Intro to CNS , Neurotransmitters and BBB Flashcards
1
Q
List the 5 major areas of the CNS
A
1- Spinal Cord 2- Brainstem 3- Diencephalon 4- Cerebellum 5- Cerebral hemispheres ( telencephalon )
2
Q
What is the role of the spinal cord
A
Receives afferent sensory information and transmits the info to reflex centres in itself or in the brainstem, cerebellum or cerebral hemispheres.
Transmits efferent information from brain to somatic and autonomic nervous systems.
3
Q
Anatomically describe the spinal cord
A
- Thin , cylinder like structure located in the vertebral canal.
- exits the base of skull via the foramen magnum
- has a conical shaped, caudal end called conus medullaris.
- thin layer of Pia extends from conus medularris called hilum terminale.
4
Q
At what vertebral level is the conus medullaris in an adult ? What about a child ?
A
Adult : L1- L2
Child : L3
5
Q
What is the most rostral region of the Spinal cord
A
Cervical Cord
6
Q
List how many pairs of spinal nerves the cervical, thoracic, lumbar , sacral and coccygeal regions have
A
Cervical : 8 Thoracic: 12 Lumbar: 5 Sacral: 5 Coccygeal: 1
7
Q
Since the spinal cord ends at L2 what does that mean for the lumbar and sacral nerve roots
A
They have to descend in the vertebral canal before exiting from respective foramina
8
Q
What surrounds the filum terminale ?
This leads to the formation of what ?
A
Lumbrosacral nerve roots surround filum terminale, forming a cluster called caudal equina
9
Q
Why does the spinal cord enlarge in the cervical and lumbosacral regions
A
to accommodate for the increased number of motor neurons to supply the arms and legs
10
Q
What does the grey matter and white matter of the spinal cord contain
A
Grey matter: nerve cell bodies ( ventral and dorsal horns )
White matter : longitudinal tracts of myelinated axons ( ascending & descending pathways)
11
Q
List the sections of the spinal cord grey matter and their purpose
A
Dorsal ( posterior ) horn : contains sensory relay neurons that receive input form periphery
Ventral ( anterior ) horn: contains motor nuclei that innervate specific muscles
12
Q
What is in the forebrain
A
1- Telencephalon
2- Diencephalon
13
Q
What is in the midbrain
A
Mesencephalon
14
Q
What is in the Hindbrian
A
1- Metencephalon
2- Myelencephalon
15
Q
Anatomically describe the brainstem
A
Brainstem is immediately above the spinal cord and connect the spinal cord with cerebral hemispheres and cerebellum
16
Q
List 3 broad functions of brainstem
A
1- Conduit for ascending and descending tracts of SC , connects them to higher centres in brain
2- contains important reflex centres
3- contains important nuclei of cranial nerves 3 to 7
17
Q
The brainstem consists of what three areas
A
1- Midbrain
2- Pons
3- Medulla Oblongata
18
Q
What is the purpose of the Midbrain
A
1- Contains somatic motor neurons that control eye movement. Neurons reside in CN 3 and CN 4
2- contains neurons responsible for reflex movements of eyes, head, neck in response to visual or auditory signals
19
Q
Where will nerve fibres from CN III reside and what is the purpose
A
Will reside in Edginer-Westphal nucleus ( accessory oculomotor nucleus ).
Purpose: responsible for pupillary diameter , accommodation of lens and convergence of eyes
20
Q
What is the purpose of Pons
A
1- contains somatic neurons controlling mastication ( CN V ) , eye movement ( CN VI ) and muscles of facial expression ( CN VII )
2- receives somatic sensory info from face, scalp , mouth and nose ( CN V )
3- processes info related to hearing and equilibrium ( CN VIII )
4- Has apneustic and penumotaxic centre to prevent apneusis by coordinating respirations
21
Q
What is apneusis
A
sustained gasping inhalation followed by short inefficient exhalation
22
Q
What is the purpose of the medulla oblongata
A
1- contains nuclei of somatic motor neurones that innervate neck ( CN XI ) and tongue ( CN XII)
2- contains nuclei controlling respiration ( CN X )
3- contains cycle involved in BP, HR and digestions ( CN IX , CN X )
23
Q
What is the Diencephalon
A
Thalamus, hypothalamus and epithalamus
24
Q
How many thalami are there
A
2 thalami , one on each side of third ventricle
25
Is the thalamus made of grey or white matter
Grey
26
Explain the purpose of the thalamus
1- Main integrating station for sensory information found for cerebral cortex ( except olfaction )
2- subcortical structures and cerebellum project to thalamus on their way to cortex to influence upper motor neurons for motor output
3- involved in arousal and aspects of memory function
4- anterior nucleus part of limbic system
27
Explain he purpose of the hypothalamus
1- central regulator of autonomic and endocrine functions
2- specialized centres involved in food intake, fluid and electrolyte balance, body temperature, sleep cycle and circadian rhythm
3- specialized hypothalamic neurons synthesis hormones and transport to posterior pituitary gland & releasing hormones to anterior pituitary
28
What part of the Brian affects the autonomic nervous system the most
Hypothalamus
29
How does the hypothalamus perform it's functions
Has strong, direct connections to autonomic nuclei in brainstem and spinal cord
30
Explain the purpose of the epithalamus
1- Consists of habenular nucleus that's the centre for integration of olfactory, visceral and somatic afferent pathways
2- has pineal gland that releases hormones ( melatonin, serotonin, noradrenaline )
31
Where is the cerebellum
Immediately dorsal ( upper ) to brainstem
32
Explain the purpose of the brainstem
1- receives peripheral information regarding proprioception , muscle tone, position of head and the environment. Compares and integrates information with plans of movement received from cortex
2- predict consequence of movement through feed forward mechanisms. coordinator and predictor of movement.
33
List three major cerebellum functions
1- Movements properly grouped for performance of selective responses that require specific adjustments
2- maintains upright posture
3- maintains muscle tone
34
What is the cerebral cortex
Covers the entire surface of brain.
Highly folded and forms gyro and sulci.
Divided into 4 lobes : frontal, parietal, occipital, temporal
35
Functional areas of cerebral cortex aka ?
Brodmann's areas
36
What is the frontal lobe
Frontal lobe is located infront of the central sulcus. Contains the primary motor, supplementary motor, premotor and prefrontal area.
37
Where is the primary motor located
Just infront of the central sulcus
38
Where is the precentral gyrus and what does It contain.
On lateral surface of each frontal lobe, anterior to central sulcus. Runs parallel to central sulcus and extends to the precentral sulcus.
Contains the primary motor cortex
39
Explain the role of the precentral gyrus
Left hemisphere sends motor commands to right side of body. High hemisphere sends motor commands to left side. Cluster of motor neurons that use somatotopy, form motor homunculus
40
What is a motor homunculus
a topographic ( map ) representation of body parts in the precentral gyrus of frontal lobe. Shows which areas of the brain are dedicated to motor process different areas in the body.
41
What determines the neuron pool supplying the musculature of a body part ( in precentral gyrus )
The size of the body part and the precise movement required from it. The more motor units a body part has the more space it will take up in precentral gyrus.
42
Which body part has a larger cortical representation , the hand or trunk
The hand because precise movement of hand require innervation of many muscles and fibres
43
Explain the supplementary motor area in frontal lobe
Contains motor maps for posture , and premotor association area.
Has a role in anticipating or planning voluntary movement
44
Explain the premotor area in the frontal lobe
Contains motor maps for movement of larger muscle groups.
| Important in higher order processing and integrating/interpreting motor information and activity.
45
What will light up ( activate ) prior to activation of primary motor area
Supplementary motor area
46
What is the role of the prefrontal area of the frontal lobe
1- extensive connections with parietal, occipital and temporal lobe via fasciculi = access to sensory processing and memory
2- Monitors behaviour and controls higher processes : judgement , emotion , motivation , personality, initiative, concentration and social inhibitions
3- Intelligence ( problem solving )
47
Where are expressive/ motor aspects of language processed
Later surface of frontal lobe in Broca's motor speech area
48
What is the central sulcus
Divides the frontal lobe from parietal lobe.
Anterior to it : precentral gyrus
Posterior to it : post central gyrus
49
What is the lateral sulcus
Divides the frontal and parietal lobe from the Temporal lobe
50
What is the parietal occipital sulcus
Divides parietal lobe from occipital lobe. Can be seen from medial view of Brain
51
What is the calcarine sulcus
Divides the occipital lobe from the temporal lobe
52
List the sulcuses dividing the lobes of the cerebrum
1- Cental
2- Lateral
3- Parietal occipital
4- Calcarine
53
What is the largest lobe of the Brain
The frontal brain
54
Does the prefrontal area of frontal lobe elicit movement
No
55
Nerves with the nervous system are called what
Fasciculi
56
Where is the parietal lobe located and what does it house
Posterior to the central sulcus in the postcentral gyrus.
| Houses the primary somatosensory area and Wernickes' area
57
Explain the purpose of the Parietal lobe
1- Important in regulating somatosensory functions
2- Initial cortical processing
3- pain perception
4- temperature and proprioception
5- spatial orientation and perception
58
What's the percentage of cerebral hemispheres taken up by association areas
75%
59
What is proprioception
Knowing where your limbs are at any point of time
60
What is Wernickes' area responsible for
Receptive or sensory aspects of language
61
What is the somatosensory association area is responsible for
Interpretation the significance of sensory information
62
Lesion in the somatosensory association area can cause which complications
1- Tactile agnosia: Deficit in ability to combine tough, pressure and proprioceptive input to interpret the significance of the sensory information.
2- Astereognosis: inability to recognize and object placed in hand
63
What is the purpose of the Occipital lobe
1- processing of visual information
64
Where are the visual association areas
Surrounding and covering the lateral surface of occipital lobe
65
Explain how the primary visual cortex receives information
Neurons from the retina project to the lateral geniculate nucleus in the thalamus which sends fibres ( aka optic radiations ) to the primary visual cortex )
66
What is the role of the visual association area
Gives meaning and interpretation to what is seen
67
A lesion in the the visual association area can result in what complications
Vision agnosia: Deficit in ability to recognize objects in the opposite visual fields despite intact vision.
Deficit in tracking objects ipsilateraly
68
The occipital lobe is separated from the parietal lobe via
The Parieto-occipiutal sulcus
69
The occipital lobe is separated from the temporal lobe via
The calcarine sulcus ( seen on medial brain surface )
70
What is the purpose of the temporal lobe
Processing of auditory information and some aspects of memory function
71
How is each ear represented on the auditory cortex
Bilaterally
72
How are the neurons in the primary auditory cortex organised
In a tonotopic arrangement that's similar to the tonotopy of the cochleae
73
Where are the auditory association areas
Superior temporal gyrus, adjacent to the primary auditory area
74
What is the role of the auditory association areas
Interprets sounds heard and gives it meaning
75
A lesion in the temporal lobe can mean ....
Word deafness.
| Acute verbal agnosia : compromise of ability to interpret what is heard
76
Which part of the temporal lobe is responsible for perception of language
The lateral surface
77
What are the anterior medial areas of the temporal lobe responsible for
Learning memory and emotion
78
Where is Broca's area located
Inferior frontal gyrus in the left hemisphere
79
What is the role of Broca's area
Generation of language ( written/ spoken/signed ). Produces symbols, signs or words for concepts, objects or ideas.
80
A lesion in Broca's area can result in ...
Broca's aphasia : difficulty generating written/spoken language but little difficulty with language comprehension
81
Where is Wernicke's area
Superior surface of temporal gyrus in the left hemisphere
82
What is the role of Wernicke's area
Comprehension of signed and spoken language. Interpretation and assigning of meaning to symbols.
83
A lesion in Wernicke's area can result in ..
Wernicke's aphasia: difficulty understanding written/spoken language. Person can speak but the language is meaningless unconnected words.
84
What is the role of the Olfactory cortex
Smell
85
What is the limbic association cortex and where is it located
Association area for behavioural regulation ( emotions, learning , memory) .
Located in the forebrain , under the medial temporal lobe
86
What is the Diencephalon
Series of paired structures located deep within the cerebral hemispheres, on either side of the third ventricle.
Made of Thalamus, Epithalamus, Subthalamus and Hypothalamus
87
What is the largest structure in the Diencephalon
Thalamus
88
What is the role of the thalamus
The sensory switchboard. All sensory information goes to the thalamus where it will then be sent to appropriate areas of Brian. Auditory and visual information is sent through there
89
What are two big nerves that go through the thalamus
Optic nerve and Vestibular nerve
90
Which sense does not go through the thalamus
Olfaction , the sense of smell
91
What does the thalamus include
Hypothalamus, posterior pituitary and pineal gland
92
What is the role of the hypothalamus
Controls homeostatic, autonomic and endocrine functions
93
What is the Epithalamus and it's role
Habenular nucleus: Regulates CNS neurotransmitters ( dopamine, serotonin) and behaviour of addictions and motivation
Pineal body : produced melatonin and maintains circadian rhythm
94
What is the role of the limbic system
Structures that have a significant role in drive related and emotional behaviours. Memory and learning.
95
What does the limbic system consist of
A ring of cortex on medial surface of brain spacing across frontal, parietal, and temporal.
Structures include subcalossal, cingulate gyrus, parahippocampal gyrus, hippocampal formation, amygdaloid nucleus , mammillary bodies and anterior thalamic nucleus
96
What are the deep forebrain structures of the limbic system located in the temporal lobe
The amygdala and hippocampus
97
How is the limbic system able to influence emotional behaviour aspects
Through the hypothalamus, connection with autonomic nervous system outflow and control of endocrine system.
98
What reactions are particularly controlled via the limbic system
Fear, Anger and emotions associated with sexual behaviour.
99
What occurs in the dentate gyrus of the hippocampus
Neurogensis: new cells believed to play a role in formation of new memories and modulating symptoms of stress and depression
100
Where can neurogenesis occur in the CNS
1- Olfactory bulb
| 2- dentate gyrus of hippocampus
101
What is the role of the hippocampus
Sends outputs to etorhinal cortex that has widespread reciprocal connections with association areas in cerebral cortex
102
A lesion in the hippocampus results in ....
Anterograde amnesia: Affects ability to store long term memory , events before lesion are unaffected
103
What is the location of the amygdala relative to the hippocampus
The amygdala is just superior to hippocampus
104
What does the amygdala consist of
Functionally diverse nuclei. Receives sensory information, info from brainstem , input from thalamus and info from cortex.
105
What sensory information is afferent to the amygdala
Visual , somatosensory , gustatory and olfactory information
106
What connections does the amygdala have
Has connections to the thalamus and indirect connections to prefrontal cortex
107
What is the role of the Amygdala
Ability to feel strong emotions, emotional memory, learning and drive related behaviours & processing of emotions related to these behaviours.
Recognition and interpretation of emotional behaviour or signals from others.
108
What behaviours is the amygdala associated with
Fear ( fear memory ) and reward ( addiction and stress )
109
Damage to the amygdala can result in ...
Reduced or absent facilitation of attention and memory of emotional stimuli
110
Where are the Basal nuclei
Located under the cortical layer
111
What are the Basal nuclei
Masses of grey matter made of groups of interconnecting nuclei within the forebrain, midbrain and diencephalon
112
What does the Basal nuclei include
```
1- Caudate nucleus
2- putamen
3- globus pallidus
4- sub thalamic nucleus
5- substantia nigra
```
113
What is the role of the basal nuclei
Basal nuclei along with cerebellum command the upper motor neurons which control movement.
Critical role in initiation and control of voluntary movement.
114
What is the striatum
The caudate nucleus and putamen
115
What is the lentiform body
The putamen and the globus pallidus
116
What is the caudate nucleus
nucleus with its head lying on floor of lateral ventricle and body over the thalamus. Input nuclei to basal nuclei, receiving excitatory input from cortical and subcortical structures
117
What is the putamen
Connected to caudate nucleus and serves as an input nuclei , receiving excitatory input from cortical and subcortical structures
118
What is the globus pallidus
Output nucleus sending inhibitory neurons to thalamus. Located medial to putamen and lateral to thalamus.
Split into External ( GPe) and inner ( GPi) globus pallidus.
119
Are GPe and GPi the same
No, they are functionally different and have different connections within basal nuclei.
120
What is the subthalamic nucleus
Nucleus inferior to thalamus and superior to the tegmenjtum of midbrain. receives afferents from cortex and other basal nuclei structures. Output is excitatory to globus pallidus and substantia nigra.
Central role in basal nuclei connectivity and defines the nuclei's rhythm
121
How is the sub thalamic nucleus excitatory to globus pallidus and substantia nigra
Through glutaminergic neurons
122
What is the Substantia Nigra
located in rostral midbrain in cerebral peduncle at level of superior colliculi. Contains dopaminergic neurons that project to putamen , caudate nucleus and sub thalamic nucleus.
123
What can neurotransmitters be
amino acids, biogenic amines, purines or neuropeptides
124
What releases ACh and what is its postsynaptic effect
Cholinergic neurons release ACh which have a excitatory effect in the PNS and CNS
125
Which common amino acids are used as neurotransmitters in
Glutamate, Aminobutyric acid ( GABA ) , Glycine, Dopamine
126
What is the most common excitatory neurotransmitter in the CNS
Glutamte
127
How is Glutamate synthesized
Synthesized in neurons from precursor glutamine spilled by astrocytes which produce glutamine from the glutamate they uptake from the synaptic cleft
128
What are the most important inhibitory neurotransmitters in the CNS
GABA and glycine. Half of inhibitory synapse in spinal cord uses glycine
129
When is Dopamine used as neurotransmitter
In forebrain circuits
130
What is the role of Dopamine neurotransmitter
Could be excitatory ( via D1 receptor ) or inhibitory ( via D2 receptor.
Associated with movement, emotion, motivation and reward
131
What's the role of Adrenaline/ Noradrenaline
Excitatory effect , Both involved in wakefulness and attention.
132
Does CNS use adrenaline or noradrenaline more
Noradrenaline
| Concentration of adrenaline in CNS is much lower than Noradrenaline.
133
What is the role of Histamine
Excitatory effect Involved in wakefulness
134
What is Serotonin derived from
Derived from amino acid tryptophan
135
What is the role of Serotonin
Could have a excitatory or inhibitory effect. Used in pathways regulating mood, emotion, sleep and serval homeostatic pathways.
136
What is the role of neuropeptide Substance P
Excitatory effect involved in pain pathways
137
What is the role of Metenkephalin or opioids
Involved in inhibitory effect of pain pathways
138
What is the role of Adrenocorticotropin
Excitatory effect in CNS
139
The smaller the molecule , the easier or harder for it to get through the BBB
The easier
140
What will help a molecule pass the BBB
If it's lipid soluble
141
What is BBB permeable to
Water, carbon dioxide, oxygen, lipid soluble substances ( ex: steroid hormones ), alcohol, anaesthetics , electrolytes
142
What is BBB impermeable to
plasma proteins, protein bound steroid hormones , non-lipid soluble large molecules.
143
Where is the BBB not present
hypothalamus, pineal gland, area postrema ( in 4th ventricle ).
