The Central Nervous System Flashcards
what makes up the central nervous system
the brain and spinal cord. lies within the skull and vertebral canal
what is the spinal cord covered by
three different meninges
- dura mater
- arachnoid membrane
- pia mater
what are the different segments/ regions of the spinal cord
- cervical
- thoracic
- lumbar
- sacral
- coccygeal
what does grey matter contain
neuron cell bodies and some axons
what does white matter contain
nerve axons
explain dorsal horn grey matter
found in the dorsal or posterior part of the spinal cord.
location of first order afferent neuron terminals
contains cell bodies of second order sensory neurons
explain ventral horn grey matter
ventral or anterior part of the spinal cord
contains cell bodies of motor neurons
motor neuron axons leave the cord via the ventral nerve roots
why is white matter grey
because it is stained for myelin and therefore appears dark.
how is white matter organised
into various groups of axons that serve particular functions
describue the regional differences in grey and white matter
cervical - more white than grey
thoracic - more white than grey
lumbar - more grey than white
sacral - more grey than white
describe the organisation of white and grey matter in the brain
the grey matter is on the outside
describe the organisation of white and grey matter on the spinal cord
the white matter surrounds the grey matter
what are the different regions of the brain
forebrain, midbrain and hindbrain
what is found within the forebrain
the cerebrum and diencephalon
what is found within the hindbrain
the pons, medulla oblongata and cerebellum
what does the midbrain control
visual and auditory reflexes
pain control
what does the hind brain control
vital centres, regulating breathing, heart, blood vessels, etc
also controls balance and posture
what is found in the forebrain diencephalon
thethalamus and the hypothalamus
what is the thalamus responsible for
sensory processing
what is the hypothalamus responsible for
homeostasis - thermoregulation
hormone production
associated with the pituitary gland
circadium rhythms
motivation
emotional responses and stress
what is the cerebrum responsible for
sensory and motor functions
language
memory
perceptions
sensory-motor integration
emotions
what form of matter is the cerebrum
grey
what form of matter is the corpus callosum
white
what are the different regions of the lateral surface of the brain
frontal lobe
parietal lobe
temperol lobe
occipital lobe
what is the function of the meninges surrounding the spinal cord
protection of the spinal cord
why is white matter white
fat content - comes from the myelination of the matter. myelin is responsible for the presence of white matter in the cns
where are cell bodies found in the cns
at the core of the spinal cord in two areas - the ventral horn at the front, and the dorsal horn at the back.
why does the outskirts of the spinal cord have white matter
due to axons bringing information up and down the spinal cord
give a summary on the dorsal grey horn
this is the posterior part of the spinal cord and is the location of first order afferent neuron terminals. the stain is for myelin and is found on white matter, which is white matter looks darker.
give a summary on ventral horn grey matter
anterior portion of the spinal cord where the cell bodies of the motor neurons leave via ventral nerve roots.
explain why there are reginal differences in the proportion of white and grey mattter in the spinal cord
every time you bring information or take it out, a cell body is needed. these generate grey matter.
every time information is gathered, it needs to travel all the way up the brain stem through the white matter
in what section of the brain can strokes have an impact on cranial nerves
the base of the brain
what is the most prominent neuron in the cerebral cortex
the pyramidal cells. they are efferent neurons that integrate sensory information and initiate motor responses
describe the dura mater
tough and fibrous, forms the outermost covering of the spinal cord. contains dense collagen fibres.
describe the arachnoid layer
this is the middle layer and is simple squamous epithelium
describe the pia mater
meshwork of collagen and elastic fibres that band to underlying neural tissue
what are nissl bodies
regions of RER clusters and free ribosomes in the cytoplasm surrounding the nucleus of neural cell bodies
what is the perikalyon
the cytoplasm surrounding the nucleus of neural cell bodies
what is the axolemma
the plasma membrane of the axon
what are telodendria
the axon terminal branches
where are axon terminals found
at the end of telodendria
what do collaterals allow
single neurons to communicate with several other cells
what are plexuses
interwoven networks of spinal nerves.
what are the different structural classifications of neurons
anaxonic
bipolar
unipolar
multipolar
what is an anaxonix neuron
has more than 2 processes and the axons are not obvious
what is a bipolar neuron
two processes separated by cell bodies
what is a unipolar neuron
a single long process
what is a multipolar neuron
a single axon with multiple dendrites
how long is the spinal cord usually
45 cm
where is the amount of grey matter in the spinal cord greater
in the regions dedicated to sensory and motor control
what are the different plexuses of the spinal cord
cervical
brachial
lumbosacral
sacral
where does the cervical plexus run from
c1-c5
where does the brachial plexus run from
c5-t1
what does the cervical plexus innervate
the muscles of the neck and diaphragm
what does the brachial plexus innervate
pectoral girdle and upper limbs
what are the major nerves of the lumbosacral plexus
femoral, obturator, and saphenous nerve
what are the major nerves of the sacral plexus
gluteal and sciatic nerves
what are the major nerves of the cervical plexus
- the lesser occipital nerve
- great auricular nerve
- trasnverse cervical nerve
- supraciavicular nerve
- phrenic nerve
which region of the spinal cord contains cell bodies of the motor neurons
ventral horn grey matter
which region of the spinal cord is the location of first afferent neuron terminals
dorsal horn grey matter
what is found in the dorsal grey matter
first order afferent neuron terminals
cell bodies of second order sensory neurons
what are second order neurons
neurons that receive synaptic input from efferent neurons and then provide this to the spinal cord - act as a bridge between the primary neuron and the spinal cord. does not directly receive or deliver stimulus from or to effectors
what is the corpus callosum
large white matter tract that connects the two hemispheres of the brain and allows us to perceive depth and communicate
what is the arachnoid trabeculae
the arachnoid trabeculae are the network of collagen and elastic fibres that extend between the arachnoid membrane and the pia mater
anaxonic neuron
bipolar neuron
interneuron
motor neuron
multipolar neuron
sensory neuron
unipolar neuron
