Biol123

• What pathogens can cause an acute infection?


  Bacteria, viruses, fungi
• What pathogens can cause chronic disease?

  Parasites
• What pathogens make up parasites?

  Protists and worms
• What is parasitism?


  A symbiotic relationship where one organism benefits at the expense of another.
• What is a mutualistic relationship?


  A symbiotic relationship where both benefit
• What is a commensal relationship?


  A symbiotic relationship where 1 organism benefits and the other is not impacted
• What is the incubation period of disease?


  The time between the infection and the first symptoms appearing
• What is the prodromal period of disease?


  Early symptoms before full onset.
• What is an illness?

  The period with the worst symptoms, before the immune system responds
• What is the convalescence stage of disease?

  Recovery
• What factors impact the severity of disease?


  Dose, age, biological sex, genetics, nutritional status, co-infection
• What are the stages of infection?


  Invasion, multiplication, spread, pathogenesis
• Can protists multiply within the body?


  Yes.
• Can helminths multiply within the body?

  No
• What is incidence?


  The number of new cases of a specific disease or condition in a population during a specific time period
• What is prevalence?


  The proportion of individuals in a population who have a specific characteristic or condition at a given point in time.
• What is mortality?


  The total number of deaths from a specific disease in a defined time period
• What is the most common cause of death in rich countries?

  Chronic diseases
• What is the most common cause of death in poor countries?

  Infectious diseases
• What is morbidity?


  Ill health associated with disease
• What is Disability Adjusted Life Years?


  A measurement of the 'life years' lost due to premature mortality and equivalent years lost because of morbidity
• Why is DALY flawed?


  It only measures direct health loss with no consideration of the economic impacts of disease
• What makes up the immune system?

  Lymphatic system, blood, antibodies, cells
• What are the mechanical barriers to disease?


  Skin, tight junctions, mucosal durfaces
• How does skin act as a mechanical barrier to disease?


  Contains dead cells and bacteria, has sebaceous glands which excrete fatty acids, and lactic acid to keep low pH, dry
• How do tight junctions acts as a mechanical barrier to disease?


  Found in intestines to stop ingested pathogens entering the bloodstream
• How do mucosal surfaces act as mechanical barriers to disease?


  Found in respiratory and digestive tracts, coated in mucous secreting cells to trap microorganisms which are swept out tby cilia
• What are the physiological barriers to disease?

  pH, chemical mediators, complement system
• How does pH act as a physiological barrier to disease?


  Stomach is acidic to kill pathogens, commensal microbiota outcompete pathogens
• How do chemical mediators act as physiological barriers to disease?


  Lysozyme enzymes in tears and saliva contain antimicrobial peptides, defensins found on skin surface, interferons induce antiviral state in cells
• How does the complement system act as a physiological barrier to disease?


  MAC lyses bacteria via osmosis
• How do parasites evade the innate immune system?


  Hookworms hook on to skin, vectors inject into skin, burrow straight through skin
• What are granulocytes?


  White blood cells that contain granules in their cytoplasm and play a role in immune response.
• What cells are examples of granulocytes?


  Neutrophils, eosinophils, basophils, mast cells
• What are phagocytes?


  White blood cells that engulf and destroy pathogens.
• What cells are examples of phagocytes?


  Macrophages, neutrophils, dendritic cells
• How do neutrophils act as phagocytes?


  Produce extracellular traps, effective against gram positive and negative bacteria
• What are lymphocytes?


  White blood cells that play a key role in the immune system.
• What cells are examples of lymphocytes?


  Innate lymphoid cells, natural killer cells
• What are the four signs of inflammation?

  Heat, redness, swelling, pain