Central Nervous system

Question 1

What is the brain composed of?

Answer 1

Forebrain (Cerebral hemisphere, diencephalon), Midbrain and

Hindbrain (Pons, Medulla, Cerebellum)

Question 2

What lobe is concerned with learning, motivation, reward, memory and emotion?

Answer 2

Limbic Lobe

Includes:
Amyglada, hippocampus, mamillary body, cingulate gyrus

Question 3

What lobe is concerned with visceral sensations, autonomic control, interoception, auditory processing, visual vestibular integration?

Answer 3

Insular cortex

Lies deep in lateral fissure

Question 4

Where is CSF formed?
Where is it found?
How is it reabsorbed?

Answer 4

Choroid plexus of lateral 3rd and 4th ventricles

Occupies ventricular system and sub-arachnoid space

By structures in the superior sagittal sinus - Arachnoid granulations arachnoid Vili

Question 5

What are the differences between plasma and CSF?

Answer 5

CSF has lower pH, Less glucose, protein and potassium.

Question 6

What are the dorsal structures of the spine?

What name is used for opposing structures?

Answer 6

Dorsal horn as a part of grey matter
Dorsal roots, rootlets
Dorsal root ganglion

Ventral (ventral rootlets, root etc)

Question 7

How is the spinal cord composed?

Answer 7

In segments with each segment giving rise to a pair of mixed spinal nerves

The nerves emerge through intervertebral foramina

Question 8

How many pairs of nerves in each spinal cord segment

• Cervical?
• Thoracic?
• Lumbar?
• Sacral?
• Coccygeal?

Answer 8

8 pairs
12 pairs
5 pairs
5 pairs
1 pair

Question 9

Where do Nerves C1-C7 emerge?

Where do Nerves C8-Co1 emerge?

Answer 9

Emerge above corresponding vertebrae

Below the corresponding vertebrae

Question 10

Where would Cranial Nerve C5 emerge?

Answer 10

Above the Cervical vertebrae C5

Question 11

Where would thoracic spinal nerve T3 emerge?

Answer 11

Below the thoracic Vertebrae T3

Question 12

Why are there enlargements in the cervical and lumbar regions of the spinal cord?

Answer 12

Due to large innervation of upper and lower limbs from those regions

Question 13

What is the corticospinal tract?

Major descending pathways

Answer 13

Major pathway for voluntary movement.

Made of upper motor neurones in primary motor cortex and lower motor neurones in brainstem (if going to head and neck) and spinal cord (if going to muscles of trunk or limbs).

Question 14

What pathways bring information about fine touch, vibration and proprioception from skin and joints?

(major ascending pathways)

Answer 14

Dorsal column pathway

Question 15

What type of pathway brings information for pain, temperature from skin?

Answer 15

Major ascending pathway

Lateral Spinothalamic tract

Question 16

What pathway brings information about crude touch to brain?

Answer 16

Ventral / Anteror Spinothalamic tract

Question 17

What does the lateral corticospinal tract supply and where did it originate?

Answer 17

Limb muscles

Came from contralateral hemisphere

Question 18

What does the anterior corticospinal tract supply?

Answer 18

Trunk muscles

Question 19

What is the decussation of the cotricospinal tract?

Answer 19

85% of fibres cross in the medulla from the lateral tract to the contralateral side and supply limb muscles .The rest remain on the anterior corticospinal tract and supply the trunk muscles

Question 20

What is the corticobulbar tract, where are their lower motor neurones?

Answer 20

pathways that go from primary motor cortex to the muscles of the face.

Lower MN are in cranial cavity in brain stem where there are nuclei for extraocular muscles, mastication, facial expression etc

Question 21

What is the internal capsule?

Answer 21

Many parts of motor cortex has been congregating together to make their way from cortex downards cord or brain stem. * Check horizontal plane represenation

Question 22

What does the vestibulospinal tract do?

Answer 22

Provides information about head movement and position and mediates postural adjustments

Question 23

What does the Tectospinal tract do?

Answer 23

Orientation of the head and neck during eye movements

Question 24

What does the reticulospinal tract do?

Answer 24

Control of breathing and emotional motor function

Question 25

What does the Rubrospinal tract do?

Answer 25

Innervate lower motor neurones of the upper limb

Question 26

What are the pyramidal tracts and extra pyramidal tract?

Answer 26

The corticobulbar tract and the corticospinal tract

(also known as brainstem motor tracts) Extra pyramidal tracts supply muscles which are more automated (vestibulospinal, Tectospinal, reticulospinal, Rubrospinal)

Question 27

(Dorsal Column pathway)

Info conveyed from lower limbs and the body - Below T6- travel ipsilaterally along?

Answer 27

gracile tract, synapse in the gracile nucleus in medulla

Question 28

(Dorsal Column pathway)

Info conveyed from upper limbs and the body - Above T6- travel ipsilaterally along?

Answer 28

Cuneate tract, synpases in cuneate nucleus in medulla

Question 29

Sensory neurons crossing to contralateral side?

Answer 29

Second order axons Decussate in caudal medulla.
From contralateral medial lemniscus tract
Synapse in the thalamus onto tertiary neurone

Question 30

What differs between the posterior column pathway and the spinothalamic?

Answer 30

Position of the secondary neurone differs and where the cell bodies of second order neurones are located.

Both pathways have 3 neurones and both pathways have crossings in 2nd neurone.

Question 31

What do the 3rd order neurones do (posterior pathway)?

Answer 31

Projecting to somatosensory cortex.

Size of somatotopic areas is proportional to density of sensory receptors in that body region.

Question 32

Spinothalamic pathway, where does primary neurone synpase?

Answer 32

In dorsal horn as they enter spinal cord. Second order neurones then decussate immediately to form spinothalamic tract (anterior or lateral depending on information)

• 2nd order neurone synapses in thalamus for both ascending pathways and then synapse at sensory cortex

Question 33

What two layers is the dura composed of?

Answer 33

Periosteal and meningeal - dense fibrous membrane