Anatomy of the Nervous System

Question 1

What are cranial nerves?

How many types are there?

Answer 1

They are part of the peripheral nervous system, they are the nerves which project from the brain

there are 12 types of cranial nerve.

Question 2

What are the only two types of cranial nerves that are purely sensory?

Answer 2

The olfactory and optic nerves.

Question 3

What is the vagus nerve

Answer 3

It is the longest cranial nerve, it contains both motor and sensory fibres and it connects the gut and the brain.

Question 4

What are meninges?

What are the three layers? (and a bonus layer/area)

Answer 4

They are the protective layers surrounding the brain (singular meninx).

The outer layer is called the dura mater (tough mother)

The middle layer is the fine arachnoid membrane

(then there is the subarachnoid space, containing blood vessels and cerebrospinal fluid)

Then there is the most inner layer, the pia mater (pious mother)

Question 5

Where do the sympathetic nerves within the ANS project from?

Answer 5

The CNS in the lumbar (small of the back) and the thoracic (chest) regions.

Question 6

Where do the parasympathetic nerves within the ANS project from?

Answer 6

They project from the brain and the sacral (lower back) regions of the CNS.

Question 7

What 2 types of nerves is the PNS comprised of?

Answer 7

afferent nerves and efferent nerves. Afferent nerves carry signals from internal organs to the CNS and efferent nerves carry signals from the CNS to internal organs.

Question 8

Where is cerebrospinal fluid produced?

Answer 8

In the choroid plexus (protrudes from the pia mater)

Question 9

What is hydrocephalus?

Answer 9

When a tumour blocks the cerebral aqueduct (which connects the third and fourth ventricles). This then causes a build up of fluid in the ventricles, causing the brain to expand.

Question 10

How does the blood brain barrier work?

Answer 10

usually, the cells that make the walls of blood vessels are loosely packed. However, in the brain, they are very tightly packed, so it forms a barrier between the brain and the blood (only very small molecules, like glucose, can get through)

Question 11

What is the difference between nuclei and ganglia?

Answer 11

clusters of cell bodies in the CNS are called nuclei, clusters of cell bodies in the PNS are called ganglia.

Question 12

Where do you find schwann cells? What does this mean about axonal regeneration?

Answer 12

In the PNS only. As axonal regeneration mainly only comes from schwann cells, we can only experience effective axonal regeneration in the PNS.

Question 13

What is neuroanatomical tracing?

Answer 13

They trace the paths of axons using chemicals/dyes. There are two types of this process, anterograde neuroanatomical tracing (when the investigator injects chemicals into the cell body for them to be transported along to the terminals, so they can track movement down the axon) and retrograde neuroanatomical tracing (when the investigator injects chemicals to be taken up by the terminals and transported back to the cell body)

Question 14

What does a cross section of the spinal chord look like?

Answer 14

There is a H shape of grey matter, surrounded by white matter. The two top horns of the h are called the dorsal horns and the ventral horns are the lower arms of the H.

Question 15

What is the difference between white matter and grey matter?

Answer 15

White matter is mainly comprised of myelinated axons, while grey matter is cell bodies and unmyelinated interneurons.

Question 16

What is the dorsal root ganglia?

Answer 16

A group of spinal nerves that form a cord and feed in to the dorsal horn part of the spinal chord. It is made of sensory, unipolar neurons.

Question 17

What is the ventral root ganglia?

Answer 17

A group of spinal nerves that form a cord and feed in to the ventral horn part of the spinal chord. It is made of motor (efferent), multipolar neurons.

Question 18

What are the 4 types of glial cell?

Answer 18

Oligodendrocytes (make up myelin), Schwann cells, Microglia and Astrocytes

Question 19

What is Golgi stain?

Answer 19

How we can view neurons, a stain discovered by Camillo Golgi. It involves exposing neural tissue with potassium dichromate and silver nitrate, which then stains neurons black, so we can then see the silhouette of individual neurons under a microscope.

Question 20

What is Nissl Stain?

Answer 20

it is similar to Golgi stain, but it allows us to see the number of neurons in an area. It uses cresyl violet dye, which binds only to the neuron’s cell bodies, which allows us to count the number of cell bodies in an area.

Question 21

What sort of matter is referred to when we talk about the cerebral hemispheres?

Answer 21

White matter- myelinated axons.

Question 22

What sort of matter is referred to when we talk about the cerebral cortex (which surrounds and covers the cerebral hemispheres)?

Answer 22

Grey matter- unmyelinated

Question 23

What are the three types of furrows/gaps in the brain?

Answer 23

fissures- (larger gaps), sulci (smaller gaps) and the ridges between these gaps are called gyrus

Question 24

What are the three main fissures in the brain?

Answer 24

The longitudinal fissure (the one between the hemispheres), the lateral fissure (horizontal) between the frontal lobe and the temporal lobe) and the central fissure (vertical, but sideways-on- when looking from the front of the head), between the frontal lobe and the parietal lobe.