1- Topography Of The Nervous System Flashcards
At what level of the spinal cord is there control of upper and lower limbs?
Cervical and lumbosacral enlargements
What is grey matter mostly composed of?
Cell bodies and dendrites
Why does white matter appear ‘white’?
Fatty content from myelin
What is white matter mostly composed of?
Axons and supporting cells
What is ‘grey matter’ in the peripheral nervous system termed?
Ganglion
Roughly how many segment is the spinal cord composed of?
31 segments
If a sensory deficit in seen in a dermatomal pattern where is it likely that the lesion is?
The dorsal root or spinal nerve level
What is a funiculus?
A block of white matter containing multiple pathways in both directions (ascending and descending)
In which funiculi would you find the lateral corticospinal tract and spinothalmic tract?
The lateral funiculus
In which funiculi would you find the dorsal column tract?
The dorsal funiculus
In which funiculi would you find the ventral corticospinal tract?
The ventral funiculus
What is a tract?
A white matter pathway connecting two distinct regions of grey matter
What is a fasiculus?
A subdivision of a tract that supplies a distinct region of the body
what are two examples of fasiculi that are subdivisions of the dorsal column tract and where do they supply?
Gracile fasiculus- lower half of body
Cuneate fasiculus- upper half excluding the head
Is the dorsal column tract sensory or motor?
Sensory
How are the cell bodies of the grey matter organised?
Into cell columns called Rexed laminae
What is a nucleus?
A collection of functionally related cell bodies
What is the cerebral cortex?
Outer layer of grey matter found on cerebral hemispheres and cerebellum
What is a fibre in comparison to just an axon?
Fibre is an axon and its supporting cells
What do association fibres connect?
Cortical regions within a hemisphere, e.g adjacent gyri
What do commissural fibres connect? and give an example..
The left and right hemispheres
E.g corpus callosum
What do projection fibres connect?
The cerebral hemispheres with the brain stem and the cord
What are some roles of the periaqueductal grey matter surrounding the cerebral aqueduct?
Pain transmission and micturition
The superior and inferior colliculi of the midbrain regulate reflex responses to what stimuli?
Superior- visual stimuli
Inferior- auditory stimuli
What cranial nerve exits from the lateral aspect of the pons?
Trigeminal nerve
What is the pons important for?
Feeding and sleep
What part of the cerebellum herniates through the foramen magnum with increased intracranial pressure and why can this lead to death?
The cerebellar tonsils can herniates compressing the cardio and respiratory centres of the medulla
What structure in the ventricles makes CSF?
Choroid plexus
What are the functions of CSF? (metabolic and mechanical)
Shock absorbs the brain and renders it effectively weightless
Contains glucose for metabolism
Where is CSF reabsorbed?
Arachnoid granulations extend into the superior sagittal sinus where CSF enters the venous blood
Through where does the CSF drain from the lateral to the third ventricle?
Interventricular foramen
Via what structure does CSF drain form the third ventricle to fourth ventricle?
Cerebral aqueduct
