week 1 Flashcards
prosencephalon is also known as the _____
forebrain
prosencephalon is composed of what parts
telencephalon and diencephalon
what is the telencephalon?
cerebrum or cerebral hemisphere
telencephalon is composed of what?
cortex, centrum, basal nuclei
what is the diencephalon composed of?
thalamus, hypothalamus, metathalamus
diencephalon is the most ____ portion of the brainstem
rostral
can you distinguish a lesion form telenephalon or diencephalon?
no (only on MRI). refer to as prosencephalon lesion
Mesencephalon is also called the ____
midbrain
what part of the brain is undivided?
mesencephalon
rhombencephalon is also called the ____
hind brain
rhombencephalon is composed of what?
metencephalon and myelencephalon
metencephalon is also called the ____
Pons
myelencephalon is also called the ____
medulla oblongata
what is the cerebellum
dorsal outgrowth from metencephalon
what is the order of the parts of the brain?
prosencephalon (forebrain)
mesencephalon (midbrain)
metencephalon (pons)
myelencephalon (medulla oblongata)
OR rhombencephalon (hindbrain)
what is the cervical spinal cord segment
C1-8
What is the thoracic spinal cord segment
T1-13 or T1-18
what is the lumbar spinal cord segement
L1-7 or L1-6
What is the sacral spinal cord segment
S1-3 or 1-4 or 1-5
What is the caudal spinal cord segment
Cd 1-5
what is the neck region of the spinal cord
C1-5
what is the forelimb spinal cord region
C6-T2
what is the back and flank (trunk) spinal cord region
T3-L3
what is the hindlimb region
L4-S2 or S3
What is the pelvis, anal, urinary bladder and tail regions of the spinal cord
S1 or S2-Cd5
what does paresis mean
partial paralysis; weakness; “paretic”
what does ataxia mean
uncoordinated gait
why do the areas of the hindlimb spinal cord and pelvic spinal cord overlap?
due to the pudendal nerve
view chart for nervous system pg. 32
x
what are the 5 key concepts of the nervous system
- nervous system is divided into two parts
- all neurons consist of 4 parts
- 3 types of neurons and functional systems within the NS
- Normal motor function requires 2 types of neurons: UMN and LMN
What are the 2 parts of the nervous system
central nervous system (brain and spinal cord)
peripheral nervous system (CNN and ganglia numbered I-XII, Spinal nerves and peripheral nerves, bulk of autonomic nervous system: sympathetic trunk, splanchnic nerves, ganglia, etc)
what are the 4 parts of a neuron
dendritic zone
cell body (soma, perikaryon)
axon (nerve fiber, axis cylinder)
telodendritic zone (end plate, synapse; TDz)
dendritic zone in a motor neuron is called a _____
dendrite (beginning of a neuron)
dendritic zone in a sensory neuron is called a _____
receptor
where do dendritic zones lie?
either in the CNS or PNS for a single neuron (NOT BOTH!)
cell body of a neuron is essential for what?
life of a neuron; can be effected by metabolic diseases
where do cell bodies lie?
in CNS or PNS for a single neuron (NOT BOTH)
What is the telodendritic zone in a nerve that innervates a muscle called?
neuromuscular junction
what are the 3 types of neurons and functional systems within the NS
- sensory/afferent neurons (system)
- integration neurons (system)
- motor/efferent neurons (system)
where is the dendritic zone of a sensory neuron located?
ALWAYS PNS
where is the cell body of a sensory neuron located?
ALWAYS PNS ganglion (Dorsal root ganglion is part of a spinal nerve, not the spinal cord); cranial ganlgion; axons are in both cns and pns (leaves pns to enter cns)
Are sensory nerves excitatory or inhibitory?
Always excitatory; turn on other neurons in the cns
where are integration neurons located (cns or pns)?
all parts are in the CNS; so cant damage with a peripheral lesion
what is the function of integration neurons
they initiate, control, or regulate all CNS functions; but since they dont leave the CNS, they depend ont the LMN to actually carry out the functions listed above
what is the function of ascending projection neurons
relay/transfer info to brain (cerebellum or conscious cortex)
what are ascending projection neurons (also called long tracts)
long interneurons
axons of ascending projection neurons travel in which direction?
axons ascend in the spinal cord white matter to multiple regions of the brain passing on sensory information
where is the cell body of a descending projection neuron located
cell body is in the brain
what is a descending projection neuron
an upper motor neuron (long interneurons)
what is the function of descending projection neurons
talk to and control function of LMN
motor/efferent neurons are what
LMN; Can be either GSE (all spinal nerves, most peripheral nerves, and cnn III, IV, V, VI, VII, IX, X, XI, XII) or GVE (all spinal/peripheral nerves and cnn III, VIII, IX, X)
Are motor/efferent neurons excitatory or inhibitory
all are excitatory
what occurs during a reflex?
extensors are relaxed (turned off by inhibitory neurons) flexors contract (turned on by excitatory)
see drawing pg 36 for DPN
X
UMN are confined to the ____
CNS
Where are the cell bodies for UMN located
Brain only (NONE IN SPINAL CORD)
Axons of UMN travel in which direction
caudally down spinal cord
UMN function to
initiate voluntary movement, regulate tone, regulate posture, help control reflexes, and help regulate balance and equilibrium, but only via a LMN can it talk to the effector organ
are UMN excitatory or inhbitory
can be both
What is the last link between the brain and skeletal muscle
LMN; only neuron that actually contacts muscle or glands
where are the cell bodies of LMN located
in the CNS
axons of LMN travel where
to the PNS
How can LMN be damaged
either centrally (the cell body of preganglionic) or peripherally (the axon or postganglionic neuron cell body)
are LMN excitatory or inhibitory
all are excitatory (tonically active!); will fire all the time if not inhibited
what happens to muscles when an UMN is damaged
muscles become rigid because the inhibitory neurons are not working; therefore LMN are continually firing and you have an exaggerated reflex
is there only a single umn for every lmn?
no; usually a dozen or more UMN communicating with a single lmn
what is a LMN unit?
cell body, axon (ventral root nerve), junction, muscle (MUST ALL BE WORKING FOR PROPER FUNCTION OF MUSCLE)
Where is a central lesion located?
either in the 5 parts of the brain or the 5 parts of the spinal cord
where is a peripheral lesion located?
anywhere outside the brain/spinal cord (However, can be inside our outside the skull or vertberal column)
what are axon bundles in the PNS called
nerves
what are axon bundles in the CNS called
tracts, fasciculi, funiculi, etc.
what is a receptor?
the dendritic zone of a sensory/afferent neurons;
what is the function of a receptor (dendritic zone)?
it transduces some form of energy into electrical signals, which, if strong enough or repetitive, can generate an AP that is carried centrally
what are the different modalities
touch (GSA) temperature (GSA) nociception (GSA; GVA) proprioception (GP; SP) vision (SSA) hearing (SSA) smell (SVA) taste (SVA) vibration (GSA) Burning (GSA; GVA) itching (GSA) pressure (GSA; GVA)
What are the 3 sensory modalities that are reliable and observable so veterinarians can use in a neuro exam
nociception/pain
proprioception
vision
review gsa, gva, gse, gve, ssa, sva
x
once the axon of a sensory neuron enters the CNS, what does it do?
it can ascend in the white matter on the same or opposite side several segments
it can descend in the white matter on the same or opposite side several segements
the axon of a sensory neuron in the cns will eventually synapse on what
interneurons, projection neurons, or motor neurons inthe ipsilateral or contralateral gray horn
LMN to skeletal muscle are ____
somatic LMN
LMN to autonomic tissue called ______
pre-ganglionic LMN, and the second LMN which has cell body in PNS is post-ganglionic LMN
nerves are classified as
motor
sensory (GSA)
both motor and sensory (mixed)
why are these faulty classifications
sensory nerves to skin also supply GVA and GVE fibers to blood vessels as well as return GSA fibers, and motor nerves also carry GVA and GVE fibers to blood vessels in muscle as well as return proprioceptive information (GSA) from muscle spindles along with the GSE fibers they send to skeletal muscle
be able to describe a nerve in great detail
x
receptors convert ______ energy into electrical signals
chemical, mechanical, thermal or radiant energy
what modalities are unconscious but important to consider
Blood pressure (GVA)
CO2 or O2 (GVA)
PH (GVA)
(baroreceptors, chemoreceptors, unconscious perception)
Plegia
paralysis
paraplegic
only half limbs are paralyzed
patient assessment includes
signalment chief complain history physical exam neurological exam localization of the lesion lesion distribution classification of the disease differential diagnosis list anciallary aids diagnosis treatment prognosis
history includes
onset (acute, subacute, chronic)
progression (progressive, intermittent, non progressive, improving)
duration
symmetry (right vs. left)
what can you assess on PE before even touching the animal
gait, posture, muscle atrophy
what are the important questions to ask yourself after Hx/PE
does the animal have a problem?
if so,could it be neurological?
if so, where is the lesion or abnormality?
after you localize the lesion, ask _____
how extensive is it?
lesion/distribution can be what?
unilateral or bilateral
asymmetric/symmetric
focal, multifocal, diffuse
focal
1 lesion
multifocal
2 or more lesions in 2 or more areas
diffuse
major areas of entire nervous system (brain/spinal cord)
can a lesion be bilateral and asymmetric?
yes
then ask yourself after localization ____
what is the lesion?
how did it get there?
what are ancillary aids
rule in/rule out
DAMN IT V system for classification of dz
Degenerative autoimmune malformation neoplastic/nutritional inflammatory traumatic vascular (stroke type events-> deprivation of blood or hemmorhage)
sign - time curve
most dz have signature time curve
curve form will vary depending on what
onset (acute vs. chronic)
progression (progressive, non progressive, intermittent)
what dz can look like anything on a sign time curve
toxic, nutritional, metabolic (typically diffuse, generated signs)
characteristics of toxic, nutritional, metabolic dz
- acute to subacute onset
- progressive but intermittent
- bilateral
- symmetric
- any age
- usually diffuse
- generalized signs
what is a lesion
something abnormal that causes a discontinuity of tissue or loss of function of a part (tissue or organ)
what is an anatomical lesion
infection, tumor, direct injury, vascular injury or clot, excessive pressure, fluid accumulation, foreign bod, etc.
what is a genetic lesion
inherited
what is a biochemical lesion
metabolic
what is a toxic lesion
due to lack of oxygen or excess co2, etc.
how can the nervous system be affected directly
- penetration
- via blood either arterial or venous
- via CSF (ear, nose, eye)
- trauma insede axial skeleton, but no penetration (laceration, vessel rupture, IV disk, pressure, etc.)
- spontaneous (tumor, genetic, inborn metabolic errors, etc,)
what are the ways the nervous system can be affected indirectly
- blockage of flow or absorption of CSF; rarely elevated CSF formation
- blockage of blood flow to NS
- Ascend nerves from receptors
- respiratory problems
- failure to eliminate waste
- metabolic problems
- malformation of immune system
what is the pia mater
directly adhered to brain
dura mater
thick cct membrane adhered to periosteum
is there an epidural space in the brain case?
no
arachnoid
beneath dura mater
subarachnoid space contains what
CSF
Blood vessels
subdural space
post mortem artifact
leptomeninges
postmortem; arachnoid that is collapsed and has trapped the blood vessels on pia mater; normally pigmented in ruminants (melanin pigmentation)
cerebral hemispheres composed of
cerebral cortex longitudinal cerebral fissue transverse cerebral fissure cruciate sulcus post-cruciate gyrus, pre-cruciate gyrus frontal lobe parietal lobe occipital lobe temporal lobe
what is the cerebral cortex composed of
gyrus (gyri)
sulcus (sulci)
fissure
what is a gyrus
elevations
what is a sulcus
valley
what is a fissure
deep valley that goes all the way to the white matter
longitudinal cerebral fissure
divides the cerebrum into 2 hemispheres
transverse cerebral fissure
separates cerebrum from cerebellum
cruciate sulcus is found in what species
varies from species to species; present in all species except cats
what is the cruciate sulcus
forms cross with longitudinal fissure
post-cruciate gyrus and pre-cruciate gyrus surround the
primary conscious motor cortex
frontal lobe is located where
area rostral to, and including, the post cruciate gyrus
what is the function of the frontal lobe
conscious initiation of motor activity
parietal lobe is located where
the area from the frontal lobe to approximately 1/3 distance to transverse fissure
parietal lobe function
conscioius somatosensory area (pain, proprioception, touch, temperature, etc.)
occipital lobe is located were
parietal lobe to transverse fissure
what is the function of the occipital lobe
conscious sight and sight association area; behavior
temporal lobe is located where
lateral side of hemisphere
temporal lobe functions in
conscious hearing and major behavior area
behavior is unique to the _____
entire forebrain
behavior problems occur from
at least one lesion on the forebrain
what is the cerebellum composed of
folia and sulci
vermis
lateral hemispheres (or lobes)
folia
gyri on cerebellum
vermis
rounded and elongated central part of the cerebellum, between the two hemispheres.
very caudal end of medulla oblongata is composed of
cerebellomedullary cistern (cisterna magna)
what is the cerebellomedullary cistern
well of CSF at beginning of brain stem (between medulla and cerebellum)
cerebral hemisphere is composed of
lateral rhinal sulcus neopallium paleopallium priform lobe sylvian (pseudosylvian) sulcus) temporal lobe frontal, parietal, occipital lobes olfactory bulb transverse fissure
what is the flocculus
most lateral small parts of each hemisphere (2 of them; one on each side)
what is the function of the flocculus
balance and equilibrium portion of cerebellum
how can you see the primary fissure
pull the cerebellum caudally to see
where is the rostral lobe
note only vermis; everything rostral to primary fissure; small
rostral lobe is primarilly associated with
motor activity of runk muscles
caudal lobe
rest of vermis and hemisphere except for floculus (caudal to primary fissure)
nodules
centrally located small lobe (1 of them; cannot see at this time)
what is the nodules and floccules called
flocculonodular lobe
what is the metencephalon composed of? (Pons)
transverse pontine fibers
middle cerebellar peduncle
CN V
choroid plexus of 4th ventricle
transverse pontine fibers come from
UMN centers in the brain
middle cerebellar peduncle
continuation of transverse pontine above CN V
choroid plexus of 4th ventricle
contains lateral aperture for CSF release into subarachnoid space (cannot see grossly)
choroid plexus produces what
CSF
Can you see midbrain or diencephalon on brain
No; may see optic nerve
