2: Neuropathology 1

Question 1

What germ cell layer do neurons and glial cells come from?

Answer 1

Ectoderm

Question 2

Which germ cell layer do microglia come from?

Answer 2

Mesoderm

Question 3

Necrosis is ___ death of brain cells and occurs in which brain disease?

Answer 3

rapid

sudden failure e.g stroke

Question 4

Atrophy is a ___ reduction in brain size.

Is it normal?

Answer 4

slow

Depends - occurs with age, but is accelerated in diseases such as Alzheimer’s

Question 5

What happens to neurons histologically in acute injury?

Answer 5

Nuclei shrink and angulate

Nucleolus is lost

Cytoplasm turns red

Question 6

___ neurons are indicative of acute neuronal injury.

Answer 6

Red

Question 7

Which types of acute injury cause red neuronal death?

Answer 7

Hypoxia

Infarction

Question 8

What is the role of astrocytes in the CNS?

Answer 8

Support cells

Maintain homeostasis, maintain BBB, role in repair

Question 9

What is reactive gliosis?

Which cells undergo it?

What does it look like?

Answer 9

Non-specific reaction to CNS injury by glial cells

Glial cells (astrocytes, microglia, ependymal cells, oligodendrocytes)

Hypertrophy and hyperplasia, nucleus enlarges

Question 10

In demyelinating diseases (e.g MS), the conduction velocity of neurons (increases / decreases).

Answer 10

decreases

Question 11

What process do astrocytes undergo in response to injury?

Answer 11

Reactive gliosis

like all glial cells

Question 12

What happens to astrocytes in gliosis?

Answer 12

Hypertrophy

Hyperplasia

Question 13

Which important processes do

a) neurons
b) glial cells

undergo in response to injury?

Answer 13

a) “Red neuron” reaction

b) Reactive gliosis

Question 14

What are the role of microglia in the CNS?

Answer 14

Immune surveillance

Phagocytosis

Question 15

Which immune cell are microglia very similar to?

Answer 15

Macrophages

do the same job i.e phagocytosis, just in the brain

Question 16

Which state causes acute brain injury and occurs in stroke, trauma and cardiac arrest?

Answer 16

Hypoxia

Question 17

Which percentage of inhaled oxygen is used by the brain?

Answer 17

20%

Question 18

Why do neurons depolarise after extended hypoxia?

Which neurotransmitter is released in response to this abnormal depolarisation?

Which ion then enters the neuron

Answer 18

Na/K ATPase stops working - so Na accumulates inside the cell, causing a depolarisation

Glutamate (excitatory)

Ca2+

Question 19

What is excitotoxicity?

What triggers it?

Answer 19

Process by which neurons are killed by excessive glutamate > Ca2+ release

Extended hypoxia - Na/KATPase fails - Depolarisation - Glutamate release - Ca2+ influx - Release of endotoxins

Question 20

Various types of swelling, or ___, occur in response to brain injury.

Answer 20

oedema

Question 21

What is vasogenic oedema?

Answer 21

Breakdown of the BBB in infarcted areas of the brain allows water, ions and protein to filter out, causing swelling

Question 22

What is cytotoxic oedema?

Answer 22

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

Question 23

Oedema causes ___ of brain tissue.

Answer 23

compression

Question 24

What can happen to the brain if intracranial pressure increases too much?

Answer 24

Herniation

which tends to be fatal

Question 25

What is **haemorrhagic conversion**?

Answer 25

**Blood vessels weakened by an ischaemic stroke rupture, causing bleeding**

Question 26

Which **three processes** cause compression, contributing to complications following a brain injury?

Answer 26

**Cytotoxic oedema** **Vasogenic oedema** **Haemorrhagic conversion**

Question 27

The area of brain affected by a stroke depends on the ___ which are affected.

Answer 27

arteries

Question 28

What is the average BP of the brain circulation?

Answer 28

20 mmHg

Question 29

What pathologies of blood vessels cause stroke?

Answer 29

**Infarction** **Haemorrhage** **AVM** **Aneurysm** **Dissection**

Question 30

What is a cardio risk factor for stroke?

Answer 30

Hypertension

Question 31

What is a) global b) focal hypoxic ischaemic injury?

Answer 31

a) Widespread brain deperfusion due to shock, hypotension, cardiac arrest, trauma... b) Damage to one specific area of the brain due to blockage of a specific artery

Question 32

What MAP is required to perfuse the brain?

Answer 32

**60 mmHg** and above

Question 33

What are risk factors for ischaemic stroke?

Answer 33

Hypertension All the CVD risk factors for atherosclerosis - smoking, diet, HT, age, male diabetes Congenital heart disease

Question 34

What colour do neurons turn in acute damage secondary to ischaemic stroke?

Answer 34

Red

Question 35

Microglia hoover up dead cell debris by \_\_\_.

Answer 35

phagocytosis

Question 36

If an ischaemic stroke turns into a bleed, what is that process called? Which structure is damaged to cause this?

Answer 36

Haemorrhagic conversion Blood brain barrier

Question 37

Which cardio risk factor is a big predictor of stroke?

Answer 37

Hypertension

Question 38

Which type of infarct affects the basal ganglia?

Answer 38

Lacunar infarction

Question 39

Haemorrhage bleeding tissue is damaged by hypoxia surrounding tissue is damaged by oedema and compression

Question 40

Which notable type of vascular disease causes subarachnoid haemorrhage?

Answer 40

Berry aneurysm

Question 41

What are some rarer causes of haemorrhagic stroke?

Answer 41

Amyloid angiopathy ARTERIOVENOUS malformation

Question 42

Which circulation is damaged to cause a Berry aneurysm?

Answer 42

Circle of Willis

Question 43

Which renal disease is associated with Berry aneurysm?

Answer 43

Polycystic kidney disease

Question 44

Why may haemorrhages secondary to Berry aneurysms cause hydrocephalus?

Answer 44

Blood stops CSF reabsorption in subarachnoid granulations