Lecture 2 - Revision of Brain, Spinal Cord & Meninges

Question 1

What is the brain made up of?

Answer 1

The brain is made up of the forebrain, brainstem, and cerebellum.

Question 2

What is the forebrain made up of?

Answer 2

The forebrain is made up of the cerebral hemispheres (the cerebrum) as well as the diencephalon.

Question 3

What is the brainstem made up of?

Answer 3

The brainstem is made up of the midbrain, pons, and the medulla.

Question 4

What makes up the hindbrain?

Answer 4

The pons and medulla

Question 5

What nervous system does cranial nerve fall under?

Answer 5

The peripheral nervous system (PNS)

Question 6

What % of neurons does the cerebellum contain?

Answer 6

50%

Question 7

What are the different lobes of the brain?

Answer 7

The frontal, parietal, occipital, temporal, and insula lobes

Question 8

Where does the spinal cord extend to?

Answer 8

The spinal cord extends from the foramen magnum to the first or second lumbar vertebra

Question 9

What are the external features of the spinal cord?

Answer 9

External features of the spinal cord include two enlargements, the conus medullaris, filum terminale, and the cauda equina.

Question 10

Describe the cervical enlargement

Answer 10

The cervical enlargement is where nerves acting on the upper limbs and brachial plexus arise.

Question 11

Describe the lumbar enlargement

Answer 11

The lumbar enlargement is where nerves acting on lower limbs arise.

Question 12

What is the conus medullaris?

Answer 12

The conus medullaris is a part of the meninges that serves to stabilise the spinal cord

Question 13

What does the filum terminale do?

Answer 13

Anchors the distal end of the spinal cord.

Question 14

What is the cauda equina?

Answer 14

A collection of nerve roots which are found at the inferior end of the vertebral canal.

Question 15

Why do we have a cauda equina?

Answer 15

Because the nerves are longer than the spinal cord itself. This happens as the vertebral column grows faster than the spinal column.

Question 16

What do we have on the posterior side of the spinal cord?

Answer 16

On the posterior side of the spinal cord we have the posterior median sulcus and afferent fibre projections. These afferent fibres form the dorsal root. The cell bodies of the afferent fibres sit in the dorsal root ganglia and provide sensory information.

Question 17

What do we have on the anterior side of the spinal cord?

Answer 17

On the anterior portion of the spinal cord we have the anterior median fissure as well as efferent fibre projections. The efferent fibres form the ventral root and they provide motor information via axons attached to effector organs.

Question 18

What can happen when we have damage to the spinal cord?

Answer 18

When injury to the spinal cord (SCI) occurs, it can lead to paralysis and paraesthesia. The location of the SCI determines the severity of the injury.

Question 19

What can happen if SCI occurs at C1-C4?

Answer 19

Injury at the C1-C4 (cervical level) causes high tetraplegia. High tetraplegia means that an individual will experience both paralysis and paraesthesia. This means they will have a loss of sense and will be unable to move their limbs and sometimes have their breathing affected due to the same area being responsible for innervating the diaphragm.

Question 20

What can happen if SCI occurs at C5-C8?

Answer 20

At the C5-C8, injury can lead to individuals having low tetraplegia meaning they have limited motor function and sensory loss.

Question 21

What is the function of the meninges?

Answer 21

The meninges act as a protective layer over the brain and spinal cord.

Question 22

What are the three layers of the meninges?

Answer 22

The meninges is made up of three layers, the dura mater, arachnoid mater, and the pia mater.

Question 23

What is the dura mater made out of?

Answer 23

The dura mater is made of a thick layer of connective tissue

Question 24

How many layers are in the dura mater?

Answer 24

In the brain we have two layers of the dura mater, the periosteal (sits next to bone) and the meningeal layer. In the spinal cord, we only have one layer of dura mater.

Question 25

What is found between the dura mater layers?

Answer 25

Between the two layers of dura mater we have venous sinuses (large veins) which drain the brain.

Question 26

How are the dural folds made?

Answer 26

The meningeal layer of the dura mater forms folds into the brain which extend inward to form flat partitions.

Question 27

Why do we have dural folds?

Answer 27

The large dural folds subdivide the cranial cavity to limit excessive movement of the brain within the cranium.

Question 28

What are our dural folds?

Answer 28

The falx cerebri, tentorium cerebelli, and falx cerebelli.

Question 29

Describe the falx cerebri

Answer 29

The falx cerebri lies in the median sagittal plane. The falx cerebri partially seperates the cerebral hemispheres and attaches anteriorly to the crista galli and posteriorly to the upper surface of tentorium cerebelli in the midline.

Question 30

Describe the tentorium cerebelli

Answer 30

The tentorium cerebelli exists horizontally to seperate the cerebrum from the cerebellum like a tent.

Question 31

Describe the falx cerebelli

Answer 31

The falx cerebelli is the smaller of the dural folds and seperates the vermis of the cerebellum to seperate two cerebellar hemispheres.

Question 32

Describe the subdural space

Answer 32

The subdural space is found between the dura mater and the arachnoid mater. It is a very narrow layer which contains a film of fluid.

Question 33

What does the central sulcus seperate?

Answer 33

Seperates frontal and parietal lobes

Question 34

What does the transverse fissure seperate?

Answer 34

The cerebrum from cerebellum

Question 35

What does the lateral sulcus seperate?

Answer 35

The temporal lobe from the parietal and frontal

Question 36

What does the parieto-occipital sulcus seperate?

Answer 36

The occipital and parietal lobes

Question 37

What is associated with the brainstem?

Answer 37

Cranial nerves + blood vessels