The Brain Flashcards
(119 cards)
1
Q
What is a tract ?
A
A fibre pathway passing through the CNS carrying a specific modality.
2
Q
What is the function of the brainstem ?
A
- Its a pathway for fibre tracts between higher and lower centres
- Involved in controlling basic body functions such as breathing and heart rate
3
Q
What reflex is the superior colliculi involved with ?
A
Visual reflex
4
Q
What reflex is the inferior colliculi involved with ?
A
Auditory reflex
5
Q
Which fissure separates the temporal and frontal/parietal lobes ?
A
Lateral fissure
6
Q
Which sulcus separates the frontal and parietal lobes ?
A
Central sulcus
7
Q
Which sulcus separates the occipital and parietal lobes ?
A
Parieto-occipital sulcus
8
Q
Where does the cerebellum get information from ?
A
- Vestibular nuclei
- Proprioceptors in limbs
- Cerebrum
9
Q
What makes up the Diencephalon ?
A
- Thalamus
- Hypothalamus
- Pineal gland
- Pituitary gland
10
Q
What is the main function of the Thalamus ?
A
It is a sensory relay centre
11
Q
What structure separates the Thalamus and Hypothalamus ?
A
The hypothalamic sulcus
12
Q
What is the basal ganglia ?
A
Collection of neuronal cell bodies buried in the white matter of the brain
13
Q
What is hemispatial neglect ?
A
A deficit in attention and awareness to one side of the field of vision. Cause by damage to one hemisphere of the brain.
14
Q
What causes right-left agnosia (confusion) ?
A
A lesion to the dominant parietal lobe
15
Q
What is Aphasia ?
A
It affects the production or comprehension of speech and the ability to read or write.
16
Q
What happens when a person has Broca’s Aphasia ?
A
They are able to understand speech but cannot or struggle to speak.
17
Q
What happens when a person has Wernicke’s Aphasia ?
A
The can’t speak but struggle to understand what someone else says. They may not make sense.
18
Q
What do commisural fibres connect ?
A
They connect corresponding areas of the two hemispheres e.g. the Corpus Callosum
19
Q
What do association fibres connect ?
A
Different areas of the same hemisphere
20
Q
What do projection fibres connect ?
A
The cortex and subcortical regions
21
Q
What makes up the basal ganglia ?
A
- Caudate Nucleus
- Putamen
- Globus Pallidus
- Substantia Nigra
22
Q
What are the input regions of the basal ganglia ?
A
The Caudate Nucleus and the Putamen
23
Q
What are the output regions of the basal ganglia ?
A
The Globus Pallidus and Substantia Nigra
24
Q
Where does the Globus Pallidus project to ?
A
Thalamus
25
What is the role of the Basal Ganglia ?
To help initiate and regulate movement
26
Definition of Cognition
The integration of sensory information to make sense of a situation
27
What role does the hippocampus have in memory ?
Memory formation
28
What role does the amygdala have in memory ?
Puts an emotive feeling on a memory
29
What role does the thalamus have in memory ?
It finds the memory
30
What role does the cortex have in memory ?
It stores the memory
31
What makes up the limbic system ?
Amygdala
Hypothalamus
Cingulate gyrus
Hippocampus
32
What determines the significance of an event ?
Frontal cortex and the limbic system
33
What is sensory memory ?
Memory of what happened seconds ago e.g. visual memory (< 1s) and auditory memory (< 4s).
34
What is short-term memory ?
Compromises daily tasks, your working memory. Last seconds to hours.
35
What is you immediate long-term memory ?
What you did last weekend, hours to weeks ago. its associated with changes in the chemical activity within synapses.
36
What is your long term memory ?
Where you lived as a child, who your friends were. Associated with structural changes in synapses.
37
What is short term memory dependent on ?
Reverberating circuits
38
What happens when a short term memory is deemed significant ?
Leaves the reverberating circuit and is stored in long-term memory.
39
Definition of Amnesia
Memory loss
40
What is Anterograde Amnesia ?
Can't form new memories
41
What is Retrograde Amnesia ?
Can't remember newer old memories
42
What is explicit long-term memory ?
Abstract memory from events. It involves the hippocampus.
43
What is procedural long-term memory ?
Through repetition its acquired slowly. Doesn't involve the hippocampus, it is mainly based in the cerebellum.
44
What is the name of the circuit that occurs in the limbic system ?
Papez circuit
45
Describe the Papez circuit
Cortex - Thalamus - Cingulate gyrus - Hippocampus - Mamillary body - Cortex or Thalamus
46
Which neurones are needed for REM sleep ?
Cholinergic
47
What do people with Alzheimers not have a lot of ?
REM sleep - little memory consolidation occurs
48
How is CSF formed ?
Sodium is pumped into the ventricles and water follows down an osmotic gradient from blood vessels.
49
What foramen/foramina in the 4th ventricle does the CSF flow out of ?
The foramina of Luschka
| The foramen of Magendie
50
Why and how does absorption of CSF occur ?
The H20 pressure is 3-5 cm higher in the subarachnoid space than in the subdural venous sinuses. Absorption occurs down a pressure gradient moving through arachnoid villi which open their valves.
51
What are the 2 types of hydrocephalus ?
Communicating and Non-Communicating
52
Features of CoH
- Cause an increase in ICP
- Usually due to the fact that production of CSF > reabsorption
- Patient gets a headache, loses consciousness, N/V, papilloedema and can't look up
- Can be due to an infection/haemorrhage/post-operation
53
Features of NCoH
- Blockage in the pipeline
- Can be due to tumours, cysts, trauma, infection and congenital malformations.
- Can vary in how quickly symptoms progressive
54
How would you investigate Hydrocephalus ?
- X-Ray and use Evans ratio
| - CT/MRI
55
What is the treatment for Hydrocephalus ?
- External ventricular drain
- Ventriculo-peritoneal shunt
- 3rd Ventriculostomy
56
What type of Hydrocephalus can cause Dementia ?
Normal pressure Hydrocephalus
57
How does a patient with Dementia present second to Hydrocephalus ?
Wet, wobble and wacky
- Incontinence
- Wobble
- Cognitive function declining
58
How would you investigate and what results would come back with Dementia present second to Hydrocephalus ?
- CT shows signs of communicating hydrocephalus
- LP normal pressure
- Symptoms resolve after drainage
59
What are the contraindications for LP ?
- If patient is unstable
- If there is increased ICP
- Possible abscess
- Bleeding disorder
- Chairhi malformations
60
What are Chairhi malformations ?
Part of the cerebellum herniates into the foramen magnum and into the spinal canal.
61
Steps for LP
- Apply topical anaesthesia to sight around 30-45 beforehead
- Use iodine solution to clean 10cm around insertion sight
- Drape the site with fenestrated drape
- With the bevel up insert largest atraumatic needle possible based on clinical judgment. Push inwards towards umbilicus.
- Pop indicates ligamentum flavum and dura have been punctured, remove stylet and check flow
- Attach manometer to get an opening pressure
62
When you are collecting samples for LP how many do you collect and what for ?
- 3 samples
| - Cell count, culture and glucose
63
What are the possible complications of LP ?
- Nerve trauma
- Infection
- Bleeding
- Disk herniation
64
What is the most common side effect of a LP ?
A spinal headache, it occurs due to the arachnoid being pulled through into the dura.
65
What is the treatment for spinal headache ?
- Bed rest
- Hydration
- Epidural blood patch
- Caffeine
66
What is the Munro-Kelly Doctrine ?
The skull is a fixed box filled with brain, blood and CSF. A change in the volume of one of these changes the overall balance/pressure. It must remain in equilibrium and therefore the volume of another must change.
67
Definition of a stroke
A stroke is a sudden interruption in the blood supply of the brain.
68
What are the three main causes of stroke ?
1. Atheroma and thrombosis
2. Thromboembolism
3. Ruptured aneurysm
69
What is a regional cerebral infarct ?
Localised area of brain death, goes soft then cystic
70
What two things cause aneurysms to form ?
1. Hypertension
| 2. Weakened vessel walls
71
What might happen to distal tissue as a result of an aneurysm ?
Vessel may spasm and so lack of blood gets to distal tissue. Further infarcts occur.
72
What two things may reduce blood flow through brain ?
1. Hypotension
| 2. Brain swelling
73
What two things reduce oxygen supply in the blood ?
1. CO2 poisoning
| 2. Near drowning
74
What are watershed infarcts ?
Zones of infarction at the interface between artery perfusion sites. Seen with hypotension.
75
Define laminar infarction
Lines of necrosis and thinning
76
What condition prevents lack of blood flow and oxygen to brain ?
Cardiac arrest
77
What perfusion level does ischaemia occur at ?
20ml/g/min
78
What perfusion level does infarction occur at ?
10g/ml/min
79
What is the equation for Cerebral Perfusion Pressure (CPP) ?
CPP = MAP - ICP
80
How do you calculate MAP ?
MAP = DP + 1/3PP
81
What effect does an increase in CPP have ?
An increase in ICP causes the CPP to decrease.
82
Define cerebral auto regulation
The ability to maintain a constant blood flow over a wide range of CPP (50-150mmHg).
83
What happens when CPP is low ?
The arterioles dilate to reduce resistance to blood flow.
84
What happens when CPP is high ?
The arterioles constrict to increase resistance to blood flow.
85
What happens if ICP increases above 150mmHg ?
The auto regulatory system fails
86
What is Vasogenic Oedema ?
Exudation of fluid from the vascular system
87
What two things can inhibit cerebral auto regulation ?
- Head trauma
| - Toxins e.g. CO2
88
Define cerebral oedema
Increase in brain volume as a result of an increase in water content.
89
Define compliance
Change in volume observed for a given change in pressure. Results in less blood and CSF in the skull.
90
What is the equation for compliance ?
dV/dP
91
Define elastance
Change in pressure observed for a change in volume. Results in outward expansion of the cranial walls.
92
What is the equation for elastance ?
dP/dV
93
When looking at ICP waveforms, what does P1 show ?
Arterial pulse
94
When looking at ICP waveforms, what does P2 show ?
Cerebral compliance
95
What are Lundberg waves ?
Show how ICP changed due to cerebral autoregulation
96
What is the Cushing's reflex ?
As CBF decreases sympathetic response is activated, this results in tachycardia and hypertension to increase blood flow. Baroreceptors in the carotid artery detect this and stimulate the vagus nerve which triggers bradycardia.
Respiratory cycles continuously change in response to ICP.
97
How do you manage patients with an increased ICP ?
- Mannitol
- Surgery - hemicraniectomy/external ventricular drainage
- Raise head
- Hyperventilation for acute resolution
98
What are the two newer concepts in management of raise ICP ?
- Brain tissue oxygen monitoring
| - Micro-dialysis
99
Why is cognitive functions assessed ? (3)
- Diagnosis
- Prognosis
- Treatment
100
Define post-traumatic amnesia
Period of recovery following traumatic brain injury the patient is unable to locate themselves in time and space and cannot remember events that have occurred since the incident.
101
How is cognition assessed via bedside ? (£)
1. Observation
2. Clinical interview
3. Screening assessments
102
Name the 3 screening assessments commonly used
1. MOCA
2. ACE III
3. Cognitive assessment for clinicians
103
Name some of the main areas of cognitive function
```
Thinking
Learning
Memory
Attention
Reasoning
Problem solving
```
104
What 4 assessment considerations should be made ?
1. Environment
2. Physical factors e.g. fatigue
3. Psychological factors e.g. mood and confidence
4. Pre-accident factors e.g. education/occupation
105
What is the name of the fissure separating the anterior and posterior lobes of the cerebellum ?
Primary fissure
106
What is the name of the fissure separating the anterior and flocculonodular lobes
Posterolateral fissure
107
What affect does GABA have ?
Slow down the brain messages - it is a neurotransmitter
108
What affect does glutamate have ?
Increases brain activity - it is a neurotransmitter
109
What is Ach ?
It is a neuromodulator and helps us decide whether to respond to a signal or not
110
What condition can lack of Ach lead to ?
Alzheimers
111
What type of channels are muscarinic channels ?
G protein channels
112
What type of channels are nicotinic channels ?
Ion channels
113
What is noradrenaline ?
A neuromodulator and keeps the brain on high alert
114
What is dopamine ?
It is involved in punishment and rewards but also movement
115
What does serotonin do ?
Depresses bad thoughts and helps you sleep
116
What functions does histamine have in the CNS ?
It keeps you awake and warm
117
Where is melatonin produced ?
Pineal gland
118
What does melatonin do ?
Makes you sleepy
119
What does orexin do ?
Keeps you awake
