Aetiology: causes of disease

Question 1

Define a/etiology.

Answer 1

• natural causes of disease
• first studied by hippocrates, 400BCE
• disease can have single cause or be the product of multiple factors.

Question 2

Define idiopathic conditions.

Answer 2

conditions with no known causes.

Question 3

What are 2 categories of classifying causes of disease?

Answer 3

• intrinsic = from within the body

- extrinsic = from outside the body

Question 4

What are intrinsic causes of disease?

Answer 4

changes in an individual’s genome
=> nuclear or mitochondrial
=> inherited mutations and other genetic variations
=> de novo modifications
Typically alter the function of a gene (or group of genes)

Question 5

define cell autonomous and cell non autonomous - as examples of intrinsic disease.

Answer 5

1. cell autonomous =
   genetic trait in multicellular organisms in which genetically mutant cell exhibit the mutant phenotype.
   x no longer expresses structural protein Y, so cell X is the wrong shape.
2. cell non-autonomously =genotypical mutant cell cause OTHER cells (regardless of their genotype) to exhibit mutant phenotype.

cell X no longer secretes protein hormone Y, so cell Z no longer function

Question 6

What are extrinsic causes of disease?

Answer 6

• injury
• infection
• nutrition and diet
• lifestyle (eg. smoking, exposure to workpace toxins)
• chemical poisioning (acute and chronic)
• Exposure to radiation

Question 7

Is age intrinsic or extrinsic cause?

Answer 7

Both
Intrinsic
- example:
age -> menopause -> decreased oestrogen -> risk of osteoporosis.

Extrinsic:
eg. cancer risk increases
as you grow older as you accumulate more mutations

Question 8

What are alternative descriptions of causes of disease?

Answer 8

• genetic (intrinsic) and environment (extrinsic)

Question 9

Give examples of intrinsic (molecular basis) disease.

Answer 9

• cancer
• Developmental disease
• inherited anaemia
• inherited metabolic disease

Question 10

covid -19 : extrinsic or intrinsic?

Answer 10

• extrinsic

- infection with SARS- CoV-2

Question 11

What are the stages of cell cycle?

Answer 11

G1= growth 
S= DNA synthesis 
G2 = growth and preparation for mitosis 
M= Mitosis (cell division)

Question 12

What are mitogens?

Answer 12

• small bioactive protein or peptide that induces a cell to begin cell division or enhances rate of division.

Question 13

What factors control the cell cycle?

Answer 13

• cylins
• cylin-dependent kinases (Cdks)
• cylin-dependent kinase inhibitors (CKIs)

Question 14

What mechanisms underlie cell death?

Answer 14

• apoptosis

- necrosis