Development, Degeneration and Recovery (DDR) Flashcards
What are encapsulated tumours more likely to be?
COMPOSITION
- 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.
What are benign tumours?
COMPOSITION AND CLASSIFICATION
- 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.
What happens if a benign tumour is left untreated?
COMPOSITION AND CLASSIFICATION
- 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.
What are malignant tumours?
COMPOSITION AND CLASSIFICATION
- 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.
What does it mean for a malignant tumour to metastasize?
COMPOSITION AND CLASSIFICATION
- 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.
What is a medullablastoma?
COMPRESSION AND CLASSIFICATION
- 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.
Why do tumours happen?
- Tumours happen because of metastases or from other cells in the brain.
What is metastases?
- Metastases is where cells are cast out from other areas of the body.
Why don’t nerve cells give rise to tumours?
- Because neurons are unable to divide and can’t proliferate. However, recent research has shown this may not be the case.
What is a glioblastoma multiforme?
TYPES OF TUMOURS
- It’s poorly differentiated glial cells leading to a tumour.
- It’s a fast growing glioma developing from star-shaped glial cells.
What is an astrocytoma?
TYPES OF TUMOURS
- 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.
What is an ependymoma?
TYPES OF TUMOURS
- Ependymal cells that line ventricles and are involved in the production of cerebral spinal fluid.
- Rare tumour.
- More common in children.
What is a medulloblastoma?
TYPES OF TUMOURS
- Medullablastomas are caused by cells in the roof of the fourth ventricle.
What is an oligodendrocytes?
TYPES OF TUMOURS
- They’re glial cells in the CNS that form myelin sheaths.
What is a meningioma?
TYPES OF TUMOURS
- 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.
What is a pituitary adenoma?
TYPES OF TUMOURS
- A tumour of the pituitary gland.
- Hormone secreting cells of the pituitary gland.
What is a neurinoma?
TYPES OF TUMOURS
- 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.
What is a metastatic carcinoma?
TYPES OF TUMOURS
- It’s the spread of cancer cells.
- Depends on the nature of the primary tumour.
What is an angioma?
TYPES OF TUMOURS
- 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.
What is a pinealoma?
TYPES OF TUMOURS
- 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.
What are malignant tumours?
- Contain cancer stem cells (have the ability to become any other type of cell).
- They propagate the initiation of cancer cells.
Can we target stem cells?
- 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.
What does the cancer stem cell do?
- It keeps the tumour alive.
What is the aim in relation to stem cells?
- The aim is to target cancer stem cells as without the stem cells the tumour is unable to generate more.
What are seizures caused by?
SEIZURE DISORDERS
- 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.
What happens if motor neurons are involved in a seizure?
SEIZURE DISORDERS
- May lead to convulsions; muscles spasm uncontrollably.
What did Hippocrates believe about seizures?
SEIZURE DISORDERS
- 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.
What was historically believed about seizures, before being refuted by Hippocrates?
SEIZURE DISORDERS
- Used to be believed that seizures were an act of God or demonic possession.
What are the 3 generalised types of seizures?
SEIZURE DISORDERS
- Tonic clonic (grand mal).
- Absence (petit mal).
- Atonic (loss of muscle tone; temporary paralysis).
- These have no apparent local onset.
What are the 5 simple partial seizures?
SEIZURE DISORDERS
- 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).
