1.1 Brain Topography And CSF Circulation Flashcards
What are the basic components of the CNS?
Cerebral Hemispheres
Brainstem and cerebellum
Spinal cord
What is the functions of the cerebral hemispheres?
Higher functions, motor and sensory (conscious), emotion, memory
What is the function of the brainstem and cerebellum?
Communication via cranial nerves including functions such as eye movement, swallowing and cardiorespiratory homeostasis
Cerebellum involved with motor sequencing and co-ordination
What is the main functions of the spinal cord?
Ascending (sensory) and descending (motor) pathways
Spinal reflex arcs
Control of upper and lower limbs at level of cervical and lumbosacral enlargements
What are the main components of the peripheral nervous system?
Dorsal and ventral roots
Spinal nerves
Peripheral nerves
What is grey matter?
Cell bodies and dendrites of neurones, and a small amount of axons to allow it communicate with white matter
Highly vascular
What is a ganglion?
A collection of cell bodies outside of the CNS
Essentially grey matter of the PNS
What is the function of grey matter?
Computation
Why is it important that the grey matter has a rich blood supply?
As lots of metabolic activity taking place
Lots of O2 and nutrients needed for synaptic activity
What is white matter composed of?
Myelinated and non-myelinated axons with no cell bodies
What is the equivalent of white matter in the PNS?
A nerve
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 the cerebral and cerebellar hemispheres
1-5mm thick
What is a fibre?
A white matter axon with its associated supporting cells
What is the function of association fibres?
To connect cortical regions within the same hemisphere
What is the function of commissural fibres?
To connect left and right hemispheres or cord halves
What is the function of projection fibres?
To connect the cerebral hemispheres with the cord/brainstem and vice versa
Describe the structure of the spinal cord?
- The cord is composed of around 31 segments, each supplying a given dermatome and myotome on each side
- The cord has a central core of grey matter and an outer shell of white matter
- Each segment connects with a spinal (mixed) nerve through dorsal (sensory) and ventral (motor) roots
What forms the roots of the spinal nerve?
Multiple rootlets, which plug directly into the cord
What is supplied by the dorsal ramus?
Instrinsic muscles of the back
A small dermatomal segment
What is found in the dorsal root ganglion?
Cell bodies of 1st order pseudounipolar sensory neurones
What does a sensory deficit in a dermatomal pattern suggest?
That the lesion is at the level of dorsal roots or spinal nerves
What might a sensory deficit across multiple dermatomal segments suggest?
A cord lesion
What might a sensory deficit in ahomuncular pattern suggest?
A lesion above the thalamus
What is a funiculus?
funiculus refers to a large segment of white matter containing multiple distinct tracts. Impulses both ascend and descend.