L6 - Overview of Nervous System 1 Flashcards
What makes up the Cerebrum, and describe some features of this part of the brain
The Cerebral hemispheres and the Thalamus
Largest part
Highest level of information processing
Grey cortex, white matter and deep seated nuclei.
Two hemispsheres, lobes and a cortex with sulci and gyri
What does the brain stem consist of?
The Pons, Medulla oblongata and the midbrain
How many pairs of spinal nerves are there?
31 pairs. 8 in the neck, 12 in the thorax, 5 in the lumbar, 5 in the sacrum/pelvis and 1 in the coccyx
What is grey matter and why is it grey?
Areas where neuron bodies predominate
They are grey because they lack a myelin sheath
Do sensory fibres utilise a nucleus, a ganglion or both for their neuron bodies?
What about motor neurons?
Both - they synapse with a ganglion, which contains some of their neuron bodies, before passing information over to a sensory nucleus in the spinal cord (inside the CNS)
Motor neurons send information out straight from a motor nucleus in the CNS, and do not utilise a ganglion until they are in the ANS
Which side of the spinal cord to motor neurons emerge from?
What about sensory neurons?
Anterior side
Posterior side
What makes up the CNS
Spinal cord + brain
What makes up the PNS?
Nerve fibres
What is a nucleus?
A group of functionally related neuron bodies within the CNS. If nerve fibres have multiple nuclei they can have different functions
What is a tract?
A bundle of functionally similar fibres within the CNS whose function is to carry sensory information from the spinal cord to the brain stem (ascending), or from a nucleus in the brain to the spinal cord (descending). If they cross the midline, they’re called “crossed”
Are sensory nerve signal afferent, or efferent?
Afferent - they enter the spinal cord from the dorsal side.
Motor are efferent
What is a ganglion?
A normal swelling along the course of a nerve, usually close to the CNS, and due to the presence of neuron bodies
What are the two components of the ANS, and what is the ANS’s role?
Parasympathetic, and sympathetic divisions
ANS gathers information from viscera and takes in back to the CNS. Most of this information is subconscious. There is a ganglion associated with every ANS nerve fibre
Where do sympathetic preganglionic fibres connect to neuron bodies?
In the thoracic+lumbar spinal vord. This is referred to as thoracolumbar outflow.
Are preganglionic nerve fibres myelinated in the ANS?
Yes. Post-ganglionic nerve fibres are not myelinated.
