006 An introduction to the Nervous system: Brain and Spinal Cord, Cranial and Spinal Nerves (and nervous system histology) Flashcards
what is a?
vertebral bodies
what is b?
spinous processes of vertebrae
what is c?
spinal cord
what are the meninges and where are they?
layers of membranes surrounding and protecting the spinal cord and the brain
what are the 3 layers of the meninges?
dura (outermost) , arachnoid, pia (inner most)
what fluid is the CNS and where is it found?
- CSF (cerebral spinal fluid) found in the subarachnoid space (between arachnoid and pia)
what is a?
dorsal column of white matter (myelinated neurons)
what is b?
dorsal horn of grey matter ( unmyelinated sensory neurones)
what is c?
ventral horn of grey matter (unmyelinated motor neurones)
what is d?
central canal
- runs all the way down the spinal cord
- some stem cells
- remains of the lumen of embryonic neural tube
- contains CSF
outline the structure of the spinal cord
- 3 layers of meninges, dura, arachnoid, pia
- subarachnoid space with CSF and vessels In it
- white matter and grey matter in middle
- grey matter making bilateral ventral and dorsal horns
- central canal in middle containing CSF
what are each segment of the spinal cord names after?
the spinal nerve they are attached to e.g. T12
where in the spinal cord is there the most white matter and why?
- cervical region
-many axons going up to the brain from all levels of the spinal cord AND there are many axons traveling from the brain down to different segments of the spinal cord
where in the spinal cord is there the most grey matter?
cervical and lumbosacral
where does the spinal cord end and what is it called?
- conus medularis at L1 vertebrae
what happens below the end of the spinal cord (below conus medularis)?
- lumber and sacral spinal nerve roots keep extending further down below L1
- called cauda equina (horse’s tail)
what is the denticulate ligament?
extension of the pia mater
= anchor spinal cord to dura mater
describe the overall development of the CNS in the embryo
- a neural plate epithelium folds to form neural groove
- the 2 sides of the neural plate fold and zip up together to form the neural tube and neural crest
what are the 4 sections that the neural tube forms of the CNS?
- forebrain, midbrain, hindbrain, spinal cord
what are the 2 outgrowths of the forebrain in development?
- telencephalon = look like bunny ears
- hollow fluid-filled space
- grow to form the cerebral hemispheres
what is the other part of the forebrain become in development (not telencephalon)?
- diencephalon
- 3rd ventricle, thalamus, hypothalamus…
what are the 8 key parts of the brain?
- cerebral cortex
- hypothalamus
- thalamus
- pituitary gland
- corpus callosum
- pons
- medulla
- cerebellum
what is a?
cerebrum/cerebral cortex
what is b?
cranium/skull
what is c?
midbrain (thalamus)
what is d?
spinal cord
what is e?
cerebellum
what is f?
medulla
what is g?
pons
what is h?
hindbrain
what is i?
pituitary gland
what is j?
hypothalamus
what is k?
forebrain
describe the double layer folding of the dura in the brain
The falx cerebri is a band of dura matter that separates a part of the cerebral hemispheres. Its inferior boundary is defined by the inferior sagittal sinus and straight sinus. = attaches to crista galli of ethmoid bone
The tentorium cerebelli (or tentorium) separates the cerebrum from the cerebellum and brain stem
where are the veins mainly in the brain?
either between the dura and arachnoid or between the dura and skull
= called venous sinuses
what is the main vein draining the cerebral cortex and where is it?
- superior sagittal sinus
-runs along the sagittal suture (midline of skull) to the confluence of sinuses superior of occipital lobe
where is the diencephalon in the brain?
central part of brain around the 3rd ventricle
- superior to brainstem
- inferior to corpus callosum and cerebralcortex
what 5 parts make up the diencephalon of the brain?
- epithalamus ( pineal gland)
- thalamus
- subthalamus
- metathalamus
- hypothalamus/pituitary gland
what are names of the cerebral ventricles in the brain?
- lateral ventricle (1 in each hemisphere)
- 3rd ventricle
- 4th ventricle
- interventricular foramen
- cerebral aqueduct
what are the cerebral ventricles for?
produce and store CSF and allow it to move through the brain through the ventricles
where is CSF made?
choroid plexuses in the lateral ventricles
what is the pathway of CSF in the brain?
- made by choroid plexeses in lateral ventricles
- CSF moves down through interventricular formanina into the 3rd ventricle in the midbrain
- then from the 3rd ventricle it moves through the cerebral aqueduct into the 4th ventricle in the brainstem where it either goes into the spinal cord or circulates back up into cerebral cortex
what is the function of arachnoid villi granulations?
The arachnoid granulations act as one-way valves. Normally the pressure of the CSF is higher than that of the venous system, so CSF flows through the villi and granulations into the blood. If the pressure is reversed for some reason, fluid will not pass back into the subarachnoid space.
- look little trees from the subarachnoid space up through dura into the venous sinuses
what is hydrocephalus?
- build up of fluid in the ventricles in the brain e.g. due to swelling, tumour…
how can hydrocephalus be treated?
- neurosurgeons use a shunt/plastic tube and put into a ventricle and drain the excess CSF from it
how is the cerebellum connected to the rest of the brain?
- cerebellar peduncles (stalk like structures)
what are the peduncles called connected the cerebellum to the brain?
- superior cerebellar peduncle = midbrain to cerebellum
- middle cerebellar peduncle = pons to cerebellum
- inferior cerebellar peduncle = medulla to cerebellum
what can you see on the anterior view of the brainstem -basics?
- pons
- medulla
- middle cerebellar peduncle - MCP
- lots of nerves and vessels branching off the pons
what can you see on the posterior view of the brainstem (after cerebellum is removed)-basics?
- medulla (b)
- back of pons
- obex (surgical landmark, when the 4th ventricle narrows to become the central canal of the spinal cord)
- all the peduncles of the cerebellum
- choroid plexus (c)
what is the red outline showing here?
- floor of the 4th ventricle
what are the 2 main neurotransmitters in the CNS?
- glutamate = excitatory
- GABA = inhibitory
what are axons bundled together called in the CNS and PNS?
CNS = tract
PNS = nerve
what is a cluster of neurons called in the CNS and PNS?
- CNS = nucleus
- PNS = ganglion
what are projection neurones?
- project from 1 region/nucleus to another
what are interneurons?
- connects neurons within the same area/nucleus
what does ipsilateral mean?
on the same side (left or right)
doesn’t cross the midline
what does contralateral mean?
- on the other side
- crosses the midline
how many pairs of cranial nerves are there?
12
what are the 12 cranial nerves?
1 = olfactory
2 = optic
3 = oculomotor
4 = trochlea
5 = trigeminal
6 = abducens
7 = facial
8 = vestibulo-cochlear
9 = glossopharyngeal
10 = vagus
11 = accessory
12 = hypoglossal
OOO, to touch and feel virgin girl’s vaginas and hymens
what are motor nuclei?
- nuclei in the brainstem that contain motor neuron cell bodies whose axons pass out into cranial nerves
what are sensory nuclei?
- nuclei in the brainstem that contain neurons that receive information from sensory axons which have cell bodies in sensory ganglia
