Introduction and basic topography Flashcards
What are the basic components of the central nervous system?
- Cerebral hemispheres
- Brainstem and cerebellum
- Spinal cord
What are the basic components of the peripheral nervous system?
- Dorsal and venral roots
- Spinal nerves
- Peripheral nerves
- Cauda Equina
How does the cell type that myelinates neurones differ in the CNS vs PNS?
CNS: oligodendrocites myelinate - cannot regenerate - multiple neurones myelinated by one cell
PNS: Schwaan cell - have some capacity to regenerate
What makes up grey matter?
Cell bodies and dendrites
Highly vascular
What makes up white matter?
White matter is composed of axons and their supporting cells
How does grey matter communicate with white matter?
Grey matter contains axons allowing it to communicate with white matter
Why does white matter appear white?
Due to presence of fatty myelin
What is the PNS equivalent of grey matter and white matter?
Grey matter = a Ganglion
White matter = peripheral nerve
How is white and grey matter arranged in the spinal cord?
Grey matter is central with an outer layer of white matter
How many segments of the spinal cord are there?
31
What is a funiculus?
What are the 3 divisions
A segment of white matter containing multiple distinct tracts
Impulses travel in multiple directions
3 divisions: Dorsal, Lateral and Ventral
What is a tract?
An anatomically and functionally defined white matter pathway that connects two distinct regions of grey matter
Impulses travel in one direction
What is a fasciculus?
A subdivision of a tract supplying a distinct region of the body
How is grey matter in the spinal cord organised?
Organised in cell columns (Rexed’s Laminae)
What is a nucleus (grey matter)?
A collection of functionally related cell bodies
What is the cortex (grey matter)?
A folded sheet of cell bodies found on the surface of a brain structure
Typically 1-5 mm thick
What is a fibre (white matter)?
A term relating to an axon in association with is supporting cells
What are the 3 types of fibre (white matter)?
- Association - connect cortical regions within the same hemisphere
- Commissural- connect left and right hemispheres or cord halves
- Projection - connect cerebral hemispheres with the cord/ brain stem and vice versa
What are the 3 components of the brainstem and the basic functions of each?
-
Midbrain (misencephalon)
- Eye movement and reflex responses to sound and vision
-
Pons
- Feeding and sleep (particularly REM)
-
Medulla
- Cardiovascular and respiratory centres
- Contrains major motor pathways (medullary pyramids)
What components make up the Diencephalon?
Thalmus and Hypothalmus
What are colliculi?
Reflex centres giving rapid response at the back of the midbrain
Identify the central sulcus
Locate the pre central gyrus and post central gyrus and give the function of each
Precentral- primary motor cortex
Postcentral- primary sensory cortex
Identify the lateral/ sylvian fissure
Identify the parieto-occipital sulcus
Identify the calcarine sulcus. What surrounds this?
Surrounded by the primary visual cortex
What is the uncus? What is its clinical significance?
Part of the temporal lobe that can herniate and compress the midbrain (squashing cranial nerve III)
Important olfactory role- site of pimrary olfactory cortex
Locate the parahyppocampal gyrus. What is its function?
Key cortical region for memory encoding
Identify the corpus coallosum. What is its function?
Fibres connecting 2 cerebral hemispheres
Identify the Thalamus. What is its function?
Sensory Relay station projecting the sensory cortex
Identify the cingulate gyrus. What is its function?
Cortical area important for emotion and memory
Identify the hypothalmus. What is its function?
Essential centre for homeostasis
Identify the fornix. What is its function?
Major output pathway from the hippocampus
Identify the tectum. What is its function?
Dorsal part of the midbrain involved in involuntary responses to auditory and visual stimuli
Identify the cerebellar tonsil. What is its clinical significance?
Part of cerebellum that can herniate through the foramen magnum and compress the medulla
Where is CSF made? How much is made each day?
In the ventricles in cells called choroid plexus
600-700ml of CSF per day
Where is CSF resorbed?
CSF circulates through ventricles and subarachnoid space before it is resobed at the arachnoid granulations
Identify the ventricles and associated features
In a monosynaptic reflex (e.g. knee jerk), where is the synapse found?
In the ventral horn
