14. Nervous System II Flashcards
1
Q
What does the CNS consist of?
A
Brain
Spinal cord
2
Q
What is the spinal cord protected by?
A
Vertebral column
Meninges
3
Q
What are meninges?
A
Layers of connective tissue
4
Q
What is the brain protected by?
A
Cranium
Cranial meninges
Cerebrospinal fluid (CSF)
Blood brain barrier (BBB)
5
Q
What are the three layers of meninges that cover the brain and spinal cord?
A
Dura mater
Arachnoid mater
Pia mater
6
Q
What is the dura mater?
A
Tough outer layer
7
Q
What is the dura mater in the brain made up of?
A
Two layers
8
Q
What do the two layers of dura mater in the brain do?
A
Create venous sinuses
9
Q
What do venous sinuses do?
A
Allow blood to drain out of the brain into the jugular veins
10
Q
What is the arachnoid mater made up of?
A
Collagen and elastic fibres
11
Q
What is the subdural space between the dura mater and arachnoid mater filled with?
A
Interstitial fluid
12
Q
What is the pia mater?
A
Thin transparent layer
13
Q
What is the pia mater made up of?
A
Blood vessels that supply the spinal cord
14
Q
What is the subarachnoid space between the arachnoid mater and pia mater filled with?
A
Cerebrospinal fluid (CSF)
15
Q
What is a subdural haematoma?
A
Venous bleed in space below the dura mater
Slowly develops
16
Q
What is a subarachnoid haemorrhage?
A
Arterial bleed in the space below the arachnoid mater
Rapid development
17
Q
What is cerebrospinal fluid (CSF)?
A
Clear liquid that protects the brain and spinal cord from mechanical and immunological injury
18
Q
What does CSF consist of?
A
Filtered blood
Water with ions and glucose
19
Q
Why is CSF colourless?
A
Blood cells are too large to filter through
20
Q
Where can you find CSF?
A
Subarachnoid space
Ventricles in brain
Central canal of spinal cord
21
Q
What is CSF produced from?
A
Ependymal cells
22
Q
How much CSF is produced a day?
A
500ml
23
Q
How much CSF can be found in the brain?
A
150ml
24
Q
What happens to excess CSF that can’t fill around the brain?
A
Gradually absorbed back into blood
25
What are the functions of CSF?
Supports/protects the brain and spinal cord
Shock absorber
Keeps them moist
Circulates nutrients and waste
Maintains uniform pressure around brain
Maintains optimal chemical environment for nerve signalling
26
Where does blood flow to the brain from?
Vertebral arteries
| Carotid arteries
27
What percentage of the body's oxygen and glucose does the brain use at rest?
20%
28
What does the blood brain barrier do?
Protects brain from toxins, harmful substances and bacteria
29
How does the BBB protect the brain from toxins, harmful substances and bacteria?
Maintaining tightness of capillaries
| Maintaining junctions between cells
30
What maintains the BBB?
Astrocytes
31
What substances can transport across the BBB?
Lipid soluble substances - alcohol, anaesthetics
Glucose
Gases
Ions
32
What substances can't transport across the BBB easily?
Proteins
| Some drugs
33
What are the four areas of the brain?
Brainstem
Diencephalon
Cerebrum
Cerebellum
34
What are the parts of the brainstem?
Midbrain
Pons
Medulla oblongata
35
What are the parts of the diencephalon?
Thalamus
Hypothalamus
Epithalamus
36
Where can you find the brainstem?
Top of the spinal cord
37
What does the brainstem pass through?
Foramen magnum (large hole)
38
Which centres are located in the medulla oblongata?
Respiratory
| Cardiac
39
What does the medulla oblongata control?
Vomiting reflex
Coughing reflex
Hiccupping reflex
40
Which cranial nerves are located in the medulla oblongata?
9-12
41
Which tract is located in the medulla oblongata?
Corticospinal tract (motor)
42
What does the pons control?
Breathing
43
Which cranial nerves are located in the pons?
5-8
44
Which tract does the pons relay?
Motor
45
What does the midbrain contain?
Substantia nigra
46
What is the substantia nigra?
Large, darky-pigmentated area
| Contains dopamine releasing hormones
47
What does the midbrain do?
Controls eye reflexes and tracking
| Controls head and neck movements
48
Which cranial nerves are located in the midbrain?
3-4
49
Which tract does the midbrain transfer?
Motor
50
What is the thalamus?
Relay centre of the brain
51
What percentage of the diencephalon is made up of the thalamus?
80%
52
What does the thalamus do?
Relays sensory information to the cerebrum
| Integrates sensory and motor information
53
What does the epithalamus do?
Connects limbic system to other parts of the brain
54
Which gland is located in the epithalamus?
Pineal gland
55
Which hormone does the pineal gland secrete?
Melatonin
56
What does the hypothalamus do?
```
Regulates hormones and homeostasis
Controls body temperature
Regulates emotional/behavioural patterns
Regulates appetite/satiety
Regulates circadian rhythm
```
57
What type of information does the hypothalamus receive?
Sensory
58
Which nervous system does the hypothalamus control?
Autonomic nervous system
59
Where is the cerebellum located?
Inferior and posterior aspect of the cranium
60
How many neurons can be found in the cerebellum?
50 billion
61
What are the functions of the cerebellum?
```
Balance/posture
Co-ordinate sequences of movement
Correct errors during ongoing movement (learning an instrument, learning to walk)
Cognition
Thoughts and language processing
```
62
What can damage the cerebellum?
Chronic alcohol abuse
Coeliac's disease
Thiamine (B1) deficiency
63
What are the symptoms of a cerebellar disease?
```
Ataxia - lack of muscle co-ordination
Stumbling
Unsteadiness
Slurred speech
Intention tremor (tremor when doing a movement e.g. hand shaking when putting key in lock)
```
64
What are the areas of the cerebrum called?
Left and right hemispheres
65
What does the cerebrum contain?
Outer cerebral cortex with multiple foldings
| Deeper cerebral region
66
What is the outer cerebral cortex also known as?
Grey matter
67
What is the deeper cerebral region also known as?
White matter
68
What is grey matter made up of?
Cell bodies
Dendrites
Unmyelinated axons
69
What is white matter made up of?
Myelinated axons
70
How are the left and right hemispheres of the cerebrum connected?
By the corpus callosum
71
What does the corpus callosum do?
Co-ordinates movements between sides e.g. walking
72
What are the functions of the cerebrum?
Sensory perception
| Motor control of skeletal muscles
73
What is the name of the descending motor tract?
Corticospinal tract
74
What is the corticospinal tract made up of?
Motor neuron axons
75
Where do the motor tracts cross over (decussate)?
In the medulla oblongata
76
What impact does the motor tracts decussating have on the body?
Left side of brain co-ordinates right side of body
| Right side of brain co-ordinates left side of body
77
What are the four lobes of the cerebrum called?
1. Frontal
2. Temporal
3. Parietal
4. Occipital
78
What does the frontal lobe of the cerebrum control?
Motor skills
79
What does the temporal lobe of the cerebrum control?
Hearing
80
What does the parietal lobe of the cerebrum control?
Sensory cortex
81
What does the occipital lobe of the cerebrum control?
Vision
82
What does the outer cerebral cortex contain?
Sensory cortex
| Motor cortex
83
What does the sensory cortex do?
Receives sensory input (e.g. touch, vibration) and maps it out
84
What does the motor cortex do?
Controls voluntary movements of specific muscles
85
What is the limbic system?
Area of brain that is active with different emotions
86
What is the limbic system formed of?
Cerebrum
Diencephalon
Midbrain
87
What are the key structures within the limbic system?
Hypothalamus
Hippocampus
Amygdala
88
When does the limbic system become active?
When dealing with emotional responses
89
What is the key area for emotions?
Amygdala
90
What does the hippocampus do?
Encode and retrieve memories
91
What percentage of cardiac output does the brain receive?
20%
92
How much blood does the brain receive?
750ml every min
93
What is the Circle of Willis?
Where the carotid and vertebral arterial systems meet
94
The Circle of Willis is a common location for which pathology?
Berry aneurysm
95
How many cranial nerves are there?
12
96
What are the cranial nerves?
1. Olfactory
2. Optic
3. Oculomotor
4. Trochlear
5. Trigeminal
6. Abducens
7. Facial
8. Vestibulocochlear
9. Glossopharyngeal
10. Vagus
11. Accessory
12. Hypoglossal
97
Which cranial nerves are located in the cerebrum?
1. Olfactory
| 2. Optic
98
Which cranial nerves are located in the midbrain?
3. Oculomotor
| 4. Trochlear
99
Which cranial nerves are located in the pons?
5. Trigeminal
6. Abducens
7. Facial
8. Vestibulocochlear
100
Which cranial nerves are located in the medulla oblongata?
9. Glossopharyngeal
10. Vagus
11. Accessory
12. Hypoglossal
101
Mnemonic for remembering the cranial nerves
```
On, Olfactory
On, Optic
On, Oculomotor
They - Trochlear
Travelled - Trigeminal
And - Abducens
Found - Facial
Voldemort - Vestibulocochlear
Guarding - Glossopharyngeal
Very - Vagus
Ancient - Accessory
Horcruxes - Hypoglossal
```
102
Cranial nerve 1 - name, function, location
Olfactory
Sense of smell
Cerebrum
103
Cranial nerve 2 - name, function, location
Optic
Vision
Cerebrum
104
Cranial nerve 3 - name, function, location
Oculomotor
Eye movements, eyelid opening, pupil dilation
Midbrain
105
Cranial nerve 4 - name, function, location
Trochlear
Eye movements
Midbrain
106
Cranial nerve 5 - name, function, location
Trigeminal
Facial sensations, chewing, some taste
Pons
107
Cranial nerve 6 - name, function, location
Abducens
Eye movement (abducts eye)
Pons
108
Cranial nerve 7 - name, function, location
Facial
Taste, facial expressions, salivary glands
Pons
109
Cranial nerve 8 - name, function, location
Vestibulocochlear
Hearing, balance
Pons
110
Cranial nerve 9 - name, function, location
Glossopharyngeal
Taste, swallowing, tongue sensations
Medulla oblongata
111
Cranial nerve 10 - name, function, location
Vagus
Sensory/motor functions in chest/abdomen
Medulla oblongata
112
Cranial nerve 11 - name, function, location
Accessory
Neck and shoulder movement
Medulla oblongata
113
Cranial nerve 12 - name, function, location
Hypoglossal
Tongue movement and speech
Medulla oblongata
114
How many eye muscles does the oculomotor nerve (3) move?
4 out of 6
115
How many eye muscles does the trochlear nerve (4) move?
1 out of 6
116
How many eye muscles does the abducens nerve (6) move?
1 out of 6
117
What can damage to the oculomotor, trochlear or abducens nerves cause?
Strabismus (squint)
Ptosis (drooping of upper eyelid)
Diplopia (double vision)
118
What is strabismus?
One eye crossed
119
What is ptosis?
Drooping of upper eyelid
120
What is diplopia?
Double vision
121
What are the branches of the trigeminal nerve (5)?
Ophthalmic
Maxillary
Mandibular
122
What is the vagus nerve?
Largest nerve of the autonomic nervous system
123
What information does the vagus nerve carry?
All sensory information from chest and abdomen
124
What can damage to the vagus nerve cause?
Tachycardia
| Dysphagia
125
Mnemonic for remembering the cranial nerve functions
```
Some - Sensory
Say - Sensory
Money - Motor
Matters - Motor
But - Both
My - Motor
Brother - Both
Says - Sensory
Big - Both
Brains - Both
Matter - Motor
More - Motor
```
126
Where does the spinal cord begin?
At the foramen magnum
127
Where does the spinal cord terminate?
At vertebral level 2 (L2)
128
Where does the spinal cord meninges tissue continue to?
To level S2 of sacrum
129
What is vertebral level 2 (L2) also known as?
Conus
130
What is the cauda equina?
Spinal nerves that continue beyond the conus
131
What does the spinal cord consist of?
White matter around a core of grey matter
132
What does the spinal cord white matter consist of?
Bundles of myelinated axons - tracts
133
Which tracts make up the spinal cord white matter?
Motor tracts
| Sensory tracts
134
Which direction does the motor tract of the spinal cord go and what does it do?
Descending
| Control voluntary and involuntary movement
135
Which direction do the sensory tracts of the spinal cord go and what do they do?
Ascending
| Transmit impulses from skin, tendons, muscles and joints
136
What does the spinal cord grey matter consist of?
Cell bodies
| Dendrites
137
How is the spinal cord grey matter divided up?
Posterior (dorsal) horn
| Anterior (ventral) horn
138
What does the posterior (dorsal) horn do?
Receive sensory impulses
139
What does the anterior (ventral) horn do?
Sends out motor impulses
140
How is information processed in the spinal cord?
1. Information enters the dorsal horn
2. It synapses with interneurons and travels up a sensory tract to the thalamus
3. Thalamus processes the information and sends it to the sensory cortex
4. Sensory cortex sends motor information down the corticospinal tract where it synapses at the level it's coming out of
5. The information then comes out of the ventral horn
141
What are the spinal cord tracts called?
Dorsal columns
Spinothalamic tract
Corticospinal tract
142
Which spinal cord tracts are ascending?
Dorsal columns
| Spinothalamic tract
143
Which spinal cord tract is descending?
Corticospinal tract
144
What information does the dorsal column receive?
Light touch
Vibration
Proprioception
145
What information does the spinothalamic tract receive?
Pain
| Temperature
146
What information does the corticospinal tract send out?
Voluntary movements
147
What is a reflex arc?
A fast, automatic and unplanned sequence of actions that occurs in response to a stimulus
148
What is the spinal reflex?
Integration of a reflex that happens in the spine
149
What does a reflex arc consist of?
1. Sensory receptor
2. Sensory neuron
3. Interneuron
4. Motor neuron
5. Effector organ
150
What are extensions of the spinal cord called?
Spinal nerves
151
Where do spinal nerves exit the vertebral column?
Through holes in the vertebra called vertebral foramina
