cns Flashcards
PNS is composed of
of nerves (cranial and spinal) and ganglia outside brain and spinal cord
CNS is composed of
brain and spinal cord
Brain is comprised
forebrain, midbrain and hindbrain
what is the forebrain composed of
cerebral hemishperes
diacephalon
hindbrain compistion
pons medulla cerebellum
Frontal function
Regulating and initiating motor function, language, cognitive functions (executive function [e.g. planning], attention, memory)
Parietal
Sensation (touch, pain), sensory aspects of language, spatial orientation and self-perception
Temporal
Processing auditory information
Occipital
Processing visual information
what is the inside lobe called
Limbic lobe
function
Concerned with learning, memory, emotion, motivation and reward.
comprises of
limbic lobeincludes the amygdala, hippocampus, mamillary body, and cingulate gyrus
which lobe lies deep within lateral fissure
Insular cortex
function
Concerned with visceral sensations, autonomic control, and interoception, auditory processing, visual-vestibular integration
what are the 2 layers of the dura called
periosteal - layer of periosteum
meningeal - durable, dense fibrous membrane
which epithelial cell produces csf
choroid plexus
where in the brain
of lateral, 3rd and 4th ventricles
where is the csf found
Occupies ventricular system and sub-arachnoid space
what strcuture reabsorbs it
Reabsorbed via arachnoid villi
to what region
superior sagittal sinus
4 diff between csf and plasma
Lower pH
less glucose
protein
potassium
how many regions does teh spine have
5
what do segments give rise to
each gives rise to a pair of mixed spinal nerves
one from right side
one from left side
what are the regions
cervical nerves thoracic nerves lumbar nerves sacral nerves conccygeal nerve
how many segmensts does cevical have
8
thoracic
12
lumbar
5
sacral
5
coccygeal
1
where do the nerves emerge from
through intervertebral foramina
where do nerves c1-c7 emerge
above vertebrae
and Nerves C8-Co1
emerge below vertebrae
why is the Cervical enlargement
innervation of upper limbs
why is Lumbar enlargement
innervation of lower limbs
Major pathway for voluntary movement is the
corticospinal tract
composed of
upper and lower motor nuerons
where are the upper motor nuerons
primary motor cortex
lower m n
brainstem and spinal cord
is it a ascending or de pathway
descending
what is the main pathway for bringing sensation from the body to the brain
dorsal column pathway
spinothalamic tract
what does the spinothalamic pathway function
pain, temperature (and crude touch) from the skin.
and Dorsal column pathway
fine touch, vibration and proprioception (position
are theu ascending or descending
a
are they motor or sensory
sensory
when are lower motor nuerons in brainstem
if they are going to the head or neck muscles
and if the l m b in spinal cord
muscle of truck and limb
lateral corticospinal tract supply
limb muscles
anterior corticospinal tract supply
truck muscles
what is the pathway that goes from primary motor cortex to the muscle of the face
corticobulbar tract
Vestibulospinal tract function
provides information about head movement and position and mediates postural adjustmentst
Tectospinal
orientation of the head and neck during eye movements
Reticulospinal
control of breathing and emotional motor function
Rubrospinal
- innervate lower motor neurons of the upper limb
where is the primary motor cortex
pre central gyrus
post central gyrus houses what
Primary somatosensory cortex
First synapse of the gracile tract is
in the gracile nucleus
First synapse of the cuneate tract
is in the cuneate nucleus
how many nuerons do the sensory pathway have
3
where does its first one have its cell body
dorsal root ganglion
2nd one has cell body where
medulla
in gracile or cuneate nuclues
where is the 3rd nueron
thalmus
the 3rd order neurons from the thalamus project to the
somatosensory cortex
Size of somatotopic areas is proportional to
density of sensory receptors in that body region (somatosensory homunculus
spinothalmic tract pathway
primary motor neurone coming into the spinal cord
second order neurone crossing nto the other side
third order nuerone from thalmus to the brain
difference between spinothalmic tract and dorsal tract
primary nuerone comes into dorsal horn
synapses onto second order nuerone on the level it comes in
crosses over into other side §
lateral spinothalamic tract sensation
Pain and temperature sensations ascend
anterior spinothalamic tract
Crude touch
how the spinal nerve break down
dorsal/ventral root
to
d/v rootlets
what do all secondary nuerons do
synapse
switch side
what are ascending tracts
neural pathways by which sensory information from the peripheral nerves is transmitted to the cerebral cortex.
how many order nuerons do they have
3
what are the 2 pathways signals travel through the dorsal column
fasciculus cuneatus
fasciculus gracilis
where do the dorsal coloumn nuerons desscuate/cross over and synapse
medulla (either in the nucleus gracilis or nucleus cuneatus)
where do the 3rd order nuerones begin
thalamus
where do the signals go from the thalamus
third order neurones transmit the sensory signals from the thalamus to the ipsilateral primary sensory cortex of the brain
in an lesion to the spinal cord affecting dorsal column will where the sensory loss will be
ipsilateral same side
as they cross over/decussation occurs in the medulla oblongata
major difference in spinothalamic tract and dorsal
The first order neurone decussate in at the tip of the dorsal horn
where do the 2nd nuerons go
thalamus
what sensation enters the anterior spinothalamic tract.
Crude touch and pressure fibres
lateral spinothalamic tract.
Pain and temperature fibres
what do the 3rd order nuerones do
The third order neurones carry the sensory signals from the thalamus to the ipsilateral primary sensory cortex of the brain
what would the sensory loss to a lesion. affecting the stt
this sensory loss will be contralateral (the spinothalamic tracts decussate within the spinal cord).
what does the middle cerebral artery supply
a portion of the frontal lobe and the lateral surface of the temporal and parietal lobes, including the primary motor and sensory areas of the face, throat, hand and arm, and in the dominant hemisphere, the areas for speech.
so a stroke to primary motor cortex can affect
it affects the ability of the brain to control the body’s movement.
Signals from the upper limb (T6 and above) (in dorsal) travel via which pathway
fasciculus cuneatus
Signals from the lower limb (below T6) – travel in the
fasciculus gracilis
