What germ cell layer do neurons and glial cells come from?
Which germ cell layer do microglia come from?
Necrosis is ___ death of brain cells and occurs in which brain disease?
sudden failure e.g stroke
Atrophy is a ___ reduction in brain size.
Is it normal?
Depends - occurs with age, but is accelerated in diseases such as Alzheimer's
What happens to neurons histologically in acute injury?
Nuclei shrink and angulate
Nucleolus is lost
Cytoplasm turns red
___ neurons are indicative of acute neuronal injury.
Which types of acute injury cause red neuronal death?
What is the role of astrocytes in the CNS?
Maintain homeostasis, maintain BBB, role in repair
What is reactive gliosis?
Which cells undergo it?
What does it look like?
Non-specific reaction to CNS injury by glial cells
Glial cells (astrocytes, microglia, ependymal cells, oligodendrocytes)
Hypertrophy and hyperplasia, nucleus enlarges
In demyelinating diseases (e.g MS), the conduction velocity of neurons (increases / decreases).
What process do astrocytes undergo in response to injury?
like all glial cells
What happens to astrocytes in gliosis?
Which important processes do
b) glial cells
undergo in response to injury?
a) "Red neuron" reaction
b) Reactive gliosis
What are the role of microglia in the CNS?
Which immune cell are microglia very similar to?
do the same job i.e phagocytosis, just in the brain
Which state causes acute brain injury and occurs in stroke, trauma and cardiac arrest?
Which percentage of inhaled oxygen is used by the brain?
Why do neurons depolarise after extended hypoxia?
Which neurotransmitter is released in response to this abnormal depolarisation?
Which ion then enters the neuron
Na/K ATPase stops working - so Na accumulates inside the cell, causing a depolarisation
What is excitotoxicity?
What triggers it?
Process by which neurons are killed by excessive glutamate > Ca2+ release
Extended hypoxia - Na/KATPase fails - Depolarisation - Glutamate release - Ca2+ influx - Release of endotoxins
Various types of swelling, or ___, occur in response to brain injury.
What is vasogenic oedema?
Breakdown of the BBB in infarcted areas of the brain allows water, ions and protein to filter out, causing swelling
What is cytotoxic oedema?
Hypoxic cells lose function of their sodium-potassium pump
Sodium accumulates in the cell
So water and chloride ions follow down the osmotic gradient
Causing the cell to swell
Protein can also get in through the wrecked cell membrane
Oedema causes ___ of brain tissue.
What can happen to the brain if intracranial pressure increases too much?
which tends to be fatal
What is haemorrhagic conversion?
Blood vessels weakened by an ischaemic stroke rupture, causing bleeding
Which three processes cause compression, contributing to complications following a brain injury?
The area of brain affected by a stroke depends on the ___ which are affected.
What is the average BP of the brain circulation?
What pathologies of blood vessels cause stroke?
What is a cardio risk factor for stroke?