14. Nervous System II Flashcards
(177 cards)
1
Q
What does the CNS consist of?
A
Brain
Spinal cord
2
Q
What is the brain protected by?
A
Cranium
Cranial meninges
Cerebrospinal fluid (CSF)
Blood brain barrier (BBB)
3
Q
What is the spinal cord protected by?
A
Vertebral column
Meninges
4
Q
What are meninges?
A
Layers of connective tissue that form protective membranes
They surround and encase the brain and spinal cord within the skull and spinal column
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?
“Tough mother”
A
Tough outer layer
Has 2 layers in the brain
7
Q
What do the two layers of dura mater in the brain do?
A
Create venous sinuses
8
Q
What do venous sinuses do?
A
AKA Bridging veins
Allow blood to drain out of the brain into the jugular veins
9
Q
What is the arachnoid mater made up of?
A
Collagen and elastic fibres
10
Q
What is the subdural space between the dura mater and arachnoid mater filled with?
A
Interstitial fluid
11
Q
What is the pia mater?
A
Innermost layer of the meninges
Thin, transparent and highly vascular
In direct contact with the brain
Follows contours of the brain
12
Q
What does the pia mater contain?
A
Blood vessels that supply the spinal cord
13
Q
What is the subarachnoid space between the arachnoid mater and pia mater filled with?
A
Cerebrospinal fluid (CSF)
14
Q
What is a subdural haematoma?
A
Venous bleed in space below the dura mater
Develops slowly
Can happen in Alzheimers disease due to brain shrinkage
15
Q
What is a subarachnoid haemorrhage?
A
Arterial bleed in the space below the arachnoid mater
Rapid development
From Berry aneurism
Feels like a thunderclap headache
16
Q
What is cerebrospinal fluid (CSF)?
A
Clear, colourless* liquid that protects the brain and spinal cord from mechanical and immunological injury
Nourishes the brain and spinal cord
*contains no blood cells
17
Q
What does CSF consist of?
A
Filtered blood
Water with ions and glucose
18
Q
Why is CSF colourless?
A
Blood cells are too large to filter through
19
Q
Where can you find CSF?
A
Subarachnoid space
Ventricles* in brain
Central canal of spinal cord
Fourth ventricle (back of brain) used in cranio-sacral therapy
20
Q
Where is CSF produced ?
A
Ependymal cells
21
Q
How much CSF is produced a day?
A
500ml
22
Q
How much CSF can be found in the brain?
A
150ml
23
Q
What happens to excess CSF that can’t fill around the brain?
A
Gradually absorbed back into blood
24
Q
What are the functions of CSF?
A
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
25
Where does blood flow to the brain from?
Vertebral arteries (x2)
Carotid arteries (x2)
26
What percentage of the body's oxygen and glucose does the brain use at rest?
20%
27
What does the blood brain barrier do?
Protects brain from toxins, harmful substances and bacteria
28
How does the BBB protect the brain from toxins, harmful substances and bacteria?
By maintaining tightness of capillaries
By maintaining junctions between cells
29
What maintains the BBB?
Astrocytes that wrap around the capillaries
30
What substances can transport across the BBB?
* Lipid soluble substances: alcohol,
anaesthetics
* Glucose (active transport)
* Gases
* Ions
31
What substances can't transport across the BBB easily?
Proteins
Some drugs
32
What are the four areas of the brain?
Brainstem
Diencephalon
Cerebrum
Cerebellum
33
What are the parts of the brainstem?
Midbrain
Pons*
Medulla oblongata
| 'Bridge'
34
What are the parts of the diencephalon*?
| interbrain
Thalamus*
Hypothalamus
Epithalamus
| *80%, core of the brain
35
Where can you find the brainstem?
Top of the spinal cord
| Continuation of the spinal cord
36
What does the brainstem pass through?
Foramen magnum (large hole)
37
Which centres are located in the medulla oblongata?
Respiratory centre
Cardiac centre
38
What does the medulla oblongata control?
Breathing
Cardiac output
Heart rate
Blood pressure
Vomiting reflex
Coughing reflex
Hiccupping reflex
39
Which cranial nerves are located in the medulla oblongata?
9-12
40
Which tract is located in the medulla oblongata?
Corticospinal tract (motor)
41
What does the pons control?
Breathing
42
Which cranial nerves are located in the pons?
5-8
43
Which tract does the pons relay?
Motor
44
What does the midbrain contain?
Substantia nigra
45
What is the substantia nigra?
Large, darkly-pigmentated area
46
What does the substantia nigra contain ?
Dopamine releasing neurons that control subconcious muscle activities
47
What does the midbrain do?
Controls eye reflexes and tracking
Controls head and neck movements
Auditory tracts
Transfers motor tracts
48
Which cranial nerves are located in the midbrain?
III - Oculomotor
IV - Trochlear
49
What is the thalamus?
Major part of the diencephelon
Relay centre of the brain
50
What percentage of the diencephalon is made up of the thalamus?
80%
51
What does the thalamus do?
Relays sensory information to the cerebrum
Integrates sensory and motor information
52
What does the epithalamus do?
Connects limbic system to other parts of the brain
53
Which gland is located in the epithalamus?
Pineal gland
54
Which hormone does the pineal gland secrete?
Melatonin
55
What does the hypothalamus do?
```
Regulates hormones and homeostasis
Controls body temperature
Regulates emotional/behavioural patterns
Regulates appetite/satiety
Regulates circadian rhythm
```
56
What type of information does the hypothalamus receive?
Sensory
57
Which nervous system does the hypothalamus control?
Autonomic nervous system
58
Where is the cerebellum located?
Inferior and posterior aspect of the cranium
59
How many neurons can be found in the cerebellum?
50 billion*
Majority are interneurons
| *Half the total number found in the brain
60
What are the functions of the cerebellum?
* Balance/posture (propreoception)
* Co-ordinates smooth sequences of movement to 'skilled' levels
* Error correction during ongoing movement (learning an instrument, learning to walk)
* Cognition, thought and language processing
61
What can damage the cerebellum?
Chronic alcohol abuse
Coeliac's disease
Thiamine (B1) deficiency (malnourished)
62
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)
| *notice wide-legged stance
63
What are the areas of the cerebrum called?
Left and right hemispheres
64
What does the cerebrum contain?
* Outer cerebral cortex with multiple foldings
* Deeper cerebral region
65
What is the outer cerebral cortex also known as?
Grey matter
66
What is the deeper cerebral region also known as?
White matter
67
What is grey matter made up of?
Cell bodies
Dendrites
Unmyelinated axons
68
What is white matter made up of?
Myelinated axons
69
How are the left and right hemispheres of the cerebrum connected?
By the corpus callosum
70
What does the corpus callosum do?
Co-ordinates movements between sides e.g. walking
71
What are the functions of the cerebrum?
Sensory perception
Motor control of skeletal muscles (movement)
72
What is the name of the descending motor tract?
Corticospinal tract
73
What is the corticospinal tract made up of?
Motor neuron axons
74
Where do the motor tracts cross over (decussate)?
In the medulla oblongata
75
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
76
What are the four lobes of the cerebrum called?
* Frontal
* Temporal
* Parietal
* Occipital
77
What does the frontal lobe of the cerebrum control?
Motor skills
78
What does the temporal lobe of the cerebrum control?
Hearing
79
What does the parietal lobe of the cerebrum contain?
Sensory cortex
80
What does the occipital lobe of the cerebrum control?
Vision
81
What does the outer cerebral cortex contain?
Sensory cortex
Motor cortex
82
What does the sensory cortex do?
Receives sensory input (e.g. touch, vibration) and maps it out
83
What does the motor cortex do?
Controls voluntary movements of specific muscles
84
What is the limbic system?
Area of brain that is active with different emotions
85
What is the limbic system formed of?
Cerebrum
Diencephalon
Midbrain
86
What are the key structures within the limbic system?
Hypothalamus (diencephalon)
Hippocampus (cerebrum)
Amygdala (cerebrum)
87
When does the limbic system become active?
When dealing with emotional responses
88
What is the key area for emotions?
Amygdala
89
What does the hippocampus do?
Encode and retrieve memories
90
What percentage of cardiac output does the brain receive?
20%
91
How much blood does the brain receive?
750ml every min
92
What is the Circle of Willis?
Where the carotid and vertebral arterial systems meet
93
The Circle of Willis is a common location for which pathology?
Berry aneurysm
94
How many cranial nerves are there?
12 pairs
95
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
96
Which cranial nerves are located in the cerebrum?
I Olfactory
II Optic
97
Which cranial nerves are located in the midbrain?
III Oculomotor
IV Trochlear
98
Which cranial nerves are located in the pons?
V Trigeminal
VI Abducens
VII Facial
VIII Vestibulocochlear
99
Which cranial nerves are located in the medulla oblongata?
IX Glossopharyngeal
X Vagus
XI Accessory
XII Hypoglossal
100
Mnemonic for remembering the cranial nerves
Oh, Oh, Oh, To Touch And Feel Vintage Green Velvet, Ahh Heaven!
101
Cranial nerve I - name, function, location
**I Olfactory**
Sense of smell
*Cerebrum*
| Unmylinated
102
Cranial nerve II - name, function, location
**II Optic**
Vision
*Cerebrum*
| Densely mylinated, highspeed avoids double vision when turning head
103
Cranial nerve III - name, function, location
**III Oculomotor**
Eye movements, eyelid opening, pupil dilation
*Midbrain*
104
Cranial nerve IV - name, function, location
**IV Trochlear**
Eye movements
*Midbrain*
105
Cranial nerve V - name, function, location
**V Trigeminal**
Facial sensations, chewing, some taste
*Pons*
106
Cranial nerve VI - name, function, location
**VI Abducens**
Eye movement (abducts eye)
*Pons*
107
Cranial nerve VII - name, function, location
**VII Facial**
Taste, facial expressions, salivary glands
Pons
108
Cranial nerve VIII - name, function, location
**VIII Vestibulocochlear**
Hearing, balance
*Pons*
109
Cranial nerve IX - name, function, location
**IX Glossopharyngeal**
Taste, swallowing, tongue sensations
*Medulla oblongata*
110
Cranial nerve X - name, function, location
**X Vagus**
Sensory/motor functions in chest/abdomen
*Medulla oblongata*
111
Cranial nerve XI - name, function, location
**Accessory**
Neck and shoulder movement
*Medulla oblongata*
112
Cranial nerve XII - name, function, location
**Hypoglossal**
Tongue movement and speech
*Medulla oblongata*
113
How many eye muscles does the oculomotor nerve (III) move?
4 out of 6
Moves eyeball
Elevates eyelid
114
How many eye muscles does the trochlear nerve (IV) move?
1 out of 6
Rotation
Used in reading
115
How many eye muscles does the abducens nerve (VI) move?
1 out of 6
Abducts eye
116
What can damage to the oculomotor, trochlear or abducens nerves cause?
Strabismus (squint)
Ptosis (drooping of upper eyelid)
Diplopia (double vision)
117
What is strabismus?
One eye crossed
118
What is ptosis?
Drooping of upper eyelid
Damage to CNIII oculomotor
119
What is diplopia?
Double vision
120
What are the branches of the trigeminal nerve (V)?
Ophthalmic
Maxillary
Mandibular
121
What is the vagus nerve?
Largest nerve of the autonomic nervous system
122
What information does the vagus nerve carry?
*All* sensory information from chest and abdomen
(Heart, GIT, lungs)
123
What can damage to the vagus nerve cause?
Tachycardia
Dysphagia
Vaso-vagal syncope (fainting)
124
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
```
125
Where does the spinal cord begin?
At the foramen magnum
126
Where does the spinal cord terminate?
At vertebral level L2
127
Where does the spinal cord meninges tissue continue to?
To level S2 (sacrum)
128
What is the name of the terminus of the spinal cord?
Conus
129
What is the *cauda equina*?
Spinal nerves that continue beyond the conus
130
What does the spinal cord consist of?
White matter around a core of grey matter
131
What does the spinal cord white matter consist of?
Tracts (bundles of myelinated axons)
132
Which tracts make up the spinal cord white matter?
Motor tracts (descending)
Sensory tracts (ascending)
133
Which direction does the motor tract of the spinal cord go and what does it do?
Descending
Controls voluntary and involuntary movement
(posture, balance)
134
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
(touch, vibration, proprioception)
135
What does the spinal cord grey matter consist of?
Cell bodies
Dendrites
136
How is the spinal cord grey matter divided up?
Posterior (dorsal) horn
Anterior (ventral) horn
137
What does the posterior (dorsal) horn do?
Receive sensory impulses
138
What does the anterior (ventral) horn do?
Sends out motor impulses
139
How is information processed up and down 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 exits the spinal column
5. The information then comes out of the ventral horn
140
What are the spinal cord tracts called?
Dorsal columns
Spinothalamic tract
Corticospinal tract
141
Which spinal cord tracts are ascending?
Dorsal columns
Spinothalamic tract
142
Which spinal cord tract is descending?
Corticospinal tract
143
What information does the dorsal column receive?
Light touch
Vibration
Proprioception
144
What information does the spinothalamic tract receive?
Pain
Temperature
145
What information does the corticospinal tract send out?
Motor impulses for voluntary movements
146
What is a reflex arc?
A fast, automatic and unplanned sequence of actions that occurs in response to a stimulus
147
What is the spinal reflex?
Integration of a reflex that happens only in the spine
148
What does a reflex arc consist of?
1. Sensory receptor
2. Sensory neuron
3. Interneuron
4. Motor neuron
5. Effector organ
149
What are extensions of the spinal cord called?
Spinal nerves
150
Where do spinal nerves exit the vertebral column?
Through holes in the vertebra called vertebral foramina
151
Where is the subarachnoid space ?
Between the arachnoid mater and pia mater
152
Where is the subdural space ?
Between the dura mater and arachnoid mater
153
What are the choroid plexi ?
A network of blood vessels covered by a layer of ependymal cells.
They are responsible for producing cerebrospinal fluid (CSF)
154
What nutrients are circulated by the CSF ?
Oxygen
Glucose
Ions (for nerve signalling/depolarisation)
155
Which part of the nervous system does the hypothalumus control?
The ANS
Major regulator of visceral activities
156
What is the key role of the hypothalamus?
Hormone regulation and maintenance of homeostasis
157
Which part of the brain controls body temperature ?
Hypothalamus
158
Which part of the brain regulates eating and drinking ?
Hypothalamus
Regulates appetite and satiety
159
What is ataxia?
Lack of voluntary muscle coordination
Unsteady movements
Difficulties with balance and coordination
Often caused by damage to the cerebellum
160
Why is cardiovascular health important for brain health ?
The brain requires a constant supply as it has a limited ability to store oxygen or glucose
161
Rule for cranial nerve locations
2,2,4,4
* 2 - Cerebrum
* 2 - Midbrain
* 4 - Pons
* 4 - Medulla oblongata
162
Why is the optic nerve useful to assess intracranial lesions ?
The optic nerve spans through the majority of the cranium.
Any abnormal pressure in the brain would likely press on this nerve
163
Is the vagus nerve sensory or motor ?
Both
90% afferent nerve fibres (sensory) but motor signals are delivered to GIT, cardiovascular and respiratory system
164
What is (vaso-vagal) syncope ?
Fainting
When the vagus nerve is overstimulated and blood pressure quickly drops
165
Where are epidurals given and why ?
| Verbal, not on slide
Below the level of the midlumbar spine
To ensure the needle doesn't go directly into the spinal cord
166
What would damage to any of the spinal tracts lead to ?
Loss of that tract's function below that level in the body
167
# Nervous System & homeostasis
Whole body
Works closely with the endocrine system to regulate most body functions
168
# Nervous System & homeostasis
Integumentary system
Controls sweating and arrector pili.
169
# Nervous System & homeostasis
Skeletal system
Pain receptors in bone tissue warn of trauma or damage.
170
# Nervous System & homeostasis
Muscular system
* Motor neurons stimulate muscular contractions.
* The cerebellum co-ordinates skilled movements.
171
# Nervous System & homeostasis
Cardiovascular system
Medulla oblongata is the home of the CV control centre. It
governs cardiac output and regulates blood pressure
172
# Nervous System & homeostasis
Endocrine system
* Hypothalamus regulates the pituitary gland.
* ANS regulates hormones (e.g. adrenaline).
173
# Nervous System & homeostasis
Respiratory system
* Respiratory areas in the brain stem control breathing rate and depth.
* ANS regulates airway diameter.
174
# Nervous System & homeostasis
Digestive system
* ANS and enteric nervous system regulate digestion.
* PNS stimulates digestive processes.
175
# Nervous System & homeostasis
Urinary system
* The ANS regulates blood flow to the kidneys.
* The CNS governs emptying of the urinary bladder.
176
# Nervous System & homeostasis
Reproductive system
* Hypothalamus and limbic system govern sexual behaviour.
* The ANS governs erection and ejaculation.
* Hypothalamus regulates the release of pituitary hormones which influence the gonads.
* Nerve impulses elicited by suckling cause the release of oxytocin and milk ejection in nursing mothers.
177
# Nervous System & homeostasis
Lymphatic and immune system
Certain neurotransmitters help regulate immune response
