Introduction the Nervous System and Topography Flashcards
Which structures form the CNS?
Brain + Spinal Cord
- (structures whose embryonic precursor is the neural tube)*
- brain = cerebral hemispheres, cerebellum & brainstem*
Which structures form the peripheral nervous system?
Dorsal and Ventral Roots
Ganglia
Spinal Nerves
Peripheral Nerves
What is a ganglia in the nervous system?
a collection of cell bodies in the peripheral nervous system
What is a nuclei in the central nervous system?
a collection of cell bodies
Outline the basic relationship of grey to white matter in the brain and spinal cord
Brain
central grey matter with white matter covering, covered in addtional cortex of grey matter
Spinal Cord
central grey matter (butterfly shaped) with white matter covering
What gives the grey matter is characteristic colour?
Lack of Myelin / Fat
Highly Vascularised
Which parts of the neuronal cell is found within the:
Grey Matter
White Matter
Grey Matter
cell bodies and dendrites
White Matter
axons and supporting cells
What is the peripheral nervous system equivalent of grey amtter and white matter?
Grey Matter
ganglion - a collection of cell bodies
White Matter
peripheral nerve
At the spinal cord, ventral and dosral nerve roots arise, what is their function and what do they eventually give rise to?
Vental - motor never
Dorsal - sensory nerve
form Spinal Nerves (mixed motor and sensory)
What are the upper and lower boundaries of the spinal cord?
Upper - formaina magnum
Lower - around L1
(cord terminates at conus medullaris)
Where could you localise a lesion if a patient presents with isolated sensory deficit in a limb, rather than both motor and sensory deficit?
localised to dorsal nerve root or dorsal root ganglion
How many pairs of spinal nerves are there along the spinal cord?
31 pairs of spinal nerves
What is a funiculus?
A segment of white matter containing multiple distinct tracts
What is a tract in the spinal cord and what is an important feature of its function?
an area of anatomically and functionally defined white matter, connecting two regions of grey matter
UNIDIRECTIONAL
What is a fasiculus in the spinal cord?
a subdivision of a tract supplying a distinct region of the body
- e.g.*
- fasiculus gracilis (supplies lower half of body)*
- fasiculus cuneatus (supplies upper half of body)*
What is the relevanve of Rexed laminae when considering the action of a muscle?
Grey matter of the spinal cord is segmented in a similar fashion to the white matter
Multiple segments (or Rexed laminae) of grey matter in the spinal cord provide motor innervation to a particular muscle group
e.g. L2, L3, L4 innervate the quadriceps femoris
What is the cortex of the brain?
a folded sheet of cell bodies on the surface of the brain
A ‘fibre’ can be used synonymously with the word axon, but name the structures that form a fibre?
axon of a neurone in associaton with its supporing cells (e.g. oligodendrocytes)
What is the role of association fibres in the nervous system?
connect cortical regons within the same hemisphere
What is the role of commissural fibres in the nervous system?
connect the left and right hemispheres or cord halves
e.g. corpus callosum
What is the role of a projection fibre in the nervous system?
connect the cerebral hemisphere with the cord/brainstem
(or vice versa)
What is the functon of the midbrain?
eye movement
reflex responses to sounds and vision
What is the functon of the pons?
feeding
sleep
What is the functon of the medulla oblongata?
cardiovascular and respiratory centres
contrains major motor pathway (medullary pyramids)
What risk is posed by the uncus in herniation over the tentorial notch?
compression of the midbrain
Which structures lie immediately anterior and posterior to the central sulcus and what is their function?
Pre-Central Gyrus
primary motor cortex
Post-Central Gyrus
primary sensory cortex
Which structures of the brain are separated by the Lateral/Sylvian fissure?
separated the temporal lobe from the frontal/parietal lobe
Which functional area of the brain surrounds the calcarine sulcus?
primary visual cortex surrounds calcarine sulcus
What structure is located within the medullary pyramids?
descending motor fibres
What is the relevance of the parahippocampal gyrus?
key cortical region for memory encoding
What is a key role of the hypothalamus?
maintain homeostasis
What is the function of the cingulate gyrus and where is it located?
important for emotion and memory
immediately above the corpus callosum
What risk is posed by the cerebellar tonsil (I)?
can herniate and compress the medulla
What is the role of the fornix?
major output pathway from the hippocampus, which regulates emotions
What is the role of the tectum and where is it located?
dorsal part of the midbrain
invovled in auditory and visual reflexes
also called the superior (visual) and inferior (auditory) colliculus
Structures To Identify
Outline the flow of CSF around the ventricular system to the blood
CSF produced by choroid plexus
lateral ventricles > interventricular foramen > third ventricle > cerebral aqueduct > fourth ventricle
> spinal cord and;
> lateral apparatus / medial apparatus > subarachoid space > arachnoid granulation project into superior saggital sinus > CSF drains into venous blood
What is the function of the CSF?
cushioning of brain tissue
removal of waste products from the brain
Where is grey matter located within the central nervous system?
Cerebral Cortex
Nuclei Deep Within Brain
Horns of Spinal Cord
Outline the meningeal layers lining the brain
Periosteal Dural Mater
Meningeal Dural Mater
Arachnoid Mater
Pia Mater
Which layer of the meningies actually has a space, rather than a potential space?
Sub Arachnoid Space
due to the prescence of structures such as the cerebral arteries
