The central nervous system

Question 1

What are the 3 parts of the brain?

Answer 1

Forebrain- composed of central hemispheres and diencephalon

Midbrain

Hindbrain- composed of medulla, pons and cerebellum

Question 2

What does the limbic lobe contain?

Answer 2

Amagdyla

Hippocampus

Mamillary body

Cingulate cortex

Question 3

What is the role of the limbic lobe?

Answer 3

Associated with learning, memory, emotion, motivation and reward

Question 4

Where is the insular cortex located?

Answer 4

Deep within the lateral fissure

Question 5

What is the insular cortex concerned with?

Answer 5

Visceral sensation

Autonomic control

Interoception

Auditory processing

Visual- vestibular integration

Question 6

What is the cerebrum also known as?

Answer 6

The cerebral cortex

Question 7

What is white matter?

Answer 7

Myelinated neuronal axons forming tracts

Question 8

What is grey matter?

Answer 8

Cell bodies of neurones

Question 9

What is lamina?

Answer 9

A layer of neurones

Question 10

Label the following

Answer 10

Question 11

What is brown sequard syndrome?

Answer 11

Caused by hemisection of spinal cord (damage to one half)

Leads to loss of function below injury

Question 12

What are symptoms of brown sequard syndrome?

Answer 12

Spinothalamic tract on contraleteral side (opposite) interruped so loss of pain and temperature in that leg

Dorsal tract on ipsilateral side interupted so loss of proprioception, touch and vibration

Corticospinal tract on ipsilateral side interupted so paralysis below leison

Question 13

How is the spinal cord arranged?

Answer 13

8 pairs cervical

12 pairs thoracic

5 pairs lumbar

5 pairs sacral

1 pair coccygeal

Nerves are in pairs: 1 left and 1 right

Question 14

Where do spinal nerves emerge?

Answer 14

Emege through invertebral foramina

C1- C7 emerge above vertibrae

C8- Co1 emerge below vertibrae

No C8 vertibrae but C8 nerve

Question 15

Where can enlargements be found along the spinal cord?

Answer 15

Enlargement in cervical due to increased innervation from upper limbs

Englargment in lumbar region due to increased innervation of lower limbs

Question 16

What descending tracts are there?

Answer 16

Corticospinal tract

Corticobulbar tract

Question 17

What is the corticospinal tract responsible for?

Answer 17

Voluntary movement

Question 18

How is the corticospinal tract structured?

Answer 18

Motor corticospinal tract has 2 neurones:

Upper motor neurones- housed in primary motor cortex

Lower motor neurones- housed in brainstem (if going to head and neck) or spinal cord (if going to trunk or limbs)

Tract on lateral side of the spinal cord is called the lateral corticospinal tract

Question 19

What journey does the lateral corticospinal tract take?

Answer 19

Fibres cross in the medulla from one motor cortex to opposite side of the cord- pyrimidal decussate

Theres tracts in both hemespheres- these form lateral corticospinal tracts which come from opposite hemispheres

Question 20

How is the corticospinal tract divided?

Answer 20

Lateral corticospinal tract supplies limb muscles

Anterior corticospinal tract: supplies trunk muscles

Question 21

What are the ascending tracts?

Answer 21

Dorsal column

Spinothalamic tract

Question 22

What is the dorsal colum responsible for?

Answer 22

Fine touch, vibrations, propriception

Question 23

What are the 2 types of fibres found in the dorsal column?

Answer 23

Gracile tract: carries fibres from lower limbs ipsilaterally- lateral part of dorsal column

Cuneate tract: carries fibres from upper limbs ipsilaterally- medial part of dorsal column

Question 24

What journey do first order neurones in the dorsal column take?

Answer 24

Sensory neurones in the dorsal root ganglia send afferent fibres via gracile or cuneate pathway

Fibres enter the dorsal horn and enter the ascending dorsal column pathway

First synapse of gracile tract is gracile nucleus

First synapse of cuneate tract is cuneate nucleus

These synapses are located in the lower medulla and is where first order neurones meet second order neurones

Question 25

What journey do second order neurones take in the dorsal colum tract?

Answer 25

Second order neurones cross in the caudal medulla to form the contralateral medial lemniscus tract These synapse in the thalamus where they meet the third order neurone

Question 26

What journey do third order neurones take in the dorsal colum tract?

Answer 26

These are found in the ventral nuclear group in the thalamus Fibres ascend to primary somatosensory cortex

Question 27

What is the spinothalamic tract responsible for?

Answer 27

Lateral spinothalamic tract: pain and temperature Anterior spinothalamic tract: crude touch

Question 28

What journey do first order neurones take in the spinothalamic?

Answer 28

Neurones origionate in dorsal root ganglia They synapse onto second order neurones

Question 29

What journey do second order neurones take in the spinothalamic tract?

Answer 29

These are found in the posterior horn They decussate immediately in the spinal cord to form the contralateral spinothalamic tract They terminate in the thalamus where they synapse at the ventroposteriorlateral nucleus

Question 30

What journey do third order neurones take in the spinothalamic tract?

Answer 30

These project through the internal capsule to the somatosensory cortex

Question 31

What is the responsibility of the corticobular tract?

Answer 31

Movement of extraoccular muscles, muscles of mastication, muscles of facial expression, muscles of tongue

Question 32

What are the 2 fibres of the corticobular tract?

Answer 32

Upper motor neurones: in primary motor cortex Lower motor neurones: in brainstem in nuclei of cranial nerve (CN 3, 4, 5, 6, 7, 12 )

Question 33

What jouney does the corticobulbar tract take?

Answer 33

UMNs go from primary motor cortex to brainstem where thay can do the following: 1. Terminate directly onto alpha motor neurones or interneurones and innervate neurones in the brainstem 2. Can dessucate in the brainstem and synapse with LMNs to innervate contralateral motor CNs 3. Can synapse with LMNs ad innervate ipsilateral CNs (not dessucate) 4. Can innervate CNs via corticospinal tract

Question 34

How are fibres organised as they descend?

Answer 34

Tracts that are descending are likely to be bundled together As the tract descends it forms the internal capsule

Question 35

What are examples of brainstem motor tracts?

Answer 35

Verstibulospinal: provides info. about head movement and position and mediates postural adjustments Tectospinal: orientation of the head and neck during eye movements Reticulospinal: control of breathing and emotional motor function Rubrospinal: innervates LMNs of upper limb