1.1 The Basics Flashcards
What does the CNS consist of?
Cerebral hemispheres
Brainstem and Cerebellum
Spinal cord
What does the PNS consist of?
Dorsal and Ventral roots
Spinal Nerves
Peripheral nerves
What is the difference between grey and white matter?
Grey matter is composed of cell bodies and dendrites and it highly vascular.
White matter is composed of axons. (Grey matter also contains axons to allow it to communicate with white matter).
What is the PNS equivalent of grey matter?
A ganglion
What is the PNS equivalent of white matter?
Peripheral nerves
Why is white matter white?
Due to the presence of fatty myelin.
What is a segment of the spine?
The cord is split into around 31 segments, each supplying a given dermatome and myotome on each side.
They each connect with a spinal (mixed) nerve through dorsal (sensory) and ventral (motor) roots.
What is a funiculus?
A segment of white matter containing multiple distinct tracts. Impulses travel in multiple directions.
What is a tract?
An anatomically and functionally defined white matter pathway connecting two distinct regions of gray matter. Impulses travel in one direction.
What is a fasciculus?
A subdivision of a tract supplying a distinct region of the body.
What are Rexed’s laminae?
The names of the cell column that divide grey matter.
The motor neurone supplying a given muscle arise from multiple segments and form a distinct population of neurones in the CNS - a nucleus.
What is the ventral horn?
Where motor neurones reside that supply skeletal muscles.
Define nucleus (grey matter)
A collection of functionally related cell bodies.
Define cortex (grey matter)
A folded sheet of cell bodies found on the surface of a brain structure. Typically 1-5mm thick.
Define fibre (white matter)
A term relating to an axe in association with its supporting cells (e.g. oligodendrocytes). Used synonymously with ‘axon’.
What are association fibres?
Fibres that connect cortical regions within the same hemisphere.
What are commissural fibres?
Fires that connect the left and right hemispheres.
What are projection fibres?
Fibres that connect the cerebral hemispheres with the cord/ brainstem and visa versa.
Are cranial nerves PNS or CNS?
All part of the PNS except I (olfactory) and II (optic)
What are the parts of the brainstem and what do the control?
Midbrain (eye movements and reflex responses to sound and vision)
Pons (sleep, feeding)
Medulla (Cardiovascular and respiratory centres, Contains medullary pyramids -a major motor pathway)
What are gyri and sulci?
Gyri - raised bits of the brain
Sulci - bits inbetween gyri
What is the Uncus?
Part of the temporal lobe that can herniate compressing the midbrain. Important role in olfaction.
What are the medullary pyramids?
The location of descending motor fibres. Contains the corticospinal tract. (each has around 1 million axons!)
What is the parahippocampal gyrus?
key cortical region for memory encoding
What is the corpus callosum
Fibres connecting the two cerebral hemispheres
What is the thalamus
A sensory relay station projecting to the sensory cortex.
What is the cingulate gyrus?
A cortical area important for emotion and memory
What is the hypothalamus?
An area of the brain essential for homeostasis.
What is the fornix?
a major output pathway from the hippocampus
What is the tectum?
Dorsal part of the midbrain involved in involuntary responses to auditory and visual stimuli.
What are the Cerebellar tonsils?
Part of the cerebellum that can herniate and compress the medulla.
What does CSF do?
Mechanical - hold brain up
Metabolic - high in glucose (meningitis drops Lacoste)
How much CSF is made every day?
600-700ml made every day
Where is CSF made?
Choroid plexus cells
What are ventricles in brain?
Hollow cavities in the brain.
The ventricles cotton the choroid plexus which make CSF.
