Unit 2, Topic 2 Infectious disease and epidemiology Flashcards
Disease, immune response, epidemiology
What is disease?
Disease is any deviation from the normal structure or function of body parts, organs, or systems, manifested by a characteristic set of symptoms.
What are the two broad categories of diseases?
Infectious diseases and non-infectious diseases.
What causes infectious diseases?
Infectious diseases are caused by pathogens, such as prions, viruses, bacteria, fungi, protists, and parasites, which can be transmitted from one host to another.
What causes non-infectious diseases?
Non-infectious diseases result from internal factors like genetic mutations or external factors such as environmental exposures and lifestyle choices. They are not caused by infectious agents.
Give examples of non-infectious diseases.
Diabetes, respiratory diseases, anaemia, and scurvy.
What are bacteria?
Bacteria are single-celled prokaryotic organisms that lack a nucleus and membrane-bound organelles. They can cause diseases like strep throat and cholera.
How do fungi obtain nutrients and what diseases can they cause?
Fungi digest food externally by secreting enzymes onto their host and absorbing nutrients. Pathogenic fungi can cause diseases like athlete’s foot and candidiasis.
What are viruses and how do they cause disease?
Viruses are composed of a DNA or RNA genome encased in a protein shell. They cannot reproduce on their own and must invade host cells to replicate. Diseases caused by viruses include HIV/AIDS and the common cold.
What are protists and what diseases can they cause?
Protists are diverse eukaryotic microorganisms. Some, like certain protozoa, are pathogenic and can cause diseases such as malaria and amoebic dysentery.
What are parasites and examples of diseases they cause?
Parasites are eukaryotic organisms that live on or inside a host, obtaining nourishment at the host’s expense. Examples include protozoa, helminths (worms), lice, and ticks. Diseases include giardiasis and schistosomiasis.
What are prions and the disease they cause?
Prions are abnormal proteins that induce normal proteins in the brain to fold incorrectly, leading to neurodegenerative diseases such as Creutzfeldt-Jakob disease.
What is pathogenesis?
Pathogenesis refers to the biological mechanisms that lead to the development and progression of a disease or disorder.
What are adherence factors in pathogens?
Adherence factors, like fimbriae and pili, enable pathogens to attach to host cells and resist physical removal, initiating infection.
What are invasion factors in pathogens?
Invasion factors are enzymes like collagenase, hyaluronidase, and lecithinase that help pathogens penetrate and spread within host tissues.
How do capsules help pathogens evade the immune system?
Capsules prevent phagocytes from adhering to pathogens, making it difficult for the immune system to recognize and engulf them.
What are exotoxins and endotoxins?
Exotoxins are toxins secreted by pathogens that disrupt cellular functions, while endotoxins are released when a pathogen’s cell wall breaks down, triggering harmful inflammatory responses.
What is the difference between ‘self’ and ‘non-self’ in the immune system?
The immune system distinguishes between the body’s own cells (‘self’) and foreign materials (‘non-self’). It responds to ‘non-self’ by initiating a response to eliminate these intruders.
What are Major Histocompatibility Complex (MHC) molecules?
MHC molecules, specifically MHC class I, are unique surface molecules on nucleated cells that signal to the immune system that the cells are ‘self’ and should not be attacked.
What are antigens and how do they trigger an immune response?
Antigens are foreign substances that trigger an immune response. They are recognized by lymphocytes, leading to the adaptive immune response where lymphocytes produce antibodies.
What is the role of antigenic determinants?
Antigenic determinants include surface markers on pathogens, self-markers on cells from different organisms, and proteins from food, which can trigger an immune response.
