Causes of disease: overview

Question 1

What are some causes of disease?

Answer 1

Natural causes of disease first studied scientifically by Hippocrates

Introduced concept of aetiology - the study of causation or origination

Diseases can have a single cause (e.g. Huntingtons), or be the product of multiple factors

Question 2

What do you call a condition with NO KNOWN cause?

Answer 2

Idiopathic

Question 3

What does sporadic mean?

Answer 3

The disease arose randomly and with no obvious pattern

Question 4

What are the 2 categories in which causes of disease are put into?

Answer 4

Extrinsic (from outside)
Intrinsic (from within)

Question 5

What are some of the intrinsic causes of disease?

Answer 5

Changes in an individual’s genome:

1. Nuclear or mitochondrial
2. Inherited mutations and other genetic variations (duplications of chromosomes, deletions, insertions etc)
3. de novo mutations (new mutations while alive e.g. cancer)
4. Epigenetic modifications (chemical methylation of DNA, phosphorylation/ acetylation of histones)

These typically alter the function of a gene or group of genes, e.g. more/less protein or same amount but more/less activity

Question 6

What levels can effects of genetic variations manifest in?

Answer 6

1. Cell autonomously:

e.g. Cell X no longer expresses structural protein Y, so cell X is the wrong shape

2. Cell non-autonomously:

e.g. Cell X no longer secretes protein hormone Y, so cell Z no longer functions

Question 7

What are some examples of some extrinsic causes of disease?

Answer 7

1. Injury
2. Infection
3. Nutrition and diet
4. Lifestyle, e.g. smoking, exposure to workplace toxins
5. Chemical poisoning (acute and chronic)
6. Exposure to radiation

Question 8

What is the cause of Downs Syndrome and is it intrinsic/extrinsic?

Answer 8

Trisomy of chromosome 21, inherited at conception

Intrinsic

Question 9

What is the cause of Covid 19 and is it intrinsic or extrinsic?

Answer 9

Infection with SARS-CoV-2

Extrinsic

Question 10

Is age an intrinsic or extrinsic factor?

Answer 10

Those two words can be ambigious sometimes, especially because disease is susually a chain of events rather than a single cause.

Time can be used as a synonym for age, so as time passes there is an accumulation of mutations (therefore not a cause)

However, there is a biological process of ageing such as menopause leading to decreased oestrogen and therefore risk of osteoporosis

Question 11

What are alternative descriptions for intrinsic and extrinsic?

Answer 11

Genetic and environmental

Question 12

What are mitogens?

Answer 12

Any substance that triggers the process of mitosis, or cell division.

Frequently, mitogens are proteins — compounds consisting of amino acid molecules that facilitate biochemical reactions in organisms

Question 13

What are the phases of the cell cycle?

Answer 13

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Question 14

What factors control the cell cycle?

Answer 14

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Question 15

What mechanisms underlie cell death?

Answer 15

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