1.1 Intro to Neuro Flashcards
Some features of the CNS
Cerebral hemispheres,
Brainstem
cerebellum and spinal cord
Some features of the PNS
Dorsal and ventral roots
Spinal nerves
Peripheral nerves
List some differences between CNS and PNS
CNS is myelinated by oligodendrocytes whereas the PNS is by schwann cells
CNS cannot regenerate axons
What is the caudal equine a part of?
PNS
What does grey matter consist of? What does it have less of?
Mainly cell bodies and dendrites and is highly vascular
Contains less myelin
Also fewer axons but still has some for communication with white matter
What does white matter consist of?
Axons and supporting cells for example oligodendrocytes
Why is white matter white?
Due to high myelin content
Explain the relationship between oligodenrocytes and axons
1 oligodendrocyte = 100s of axons
What is the PNS equivalent of grey matter?
Ganglion, a collection og neuronal ce;; bodies in PNS
What is the PNS equivalent of white matter?
Peripheral nerve
Where is the basal ganglia found?
In CNS
What is a neurone?
Transmits action potentials, it integrates and adds up impulses going to it an decides whether to fire or not- a decision making device.
How many segments is the spinal cord made up of?
31
What does each segment connect to?
Connects to s apsidal (mixed) nerve through dorsal and ventral (motor) roots
What are the sections of white matter?
Ventral, dorsal, and lateral
What is a tract? What direction do the impulses travel in?
An anatomically and functionally defined white matter pathway connecting 2 distinct regions of grey matter.
Unidirectional impulses
What is a funicular? What direction do impulses travel?
A segment of white matter containing multiple distinct tracts.
Impulses travel in multiple directions
What is a fasciculus?
Subdivision of a tract supplying a distinct part of the body
How is grey matter organised?
In columns as opposed to tracts, and each column is numbered
What is a nucleus?
A distinct population of neurones in the ins that are formed by motor neurones that supply a given muscle from multiple segments
Is the nucleus a part of the grey or white matter?
Grey
What is the cortex?
A folded sheet of cell bodies found on the surface of the brain structure. 1-5mm thick
Is the cortex white or grey matter?
Grey Matter
Why is the cortex made of a folded sheath?
Maximises volume so can stuff in as many neurones as possible
What is a fibre?
An axon in association with its supporting cells, can be used synonymously with axon
Is a fibre white or grey matter?
White matter
What are the types of fibre?
Association
Commissural
Projection
What is an association fibre?
It connects cortical regions WITHIN the SAME hemisphere
What is a commissural fibre?
Connects left and right hemispheres
What is a projection fibre?
Connects the cerebral hemispheres with the cord/brainstem and vice versa
Look at lecture for drawings
Go now before you forget
Why is the brainstem thicker than the spinal cord?
Due to interneurons
What are the main functions of the midbrain?
Eye movements and reflex responses to sound and vision
Main functions of the pons?
Feeding and sleep (REM)
Main functions of medulla?
Hoemostatic centres- CVS and resp centres and contains the major motor pathway
What are the colliculi and where are they found?
Bumos on the back of the midbrain that are the reflex centres, rapid response to visual and auditory stimulus
What are gyri?
The bumps
What are sulci?
The dips
What splits the frontal and parietal lobe?
Centreal sulcus
What does the lateral fissure do?
Separates the temporal from frontal/parietal lobes
What is the pareito-occipital sulcus
Separates the parietal from the occipital lobe
What seperates the visual cortex?
Calcarine sulcus
Which features are present in the inferior aspect of the brain?
Optic chasm
Uncus
Medullary pyramids
Parahippocampal gyrus
What is the uncus? What is clinically singificant about it?
Part of the temporal lobe that can herniate, compressing the midbrain. Has an important olfactory role. Can herniate easily due to surroundings.
What are the medullary pyramids?
The location of descending motor fibres
What is the prehippocampal gyrus? What is it important for?
Key cortical region for memory encoding. It is an important point for the converging of stimuli.
What are the key features of the midline of the brain?
Corpus collosum Thalamus Cingulate gyrus Hypothalamus Fornix Tectu, Cerebellar tonsil LOOK UP ALL LOCATIONS IN THE LECTURE
Function of the thalamus?
Sensory relay station projecting to sensory cortex
Function of Cingulate gyrus?
Cortical area important for emotion and memory
Function of Hypothalamus?
Essential centre for homeostasis
What is the fornix?
Major output pathway from the hippocampus
What is the tectum? And where is it?
Dorsal part of the midbrain involved in involuntary responses to auditory and visual stimuli.
What is the cerebellar tonsil? What effect can it have on surrounding structures?
Part of the cerebellum that can herniate and compress the medulla
What is the choroid plexus and where can it be found?
Produces the CSF and can be found in the ventricular system
What are the functions of CSF?
Metabolic anf mechanical functions.
It can act as a buffer
It is rich in glucose for metabolism
Rich in immune cells
Describe the route of CSF movement and circulation
CSF circulates through the ventricular system and subarachnoid space before being absorbed at the arachnoid granulations
Where are the arachnoid granulations mainly found?
Superior sagittal sinus
How manu ventricles are there?
4
What joins the first 2 ventricles?
Intraventricular foraman
What is in close proximity to the third ventricle?
2 thalami squash the 3rd ventricle
Where dies the third ventricle drain CSF through?
Cerebral aqueduct
What are the 3/4 apertures of the 4th ventricle?
Cantral canal of
Lateral x 2
Medial
What is the name of the lateral aperture?
Foraman of Luschka (L L)
What is the name of the medial aperture?
Foraman of Magendie (M M)
