Genetic and Environmental Causes of Disease Flashcards
What are the four main causes of disease?
1- Genetic
2- Environmental
3- Combination (multi-factorial)
4- Unknown
How can the cause of diseases be identified?
1- Laboratory studies
2- Family studies
3- Epidemiology
What is heritability?
A statistic which estimates the extent to which observed differences are caused by genes.
What factors could lead to traits running in families?
1- Genes
2- Social learning or modeling
3- Operant conditioning (reward-based learning, positive/negative reinforcement and punishment)
4- Chance
What heritable trait can change across generations?
Height
What highly heritable conditions are easily modified?
1- Vision
2- Mental retardation due to Phenylketonuria (PKU)
What interventions can heritable conditions respond to?
1- Drug intervention
2- Social intervention
3- Behavioural intervention
How is heritabililty measured?
1- Family studies
2- Twin studies
3- Adoption studies
4- Migrant studies
What factors do mono zygotic twins share?
1- Genes
2- Environment
What factors do dizygotic twins share?
1- Environment
2- Same amount of genetic info as any other sibling
In twin studies conducted to see if IQ is heritable, what problems may affect the results?
1- Monozygotic twins share their environment more than dizygotic twins due to being more encouraged to spent time together
2- Monozygotic twins may not have shared the same uterine environment due to varying concentrations of amniotic fluid cells
How are phenotypes quantified?
Phenotype = genes + environment + (genes * environment)
How is heritability quantified?
H2= Vg/Vg+Ve+V(g*e)
What four factors or types of disease can be influenced by the environment?
1- Infection
2- Injury from chemical agents
3- Injury from physical agents
4- Behaviour
What are the seven infectious agents?
1- Bacteria 2- Viruses 3- Fungi 4- Yeast 5- Protozoa 6- Parasites 7- Prions
What are prions?
1- Proteins that replicate
2- E.g. mad cow disease or Creutzfeldt-Jakob disease in humans
What is viral tropism?
A virus which will only infect a host if it has the right receptors, cell types, or environment.
What are the seven modes of transmission?
1- Droplet (droplets from cough or sneeze)
2- Faeco-oral (fecal particles enter oral cavity)
3- Venereal (STI)
4- Blood
5- Water
6- Food
7- Vectors/fomites (inanimate vector e.g. touching a public phone)
What are the four types of transmission?
1- Horizontal (individuals of same generation)
2- Vertical (across generations)
3- Zoonoses (from animals to humans)
4- Nosocomial (healthcare transmitted infections)
What chemical agents can lead to disease?
1- Smoking 2- Alcohol 3- Drugs 4- Dust 5- Food
What diseases are associated with smoking?
1- Mutagenic- cancer
2- Inflammation- chronic obstructive pulmonary disease (COPD)
3- Nicotine receptors- increased blood pressure and heart rate
4- Endothelial damage
5- Carbon monoxide levels- intrauterine growth retardation
What are the benefits of alcohol?
In small amounts, alcohol can reduce the risk of heart disease
What can large doses of alcohol lead to?
Cirrhosis (chronic disease of liver due to increased scar tissue)
The metabolism of alcohol leads to what consequences which underlie disease?
1- Acetaldehyde- carcinogenesis
2- Increased oestrogen levels
3- Decreased NAD levels alters lipid metabolism
4- Reactive oxygen damages lipid membranes
5- Decreased vitamin B levels
6- Depressed CNS function
7- Teratogenic (affects development of embryo)
