Principles of Neuroanatomy Flashcards
1
Q
What is the largest part of the brain?
A
The cerebrum
2
Q
What is the cerebrum divided into?
A
Two cerebral hemispheres
3
Q
What is situated below, and separate from the cerebrum?
A
Cerebellum
4
Q
What do the cerebrum and cerebellum grow out of?
A
The brain stem
5
Q
With what does the brainstem become continuous below?
A
The spinal cord
6
Q
What thick layer of brain tissue covers the cerebral hemispheres
A
Cerebral cortex
7
Q
What are the ridges and grooves of the cerebral cortex known as?
A
Ridges = GYRI Grooves = SULCI
8
Q
Why is the cerebral cortex folded?
A
To provide a larger surface area
9
Q
What sulcus divides the frontal lobe from the parietal lobe?
A
Central sulcus
10
Q
What sulcus separates the temporal lobe from the rest of the cerebral hemisphere?
A
SYLVIAN FISSURE
11
Q
Where is the occipital lobe?
A
At the back of the brain
12
Q
What are the primary functions of the frontal lobe?
A
Movement and higher-order cognition e.g. rational thought, decision making + planning.
13
Q
What is the area in front of the central sulcus called?
A
Precentral Gyrus
14
Q
What is the precentral gyrus essential for?
A
For motor control, as it is the location of the primary motor cortex
15
Q
What are the primary functions of the parietal lobes?
A
Processing of sensory information. Also involved in attention and representation of the space around us
16
Q
What does the post central gyrus contain?
A
The primary somatosensory cortex
17
Q
What is the function of the primary somatosensory cortex?
A
Where sense of touch is processed
18
Q
What is the function of the temporal lobes?
A
It is involved in processing auditory signals and important in aspects of learning and memory
19
Q
What is the function of the occipital lobes?
A
Contains major visual processing areas of the brain, like the primary visual cortex
20
Q
In the vertebral canal, where are the two lines of nerve filaments situated on each side of the spinal cord?
A
The dorsal and ventral aspects
21
Q
What is the protective layer that the spinal lies within called?
A
the Dura
22
Q
What is the loosely lined membrane along the Dura?
A
the Arachnoid
23
Q
What is the pia?
A
A firmly attached membrane that covers the spinal cord
24
Q
What is the space between the arachnoid and the pia called?
A
the Sub-arachnoid space
25
The sub-arachnoid space is filled with what?
Cerebrospinal fluid
26
What is the space between the Dura and the Vertebral canal wall called?
the Epidural space
27
What is the epidural space filled with?
Fat, loose connective tissue and blood vessels
28
What is the sleeve of Dura called?
the Dural sac (open at top end, closed at the bottom)
29
At the base of the skull, where does the Dural sac pass through?
The foramen magnum - this makes it continuous with the layer of Dura that surrounds the brain
30
Where does the Dural sac taper down to a point?
At the bottom end, within the vertebral canal of the sacrum - At the level of the second sacral segment
31
Where is the lower end of the spinal cord in an adult?
At the level of the first lumbar vertebra
32
What does meninges refer to?
The 3 membranes that surround the brain and spinal cord:
Dura Mater
Arachnoid Mater
Pia Mater
33
Function of Meninges?
Protect and provide structural support for the brain. Also contains cerebrospinal fluid
34
What is the outermost layer of the meninges?
Dura Mater (means "hard mother")
35
What does the dura mater adhere to
The skull on one side, arachnoid mater on the other side
36
Function of the dura mater?
1. Provides brain and spinal cord with an extra protective layer.
2. Attaches brain to the skull, and the spinal cord to the vertebral column -Keeps them from being jostled around
3. Provides a system of veinous drainage through which blood can leave the brain
37
How did the arachnoid mater get its name?
Has the consistency and appearance of a cobweb
38
What are the strands of connective tissue that stretch between the arachnoid and pia mater called?
Arachnoid trabeculae
39
What do the arachnoid trabeculae do?
Help to suspend the brain in place
40
What is the space between the arachnoid and pia mater called?
Sub-arachnoid space - filled with cerebrospinal fluid
41
What is the pia mater?
A thin layer that closely follows the contours of the brain
42
What is the function of the pia mater?
Forms a tight membrane around the brain and spinal cord.
1. Acts as additional barrier
2. Aids in secretion and containment of cerebrospinal fluid
43
How are blood vessels held against the pia mater?
By connective tissue (this is before they penetrate the brain
44
Where can analgesics and anaesthesia sometimes be administered in the spine?
In the epidural space
45
How is the lumbar cistern formed?
By the dura and arachnoid mater extending several vertebrae below the end of the spinal cord.
The lumbar cistern is filled with cerebrospinal fluid
46
Why can cerebrospinal fluid be drawn from the lumbar cistern?
Because a needle can be inserted with little risk of damaging the spinal cord.
I.e. LUMBAR PUNCTURES can take place in the lumbar cistern
47
What disease can we diagnose using a lumbar puncture?
Meningitis - inflammation of the meninges ----> Life threatening
48
What does meninges refer to?
The 3 membranes that surround the brain and spinal cord:
Dura Mater
Arachnoid Mater
Pia Mater
49
Function of Meninges?
Protect and provide structural support for the brain. Also contains cerebrospinal fluid
50
What is the outermost layer of the meninges?
Dura Mater (means "hard mother")
51
What does the dura mater adhere to
The skull on one side, arachnoid mater on the other side
52
Function of the dura mater?
1. Provides brain and spinal cord with an extra protective layer.
2. Attaches brain to the skull, and the spinal cord to the vertebral column -Keeps them from being jostled around
3. Provides a system of veinous drainage through which blood can leave the brain
53
How did the arachnoid mater get its name?
Has the consistency and appearance of a cobweb
54
What are the strands of connective tissue that stretch between the arachnoid and pia mater called?
Arachnoid trabeculae
55
What do the arachnoid trabeculae do?
Help to suspend the brain in place
56
What is the space between the arachnoid and pia mater called?
Sub-arachnoid space - filled with cerebrospinal fluid
57
What is the pia mater?
A thin layer that closely follows the contours of the brain
58
What is the function of the pia mater?
Forms a tight membrane around the brain and spinal cord.
1. Acts as additional barrier
2. Aids in secretion and containment of cerebrospinal fluid
59
How are blood vessels held against the pia mater?
By connective tissue (this is before they penetrate the brain
60
Where can analgesics and anaesthesia sometimes be administered in the spine?
In the epidural space
61
What is the somatic nervous system?
Neurones that are concerned with detecting changes in external environment, or with the control of movement (voluntary movement)
62
What is the autonomic nervous system?
Neurones that detect changes in and control activity of the viscera (internal organs) ----> internal, involuntary control of automatic processes
63
What disease can we diagnose using a lumbar puncture?
Meningitis - inflammation of the meninges ----> Life threatening
64
What is the autonomic nervous system divided into?
The sympathetic and parasympathetic divisions - they have antagonistic effects on structures they innervate.
Sympathetic ---> increases energy e.g. increase in heart rate, blood pressure and stimulation of sweat glands = FIGHT OR FLIGHT
Parasympathetic ---> conserves energy e.g. slows heart rate, increases digestion and salivation = REST AND DIGEST
65
What does caudal mean?
Towards the tail end = inferior
66
What does dorsal mean?
The back = posterior
67
What does ventral mean?
The front = anterior
68
In transverse sections through the spinal cord and lower part of the brainstem, where are the dorsal and ventral aspects depicted?
Dorsal is at the top of the image
| Ventral is at the bottom
69
In axial/transverse images of the brain that contain the brainstem, where are the dorsal and ventral aspects depicted?
Dorsal is at the bottom of the image
| Ventral is at the top of the image (this means that left and right are also reversed)
70
What are the two components of the nervous system?
Central Nervous System (CNS)
| Peripheral Nervous System (PNS)
71
What does the CNS consist of?
Brain and Spinal cord - contains most of nerve cell bodies and synaptic connections
72
What does the PNS do?
Constitutes the link between CNS and structures in the periphery of the body - receives sensory information and sends controlling impulses
73
What do groups called Nuclei consist of?
Nerve cell bodies with similar anatomical connections and functions e.g. motor neurones innervating a group of related muscles
74
How is the brachial plexus formed?
When spinal nerves serving the upper limbs coalesce (i.e. join together) within which fibres are redistributed into peripheral nerves
75
How is the lumbar plexus formed?
When spinal nerves serving the lower limbs coalesce (i.e. join together) within which fibres are redistributed into peripheral nerves
76
What are ganglia?
Structures in which peripherally located nerve cell bodies aggregate
77
What is the somatic nervous system?
Neurones that are concerned with detecting changes in external environment, or with the control of movement
78
What parts of the brain do the middle cerebral arteries supply?
Most of the lateral surface of the cerebral hemispheres
79
Where are somatic and autonomic components found?
In the CNS AND PNS
80
What is the autonomic nervous system divided into?
The sympathetic and parasympathetic divisions - they have antagonistic effects on structures they innervate
81
What does the autonomic nervous system do?
Innervates smooth muscle, cardiac muscle and secretory glands.
82
Nerve cells that carry info from peripheral receptors to the CNS are called...
AFFERENT neurones
83
If the information that afferent neurones carry reaches consciousness they are called what?
Sensory neurones
84
Nerve cells that carry impulses AWAY from the CNS are called...
EFFERENT neurones
85
If the efferent neurones innervate skeletal muscle to cause movement, they are called what?
Motor neurones
86
Where are the vast majority of neurones located and what are they called?
Interneurones - located entirely within the CNS
87
Regions that are relatively enriched with nerve cell bodies are referred to as what?
Grey matter
88
Regions that contain mostly nerve processes (usually axons) are referred to as what?
White matter ----> often ensheathed in myelin, which is why it has a paler coloration
89
What are tracts?
When nerve processes sharing common connections and functions tend to follow the same course i.e. they run in tracts
90
Which blood vessels supply the brain with blood?
Internal carotid arteries contribute 80% of blood
Vertebral contributes remaining 20%)
91
After ascending the brain, which artery splits into the anterior and middle cerebral arteries?
The internal carotid arteries
92
What parts of the brain do the anterior cerebral arteries supply with blood?
Medial, frontal and parietal lobes ---> connected by the anterior communicating artery
93
Before splitting into the anterior and middle cerebral arteries, what do the internal carotid arteries give rise to?
The anterior choroidal arteries ----> supply a number of different structures
Posterior communicating arteries ----> connect internal carotid arteries to the posterior cerebral arteries
94
What is the fourth ventricle?
A cavity formed on the dorsal surface of the medulla and pons, wedged beneath the cerebellum and above the brainstem
95
What do posterior inferior cerebellar arteries do?
Supply the inferior surface of the cerebellum
ALSO gives rise to posterior spinal arteries, which supply the posterior spinal cord
96
Where does the anterior spinal artery branch off of?
The vertebral arteries
97
What does the anterior spinal artery supply?
The anterior spinal cord
98
How is the Basilar artery formed?
When the two vertebral arteries come together
99
What does the Basilar artery give rise to?
The anterior inferior cerebellar arteries -----> These supply the rest of the cerebellar surface
100
Where does the basilar artery split into two posterior cerebral arteries?
At the level of the midbrain
101
What do the posterior cerebral arteries supply?
The medial and inferior surfaces of the occipital and temporal lobes
102
How is the CIRCLE OF WILLIS formed?
The anterior cerebral arteries, internal carotid arteries and posterior cerebral arteries of the brain are all connected
103
Function of the circle of willis?
Interconnection allows blood flow to continue if a major vessel is blocked on one side of the brain
104
What are the ventricles?
A network of cavities that are distributed throughout the brain
105
What is the choroid plexus?
A substance that lines the ventricles, made up of ependymal cells that secretes cerebrospinal fluid
106
Two sheets of cranial dura mater incompletely divide the cranial cavity into two compartments, what are they called?
the Falx Cerebri
| the Tentorium Cerebelli
107
Cranial dura mater contains dural venous sinuses. What do dural venous sinuses act as?
Channels for the venous drainage of the brain
108
What is the fourth ventricle?
A cavity formed on the dorsal surface of the medulla and pons, beneath the cerebellum
109
How is the cerebral aqueduct formed?
When the walls of the fourth ventricle converge, forming a narrow tube
110
Where is the cerebral aqueduct situated?
It runs the length of the midbrain, beneath the inferior and superior colliculi
111
At the junction of the midbrain and forebrain, the aqueduct opens into ...
the Third ventricle
112
What is the size of the third ventricle?
Narrow from side-side, but extensive in dorsoventral and rostrocaudal dimensions
113
What forms the lateral walls of the third ventricle?
The thalamus and hypothalamus of the diencephalon
114
What is the interventricular foramen (foramen of Monro)?
A small aperture, near the rostral end of the third ventricle
115
What does the Interventricular foramen do?
Communicate with an extensive chamber, the LATERAL VENTRICLE, within each cerebral hemisphere.
116
What is cerebrospinal fluid (CSF)?
A clear, colourless liquid that:
1. Performs important processes in the brain
2. Surrounds the brain, forming a protective layer and suspending it in fluid ----> reduces the strain that forces like gravity would have on the brain
3. Constantly flows through and around the brain, removes toxins and regulates the extracellular environment of neurones
117
What is the hole area in the third ventricle called?
The interthalamic adhesion
118
Where does CSF leave the brain?
At the 4th ventricle
119
How far does the 4th ventricle extend?
It extends to and is continuous with the central canal, a CSF-filled cavity that extends the length of the spinal cord
120
What happens if CSF circulation is blocked by a tumour or is otherwise abnormally excessive?
Can result in increased pressure, and expansion of the ventricles = HYDROCEPHALUS
