Intro to neuroanatomy Flashcards
1
Q
What is the CNS
A
Encompasses the brain at the rostral end, and the spinal cord at the caudal end.
2
Q
Where is the dorsal surface of the spinal cord?
A
Closer to the spinous processes of the vertebrae
3
Q
Where is the ventral surface of the spinal cord?
A
Closer to the body of the vertebrae
4
Q
What are the 5 major regions of the brain?
A
- Telencephalon
- Diencephalon
- Mesencephalon
- Metencephalon
- Myelencephalon
5
Q
What is the telencephalon composed of?
A
The cerebral hemispheres
6
Q
What are the components of the diencephalon?
A
The epithalamus, thalamus, hypothalamus and subthalamus
7
Q
What does the mesencephalon consist of?
A
The cerebral peduncles and the tectum
8
Q
What are the cerebral peduncles?
A
The tegmentum and crus cerebri
9
Q
What are the tectum?
A
Superior and inferior colliculi
10
Q
What makes up the metencephalon?
A
Pons and cerebellum
11
Q
What is the myelencephalon?
A
The medulla oblongata
12
Q
What is the central canal in the spinal cord?
A
A narrow slit, or lumen in the spinal cord
13
Q
What are the ventricles?
A
The lumen within the brain
14
Q
What are the ventricles filled with?
A
CSF
15
Q
How many cranial nerves are there?
A
12 pairs
16
Q
Where are the somatic motor neurons found in the spinal cord?
A
In the ventral horn
17
Q
Where do the axons of the somatic motor neurons leave?
A
Via the ventral rootlets
18
Q
Where are the axons of the preganglionic sympathetic neurons found?
A
In the lateral horn of the spinal cord
19
Q
What is located within the dorsal horn of the spinal cord?
A
The central processes of unipolar neurons of dorsal root ganglia
20
Q
What is the function of the axons within the dorsal root ganglia?
A
To bring sensory information to the CNS
21
Q
What are interneurons?
A
Cells that connect two types of neurons together
22
Q
What is the grey matter?
A
The nerve cell bodies of the CNS grouped together into large aggregates
23
Q
What is white matter?
A
The area consisting of the neuron processes and the neuroglia surrounding them
24
Q
What is the PNS?
A
A continuation of the CNS that extends to the peripheries
25
What does the somatic nervous system consist of?
The 12 pairs of cranial nerves and their ganglia.
| The 31 pairs of spinal nerves and their dorsal root ganglia
26
What is a dermatome?
An area of skin that is innervated by a spinal cord from a certain segment
N.B - overlaps are present so a single dermatome is supplied by more than 1 nerve to prevent total anesthesia
27
What is the autonomic nervous system?
Regulates the activities of smooth muscle, cardiac muscle and glands
28
What are the components of the autonomic nervous system?
The sympathetic, parasympathetic and enteric nervous systems.
29
How does the ANS differ from other motor neurons?
A somatic motoneuron directly innervates a muscle cell. In the ANS, the cell is within the CNS and synapses with a second neuron located in the ganglion of the PNS (Therefore a 2-cell system)
30
What does the ANS do?
Controls homeostasis
31
What is the sympathetic component?
"Fight, flight or freeze"
32
What is the parasympathetic component?
"Rest and digest"
33
Where are postganglionic cell bodies of the sympathetic neurons found?
Near the spinal cord, laterally to the vertebral column. Within the sympatehetic chain ganglia, or in collateral ganglia
34
Where are postganglionic cell bodies of the parasympathetic neurons found?
Located within ganglia that are in the vicinity of the viscera being innervated
35
Where are the cell bodies of sensory neurons that supply the viscera found?
In the dorsal root ganglia of spinal nerves or in the sensory ganglia of cranial nerves, along with the somatic sensory neurons
36
What are the meninges?
A tough protective connective tissue around the central nervous system, surrounds the spinal cord, cerebellum and the brain itself.
37
How is the spinal cord organised?
Segmentally
38
What are the segments of the spinal cord?
The area that gives rise to a pair of spinal nerves
39
How many segments are in the cervical region?
8
40
How many segments are in the thoracic region?
12
41
How many segments are in the lumbar region?
5
42
How many segments are in the sacral region?
5
43
How many segments are in the coccygeal region?
1
44
Where do the cervical nerves pass?
C1-C7 pass through the intervertebral foramen above their appropriate vertebrae
C8 passes through the intervertebral foramen below its appropriate vertebra
45
What is the upper limit of the spinal cord?
The junction with the medulla oblongata
46
Where is the lower limit of the spinal cord in an adult?
At the level of L1-L2
47
Where is the lower limit of the spinal cord in a baby?
At the level of L3-L4
48
Where does the spinal cord develop from?
Neuroectoderm
49
Where does the dorsal horn develop from?
The alar plate
50
Where does the ventral horn develop from?
The basal plate
51
What are the features of the cervical spinal cord?
Relatively large dorsal and ventral horns
52
What areas does the cervical spinal cord innervate?
The head, neck, upper chest and most of the forearms
53
What are the features of the thoracic spinal cord?
Smaller dorsal and ventral horns
54
What areas does the thoracic spinal cord innervate?
The trunk and thin strips of the forearm
55
What are the features of the lumbar spinal cord?
Large ventral and dorsal horns
56
What areas does the lumbar spinal cord innervate?
The legs
57
What are the features of the sacral spinal cord?
Equal dorsal and ventral horns that are relatively smaller in size.
58
What areas does the sacral spinal cord innervate?
The genitalia
59
What are the different layers of the meninges?
- The dura mater
- The arachnoid mater
- The pia mater
60
What are the features of the dura mater?
Outer layer
Thick, inelastic membrane
Fuses with the endosteum cranium at the foramen magnum
61
What is the function of the dura mater?
Provides maximum mechanical protection to the spinal cord, which is otherwise surrounded by bone
62
What does the dura mater give rise to?
The epidural space that separates the spinal cord from the vertebrae
63
What are the features of the arachnoid mater?
The middle layer
A thin, fibrous membrane
Contains trabeculae that bridge the subarachnoid space and adhere to the pia mater
64
What is contained within the subarachnoid space?
CSF
65
What is CSF?
Filtrate of blood
66
Where is the CSF made?
In the choroid plexus, within the ventricular system in the brain
67
How much CSF is produced each day?
~500ml
68
What is the purpose of CSF?
To provide mechanical and immunological protection to the brain and spinal cord
69
What happens to CSF?
It circulates around the cranium and spinal cord and is reabsorbed into the venous system of the head
70
What are the features of the pia mater?
The innermost layer
Unicellular membrane
Separated from the cord by small areas of gaps called the subpial space
Forms 21 denticulate ligaments laterally
71
What vessels are found within the extradural space?
Vertebral/Batson venous plexus (Batson veins)
72
What are the key features of Batson veins?
They don't have any valves
73
Describe the circulation of the Batson veins
They drain out via the subarachnoid space and into the venous system at appropriate spinal levels.
74
Describe the arterial supply of the spinal cord
- The aorta sits anteriorly
- There are segmental arteries at the various intercostal levels and these will branch off to supply the spinal cord
- There is one anterior spinal artery and two posterior spinal arteries
- artery of adamkiewicz
75
Which artery supplies the lower 1/3 of the spinal cord?
Artery of adamkiewicz
76
Where does the medulla oblongata exit?
The foramen magnum
77
What is continuous with the medulla oblongata?
The C1 level of the spinal cord
78
What forms the boundaries of the foramen magnum?
The occipital bone
79
What is the lowest point of the spinal cord called?
Conus medullaris
80
What is the filum terminale?
A thin filament that tethers the cord to stop movement
81
What is the cauda equina?
a whole series of spinal nerves that project down to leave at the appropriate spinal level. This is likened to a horses tail
82
What is the longest nerve in the human body?
The sciatic nerve
83
What are the processes of neurons called?
Dendrites
84
What is the single process of a neuron called?
Axon
85
What do dendrites do?
Conduct information towards the cell body
86
What is the area between cells called?
Synapse
87
What are released from the axon terminals?
Neurotransmitters
88
What junctions can form between neurons?
Gap junctions
89
What are neuroglia?
Several categories of non-neuronal cells.
- microglia
- macroglia
- ependymal cells
90
What are microglia?
Macrophages
91
Where are ependymal cells found?
In the epithelium surrounding the central canal of the spinal cord and ventricles surrounding the brain.
Also participates in the formation of the choroid plexus.
92
What are macroglia?
Term given to protoplasmic astrocytes, fibrous astrocytes and oligodendroglia
93
What are protoplasmic astrocytes?
Support neurons in the grey matter forming a subpial barrier and envelop capillaries
94
What are fibrous astrocytes?
Located in the white matter and function in a similar way to protoplasmic astrocytes
95
What are oligodendroglia?
They form myelin sheaths around axons and also surround dendrites and cell bodies of neurons in the CNS
96
What are Schwann cells?
Myelin secreting cells located in the PNS that envelop unmyelinated axons
97
What are the three visible regions of the brain?
Cerebrum
Cerebellum
Brainstem
