Development, Degeneration and Recovery (DDR)

Question 1

What are encapsulated tumours more likely to be?

COMPOSITION

Answer 1

• Benign.
• Case study: woman with a tumour on the optic nerve.
• Optic nerve takes info from left eye and transfers it to occipital lobe at the back of the brain, allowing it to be processed meaningfully.
• If a tumour grows on the optic nerve, it will at the very least apply pressure to the optic nerve and stop it from functioning properly.
• If a tumour is on the optic nerve, it can easily be extracted.
• The woman in the case study would experience blurred vision while driving.

Question 2

What are benign tumours?

COMPOSITION AND CLASSIFICATION

Answer 2

• Not cancerous.
• Mass of cells which have come together and have clearly defined borders meaning that you can see the outline clearly.
• This means that it doesn’t infiltrate the surrounding tumour, unlike in cancerous tumours.
• They do cause compression and can cause debilitating, or even life-threatening damage dependent on location.

Question 3

What happens if a benign tumour is left untreated?

COMPOSITION AND CLASSIFICATION

Answer 3

• It can lead to a condition known as hydrocephalus. CBF can show whether you have meningitis etc. dependent on where the tumour is sitting,
• It may stop the movement of the CBF and so it’ll build up and push the brain outwards and can be fatal if not treated.

Question 4

What are malignant tumours?

COMPOSITION AND CLASSIFICATION

Answer 4

• They’re catastrophic and cancerous.
• They’re not encapsulated, and so they don’t have well defined borders and can infiltrate the surrounding tissue.
• This makes removal difficult as there is always possible that left over cells will remain and continue to infiltrate other areas of the brain.
• There’s the suggestion that a catastrophic tumour will come from elsewhere in the body, and through blood movement they’ve ended up in the brain and have started to develop.

Question 5

What does it mean for a malignant tumour to metastasize?

COMPOSITION AND CLASSIFICATION

Answer 5

• Sheds cells travelling in the bloodstream and grows in other areas of the body.
• It is more likely that metastases from other areas in the body give rise to metastatic brain tumours than the other way round.

Question 6

What is a medullablastoma?

COMPRESSION AND CLASSIFICATION

Answer 6

• Uncommon form of brain cancer where the tumour is atop the medulla.
• Blocks the passage of the 4th ventricle, however this passage is important.
• Brain is pushed out as far as possible, however can only go so far because it’s encapsulated in the skull.
• This then leads to hydrocephalus and can be very dangerous.

Question 7

Why do tumours happen?

Answer 7

• Tumours happen because of metastases or from other cells in the brain.

Question 8

What is metastases?

Answer 8

• Metastases is where cells are cast out from other areas of the body.

Question 9

Why don’t nerve cells give rise to tumours?

Answer 9

• Because neurons are unable to divide and can’t proliferate. However, recent research has shown this may not be the case.

Question 10

What is a glioblastoma multiforme?

TYPES OF TUMOURS

Answer 10

• It’s poorly differentiated glial cells leading to a tumour.
• It’s a fast growing glioma developing from star-shaped glial cells.

Question 11

What is an astrocytoma?

TYPES OF TUMOURS

Answer 11

• Caused by astrocytes, which are a supportive function.
• Glial cells in the CNS provide support for neurons by providing nutrients and other substances, and also regulate chemical composition of extracellular fluid.
• Doesn’t usually spread outside the brain and spinal cord and doesn’t usually affect other organs.

Question 12

What is an ependymoma?

TYPES OF TUMOURS

Answer 12

• Ependymal cells that line ventricles and are involved in the production of cerebral spinal fluid.
• Rare tumour.
• More common in children.

Question 13

What is a medulloblastoma?

TYPES OF TUMOURS

Answer 13

• Medullablastomas are caused by cells in the roof of the fourth ventricle.

Question 14

What is an oligodendrocytes?

TYPES OF TUMOURS

Answer 14

• They’re glial cells in the CNS that form myelin sheaths.

Question 15

What is a meningioma?

TYPES OF TUMOURS

Answer 15

• Cells of the meninges.
• Forms on the membranes that cover the brain and spinal cord just inside the skull.
• Forms on three layers of membranes called meninges.
• They’re slow growing.
• Most (90%) are benign.

Question 16

What is a pituitary adenoma?

TYPES OF TUMOURS

Answer 16

• A tumour of the pituitary gland.

- Hormone secreting cells of the pituitary gland.

Question 17

What is a neurinoma?

TYPES OF TUMOURS

Answer 17

• Schwann cells or cells of connective tissue covering the cranial nerves.
• A benign tumour; may develop on hearing and balance nerves of the inner ear.
• Results from an overabundance of Schwann cells, which usually support the nerves.

Question 18

What is a metastatic carcinoma?

TYPES OF TUMOURS

Answer 18

• It’s the spread of cancer cells.

- Depends on the nature of the primary tumour.

Question 19

What is an angioma?

TYPES OF TUMOURS

Answer 19

• Angiomas are benign tumors derived from cells of the vascular or lymphatic vessel walls (endothelium) or derived from cells of the tissues surrounding these vessels.
• Cells of the blood vessels.
• Angiomas are a frequent occurrence as patients age, but they might be an indicator of systemic problems such as liver disease.

Question 20

What is a pinealoma?

TYPES OF TUMOURS

Answer 20

• Cells of the pineal gland.
• A pinealoma is a tumor of the pineal gland, a part of the brain that produces melatonin.
• If a pinealoma destroys the cells of the pineal gland in a child, it can cause precocious puberty.

Question 21

What are malignant tumours?

Answer 21

• Contain cancer stem cells (have the ability to become any other type of cell).
• They propagate the initiation of cancer cells.

Question 22

Can we target stem cells?

Answer 22

• Previously we didn’t have the knowledge to, however recent research investigates how we can target stem cells.
• Previously, drugs couldn’t kill the cancer stem cells, meaning the tumour would shrink and then grow back.

Question 23

What does the cancer stem cell do?

Answer 23

• It keeps the tumour alive.

Question 24

What is the aim in relation to stem cells?

Answer 24

• The aim is to target cancer stem cells as without the stem cells the tumour is unable to generate more.

Question 25

What are seizures caused by?

SEIZURE DISORDERS

Answer 25

• The sudden disruption of the brain’s electrical activity.
• If you have a seizure it’s because the electrical activity is ramped up to a point that you’re brain can’t handle, therefore leading to seizure symptoms.
• They’re typically transient, and so eventually the brain regains control and seizures stop.

Question 26

What happens if motor neurons are involved in a seizure?

SEIZURE DISORDERS

Answer 26

• May lead to convulsions; muscles spasm uncontrollably.

Question 27

What did Hippocrates believe about seizures?

SEIZURE DISORDERS

Answer 27

• Wrote the first book on epilepsy: On the Sacred Disease.
• Refuted idea that epilepsy was a cure or prophetic power.
• States it was a brain disorder; ‘Sacred’ - has a natural cause.

Question 28

What was historically believed about seizures, before being refuted by Hippocrates?
SEIZURE DISORDERS

Answer 28

• Used to be believed that seizures were an act of God or demonic possession.

Question 29

What are the 3 generalised types of seizures?

SEIZURE DISORDERS

Answer 29

• Tonic clonic (grand mal).
• Absence (petit mal).
• Atonic (loss of muscle tone; temporary paralysis).
• These have no apparent local onset.

Question 30

What are the 5 simple partial seizures?

SEIZURE DISORDERS

Answer 30

• Partial seizures start from a focus, and simple seizures mean that there is no major change in consciousness.
• Localised motor seizure.
• Motor seizure, with progression of movements as seizure spreads along the primary motor cortex.
• Sensory (somatosensory, visual, auditory, olfactory, vestibular).