Peripheral Nervous System Flashcards
1
Q
What is the function of the nervous system?
A
Coordinates voluntary and involuntary actions and transmits signals between different parts of the body
2
Q
What is the function of the neuroglia?
A
Separate and protect neurons and provide a supportive framework
3
Q
What is the CNS responsible for?
A
integrating, processing, and coordinating sensory data and motor commands. Also higher cognitive functions (intelligence, memory, learning and emotion)
4
Q
What does the PNS do?
A
Delivers sensory information to the CNS and carries motor commands to peripheral tissues and systems
5
Q
What is the function of the afferent PNS?
A
Brings sensation into the CNS from receptors in peripheral tissues and organs
6
Q
What is the function of the efferent PNS?
A
Carries motor commands from the CNS to muscles and glands
7
Q
Where do cranial nerves come from?
A
Brainstem
8
Q
Where do spinal nerves come from?
A
Spinal cord
9
Q
What does the somatic nervous system innervate?
A
Musculoskeletal structures and sensory organs of the skin
10
Q
What does the autonomic nervous system innervate?
A
Smooth muscles and glands
11
Q
What divisions is the autonomic nervous system split into?
A
Sympathetic, parasympathetic and enteric
12
Q
Where do the sympathetic nerves come from in the spinal cord?
A
Only thoracic and lumbar
13
Q
Where do the parasympathetic nerves come from in the spinal cord?
A
Only cranial and sacral
14
Q
What is the spinal cord continuous with?
A
Medulla oblongata
15
Q
What is the cone-shaped swelling at the bottom of the spinal cord?
A
Conus medullaris
16
Q
Where does the spinal cord terminate?
A
L1/L2
17
Q
What is the cauda equina?
A
The splaying of spinal nerves at the bottom of the spinal cord
18
Q
What is the filum terminale?
A
A thin, fibrous strand that attaches the end of the spinal cord to the sacrum
19
Q
What does grey matter contain?
A
Cell bodies, dendrites and proximal parts of axons and neurons
20
Q
What does white matter contain?
A
An abundance of myelinated axons which run in tracts carrying signals from one part of the CNS to another
21
Q
What shape is the spinal cord grey matter in cross section?
A
Butterfly shaped
22
Q
What makes up the spinal cord grey matter?
A
Two posterior (dorsal) and two anterior (ventral) horns
23
Q
What is the function of the two dorsal horns in the spinal cord?
A
Receive sensory information
24
Q
What is present in the two ventral horns in the spinal cord?
A
Cell bodies of motor neurons
25
Where are the ventral horns found?
Only in the thoracolumbar region
26
Why are the ventral horns only found in the thoracolumbar region?
Thats where the sympathetic nervous system is
27
Where is the most spinal cord grey matter found?
In the cervical and lumbar regions where motor control of limbs is the greatest
28
What does spinal cord white matter contain?
Axons that move up and down the cord
29
What are the spinal cord white matter axon bundles arranged in?
Three pairs called columns (or funiculi)
30
What are the names of the spinal cord white matter axon bundles?
Posterior (dorsal), anterior (ventral) and lateral
31
What do the ascending tracts of spinal cord white matter carry?
Sensory info up the cord
32
What do the descending tracts of spinal cord white matter carry?
Motor impulses down the cord
33
What does the PNS consist of?
Cranial nerves and spinal nerves
34
How many pairs of cranial nerves do you have?
12
35
How many pairs of spinal nerves do you have?
31
36
Where does the first pair of spinal nerves pass?
Between the skull and C1
37
How many cranial nerves are there?
8
38
How many thoracic nerves are there?
12
39
How many lumbar nerves are there?
5
40
How many sacral nerves are there?
5
41
How many coccygeal nerves are there?
1
42
What are the types of spinal nerve?
Motor, sensory and autonomic fibres
43
What are the two roots of spinal nerves called?
Ventral and dorsal
44
What do the ventral roots of spinal nerves contain?
Efferent nerve fibres carrying motor neurons
45
What do the dorsal root of spinal nerves contain?
Afferent nerve fibres carrying sensory neurons
46
Where are the cell bodies of the dorsal root located?
Ganglion
47
What do both the ventral and dorsal roots converge to form?
Mixed spinal nerve
48
What does the mixed spinal nerve split into?
Dorsal and ventral ramus
49
Where does the dorsal ramus travel to?
Muscles and skin in the region of the back
50
Where does the ventral ramus travel to?
Anterior and lateral muscles and skin of the trunk
51
What does the ventral ramus give rise to?
Nerves of the limbs
52
What is a dermatome?
A skin area supplied by the sensory fibres of a single nerve root
53
Why are dermatomes useful?
Helpful in localising pathologies
54
What is a myotome?
A group of muscles primarily innervated by the motor fibres of a single nerve root
55
What are the 5 spinal plexuses?
Cervical, brachial, lumbar, sacral and coccygeal
56
What merges to form nerve plexuses?
Ventral rami of adjacent spinal nerves
57
What type of fibres make up the nerve plexuses?
Sensory and motor fibres
58
What does the brachial plexus innervate?
Pectoral girdle and upper limb
59
Where do the nerves of the brachial plexus originate from?
Roots, trunks, cords and branches
60
Where does the nerves of the brachial plexus come from?
Spinal nerves C5-T1
61
Where do the nerves of the brachial plexus pass through?
The triangles of the neck, between anterior and medial scalene muscles
62
What are the three trunks of the brachial plexus?
Superior, middle and inferior
63
What nerves converge to form the superior trunk of the brachial plexus?
C5 and C6
64
What nerves converge to form the middle trunk of the brachial plexus?
C7
65
What nerves converge to form the inferior trunk of the brachial plexus?
C8-T1
66
What does each trunk of the brachial plexus divide into?
Anterior and posterior divisions
67
What do the divisions of the trunks of the brachial plexus combine to form?
Lateral, posterior and medial cords
68
What do the lateral, posterior and medial cords give rise to?
The major branches of the brachial plexus
69
What are the major branches of the brachial plexus?
Musculocutaneous, median, radial, ulnar and axillary
70
Which spinal segments does the musculocutaneous nerve come from?
C5, 6 and 7
71
What does the musculocutanous nerve innervate?
All three flexor muscles in the anterior compartment of the arm
72
What route does the musculocutanous nerve take?
Penetrates the coracobrachialis muscle and passes between the biceps brachii and brachialis muscle
73
Which spinal segments does the median nerve come from?
C5,6,7,8 and T1
74
Which spinal segments does the radial nerve come from?
C5, 6, 7, 8 and T1
75
Which spinal segments does the ulnar nerve come from?
C7, 8 and T1
76
Which spinal segments does the femoral nerve come from?
L2, 3 and 4
77
Which spinal segments does the sciatic nerve come from?
L4-S3
78
What route does the median nerve take?
Passes through the arm and into the forearm through the cubical fossa
79
What route does the radial nerve take?
Enters the arm crossing the inferior margin of the teres major muscle
In the arm- passes diagonally from medial to lateral through the posterior compartment
Then passes anteriorly through the lateral intermuscular septum and enters the anterior compartment of the forearm
80
What does the median nerve innervate?
Most of the muscles in the interior compartment of the forearm
81
Which of the muscles in the interior compartment of the forearm does the median nerve NOT innervate?
Flexor carpi ulnaris and medial half of the flexor digitorum profundus
82
How does the median nerve continue to the hand?
Via the carpal tunnel
83
What does the radial nerve bifocate into?
Deep and superficial
84
What is the function of the deep branch of the radial nerve?
Mainly motor
85
What is the function of the superficial branch of the radial nerve?
Sensory
86
What does the radial nerve innervate?
All muscles in the posterior compartment of the arm and forearm and sensory innervation to the skin on the posterior aspect of the arm and forearm and dorsal lateral surface of the hand
87
What route does the ulnar nerve take?
Passes through the arm and posterior to the medial epicondyle of the humerus and into the anterior compartment of the forearm
Then down the medial side of the forearm between the flexor carpi ulnaris and flexor digitorum profundus
Then passes into the hand, superficial to the flexor retinaculum
88
What does the lumbar plexus supply?
Skin and musculature of the lower limb
89
Where is the lumbar plexus located?
Within the soas major muscle
90
What is the lumbar plexus formed of?
The anterior rami of T12-L4
91
What are the six major branches of the lumbar plexus?
Femoral, obturator, lateral femoral cutaneous, genitofemoral, ilio-inguinal and ilio-pogastric
92
What route does the femoral nerve take?
Leaves the abdomen under the inguinal ligament to enter the anterior thigh compartment
93
What does the femoral nerve innervate?
All the muscles in the anterior thigh compartment and skin of the anterior thigh, antromedial side of the knee, medial side of the leg and medial side of the foot
94
Which is the largest nerve of the body?
Sciatic nerve
95
Which spinal nerves form the sciatic nerve?
L4-S3
96
What route does the sciatic nerve take?
Leaves the pelvis through the greater sciatic foramen into the gluteal region and enters the posterior compartment of the thigh
97
What does the sciatic nerve innervate?
```
Posterior muscles of the thigh,
part of the adductor Magnus,
all leg muscles,
all foot muscles
skin on lateral side of leg and foot and sole of foot
```
98
What branches does the sciatic nerve divide into?
Common fibular and tibial
99
What are the spinal meninges?
Membranes that protect the spinal cord from the bony walls of the vertebral canal
100
What do the spinal meninges form distally?
Phylum terminale
101
What are the three layers of the spinal meninges?
Dura mater, arachnoid mater and pia mater
102
Which is the outermost mater?
Dura mater
103
What lies between the dura mater and the walls of the vertebral canal?
Epidural space
104
What does the dura mater contain?
Areolar tissue, blood vessels and adipose tissues
105
What does the dura mater fuse with?
The outer connective nerve covering
106
Does the dura mater have a lot of attachments along the vertebral canal?
No
107
What is the dura mater attached superiorly to?
The occipital bone
108
What does the dura mater blend inferiorly with?
The filum terminale to form the coccygeal ligament
109
What does the arachnoid mater consist of?
Arachnoid membrane and the arachnoid trabeculae
110
What is the arachnoid mater made up of?
Delicate network of collagen and elastic fibres extend to the outer surface of the pia mater
111
What is the space between the arachnoid and pia mater called?
Subarachnoid space
112
What does the subarachnoid space contain?
CSF
113
What sort of attachment does the pia mater form?
Firmly bound to underlying neural tissue
114
What runs along the surface of the pia mater?
Blood vessels servicing the spinal cord
115
Where do ligaments extend from/to in the meninges?
From the pia mater through the arachnoid mater to the dura mater along the length of the spinal cord
116
What are the meningeal ligaments called?
Denticulate ligaments
117
What are the spinal meninges continuous with and where?
Cranial meninges at the foramen magnum
