Biology Unit 5

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  • Created by: Weronika
  • Created on: 17-06-13 10:58
Explain the formation of tumours.
Tumours are caused by gene mutations of tumour suppressor genes and oncogenes which are responsible for regulation of the cell cycle, which cause uncontrolled cell division. The rate of cell proliferation is greater than that of cell death.
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Explain how a stroke may be caused.
Atheroma formation and thrombosis in cerebral arteries lead to ischaemia in the brain. This leads to necrosis of the neurones in the brain. This is the main cause of strokes.
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State the risk factors for a stroke.
High blood pressure, high levels of LDL cholesterol, lack of exercise, ageing, gender, smoking, genetic factors and diet.
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Explain the causal link between ageing and a stroke.
Ageing makes the arteries less elastic. This increases the blood pressure in the vessels and causes endothelial damage. Plaque forms due to deposits of Calcium ions, LDL and cell debris by T cells. This narrows the lumen of the arteries in the brain.
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Pain is caused when specific receptors and C fibre receptors are stimulated. Explain how an action potential will be initiated in those neurones.
The stimulus will cause the Sodium channels to open. The influx of Sodium ions into the neuron will initiate the action potential.
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Other cards in this set

Card 2

Front

Explain how a stroke may be caused.

Back

Atheroma formation and thrombosis in cerebral arteries lead to ischaemia in the brain. This leads to necrosis of the neurones in the brain. This is the main cause of strokes.

Card 3

Front

State the risk factors for a stroke.

Back

Preview of the front of card 3

Card 4

Front

Explain the causal link between ageing and a stroke.

Back

Preview of the front of card 4

Card 5

Front

Pain is caused when specific receptors and C fibre receptors are stimulated. Explain how an action potential will be initiated in those neurones.

Back

Preview of the front of card 5

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