Structure of the nervous system

Question 1

What some nervous system key terms?

Answer 1

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

Question 2

How many bones does the skull consist of?

Answer 2

22 bones: 8 form the cranium, and 14 form the face

Question 3

What joins the bones in the skull together?

Answer 3

Sutures (e.g. coronal and sagittal sutures)

Question 4

What is the dural partition?

Answer 4

The thick portion between the two hemispheres of the brain

Question 5

What are the major parts of the brain?

Answer 5

• Telecephalon (cerebral hemisphere)
• Diencepahlon (thalamus and hypothalamus, and the posterior portion of the frontal brain)
• Mesencephalon (anterior and posterior)
• Metencephalon
• Myelencephalon

Question 6

Where does sensory processing happen?

Answer 6

In the motor cortex and sensory cortex

Question 7

Where do though processes occur?

Answer 7

In the frontal cortex

Question 8

What connects the cortexes of the brain?

Answer 8

The corpus callosum

Question 9

Which part of the brain controls speech?

Answer 9

Broca’s area - we have one on both hemispheres. The larger the gyri, the more sensitive the area it goes to

Question 10

What are the three layers of the brain?

Answer 10

• 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.

Question 11

What is the blood-brain barrier?

Answer 11

A specialised interface between the CSF and your venous sinus

Question 12

How does the bbb protect our brain?

Answer 12

It only allows certain types of molecules to pass.

Question 13

How is the bbb affected in meningitis?

Answer 13

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

Question 14

What forms our external jugular veins?

Answer 14

2 x sigmoid sinuses

Question 15

Where do we do a lumbar puncture?

Answer 15

Our arachnoid is where all the CSF passes through. At L1 and L2, the horse’s tail, is called the safe zone

Question 16

What would happen if we did a lumbar puncture up in the T spine?

Answer 16

You could paralyse that person

Question 17

How many ventricles have we got?

Answer 17

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.

Question 18

What is the brainstem composed of?

Answer 18

• Midbrain
• Pons
• Medulla

Question 19

Describe the olfactory nerve?

Answer 19

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.

Question 20

Describe the optic nerve?

Answer 20

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.

Question 21

Describe the vagus nerve?

Answer 21

Goes everywhere, all the way down to your stomach. It is the longest nerve in the body. It also supplies the larynx/vocal cords.