Structure and function of the CNS 2 Flashcards Preview

Nervous system > Structure and function of the CNS 2 > Flashcards

Flashcards in Structure and function of the CNS 2 Deck (90)
Loading flashcards...
1
Q

What does the trigeminal nerve do?

A

General sensation of the head

2
Q

What do nuclei cutaneous and gracilis do?

A

Dorsal columns for proprioception and discriminative touch

3
Q

What is the decussation of pyramids?

A

Crossing over of descending corticospinal tract

4
Q

Function of spinocerebellar tracts

A

Control of posture and movement coordination

5
Q

What is found at level of mid-medulla?

A
  • 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
6
Q

What do pyramid, pyramidal tract and corticospinal tract do?

A

Control of voluntary, discrete skilled movements

7
Q

What is found at the level of the rostral medulla?

A
  • Fourth ventricle
  • Dorsal motor nucleus of Vagus
  • Hypoglossal nucleus and nerve fibers
  • Inferior cerebellar peduncle
  • Pyramid
  • Inferior olivary nucleus
8
Q

What does inferior olivary nucleus do?

A

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

9
Q

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

A
  • Middle cerebellar peduncle
  • Superior cerebellar peduncle
  • Trigeminal nerve
  • Fourth ventricle
  • Corticospinal fibres
  • Reticular formation
10
Q

What is reticular formation?

A

Network of neurone in mid pons

11
Q

What is Pontine and Medullary reticular formatuin?

A

Respiratory and cardiovascular centers which control respiratory movements and cardiovascular functions

12
Q

What is the reticular activating system?

A

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

13
Q

What is found at the level of the inferior colliculus?

A
  • Crus cerebri (cerebral peduncle)
  • Superior cerebellar peduncle
  • Trochlear nucleus
  • Substantia nigra
  • Inferior colliculus - auditory pathway relay station
  • Cerebral aqueduct
14
Q

Function of substantial nigra

A

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

15
Q

What is the inferior colliculus?

A

Auditory pathway relay station

16
Q

What can be found at level of the superior colliculus?

A
  • Crus cerebri (cerebral peduncle)
  • Substantia nigra
  • Red nucleus
  • Oculomotor nucleus
  • Cerebral aqueduct
  • Superior colliculus
17
Q

What does the cerebral peduncles do?

A

Attach the cerebrum to brainstem

18
Q

Function of red nucleus

A

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

19
Q

Where is oculomotor nucleus found in superior colliculus?

A

Floor of fourth ventricle

20
Q

Function of superior colliculus

A

Relay station for visual pathway

21
Q

What are the two cerebellar hemispheres separated by?

A

Midline vermis

22
Q

What is the cerebellum divided into?

A

Small anterior and large posterior lobes

23
Q

What does the posterolateral fissure do?

A

Separates the cerebellar hemisphere from the flocculonodular lobe

24
Q

How is the brainstem connected to the cerebellum?

A

Inferior, middle and superior cerebellar peduncles

25
Q

Does the cerebellum have sensory function?

A

No - it is entirely motor

26
Q

What does the cerebellum do?

A

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

27
Q

What are the 3 subdivisions of the cerebellum?

A

Archicerebellum
Paleocerebellum
Neocerebellum

28
Q

What does the archicerebellum do?

A

Maintenance of balance

29
Q

What is the archicerebellum made of?

A

Flocculonodular lobe, fastigi nuclei

30
Q

What does the paleo cerebellum do?

A

Muscle tone and posture

31
Q

What is the paleo-cerebellum made of?

A

Midline vermis, paravermis with globes and emboli form nuclei

32
Q

What is the neocerebellum made from?

A

Cerebellar hemisphere and dentate nuclei

33
Q

What does the neocerebellum do?

A

Muscle coordination, trajectory, speed and force of movements

34
Q

What are the 4 nuclear masses found in the cerebellum?

A

Dentate nucleus
Emboliform
Fastigial nucleus
Globose nuclei

35
Q

Symptoms of cerebellar lesions

A

Incoordination of upper/lower limbs, speech and eyes

36
Q

Symptoms of a midline lesion

A

Loss of postural control

37
Q

Symptoms of unilateral lesion of cerebellar hemisphere

A

Symptoms on same side of body, unsteady gait

38
Q

Symptoms of alcohol intoxication/hypothyroidism

A

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

39
Q

What is Charcot’s triad?

A

Nystagmus, dysarthria and intention tremor

40
Q

What are the meninges?

A

3 layers of membranes that cover the brain and spinal cord

41
Q

What is the outer layer?

A

Dura mater

42
Q

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

A

2 - endosteal and meningeal bn

43
Q

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

A

One

44
Q

What is the middle layer of the meninges?

A

Arachnoid mater

45
Q

What separates the dura and arachnoid maters?

A

Subdural space

46
Q

What is the inner layer of the meninges?

A

Pia mater

47
Q

What separates the Pia from the arachnoid mater?

A

Subarachnoid space

48
Q

4 components of the dura mater

A

Falx cerebri
Tentorium cerebelli
Tentorial notch
Falx cerebelli

49
Q

What are arachnoid villi?

A

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

50
Q

What do arachnoid granulations do?

A

Return CSF to venous system

51
Q

What does the trigeminal nerve supply?

A

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

52
Q

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

A

C2 and C3

Via Vagus and Hypoglossal nerves

53
Q

Does the arachnoid mater receive any nerve supply?

A

No

54
Q

How is pain from the dura mater perceived?

A

Headache via spinal or diversion of trigeminal nerve

55
Q

What are brain ventricles?

A

Interconnecting chambers filled with CSF

56
Q

Where is CSF produced?

A

Choroid plexus (formed by Pia mater)

57
Q

Characteristics of brain ventricular system

A
  • 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
58
Q

How is the fourth ventricle connected to the third?

A

Cerebral aqueduct

59
Q

What does the spinal cord do?

A

Carries sensory, motor and autonomic innervation

60
Q

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

A

Adult: between L1 and L2
Child: L3

61
Q

What are the two enlargements of the spinal cord?

A

Cervical and lumbar

62
Q

What does the cervical enlargement of the spinal cord do?

A

Supplies upper limb

63
Q

What does the lumbar enlargement of the spinal cord do?

A

Supplies lower limb

64
Q

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

A

C4-T1

65
Q

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

A

L1-S3

66
Q

What is the conus medullar is?

A

Conical termination of spinal cord

67
Q

What is the filum terminale?

A

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

68
Q

How many pairs of spinal nerves are there?

A

31 pairs

69
Q

What are the different types of spinal nerves?

A

8 cervical, 12 thoracic, 5 lumbar and 5 sacral

70
Q

What is the cauda equina?

A

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

71
Q

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

A

Below vertebrae

72
Q

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

A

Above vertebrae

73
Q

What are the two roots of each spinal nerve?

A

Dorsal and ventral

74
Q

Do dorsal roots carry afferent or efferent information?

A

Afferent

75
Q

Do ventral roots carry afferent or efferent information?

A

Efferent

76
Q

How do spinal nerves exit the vertebral column?

A

Intervertebral foramen

77
Q

What are the three horns of the grey matter?

A

Ventral, dorsal and lateral horns

78
Q

In which area is the lateral horn present?

A

Thoracic and lumbar segments of spinal cord

79
Q

What is contained in the lateral horn?

A

Cell bodies of the preganglionic sympathetic neurons

80
Q

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

A

Fasciculus gracilis and fasciculus cuneatus

81
Q

What does the spinothalamic tract do?

A

Pain and temperature

82
Q

What do the spinocerebellar tracts do?

A

Coordination of movement

83
Q

Are ascending tracts motor or sensory?

A

Sensory - come from periphery to CNS

84
Q

Are descending tracts motor or sensory?

A

Motor - from brain to periphery

85
Q

What are the 4 descending tracts?

A

Ventral corticospinal
Lateral vestibulospinal
Medial longitudinal fasciculus
Lateral corticospinal

86
Q

Symptoms of unilateral brainstem lesion

A

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

87
Q

Why are bilateral lesions dangerous?

A

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

88
Q

Causes of bilateral lesions

A

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

89
Q

Why re focal lesions dangerous?

A

Can lead to destruction of functions at segmental levels

90
Q

How is Brown-Sequard syndrome caused?

A

Heme-lesion of thoracic spinal cord