Structure of the nervous system Flashcards
What some nervous system key terms?
Sulcus: crevices/trench on brain surface
Gyrus: ridge on brain surface
Foramina: hole to allow structures to pass through
Choroid plexus: lines the ventricle system in the brain, production sight of CSF
Falx cerebri: longitudinal crescent-shaped fold of meningeal layer of dura mater between the cerebral hemispheres
Ventricle: system filled with CSF in the brain
Sinus: sac/cavity in organ or tissue (e.g. frontal sinus)
Sella Turcica: saddle-shaped depression in sphenoid bone which houses pituitary gland
Cerebrum: uppermost region of nervous system, containing white and grey matter
Cerebellum: little brain situated in back of the brain
Meninges: membrane layers covering the brain consisting of dura, arachnoid, and pia layers
How many bones does the skull consist of?
22 bones: 8 form the cranium, and 14 form the face
What joins the bones in the skull together?
Sutures (e.g. coronal and sagittal sutures)
What is the dural partition?
The thick portion between the two hemispheres of the brain
What are the major parts of the brain?
- Telecephalon (cerebral hemisphere)
- Diencepahlon (thalamus and hypothalamus, and the posterior portion of the frontal brain)
- Mesencephalon (anterior and posterior)
- Metencephalon
- Myelencephalon
Where does sensory processing happen?
In the motor cortex and sensory cortex
Where do though processes occur?
In the frontal cortex
What connects the cortexes of the brain?
The corpus callosum
Which part of the brain controls speech?
Broca’s area - we have one on both hemispheres. The larger the gyri, the more sensitive the area it goes to
What are the three layers of the brain?
- the dura
- the arachnoid
- the pia
That pia continues all the way in those sulci, and all three layers continue all the way in the spinal cord. This is what we call the blood-brain barrier. There is arachnoid space with arachnoid granulation.
What is the blood-brain barrier?
A specialised interface between the CSF and your venous sinus
How does the bbb protect our brain?
It only allows certain types of molecules to pass.
How is the bbb affected in meningitis?
In meningitis, bacterial causes inflammation of the meninges, so the structures in the blood brain barriers become inflamed, therefore allowing openings. Meaning more molecules can pass through the blood brain barrier, which is why certain drugs for meningitis can work and others do not
What forms our external jugular veins?
2 x sigmoid sinuses
Where do we do a lumbar puncture?
Our arachnoid is where all the CSF passes through. At L1 and L2, the horse’s tail, is called the safe zone
What would happen if we did a lumbar puncture up in the T spine?
You could paralyse that person
How many ventricles have we got?
2 lateral ventricles which expand from the frontal to the occipital. These are connected by ducts in the third ventricle, down to the fourth ventricle. They are just a connection.The lateral ventricles spread from the frontal to the occipital, and the fourth one is down to the cerebellum.
What is the brainstem composed of?
- Midbrain
- Pons
- Medulla
Describe the olfactory nerve?
Responsible for smells. They have fibres which protect down. Your nerves run through the olfactory bulbs and go through to the limbic system for memory, processing what you are smelling at that time. So if you are exposed to a smell, after about 30-40 seconds, you don’t notice it anymore, because your brain has processed what that smell is, and because you are so used to it, it dissipates.
Describe the optic nerve?
Useful for vision. We have two eyes, so cranial nerve two. Your optic radiations come all the way back to your occipital lobes. We have a chiasm in the middle that sits over the pituitary gland, so any tumours around that area will affect vision.
Describe the vagus nerve?
Goes everywhere, all the way down to your stomach. It is the longest nerve in the body. It also supplies the larynx/vocal cords.
