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Flashcards in The Nervous System Deck (123):
1

What determines whether peripheral nerves are classified into the efferent or afferent branch of the PNS?

The efferent branch of the PNS contains fibres that are the axons of efferent neurones. The afferent branch of the PNS contains fibres that are the axons of afferent neurones.

2

What is the function of afferent neurones?

To convey information from sensory receptors at their peripheral ending to the CNS.

3

Where does the longest part of the axon of an afferent neurone lie?

The longest part lies outside the CNS and is part of the PNS.

4

Afferent neurones are often referred to as what? (and why?)

First-order neurones as they are the first cells entering the CNS.

5

What is the function of efferent neurones?

To carry signals from the CNS to muscles, glands and other tissues.

6

Efferent neurones can make up which two subdivisions of the peripheral nervous system?

The somatic nervous system and the autonomic nervous system.

7

The somatic nervous system innervates ______ _______.

Skeletal muscle.

8

How many neurones make up the somatic nervous system between the CNS and skeletal muscle cells?

One.

9

Innervation of skeletal muscle cells by the somatic nervous system leads to what?

Voluntary (conscious) muscle excitation.

10

Where are the cells bodies of the neurones of the somatic nervous system located?

In groups in the brainstem or the ventral horn of the spinal cord.

11

Describe the axons of the somatic nervous system.

The axons have a large diameter and are myelinated

12

Why are somatic neurones called motor neurones?

They result in contraction of the innervated skeletal muscle cells.

13

What neurotransmitter is involved in the somatic nervous system?

Acetylcholine (ACh).

14

Give innervations of the autonomic nervous system?

Smooth muscle cells, cardiac muscle cells, glands, the enteric nervous system and other tissues.

15

What is the enteric nervous system?

A network of neurones that governs the function of the gastrointestinal tract. The nervous system of the GI tract.

16

How many neurones make up the autonomic nervous system between the CNS and effector organ?

Two (two-neurone chain).

17

Where is the cell body of the first neurone in the autonomic nervous system?

In the CNS.

18

Where is the cell body of the second neurone in the autonomic nervous system?

Outside the CNS in an autonomic ganglion (a cell cluster).

19

What is the name of the neurones passing between the CNS and the ganglia in the autonomic nervous system?

Preganglionic neurones.

20

What is the name of the neurones passing between the ganglia and the effector cells in the autonomic nervous system?

Postganglionic neurones.

21

Innervation of tissue by the autonomic nervous system leads to what?

Involuntary (unconscious) excitation or inhibition.

22

Which neurotransmitter(s) are use before the ganglion in the autonomic nervous system?

Acetylcholine (ACh).

23

Which neurotransmitter(s) are use after the ganglion in the autonomic nervous system? (and state whether it has an excitatory or inhibitory effect).

Acetylcholine (excitatory) or noradrenaline (inhibitory).

24

What are the two divisions of the autonomic nervous system?

The sympathetic and parasympathetic divisions.

25

What is the primary process of the sympathetic nervous system?

The fight or flight response.

26

The sympathetic nervous system leaves the CNS from which regions of the spinal cord?

The thoracic and lumbar regions (T1 to L2).

27

What are the names of the chains of ganglia that lie either side of the spinal cord as part of the sympathetic nervous system?

Sympathetic trunks.

28

Name the neurotransmitter and receptor present at the preganglionic synapse of the sympathetic nervous system.

Acetylcholine at nicotinic receptors.

29

Name the neurotransmitter and receptor present at the effector cell synapse of the sympathetic nervous system.

Noradrenaline at adrenergic receptors.

30

The preganglionic fibres of the sympathetic nervous system form which part of the spinal cord?

Lateral grey horn.

31

Which parts of the body does the sympathetic nervous system supply?

The visceral organs (in body trunk) and the structures of the superficial body regions.

32

Does the sympathetic nervous system contain more or less ganglia than the parasympathetic division?

More.

33

The effects of the sympathetic nervous system are amplified by what?

Adrenal glands, which release adrenaline into the blood resulting in a high blood pressure and heart rate.

34

Give examples of the effects produced by the sympathetic nervous system.

Increased heart rate. Increased force of contractions in the heart. Vasoconstriction. Bronchodilation. Reduction in gastric motility. Sphincter contraction. Decreased gastric secretions. Male ejaculation.

35

The parasympathetic nervous system leaves the CNS from which regions?

The brainstem and the sacral portion of the spinal cord.

36

The preganglionic fibres of the parasympathetic nervous system run via which cranial nerves?

Oculomotor nerve to the pupil. Facial nerve to the salivary glands. Glossopharyngeal nerve for the swallowing reflex. Vagus nerve to the thorax and abdomen.

37

Where are the cell bodies of the preganglionic neurones of the parasympathetic nervous system located?

In the cranial nerve nuclei in the brainstem.

38

The sacral outflow of the parasympathetic nervous system supplies what?

Supplies the remaining abdominal and pelvic organs.

39

Where are the ganglia of the parasympathetic nervous system found?

Either within or very close to the organs that the post ganglionic neurones innervate.

40

Name the neurotransmitter and receptor found at the synapse of the preganglionic neurone of the parasympathetic nervous system.

Acetylcholine at nicotinic receptors.

41

Name the neurotransmitter and receptor found at the synapse of the effector cell of the parasympathetic nervous system.

Acetylcholine at muscarinic receptors.

42

Give examples of the effects produced by the parasympathetic nervous system.

Decreased heart rate. Decreased force of contraction. Vasodilation. Bronchoconstriction. Increased gastric motility. Sphincter relaxation. Increased gastric secretions. Male erection.

43

What is the third branch of the autonomic nervous system?

The enteric nervous system.

44

Why is the enteric nervous system not always considered as a branch of the autonomic nervous system?

It can operate independently of the autonomic nervous system.

45

In total how many vertebra does the vertebral column consist of?

33.

46

Name the groups of vertebra that make up the vertebral column and how many there are of each.

7 cervical. 12 thoracic. 5 lumbar (fused). 4 coccyx (fused).

47

Identify the structure highlighted. 

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Vertebral body. 

48

Identify the structure highlighted. 

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Vertebral arch. 

49

Identify the structure highlighted. 

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Spinous process. 

50

Identify the structure highlighted. 

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Transverse process. 

51

Identify the structure highlighted. 

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Vertebral foramen. 

52

Identify the structure highlighted. 

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Pedicle. 

53

Identify the structure highlighted. 

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Lamina. 

54

Identify the structure highlighted. 

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Superior articular process. 

55

Identify the structure highlighted. 

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Inferior articular process. 

56

What is the function of the vertebral arch?

To protect the spinal cord. 

57

What are the names of the C1 and C2 vertebra and what are their functions?

C1 - the atlas. C2 - the axis. They are specialised to allow for the movement of the head.

58

What is the main feature of the axis (C2 vertebra)?

Prominent spike at the top called the dens.

59

Give three distinguishing features of the cervical vertebrae.

Spinous process bifurcates into two parts (bifid spinous process). Two transverse foramina. Vertebral foramen is triangular in shape.

60

What is the purpose of the transverse foramina on the cervical vertebrae?

To conduct the vertebral arteries and the sympathetic chain on either side.

61

Identify this vertebra. 

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Atlas. 

62

Identify this vertebra. 

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Axis. 

63

Which of the cervical vertebra has a spinous process that does not bifurcate?

The C7 vetebra. The spinous process is also longer. 

64

Give three distinguishing features of the thoracic vertebra.

The spinous processes are much thinner and more descending. 

The vertebral foramen are circular. 

The vertebra have costal facets and demi facets. 

65

Give three identifying features of the lumbar vetebra. 

Large, kidney-shaped, vertebral bodies. 

Triangular shaped vertebral foramen. 

Thick and broad spinus processes. 

(No transverse foramina, costal facets or bifid spinous processes).

66

Name the three mater the spinal cord is covered in from outside in. 

Dura. Arachnoid. Pia. 

67

The central canal of the spinal cord contains what?

CSF. 

68

The spinal cord controls the movements of...

the trunk and limbs. 

69

The spinal cord communicates extensively with the brain through...

the ascending and descending tracts. 

70

Where are the two enlargements of the spinal cord?

The cervical enlargement is between C3 and T1 (to the upper limb). 

The lumbar enlargement is between L1 and S3 (to the lower limb).

71

The spinal cord tapers to a cone called what?

The conus medullaris. 

72

The spinal cord ends as a strand of tissue known as what?

The filum terminale. 

73

At what age does the spinal cord run the whole length of the vertebral canal?

3 months of fetal life. 

74

At birth, the spinal cord ends at which part of the vertebral canal?

L3. 

75

In adulthood, the spinal cord ends at which part of the vertebral canal?

Between L1 and L2. 

76

Axons in the dorsal part of the spinal cord convery afferent or efferent neurones?

Axons in the dorsal part of the spinal cord convery afferent neurones. Axons in the ventral part of the spinal cord convery efferent neurones. 

77

Name the spinal nerve groups and how many spinal nerves there are of each. 

8 cervical. 

12 thoracic. 

5 lumbar. 

5 sacral. 

1 coccyx. 

78

The cervical spinal nerves leave the spine around... than their corresponding vertebra. 

The cervical spinal nerves leave the spine around 1 vertebra higher than their corresponding vertebra. Except C8 which is 1 below. 

79

The thoracic spinal nerves leave the spine around... their corresponding vertebra. 

The thoracic spinal nerves leave the spine around 1-2 vertebra below their corresponding vertebra.

80

The lumbar spinal nerves leave the spine around... their corresponding vertebra. 

The lumbar spinal nerves leave the spine around 3-4 vertebra below their corresponding vertebra. 

81

The sacral spinal nerves leave the spine around... their corresponding vertebra. 

The sacral spinal nerves leave the spine around 5 vertebra below their corresponding vertebra. 

82

What are lower motor neurones?

Motor neurones of the cord and brainstem. 

83

What are mixed spinal nerves formed from?

The joining of the two fascicles (axon bundles) near the intervertebral foramen. Dorsal roots and ventral roots join. 

84

Spinal nerves divide to form what?

A small dorsal (posterior) ramus and a larger ventral (anterior) ramus. 

85

Which three layers cover the fasiscles entering/leaving the spinal cord?

Epineurium. 

Perineurium. 

Endoneurium. 

86

Describe the sturcture of the epineurium. 

A layer of loose vascular tissue surrounding several fasicles. 

87

Describe the structure of the perineurium. 

The perineurium is composed of several lyaers of pavement epithelium bound by tight junction. The perineurium covers each fasicle. 

 

88

Describe the structure of the endoneurium. 

A layer of delicate connective tissue around the myelin sheath of each myelinated nerve fibre, surrounding individual Schwann cells. 

89

What is the name of a bundle of fascicles?

Funiculi. 

90

What is osmium stain used for?

To stain the white matter (myelin) black. 

91

What is silver stain used for?

To stain grey matter (cell bodies) black. 

92

How do the proportions of grey and white matter vary along the spinal cord?

The higher levels of the spinal cord have more white matter. 

93

What shape does the grey matter in the spinal cord form?

A H shape. 

94

What are the four protrusions of the grey matter in the spinal cord?

Two dorsal horns. Two ventral horns. 

95

Identify A and B. 

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A - fasciculus gracilis

B - fasciculus cuneatus 

96

Identify C. 

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C - spinothalamic tract

97

Identify D and E. 

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D - lateral corticospinal tract

E - ventral corticospinal tract

98

Identify F and G. 

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F - ascending tract

G - descending tract

99

What is the dorsal column medial lemniscus?

An ascending tract that transmits to the postcentral gyrus - the primary somatosensory cortex. 

100

What is the function of the dorsal column medial lemniscus?

To carry proprioception, vibration and discriminative/fine touch. 

101

The dorsal column medial lemniscus are made up of...

The fasciculus cuneatus and the fasciculus gracilis. 

102

Describe the anatomy and function of the fasciculus cuneatus. 

Lateral. Carries the infromation from the upper body to the cuneate tubercle in the medulla. 

103

Describe the anatomy and function of the fasciculus gracilis. 

Medial. Carries information from the lower body to the gracile tubercle in the medulla. 

104

Where does the dorsal column medial lemniscus decussate?

Once they ascend to the medulla, they decussate to become the medial lemniscus then ascend to the thalamus then to the cortex. 

105

Name the four sensory nerve endings that may sense fine touch. 

Pacinian corpuscle. 

Meissner's corpuscle. 

Ruffini endings. 

Merkel endings. 

106

Where are the three neurones in the pathway of the dorsal column medial lemniscus?

In the dorsal root ganglion. 

In the cuneate and gracile nuclei. 

In the ventral posterolateral nucleus of the thalamus. 

107

What is the corticospinal tract and what is its function?

Motor tract that conveys axial and limb motor control. 

108

Where does the corticospinal tract begin?

The precentral gyrus - primary motor cortex. 

109

Where does the corticospinal tract decussate?

At the medullary pyramids. 

110

What is the spinothalamic tract?

An ascending tract. 

111

What is the function of the lateral spinothalamic tract?

To convey pain and temperature. 

112

What is the function of the medial spinothalamic tract?

To convey crude touch. 

113

Where do the cell bodies of the spinothalamic tract lie?

The dorsal root ganglion. 

114

Where does the spinothalamic tract enter the spinal cord?

The lissauer's fasciculus. 

115

What does the spinothalamic tract synapse with in the spinal cord?

It synapses with a cell body in the dorsal horn of the grey matter. 

116

Where secondary afferent (of the spinothalamic tract) decussate?

Immediately across the white anterior commissure of the spinal cord. 

117

Where are the three neurones in the pathway of the spinothalamic tract?

In the dorsal root ganglion. 

In the dorsal horn of the spinal cord. 

In the thalamus. 

118

The spinothalamic tract travels from the dorsal horn to the thalamus on which side?

The opposite side (contralateral). 

119

The lateral and medial spinothalamic tracts merge in the medulla to form the...

spinal lemniscus. 

120

What is the effect of damaging (hemisection) the corticospinal tract?

Ipsilateral weakness below the lesion. 

121

What is the effect of damaging (hemisection) the dorsal column?

Ipsilateral loss of proprioception, vibration and fine touch below the lesion. 

122

What is the effect of damaging (hemisection) the spinothalamic tract?

Contralateral loss of temperature, pain and crude touch below the lesion. 

123

Explain why Brown-Sequard syndrome occurs after hemisection of the spinal cord. 

Corticospinal tract and dorsal column decussate in the medulla - ipsilateral loss of function. 

Spinothalamic tract deccusates in the spinal cord - contralateral loss of function.