week 8 - nervous system Flashcards

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1
Q

What are the steps on how the synapse operates?

A
  1. The action potential from the pre-synaptic neuron reaches the synaptic terminal
  2. The synaptic vesicle releases the neurotransmitter
  3. The neurotransmitters travel across the synapse and bind to the receptors in the post-synaptic neurone
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2
Q

What do sensory neurones do?

A

They receive information from the environment

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3
Q

What do interneurones do?

A

They carry signals between sensory and motor neurones

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4
Q

What do motor neurones do?

A

They generate a response

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5
Q

What are the 4 main mechanisms of brain injury/

A
  1. Brain Contusion
  2. Increased Intercranial Pressure - ICP
  3. Diffuse Axonal Injury
  4. Stroke
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6
Q

What is a brain contusion?

A

It is cell death in the brain accompanied by haemorrhage/internal bleeding.

Can occur distant from point of impact

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7
Q

What is ICP?

A

Your bone does not expand, the intracranial vault is a fixed volume.
Therefore, if more material (like blood, CSF) is added, the pressure also increases

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8
Q

What else happens as ICP increases?

A

As more material is added in, substances are forced out of the cranial vault.

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9
Q

What is herniation?

A

This is when the brain is squeezed out through the foramen magnum(opening at the base of the skull) bc of increased ICP.

The brainstem becomes compressed, damaging the brain, patient stops breathing

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10
Q

Why is brainstem herniation the most life threatening type of herniation?

A

Bc the brainstem regulates unconscious processes essential to life - such as breathing

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11
Q

What is diffuse axonal injury/

A

Diffuse meaning damage is over a widespread area

Involves the shearing of axons in white matter tracts

Occurs when grey matter and white matter slide over each other, severing the axons

Causes unconsciousness and persistent vegetative state

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12
Q

How can mechanical pressure be put on the brain to cause diffuse axonal injury?

A
  1. Encephalitis - viral, inflammation of brain
  2. Rabies - from bites
  3. Meningitis - inflammation of the meninges
  4. Brain tumours
  5. Abscesses
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13
Q

What is a stroke?

A

It is a loss of blood supply to some or all of the brain which results in cerebral deficit that lasts for at least 24 hours - unless fatal

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14
Q

What are the symptoms of stroke determined by/

A

The areas that are damaged by the stroke. For example, right side brain injury can cause symptoms in the left side of the body - as right side controls left side of body

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15
Q

What is a transient ischaemic attack?

A

It’s like as stroke that lasts for less than 24 hours caused by inadequate cerebral blood supply

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16
Q

How does a loss of blood supply occur?

A

A lack of blood flow top brain caused by clot/rupture of blood vessel

17
Q

What are the 2 classifications of stroke?

A

Ischaemic stroke - caused by decreased oxygen delivery to brain tissue due to swelling which compresses nearby arteries

Haemorrhagic stroke - decreased oxygen delivery because of blood leaking into the brain

18
Q

What are the main things that protect the brain?

A

Circle of Willis - 4 main blood vessels supply blood to circle of Willis, blood leaves via 3 other blood vessels????????

19
Q

What can put you at risk of stroke?

A

Modifiable - smoking
diabetes
hypertension
obesity etc

Uncontrollable -
Age
Genetics
Prior stroke

20
Q

What is intracerebral haemorrhage

A

Bleeding within the brain, which leads to blood in parenchyma, causing a haematoma, causing rupture of vessels nearby.

The growth is stopped by counter pressure

21
Q

What is subarachnoiud haemorrhage

A

Occurs when saccular aneurysms located at cerebral arteries of circle of willis rupture

22
Q

Hunt Hess scale?

A
23
Q

What is the diagnosis of hemorrhagic stroke?

A
  1. Thunderclap headache
  2. Xanthochromic lumbar puncture (blood in places such as CSF)
  3. Star pattern on CT Scan
24
Q

How can you try prevent the bursting of aneurysms which can cause stroke?

A
  1. Clipping
  2. Endovascular coils
25
Q

Compare ischaemic and haemorrhagic strokes

A
26
Q
A
27
Q
A