Structure and function of the CNS 2

Question 1

What does the trigeminal nerve do?

Answer 1

General sensation of the head

Question 2

What do nuclei cutaneous and gracilis do?

Answer 2

Dorsal columns for proprioception and discriminative touch

Question 3

What is the decussation of pyramids?

Answer 3

Crossing over of descending corticospinal tract

Question 4

Function of spinocerebellar tracts

Answer 4

Control of posture and movement coordination

Question 5

What is found at level of mid-medulla?

Answer 5

• Nucleus of the spinal tract of trigeminal nerve
• Fasciculus and nucleus cuneatus
• Fasciculus and nucleus gracilis
• Pyramid, the pyramidal tract or corticospinal tract
• Spinocerebellar tracts

Question 6

What do pyramid, pyramidal tract and corticospinal tract do?

Answer 6

Control of voluntary, discrete skilled movements

Question 7

What is found at the level of the rostral medulla?

Answer 7

• Fourth ventricle
• Dorsal motor nucleus of Vagus
• Hypoglossal nucleus and nerve fibers
• Inferior cerebellar peduncle
• Pyramid
• Inferior olivary nucleus

Question 8

What does inferior olivary nucleus do?

Answer 8

Receives afferent fibers from motor and sensory cortices of the cerebral hemisphere and red nucleus of midbrain, for control of movement through cerebellum

Question 9

What is found at the level of the mid pons and trigeminal nerve?

Answer 9

• Middle cerebellar peduncle
• Superior cerebellar peduncle
• Trigeminal nerve
• Fourth ventricle
• Corticospinal fibres
• Reticular formation

Question 10

What is reticular formation?

Answer 10

Network of neurone in mid pons

Question 11

What is Pontine and Medullary reticular formatuin?

Answer 11

Respiratory and cardiovascular centers which control respiratory movements and cardiovascular functions

Question 12

What is the reticular activating system?

Answer 12

Some ascending fibers of the reticular formation act via thalamic nuclei to cause activation of the cerebral cortex and heightened arousal

Question 13

What is found at the level of the inferior colliculus?

Answer 13

• Crus cerebri (cerebral peduncle)
• Superior cerebellar peduncle
• Trochlear nucleus
• Substantia nigra
• Inferior colliculus - auditory pathway relay station
• Cerebral aqueduct

Question 14

Function of substantial nigra

Answer 14

Contains pigmented, melanin-containing neurons that synthesise dopamine and is connected with the basal ganglia

Question 15

What is the inferior colliculus?

Answer 15

Auditory pathway relay station

Question 16

What can be found at level of the superior colliculus?

Answer 16

• Crus cerebri (cerebral peduncle)
• Substantia nigra
• Red nucleus
• Oculomotor nucleus
• Cerebral aqueduct
• Superior colliculus

Question 17

What does the cerebral peduncles do?

Answer 17

Attach the cerebrum to brainstem

Question 18

Function of red nucleus

Answer 18

Involved in motor control and receives fibers from motor cortex of the frontal lobe

Question 19

Where is oculomotor nucleus found in superior colliculus?

Answer 19

Floor of fourth ventricle

Question 20

Function of superior colliculus

Answer 20

Relay station for visual pathway

Question 21

What are the two cerebellar hemispheres separated by?

Answer 21

Midline vermis

Question 22

What is the cerebellum divided into?

Answer 22

Small anterior and large posterior lobes

Question 23

What does the posterolateral fissure do?

Answer 23

Separates the cerebellar hemisphere from the flocculonodular lobe

Question 24

How is the brainstem connected to the cerebellum?

Answer 24

Inferior, middle and superior cerebellar peduncles

Question 25

Does the cerebellum have sensory function?

Answer 25

No - it is entirely motor

Question 26

What does the cerebellum do?

Answer 26

Maintenance of equilibrium (balance), influences posture and muscle tone and coordinates movement

Question 27

What are the 3 subdivisions of the cerebellum?

Answer 27

Archicerebellum Paleocerebellum Neocerebellum

Question 28

What does the archicerebellum do?

Answer 28

Maintenance of balance

Question 29

What is the archicerebellum made of?

Answer 29

Flocculonodular lobe, fastigi nuclei

Question 30

What does the paleo cerebellum do?

Answer 30

Muscle tone and posture

Question 31

What is the paleo-cerebellum made of?

Answer 31

Midline vermis, paravermis with globes and emboli form nuclei

Question 32

What is the neocerebellum made from?

Answer 32

Cerebellar hemisphere and dentate nuclei

Question 33

What does the neocerebellum do?

Answer 33

Muscle coordination, trajectory, speed and force of movements

Question 34

What are the 4 nuclear masses found in the cerebellum?

Answer 34

Dentate nucleus Emboliform Fastigial nucleus Globose nuclei

Question 35

Symptoms of cerebellar lesions

Answer 35

Incoordination of upper/lower limbs, speech and eyes

Question 36

Symptoms of a midline lesion

Answer 36

Loss of postural control

Question 37

Symptoms of unilateral lesion of cerebellar hemisphere

Answer 37

Symptoms on same side of body, unsteady gait

Question 38

Symptoms of alcohol intoxication/hypothyroidism

Answer 38

Slowness and slurring of speech (dysarthria), incoordination of both arms and staggering, wide-based and unsteady gait (cerebellar ataxia)

Question 39

What is Charcot's triad?

Answer 39

Nystagmus, dysarthria and intention tremor

Question 40

What are the meninges?

Answer 40

3 layers of membranes that cover the brain and spinal cord

Question 41

What is the outer layer?

Answer 41

Dura mater

Question 42

How many layers of the dura mater are there around the brain?

Answer 42

2 - endosteal and meningeal bn

Question 43

How many layers of the dura mater are there around the spinal cord ?

Answer 43

One

Question 44

What is the middle layer of the meninges?

Answer 44

Arachnoid mater

Question 45

What separates the dura and arachnoid maters?

Answer 45

Subdural space

Question 46

What is the inner layer of the meninges?

Answer 46

Pia mater

Question 47

What separates the Pia from the arachnoid mater?

Answer 47

Subarachnoid space

Question 48

4 components of the dura mater

Answer 48

Falx cerebri Tentorium cerebelli Tentorial notch Falx cerebelli

Question 49

What are arachnoid villi?

Answer 49

Arachnoid mater forms processes that project as clumps called granulations into superior sagittal sinus

Question 50

What do arachnoid granulations do?

Answer 50

Return CSF to venous system

Question 51

What does the trigeminal nerve supply?

Answer 51

Cranial dura mater of the floor of the anterior, middle and roof of the posterior cranial fossae including the falx cerebri

Question 52

Which spinal nerves innervate the dura of the floor of the posterior cranial fossa?

Answer 52

C2 and C3 | Via Vagus and Hypoglossal nerves

Question 53

Does the arachnoid mater receive any nerve supply?

Answer 53

No

Question 54

How is pain from the dura mater perceived?

Answer 54

Headache via spinal or diversion of trigeminal nerve

Question 55

What are brain ventricles?

Answer 55

Interconnecting chambers filled with CSF

Question 56

Where is CSF produced?

Answer 56

Choroid plexus (formed by Pia mater)

Question 57

Characteristics of brain ventricular system

Answer 57

- Paired lateral ventricles (left and right) - Unpaired third ventricle - Unpaired fourth ventricle - Fourth connected to third by cerebral aqueduct - The ventricular system communicates with the subarachnoid space - Involved in cerebrospinal fluid drainage from brain and brain stem

Question 58

How is the fourth ventricle connected to the third?

Answer 58

Cerebral aqueduct

Question 59

What does the spinal cord do?

Answer 59

Carries sensory, motor and autonomic innervation

Question 60

Where does the spinal cord terminate caudally in adult and child?

Answer 60

Adult: between L1 and L2 Child: L3

Question 61

What are the two enlargements of the spinal cord?

Answer 61

Cervical and lumbar

Question 62

What does the cervical enlargement of the spinal cord do?

Answer 62

Supplies upper limb

Question 63

What does the lumbar enlargement of the spinal cord do?

Answer 63

Supplies lower limb

Question 64

Which spinal nerves make up the cervical enlargement of the spinal cord?

Answer 64

C4-T1

Question 65

Which spinal nerves make up the lumbar enlargement of the spinal cord?

Answer 65

L1-S3

Question 66

What is the conus medullar is?

Answer 66

Conical termination of spinal cord

Question 67

What is the filum terminale?

Answer 67

Connective tissue extending from tip of conus medullar is to the dorsal surface of the first coccygeal vertebral

Question 68

How many pairs of spinal nerves are there?

Answer 68

31 pairs

Question 69

What are the different types of spinal nerves?

Answer 69

8 cervical, 12 thoracic, 5 lumbar and 5 sacral

Question 70

What is the cauda equina?

Answer 70

Below termination of spinal cord, nerves descend in the cauda equina before exiting the vertebral column through their respective foramina

Question 71

Where do thoracic nerves emerge, respective to their corresponding vertebrae?

Answer 71

Below vertebrae

Question 72

Where do cervical spinal nerves emerge respective to their corresponding vertebrae?

Answer 72

Above vertebrae

Question 73

What are the two roots of each spinal nerve?

Answer 73

Dorsal and ventral

Question 74

Do dorsal roots carry afferent or efferent information?

Answer 74

Afferent

Question 75

Do ventral roots carry afferent or efferent information?

Answer 75

Efferent

Question 76

How do spinal nerves exit the vertebral column?

Answer 76

Intervertebral foramen

Question 77

What are the three horns of the grey matter?

Answer 77

Ventral, dorsal and lateral horns

Question 78

In which area is the lateral horn present?

Answer 78

Thoracic and lumbar segments of spinal cord

Question 79

What is contained in the lateral horn?

Answer 79

Cell bodies of the preganglionic sympathetic neurons

Question 80

What is found in the dorsal column of the ascending tract of the spinal cord?

Answer 80

Fasciculus gracilis and fasciculus cuneatus

Question 81

What does the spinothalamic tract do?

Answer 81

Pain and temperature

Question 82

What do the spinocerebellar tracts do?

Answer 82

Coordination of movement

Question 83

Are ascending tracts motor or sensory?

Answer 83

Sensory - come from periphery to CNS

Question 84

Are descending tracts motor or sensory?

Answer 84

Motor - from brain to periphery

Question 85

What are the 4 descending tracts?

Answer 85

Ventral corticospinal Lateral vestibulospinal Medial longitudinal fasciculus Lateral corticospinal

Question 86

Symptoms of unilateral brainstem lesion

Answer 86

Ipsilateral cranial nerve dysfunction, contralateral spastic hemiparesis, hyperreflexia and extensor plantar response

Question 87

Why are bilateral lesions dangerous?

Answer 87

Destroys vital centers controlling breathing and circulation, leading to coma and death

Question 88

Causes of bilateral lesions

Answer 88

Occlusion of anterior spinal artery, fractures of spine, compression of spinal cord and nerve roots, prolapsed intervertebral disc

Question 89

Why re focal lesions dangerous?

Answer 89

Can lead to destruction of functions at segmental levels

Question 90

How is Brown-Sequard syndrome caused?

Answer 90

Heme-lesion of thoracic spinal cord