabolic, nutritional or neoplastic, infectious, inflammatory, immune mediated, or idiopathic, trauma or toxic, and vascular
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What are the 2 categories of IVDD
Degenerative or traumatic
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What is type 1 degenerative IVDD
The nucleus pulposus degeneration and extrusion from the surrounding annulus fibrosis
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What is type 2 degenerative IVDD
Annulus fibrosis degenerates and protrudes
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What is traumatic IVDD
Acute non compressive nucleus pulposus extrusion
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What are the treatments for IVDD
Drug therapy w/ anti-inflammatories (NSAID vs corticosteroid), analgesias (NSAID, gaba, and or opioids), muscle relaxers (alprazolam and methocarbamol), and cage rest or surgery
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What is tick paralysis
Rapidly progressive motor paralysis due to a toxin in the tick's saliva that attacks the nervous system
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What are symptoms of tick paralysis
Presenting 3-9 days after tick attaches the dog may have a loss/change in voice, ataxia, abnormal respirations/rate, gagging, coughing, vomiting, and mydriasis
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What is the difference btw vomiting and regurgitation
Vomiting takes abdominal effort to force food up and out of the stomach while regurgitation is a random blah of food that was likely stuck in the esophagus
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What is mysthenia gravis
A rare autoimmune disorder where Ab form against nicotinic acetylcholine post synaptic receptors at the neuromuscular junction of skeletal muscles and can causes megaesophagus this can be tested w/ a blood test to check for Ab, tensilon test, and fatigue test
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How is myasthenia gravis treated
Acetylcholinesterase inhibition, immunosuppressant therapy, and a bailey chair
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What is the process of the rabies virus
Enters tissue thru saliva of infected animal, virus replicates in muscle near bite, moves up PNS to CNS, ascends to spinal cord, reaches brain and causes fatel encephalitis, and enters salivary glands and other organs of victim
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What are the types of seizures
Generalized/grand mal, focal, psychomotor, and cluster
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What is a psychomotor seizure
Odd behavior such as chasing tail or appearing to see things that arent there
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What are cluster seizures
A group of seizures w/in a shorter than normal interval clinically defined as 2 or more seizures w/in a 24 hr period
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What are the stages of seizures
Prodromal, aural, ictal, and postictal
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What is the prodromal phase of a seizure
The animal experiences an indication of forthcoming seizure hrs to days before
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What is the aural phase of a seizure
This is the very start of the seizure where behavior changes may be apparent
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What is the ictal phase of a seizure
The seizure itself
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What is the postictal phase
Consists of transient neurological and behaviour changes which lasts from hrs to days
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What are at home treatment options for seizures
Phenobarbital, potassium bromide, levetiracetam (keppra), and zonisamide
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What is automatisms
Repetitive motor activity that resembles movement under voluntary control such as lip smacking, licking, or chewing
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What is an atonic seizure
Sudden loss of muscle tone lasting several seconds or more not following a tonic or myoclonic event
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What is a generalized seizure
Seizures originating from both hemispheres of the brain
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What is idiopathic epilepsy
Epilepsy w/o an identifiable structural cause typically assumed to be genetic
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What is interictal period
The time btw seizures
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What is myoclonic seizure
Sudden brief contractions of a muscle or group of muscles
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What is the refractory epilepsy
Seizures that occur even during treatment w/ therapeutic doses of antiepileptic medication and medication stops being effective
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What is status epilepticus
A serious condition where seizures follow closely on one another w/o a break or where a single seizure lasts more than 5 mins
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What is a tonic seizure
A sustained increase in muscle tone lasting up to several mins
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What is a tonic clonic seizure
A seizure where the tonic phase is followed by shorter clonic movements
