8.2.1 - NonInfectious Diseases Flashcards
(17 cards)
Non-infectious diseases
Non-transmissible
- Not caused by a pathogen
- The top 2 leading causes of death in Australia in 2019 - ischemic heart disease, dementia.
- The risk of developing a specific non-infectious disease is influenced by age, gender, economic and social conditions, culture, race, lifestyle, environment, genetics and nutrition.
- Many are prevantable. E.g. reduced exposure to UV, proper nutriion.
Major types:
- Genetic
- Nutritional
- Cancer
- Environment exposure
Global patterns:
- Diet and lifestyle are the leading cause of non-infectious diseases in developed countries, e.g. alcohol consumption, inactivity, tobacco use
- Lack of food, limited access to clean water, and poor hygiene are the leading causes in developing countries
E.g. maori people are more prone to obesity as historically their diet was low in carbs - therefore a Western diet can cause quick weight gain.
Disease/Disorder/Syndrome
Genetic disease: abnormality in the genome
Disorder: abnormal physical or mental condition whether or not the cause is known.
Diseases are always disorders but disorders are not always diseases unless we know the cause of it.
A syndrome is a group of symptoms that consistently occur together.
Genetic diseases
- Caused by mutations of the genes/chromosomes of an individual.
- Inheriting a genetic mutation can result in disruption to normal gene expression and protein reproduction.
These can be caused by:
* Mutation in one gene
* Mutation in multiple genes
Single gene abnormalities: cystic fibrosis
Single gene abnormalities are caused due to inherited mutated genes from parents.
E.g. cystic fibrosis, sickle cell anaemia.
* Caused by mutation of the CFTR gene on Chromosome 7. Is recessive.
* Generally for those of caucasian descent, and 1/3000 affected.
* There is limited treatment, and this life-long disease can cause death (lifespan until 60s)
* The faulty gene changes the protein that regulates the normal movement of sodium chloride in and out of cells. This causes the mucus secreting organs to produce abnormally thick mucus.
* Impacts the respiratory, digestive and reproductive system, as well as sweat glands. Excess mucus in pancreas –> becomes inflamed from build up of enzymes, digestive system less effective at absorping nutrients.
* Mucus is very thick and blocks passageways in the lungs and digestive tracts –> chest infections, respiratory problems, malabsorption of nutrients.
Chromosomal abnormalities
Non-disjunction: incorrect separation of chromosomes during cell division. Chromosomal abnormalities are more prevalent in children born to older parents than younger parents
- Trisomy: one extra chromosome along with the normal chromosome pair.
- Monosomy: one member of a chromosome pair is missing.
Embryos with monosomy and trisomy will have a genetic disease or syndrome. Impacts every cell.
E.g. down syndrome (trisomy 21)
- Characteristic facial features include a small flattened skull, short flat bridged nose, wide set of almond shaped eyes, skin folds on the eyes.
- Intellectual disability
- Heart defects
- Susceptibility to infection.
Disease caused by environmental exposure
E.g. exposure to radiation or certain chemicals can damage DNA.
Agents that cause damage to DNA are called mutagens. These diseases are not necessarily due to genetic change.
Broad categories:
* Lifestyle diseases
* Diseases caused by physical factors in the environment - light, radiation.
* Diseases caused by expsoure to chemicals in the environment.
Environmental diseases: lifestyle
- Lifestyle diseases are those that arise as a direct results of the waty in which individuals live their lives.
E.g. cardiovascular disease, diabetes, cancers, chronic lung disease.
Risk factors: tobacco use, unhealthy diet, physical inactivity and harmful use of tobacco.
E.g. atherosclerosis
* Cardiovascular disease where unhealthy
Environmental disease: physical factors
Exposure to physical factors such as UV light from the sun or radiation from nuclear substances can cause disease.
Skin cancer:
* Excessive exposure to UV light.
* The UV light causes changes to the DNA of the skin cells, which may cause continued abnormal cell division.
* This can lead to the formation of basal cell carcinomas, squamous cell carcinomas, or malignant meanomas.
* Malignant melanoma is the most serious and can spread to other areas of the body unless identified and treated early.
Environmental disease: exposure to chemicals
Can cause disease, though the type of chemical and period of exposure will vary.
Exposure can be sourced from:
* Land homes were built on may be polluted, or used to dispose of waste.
* Toxic discharges into the atmosphere or waterways as a result of industrial processes.
* Pollution of the air and water.
* Heavy metals in the environment - lead and mercury. It cannot be removed from the body, and can accumulate. E.g. lead accumulates in the brain.
E.g. absestos. It grows in long, flexible fibres that makes it very useful in industry. Amphibole are hydrophobic, therefore cannot be dissolved in mucus and coughed up.
* Used as an insulator. By the fibres can penetrate the nucleus of the cells, and cannot be removed from the body.
* Asbestosis: inhaled absestos fibres cause inflammatory reaction in the lung tissue. This leads to scarring and stiffening of the lung tissue, which makes breathing difficult –> mesothelioma, type of lung cancer.
Nutritional diseases
Many nutrients are essential for health, as the body is not able to synthesise these molecules and most obtain them from consuming a balanced diet.
- Minerals: calcium, magnesium
- Vitamins: A, C, D, K
- Amino acids (from protein)
- Fatty acids
Nutritional diseases are caused by diets lacking the proper balane and amount of nutrition. This imbalance of diet can lead to malnutrition:
- Overnutrition
- Undernutrition
Undernutrition
Lack of protein and energy rich food
* In developing countries, kwashiorkor is caused by a severe lack of proetin in the diet and result in failure to grow, enlarged liver, hair chances, increases susceptibility to infectious diseases, fluid retention.
Lack of vitamins
* Lack of vitamin A can lead to blindness, dry skin, susceptibility to infection.
* Lack of vitamin D can lead to rickets.
Overnutrition
E.g. obesity
- From consuming more kilojoules than the body burns, resulting in an accumulation of fat in the body.
- Can be determined through the Body Mass Index. But this only an estimate. Athletes have a higher BMI - muscle mass and waist circumference must be assessed too.
Adverse health effects:
- Increases blood pressure
- Stroke
- Gallbladder disease
- Type 2 diabetes
- Increased risk of developing certain cancers such as colorectal cancer.
Nutritional disease: liver disease
People who drink alcohol excessively are prone to severe and often fatal liver disease.
* Alcohol is a toxic substance. Special enzymes are needed to break it down, from the liver. However, the processing needed to break down alcohol from a heavy drinker, the liver cell cannot carry out their normal levels of cellular respiration.
* Continual overwork of the liver can cause inflammation and scarring.
cont
Cancer
Group of diseases that commonly involve unregulated and abnormally cell growth and division.
* Caused by genetic mutations in the cells that increase the rate of cell division and/or result in the suppression of apoptosis. Either case can lead to the growth of tumours
Tumours:
* Benign: not considered cancerous, does not spread to other body tissues.
* Malignant: abnormal cancerous cells that are not confied by the boundary of the intial tumour. These can impair organ function.
Cancers:
- Sarcoma: forms in muscles, connective tissue such as bone or bloodvessels
- Carcinoma: epithelial tissue - skin
- Lymphonma and myeloma: lympthatic and plasma cells.
- Leukemia: bone marow, blood forming tissues
- Central nervous system: brain, spinal cord. Very dangerous.
Chemotheraphy:
* Targets fast growing cells. Therefore, hair falls out.
Genetic disease
Sickle Cell Anaemia
Overview
- Caused by a missense mutation in the HBB gene causes irregularly-shaped haemoglobin molecules to be produced
- The misshapen molecules break down
- Autosomal recessive inheritance, so in order to have sickle cell disease, the offspring must inherit 2 copies of the allele from their parents
Effects
- Production of sickle cell haemoglobin causes an inadequate amount of healthy haemoglobins to carry oxygen to cells, leading to fatigue and painful swelling in the hands and feet, as well as frequent infections
- Sickle cells are less efficient at carrying oxygen, and can also block capillaries due to their shape. This restricts blood flow in regions, causing intense pain and death of the surrounding tissue
- Individuals who are homozygous for this trait rarely live past the age of 10. In those who are heterozygous, anaemia is also experienced when the person is under stress from exercise or high altitude
- Heterozygous form has an adaptive advantage in malarial areas, as the rapid sickling of the cells kills the Plasmodium parasite before it can complete its life cycle
Phenylketonuria (PKU)
Overview
- PKU is an autosomal recessive disease caused by a mutation of the gene on chromosome 12 which codes for the PAH enzyme (phenylalanine hydroxylase)
- PAH is needed for the first step of the breakdown of the phenylalaline amino acid. As the mutation causes PAH to be manufactured incorrectly, phenylalaline cannot be broken down
Effect
- Can lead to a buildup of phenylalanine in blood and tissues, leading to intellectual disabilities, developmental delays, social, emotional, and behavioural problems, psychiatric disorders, and risk of seizures
- Individuals diagnosed with PKU must follow a diet low in protein-rich food such as milk, nuts, and egg, for the rest of their lives. The person also has to avoid consuming products that contain artificial sweeteners made with phenylalanine
