Defence against disease Flashcards
What is a pathogen?
A pathogen is a disease-causing organism that can infect humans and other organisms.
What are the main types of pathogens?
The main types of pathogens are viruses, bacteria, fungi, and protists.
Are archaea known to cause diseases in humans?
No, archaea are not known to cause any diseases in humans.
What are some examples of bacterial pathogens?
Examples include Streptococcus pneumoniae, Staphylococcus aureus, Escherichia coli (E. coli), and Klebsiella pneumoniae.
What types of diseases can viruses cause?
Viruses can cause a wide range of diseases, from the common cold to AIDs.
What are some examples of diseases caused by fungi?
Fungi can cause skin diseases like ringworm and athlete’s foot, as well as infections in the lungs or nervous system.
What is an example of a disease caused by a protist?
Malaria is caused by a protist parasite called Plasmodium.
What was the significance of Ignaz Semmelweis’s observations in Vienna during the 1840s?
Semmelweis observed higher mortality rates in maternity wards attended by medical students compared to midwives, leading to the introduction of hand washing with chlorinated lime solution, which dramatically reduced mortality rates.
What important discovery did John Snow make during the 1854 cholera epidemic in London?
John Snow mapped cholera cases in London, identifying a contaminated water pump as the source, which led to the understanding of cholera as a waterborne disease and improvements in urban sanitation.
How did the observations of Semmelweis and Snow contribute to the field of infectious diseases?
These observations were crucial in developing germ theory and improving public health measures to control infectious diseases.
What is the primary function of the skin as a barrier?
The skin acts as both a physical and chemical barrier to protect against pathogens.
How does the skin serve as a physical barrier?
The skin provides a continuous, impassable barrier that prevents the entry of potentially infectious pathogens.
What role does desquamation play in skin defense?
Desquamation, or the shedding of dead skin cells, helps dislodge pathogens that may have adhered to the skin surface.
How does the skin’s acidity contribute to pathogen defense?
The skin’s acidity creates an unfavorable environment for many pathogens, helping to kill or inactivate them.
What is the role of beneficial microorganisms on the skin?
Beneficial microorganisms compete with invading pathogens, preventing their colonization and reducing the risk of infection.
What are antimicrobial peptides (AMPs)?
AMPs are small peptides secreted by skin cells that have antibiotic-like properties, directly killing pathogens and enhancing immune responses.
How do keratinocytes contribute to skin immunity?
Keratinocytes act as active immune cells that release inflammatory cytokines and antimicrobial molecules in response to pathogens.
What is the function of mucous membranes in pathogen defense?
Mucous membranes line body cavities and secrete mucus, which traps pathogens and facilitates their removal from the body.
How do tears contribute to eye health?
Tears contain enzymes that act as chemical barriers, helping to wash away pathogens and prevent infections in the eyes.
What happens when the skin barrier is breached?
When the skin barrier is compromised, it allows pathogens to enter, leading to potential infections; this activates the innate immune system for protection.
What is the primary purpose of blood clotting?
The primary purpose of blood clotting is to seal cuts in the skin, preventing blood loss and pathogen entry.
What initiates the blood clotting process?
The process is initiated when platelets adhere to the site of a cut or injury.
What do platelets release during the clotting process?
Platelets release clotting factors that trigger a cascade of reactions leading to blood clot formation.
What is the coagulation cascade?
The coagulation cascade is a series of complex biochemical reactions that lead to the formation of a blood clot.
What enzyme is activated during the coagulation cascade?
The enzyme thrombin is activated during the coagulation cascade.
What is the role of thrombin in blood clotting?
Thrombin catalyzes the conversion of fibrinogen, a soluble plasma protein, into fibrin, which is insoluble.
How does fibrin contribute to clot formation?
Fibrin strands form a mesh that traps platelets and erythrocytes (red blood cells), stabilizing the clot at the injury site.
What happens to erythrocytes during clot formation?
Erythrocytes are trapped within the fibrin mesh, contributing to the overall structure and stability of the clot.
What is the significance of rapid conversion of fibrinogen to fibrin?
The rapid conversion ensures that bleeding is quickly controlled and that a stable barrier is formed to protect against infection.
How does the body eventually remove a blood clot once healing occurs?
Once healing is complete, an enzyme called plasmin is activated to dissolve the clot in a process known as fibrinolysis.
What is the primary characteristic of the innate immune system?
The innate immune system responds to broad categories of pathogens and provides an immediate, non-specific defense.
How does the adaptive immune system differ from the innate immune system?
The adaptive immune system responds in a specific way to particular pathogens and develops memory for previously encountered pathogens.
Does the innate immune system change throughout an organism’s life?
No, the innate immune system does not change during an organism’s life; it remains constant.
What is the response time of the innate immune system?
The innate immune system responds rapidly, typically within minutes to hours after exposure to pathogens.
What is the response time of the adaptive immune system?
The adaptive immune system has a slower response time, taking days or even weeks to develop on first encounter with a pathogen.
What role do phagocytes play in the innate immune system?
Phagocytes are key components of the innate immune system that engulf and destroy pathogens.
How does the adaptive immune system build memory?
The adaptive immune system builds memory by creating long-lived memory cells that remember specific pathogens for faster responses upon re-exposure.
What type of immunity does the adaptive immune system provide?
The adaptive immune system provides specific immunity against particular pathogens, allowing for a targeted response.
Can the adaptive immune system be enhanced through vaccination?
Yes, vaccination stimulates the adaptive immune system to recognize and remember specific pathogens without causing disease.
Why is it important for both the innate and adaptive immune systems to work together?
The collaboration between both systems ensures a comprehensive defense against infections, with the innate system providing immediate protection while the adaptive system develops long-term immunity.
What is the primary function of phagocytes in the immune system?
Phagocytes are responsible for engulfing and digesting pathogens to help control infections.
How do phagocytes move to sites of infection?
Phagocytes use amoeboid movement to migrate from the blood to sites of infection.
What is amoeboid movement?
Amoeboid movement is a crawling-like motion where phagocytes change shape by extending parts of their cell membrane to form pseudopodia.
How do phagocytes recognize pathogens?
Phagocytes recognize pathogens through specific receptors that bind to pathogen-associated molecular patterns (PAMPs).
What process do phagocytes use to engulf pathogens?
Phagocytes engulf pathogens through a process called endocytosis, forming a vesicle known as a phagosome.
What happens to the phagosome after engulfing a pathogen?
The phagosome matures into a phagolysosome, where it fuses with lysosomes that contain digestive enzymes.
What role do lysosomal enzymes play in pathogen destruction?
Lysosomal enzymes digest the engulfed pathogens, breaking them down into smaller components.
How do reactive oxygen species (ROS) contribute to pathogen killing?
Reactive oxygen species generated in the phagolysosome help kill pathogens through oxidative damage.
What is the significance of phagocytosis in the immune response?
Phagocytosis is crucial for eliminating invading pathogens and maintaining homeostasis by clearing dead cells and debris.
How do phagocytes communicate with other immune cells during an infection?
Phagocytes produce cytokines that recruit other immune cells to the site of infection, enhancing the overall immune response.
What are lymphocytes?
Lymphocytes are a type of white blood cell that plays a crucial role in the adaptive immune system.
What are the two main types of lymphocytes involved in the adaptive immune response?
The two main types are B lymphocytes (B cells) and T lymphocytes (T cells).
Where do lymphocytes circulate in the body?
Lymphocytes circulate in the blood and are also contained in lymph nodes.
What is the primary function of B lymphocytes?
B lymphocytes are responsible for producing antibodies specific to particular antigens.
How many different types of B lymphocytes does an individual typically have?
An individual has a very large number of B lymphocytes, each producing a specific type of antibody.
What happens when a B cell encounters its specific antigen?
Upon encountering its specific antigen, a B cell becomes activated, proliferates, and differentiates into plasma cells and memory B cells.
What do plasma cells do?
Plasma cells are specialized B cells that secrete large quantities of antibodies into the bloodstream.
What is the role of memory B cells?
Memory B cells provide long-lasting immunity by remaining in the body and responding more rapidly upon re-exposure to the same pathogen.
How do antibodies function in the immune response?
Antibodies bind to specific antigens on pathogens, neutralizing them or marking them for destruction by other immune cells.
How do T lymphocytes assist B lymphocytes in producing antibodies?
Helper T cells provide signals and cytokines that activate B cells, enhancing their ability to produce antibodies effectively.
What is an antigen?
An antigen is a molecule that can trigger an immune response, specifically activating lymphocytes to produce antibodies.
What types of molecules are most antigens typically composed of?
Most antigens are glycoproteins or other proteins located on the outer surfaces of pathogens.
How do antigens function in the immune system?
Antigens serve as recognition molecules that help the immune system identify foreign substances, prompting an immune response.
Where are antigens commonly found?
Antigens are usually found on the surfaces of viruses, bacteria, fungi, and other pathogens, as well as on the surface of cells.
What happens when an antigen is recognized by the immune system?
When recognized, the immune system activates specific lymphocytes (B cells and T cells) to respond to the pathogen.
What role do antibodies play in response to antigens?
Antibodies bind to specific antigens, neutralizing pathogens or marking them for destruction by other immune cells.
How do blood group antigens relate to transfusions?
Antigens on the surface of erythrocytes (red blood cells) can stimulate antibody production if transfused into a person with a different blood group, leading to potential transfusion reactions.
What is the significance of glycosylation in antigens?
Glycosylation can influence the antigenic properties of proteins, affecting how they are recognized by the immune system.
What are epitopes?
Epitopes are specific regions or fragments of an antigen that are recognized by antibodies or T-cell receptors.
Why is it important for the immune system to distinguish between self and non-self antigens?
The ability to distinguish self from non-self helps prevent autoimmune reactions, where the immune system mistakenly attacks the body’s own tissues.
What is the role of B-lymphocytes in the immune system?
B-lymphocytes (B cells) produce antibodies and can become memory cells upon activation.
How are B cells activated?
B cells are activated when they encounter their specific antigen and receive signals from helper T-lymphocytes that have also been activated by the same antigen.
