central nervous system Flashcards
central nervous system organisation: explain the relationship between the major divisions of the central nervous system, including spinal cord, brainstem, cerebellum, diencephalon and cerebral hemispheres
what does the CNS consist of
brain and spinal cord
what makes the human brain different to other animals
increased surface area (of cortex) so greater number of cerebral cortex neurons
3 layers of brain
cerebrum, brainstem, cerebellum
what does the cerebrum consist of
diencephalon and cerebral hemisphere
what does the diencephalon consist of
thalamus and hypothalamus
what does the brainstem consist of
midbrain, pons, medulla oblongata
what does the spinal cord consist of
lies in the vertebral column, consisting of vertebra, in between which are the intervertebral foramen, and is surrounded by 3 membranes (meninges)
how many pairs of nerves in the spinal cord and how many vertebra
31 pairs of nerves coming out just below corresponding vertebra, of which there are 30
where is the extra nerve
extra cervical nerves from C1 to C8 (only 7 vertebra)
spinal cord length vs vertebral colum
spinal cord shorter than vertebral column as horse tail shape (cauda equina from L2 downwards)
spinal cord: dorsal to ventral and relative size
cervical (enlargement; 7 vertebra and 8 nerves) → thoracic (12) → lumbar (enlargement; 5) → sacral (5) → coccygeal (1)
why is a lumbar puncture conducted between L3 and L4 or L4 and L5 form the lumbar cistern
no nervous tissue just fibres so able to do lumbar puncture for CSF
what does each spinal cord segment innervate
a particular skin area (dermatome) and muscle area (myotome)
structure of spinal cord
grey matter (butterfly shape; either side are dorsal horns and ventral horns) and white matter
what is present in grey matter
motor soma and interneurons
what is present in white matter
nerve bundles (axons) with short connections between adjacent segments and long tracts connecting all levels of the spinal cord with the brain
what occurs at dorsal horns
sensory neurone make connection (soma in dorsal root ganglion)
what occurs at ventral horns
motor somas present
diagram of spinal cord cross section
diagram from Medlearn
where do nerves exit from the spinal cord
intervertebral foramina
where does the brain lie
within cranial cavity of skull
what surrounds the brain
meninges
what does the brainstem connect
connects cortex to spinal cord via pons
significance of where brainstem connects
where nerves cross so left side of brain controls right side of body and vice versa
where do some cranial nerves have their origin
medulla oblongata
what do cranial nerves in the medulla oblongata do
control basic vital functions like heartbeat, swallowing, breathing, as well as supplying motor, sensory and autonomic innervation to the head
what does the cerebral hemisphere consist of
basal ganglia, cerebral cortex and corpus collosum
what is present in the basal ganglia
nuclei
basal ganglia: what do the caudate and putamen form together
corpus striatum which is connected to cortex, thalamus and substantia nigra
basal ganglia: what do the putamen and globus pallidus form together
lentiform nucleus
what do the basal ganglia and substantia nigra degenerate to cause
Parkinson’s disease
cerebral cortex: what are gyri and sulci
bumps and fissures
cerebral cortex: 4 lobes
frontal lobe, parietal lobe, temporal lobes and occipital lobe
features of cerebral cortex
laminar (layered) and somatotropic (nerve terminals to range of locations)
what does the limbic system consist of
various components of brain (cerebrum and diencephalon)
what connects the two cerebellum hemispheres
vermis
what is the posterior section of the cerebellum connected to
brainstem; grey cortex (deep parallel folds), deeper white matter, with nuclei
what is cerebellum connected to
vestibular system, spinal cord and muscles, and motor cortex and thalamus
white matter: corpus callosum function
commissural fibers allowing for association between hemispheres
white matter: location of association fibres
within hemispheres
white matter: corona radiata function
connects both motor and sensory nerve pathways in brain stem and cortex using projection fibres
