nervous system Flashcards
(149 cards)
1
Q
central nervous system (cns)
A
consists of the brain and spinal cord
2
Q
peripheral nervous system (pns)
A
consists of all of the outside of the body outside the cns
cranial nerves emerge from the brain
spinal nerves emerge the spinal cord
3
Q
afferent nerves (aka Sensory nerves)
A
conduct impulses toward CNS
4
Q
efferent nerves (aka Motor nerves)
A
conduct impulses away from cns
5
Q
somatic nervous system
A
under voluntary control
stress, fight or flight
6
Q
autonomic nervous system
A
not under voluntary control
at rest rest and restore
7
Q
neuron
A
basic functioning unit of nervous system
high requirement for oxygen , cannot reproduce, can regenerate if cell body stays intact
8
Q
dendrites
A
receive impulses, transmit to cell body
may serve as sensory receptors
short numerous multi branched
9
Q
axon
A
conducts impulses away from cell body
single long
10
Q
neuroglia (aka glial cells)
A
support and protect neurons
wrap around cells pf neurons creating myelin sheeth
increases speed of impulses conducting through saltatory conduction
impulse skips glial cells and is only transmitted by nodes of ranvier (gaps between glial cells)
enables fine motor movement
11
Q
oligodendrocytes
A
in cns
12
Q
schwann cells
A
pns
13
Q
white matter
A
nervous tissue containing mostly neurons with myelinated axons
14
Q
gray matter
A
nervous tissue containing mostly neurons with unmiolinated axons
15
Q
resting state
A
neuron not being stimulated
net charge within neuron is more polarized than outside
net charge outside of cell is more negative
16
Q
resting membrane potential
A
electrical difference in charges across the cm
17
Q
sodium potassium pumps
A
embedded in plasma membrane of neuron pumps
sodium from inside of cell to outside
potassium from outside of cell to inside
18
Q
depolarization
A
net charge within cell becomes more positive due to influx of sodium the change in net electrical charge is action potential
19
Q
steps in depolarization
A
neuron receives external stimulus or impulse from adjacent neuron
sodium channels to open
sodium flows into cell via passive diffusion ions are driven into cell by concentration gradient attraction to negative charge within cell
20
Q
repolarization
A
sodium channels close
potassium channels open
potassium diffuses out of the cel due to concentration gradient repulsion from net positive charge within cell any misplaced ions are moved back to original sides by sodium potassium pump resting state restored
wave of depolarization moves down axon in the conduction of he action potentil
21
Q
threshold stimulus
A
stimulus of sufficient intensity to generate nerve impulse
stimulus must be sufficient to cause complete depolarization to reach threshold
22
Q
all or nothing principle
A
neuron depolarizes completely or not at all
23
Q
refractory period
A
cell must complete each depolarization/repolarization cycle
24
Q
absolute refractory period
A
during sodium influx and early potassium outflow cell can absolutely not respond
25
relative refractory period
during end of repolarization another depolarization may begin if stimulus is very large
26
saltatory conduction
myelin sheeth prevents sodium ions from flowing across cm
depolarization in myelinated axons only takes place at nodes of ranvier
greatly increase rate of conduction
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synapse
junction between two neurons or a neuron and a target cell
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synaptic cleft
gap between adjacent neurons or a neuron and a target cell
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synaptic transmission
perpetuation of nerve impulse from one neuron to the next or from a neuron to a target cell across synaptic cleft
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pre synaptic neuron
neuron bringing depolarization wave to synapse releasing neurotransmitter into synaptic space
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post synaptic neuron
neuron receiving neurotransmitter
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telodendron
branched structure at end of axon of pre synaptic neuron
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synaptic knob
enlarged bulb at end of tolenderon
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excitatory neurotransmitters
cause an influx of sodium ions into post synaptic membrane
inside of cell becomes more positively charged
post synaptic membrane moves toward threshold
35
inhibatory transmitters
cause Cl ions to enter cell and potassium ions to leave
inside cell becomes more negatively charged
post synaptic membrane moves away from threshold
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acetycholine
excitatory at neuromuscular junction
| inhibatory inside the heart
37
catecholemines
norepinephrine and epineprine - excitatory associated with fight or flight response
dopamine excitatory inhibatory involved with autonomic functions and muscle control
38
gamma aminobutyric acid (GABA)
inhibatory found in the brain
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serotonin
found in the brain involved in regulation of feeling , appetite, sleep
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glycine
inhibatory found in spinal cord
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acetycholinesterase
breaks down acetycholine
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monoamine oxidase (MAO) and catechol o methyl transferase (COMT)
break down catecholimines, epinephrin
43
cerebrum
largest part of brain in mammals
responsible for highest centers of function
receives and interprets sensory input info
initiates consious impulse to skeletal muscles (voluntary )
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gyri
folds in cerebral hemispheres
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sulci
shallow grooves seperating gyri, divides cerebrum into lobes
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longitudinal fissures
divides cerebrum into left and right hemispheres
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cerebral cortex
outside layer of cerebrum composed of gray matter
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cerebral medulla
inner layer of cerebrum composed of white matter
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corpus callosum
nerve fibers that connect left and right hemispheres
50
cerebellum
coordinates motor control balance complex reflexes
| stimulates or inhibits specific muscle fibers to fine tune movements
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diancephelon
controls primitive , autonomic functions
| passageway between cerebrum and the brain stem
52
thalumus
regulates sensory inputs to cerebrum
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pineal body
influences suiclic (sleep and wave cycles) activates by secreting melatonin
54
hypothalamus
is the interface between the nervous system and endocrine system ; major roles in temperature regulation, hunger, thirst, anger
55
pituitary
attached but not apart of diancephelon os the endocring "master gland" regulates hormone production/ release throughout the body
56
brain stem
composed of medulla ablongata, pons midbrain
connects brain and spinal cord
regulates basic support functions
swallowing vomiting hr blood vessel diamtere
57
blood brain barrier
oligodendrocytes cover fenestrations of glial cell in brain
| prevents molecules cells ions from readily passing bloodstream into brain
58
spinal cord
conducts sensory info and motor instructions between brain and peripheral nervous system
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spinal cord anatomy
cortex outermost; white matter
| medulla central tissue ; gray matter
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dorsal horns in spinal cord
receives and forward afferant impulses
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ventral horns in spinal cord
transmit efferant impulses to spinal nerves
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central canal in spinal cord
center of medulla of spinal cord
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dorsal and ventral nerve roots of spinal cord
emerge from spinal cord between ?
dorsal contain afferant fibers
ventral contain effernt fibers
64
meninges
connective tissue layers covering the cns
bloodo vessels fluid fat fibrous connective tissue
supply superficial tissues of cns with oxygen and nutrients PROVIDE CUSHIONING AND KEEPS BRAIN AND SPINAL CORD AT CORRECT TEMP
dura matter arachnoid pia mater
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cerebrospinal fluid
found in subarachnoid space cools and protects cns absorbs and carries away wastes
66
autonomic nervous system
all body functions not controlled by self
67
sympathetic nervous system
nerves emerge from thoracic and lumbar regions of spinal cord
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parasympathetic nervous system
nerves emerge from brain and sacral regions of spinal cord
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efferent motor nerves composed of
two neurons
pre gnglionic cell body in target organ
post ganglionic synaoses with target organ
70
pah of impulse
CNS --->preganglionic neuron --> autonimic ganglion --> post ganglionic neuron --> target organ
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primary transmitters of sympathetic nervous system
are the catecholimines epinephrine and norepinephrine
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adrenergic neurons
release catecholimines
73
cholinergic neurons
release acetycholine
74
nicotinic receptors
are located on post ganglionic neurons
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muscarinic receptors
located on target organs
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somatic reflexes
involve contraction of skeletal (voluntary)
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autonimic reflexes
affect smooth, cardicac, and endocrine glands
78
contralateral reflex
involves stimulus on one side of body with a response on the opposite side
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ipsilateral reflex
involves stimulus on one side of body with a response on the same side
80
reflex arc
sensory receptors on afferant neuron relays impulse to grey matter of cns
cns integrates impulse with impulses from other afferant neurons
cns sends integrated response to efferent neurons
EFFERENT NEURONS RELAYS IMPULSE TO TARGET TISSUE
target tissue performs reflex action
81
stretch reflex
muscle is stretched stimulates stretch receptors
stretch receptors sends impulse via afferant to ?
at spimal cord afferant neuron synapses with efferent neuron that innervates the same muscle
muscle contracts opposing muscle relaxes
prevents over stretching
82
withdrawal reflex
receptor on affersnt neuron picks up noxious stiumulus
impulse sent via afferant neuron to spinal cord
AT SPINAL CORD AFFERANT NEURON SYNAPSES WITH EFFERENT NEURON THST INNERVATES THE SAME MUSCLE
muscle contracts opposing muscle relaxes
withdrawal occurs before brain is contiously aware of stimulus
83
crossed extensor reflex
works in concert with withdrawal reflex
causes contraction of corresponding extensor muscl eon opposite side of body
prevents animal from falling over when limo is withdrawn
84
palpebral reflex
light tap on medial canthus causes blink
85
pupilary light reflex
shining of light on eye causes both pupils to constrict
| does not assess vision
86
menace reflex
blink occurs in response to rapid approach of an object
87
anal/perineal reflex
contraction of external anal sphincter upon stimulation of perineum
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panniculus reflex
pinpricks spplied to skin of thorax nd abdomen result in contraction of cutaneous trunci muscles
(skin quiver)
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corneal reflex
blink occurs in response to stimulation pf the cornea
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hyperreflexive
trauma to area cranial to reflex
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hyporeflexive or absent
trauma to dorsal or ventral nerve root to afferant or efferent nerves
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the neurologic exam
allow to move normally
| assess BAR, QAR,
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obtunded
responsive to stimulit but lethargic
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stupor
unresponsive to normal stimulit responds to painful stimulit
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coma
unreaponsive to all stimuli
96
test spinal reflexes grade
```
0- absent response
1- hyporeflexive
2- normal response
3-hyperreflexive
4-clonus
```
97
lab diagnostics
serum chems rules out metabolic
serology may rule out infectious dz
CBC may rule out inflammation
98
myelography
injection of radiopaque contrast medium into subarachnoid space followed by radiograph
identify specific site of lesion and often etiology
99
purpose of cns analysis
differentiates between infectious and noninfecious agents inflammation
in small animals performed at atlanto occipital joint
large animals - lumbo sacral joint
100
ataxia
lack of voluntary control of muscl emovement (drunk)
101
paresis
limb weakness
102
paralysis
total loss of control of limb
103
dysemetria
choppy uncoordinated gait
104
hypermetria
exagerrated flexion and extension of limbs
105
tetanus
serve generalized miscle twitching that may progress to seizures
106
opisthotonus
spasm of front limb and neck muscles results in lateral recumbancy
107
aniscoria
unequal pupil size
108
horners syndrome
enopthalmos, miosis, drooping eyelid, prominent nictitating(3rd eye exposed) membrane
interupion of sympathetic innervations to eye due to traumu surgery inflammation or neoplasias identical signs may be observed in cases of neck trauma
109
subclinical seizure
more subtle, often manifests as bizarre
110
status elepticus
more than 5 minutes multiple seizures with conciousness incompletely regained between episodes
111
cluster seizures
series of 3 + distinct seizure over a period of 24 h consciousness is regained between episodes
112
seizure etiology
< 1 year old infection or hypoglycemia
1-5 years old epilepsy idiopathic
5 years neoplasia
113
seizure immediate treatment
prevent patient from hurting himself or others
do not move patient
if enters status elepticus dvm may direct iv benzidiazepine propofol or pheonobarbital
114
cognitive function
change in behavior linked to aging that are not due to failure of any organ
elevated levels of free radicals
115
spinal disorders etiology
trauma IVDD disospondylosis degenerative dz congenital deformity
treatment NSAIDS or corticosteroids rest minimal activity
116
IVDD
degeneration and subsequent herniation of the intervertebral disks resulting in compression of the spinal cord spinal nerve and or nerve root
treatment rest minimal activity nsais or corticosteroids
surgical- hemilaminectomy dorsal laminectomy
117
vestibular dz etiology
periperal vestibular dz middle ear infection
central vestibular dz CNS dz
neoplasia of brain, cerebrovascular accident (stroke)
rocky mountain spotted fever '
old dog vestibular dz idiopathic
118
myasthenia gravis
failure of neuromusclular conduction
| development of circulating antibodies against acetycholin receptors
119
infectious dz of the nervous system
| inflammation of cns- encephalitis, myelitis, meningitis etc
bacterial or fungal infection
canine distemper
toxoplasmosis , rabies, FIP
120
cerebellar hypoplasia
seen in kittens in utero with panlukopenia
121
nuerotoxins
found in slug or snail baits , highly palpatable liquid, dust or granules, readily absorbed from GI tract rapidly metabolized
122
pathogenisis of neurotoxins
reduces concentrations of y-aminobutyric acid causing overexcitment in CBS
reduces concentrations of seratonin and epinephrin decreases the seizure threshold increases activity of monoamine oxidase
123
strychnine
found in goeffer bait
readily absorbed from gi rapidly metabolized
clinical signs develop 30 - 60 min post ingestion spontaneous seizures initiated by mild stimuli hyperthermia cyanosis
124
organophosphates
SLUDDE nicotinic, central ataxia and seizures
| treatment, atropine and diazepam
125
physiology of pain
mechanical-touch vibration
thermal- heat cold
electromanetic, vision,
chemical taste smell
126
nociception
process of experiencing a noxious stimulus
| pain receptors are nociceptors
127
1 in pain pathway is transduction
conversion of noxious stimulus to nerve impulse
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2 in pain pathway transmission
conduction of impulse via afferant nerve to spinal cord
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3 in pain pathway modulation
amplification or suppression of impulse
occurs at dorsal horn of spinal cord alters info before sending to brain
suppression involve release of enkephalins (bodys opioids)
130
4 in pain pathway perception
consious awareness of pain
| stimulates sympathetic response
131
5 in pain pathway
analgesics and anesthesetic affets one or more steps
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physiologic pain
bodys protective mechanism o avoid tissue injury
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pathologic pain
follows tissue injury , inflammation , or nerve damage
134
neuropathic pain
due to damage to PNS or CNS
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nocioceptive pain
due to damage of any other type of tissue
136
somatic pain
affects skin and limbs
137
visceral pain
affects internal organs
138
anticonvulsants controll active seizures
diazepam or midazolam iv or rectal to effect
| propofol pentobarbital - low margin of safety
139
benzodiazepines, barbiturate
c-iv
140
barbituate
c-ii
141
contraindications with phenobarbital
quick tolerance gained due to liver enzymes
142
analgesics
prevent and relieve pain more effective ar preventing pain thsn relieving pain once established
143
side effects with long term drug therapy
liver, kidney, cardiovascular effects.
| regular cbc, serum chemistries ecg
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phenothiazines
blocks dopamine and a adrenergic receptors
| relieve fear and anxiety anti emetics
145
phenothiazines adverse effects******
hypotension, paraphimosis , aggression, lowering of seizure thrshold
examples- acepromazine
146
anti depressants
used to treat mood changes aggression cognitive dysfunction can cause liver damage thyroid effects
147
MAO inhibitors
inhibit the MAO enzyme in the brain causing dopamine norepinephrine and seratonine to remain in the synaptic space
causes hypotension
148
SSRIs
```
selectively inhibit serotonin reuptake in the brain
can cause lathargy reduced appetire gi affecs restlessnes shaking
fluxetine I(prozac)
uses depression af=ggression anxiety phobias compulsive disorders
```
149
cause for cerebellar hypoplasia in felines
There are several bacterial infections and viral infections such as feline panleukopenia, caused by feline parvovirus (while in utero),[2] that can result in the disorder in both cats and dogs. The disease can also be caused by malnutrition, poisoning, injury or general accidents during development in the fetus.[3]
