Topic 2C – Cells and the Immune System Flashcards
What are antigens?
Antigens are molecules, typically found on the surface of pathogens, that trigger an immune response.
What is the role of phagocytes in the immune system?
Phagocytes engulf and digest pathogens through a process called phagocytosis.
What are the two main types of white blood cells involved in the immune response?
~B cells: Produce antibodies and are involved in humoral immunity.
~T cells: Involved in cell-mediated immunity and help activate B cells.
What are the two types of T cells and their functions?
~Helper T cells (Th cells): Activate B cells and cytotoxic T cells.
~Cytotoxic T cells (Tc cells): Destroy infected cells by releasing toxic substances.
What is an antibody?
An antibody is a protein produced by B cells that binds to antigens, marking them for destruction.
What is the process of antigen presentation?
Phagocytes or infected cells display antigens on their surface to activate T cells, initiating an immune response.
What is immunity?
Immunity is the body’s ability to resist infection through the recognition and destruction of pathogens.
What is the difference between active and passive immunity?
~Active immunity: The body produces its own antibodies after exposure to a pathogen or through vaccination.
~Passive immunity: The body receives antibodies from an external source, such as breast milk or antibody injections.
What is vaccination?
Vaccination involves introducing a harmless form of a pathogen (e.g., dead, weakened, or inactivated) to stimulate an immune response without causing disease.
How do vaccines work?
Vaccines stimulate the immune system to produce antibodies and memory cells against a specific pathogen, providing future protection.
What are memory cells?
Memory cells are long-lived cells that remember the antigen after an infection or vaccination, enabling a faster and stronger immune response if the pathogen is encountered again.
What is herd immunity?
Herd immunity occurs when a large proportion of the population is immune to a disease, reducing its spread and protecting those who are not immune.
How is vaccine efficacy typically measured?
Vaccine efficacy is measured by the proportion of vaccinated individuals who do not develop the disease after exposure to the pathogen.
What does a high antibody titer indicate?
A high antibody titer indicates a strong immune response and a high level of antibodies in the bloodstream, usually following vaccination or infection.
How can the presence of antibodies be used to detect infections?
Antibodies specific to a pathogen can be detected in blood tests to confirm current or past infections.
What does a seroconversion mean in the context of vaccination?
Seroconversion refers to the development of detectable antibodies in the blood following vaccination or infection.
What is HIV?
Human Immunodeficiency Virus (HIV) is a virus that attacks and weakens the immune system by targeting helper T cells.
How does HIV affect the immune system?
HIV attacks and destroys helper T cells, which are essential for coordinating the immune response, leaving the body vulnerable to infections.
What is AIDS?
Acquired Immune Deficiency Syndrome (AIDS) is the final stage of HIV infection, where the immune system is severely damaged, leading to opportunistic infections and cancers.
How is HIV transmitted?
HIV is primarily transmitted through blood, semen, vaginal fluids, and breast milk. It can be spread through unprotected sex, sharing needles, or from mother to child during birth or breastfeeding.
What is the function of the immune system?
The immune system protects the body from pathogens, such as bacteria, viruses, and parasites.
What is Phagocytosis?
The process by which a phagocyte engulfs and digests pathogens.
What is antiretroviral therapy (ART)?
ART is a combination of drugs used to treat HIV by preventing the virus from replicating, thus helping to maintain a functional immune system.
Why can’t HIV be cured?
HIV integrates its genetic material into the host’s DNA, making it difficult to completely eliminate. However, ART helps manage the virus effectively.
What is the difference between HIV and AIDS?
HIV is the virus that causes the disease, while AIDS is the condition that develops in the final stages of HIV infection when the immune system is severely weakened.
What are the key features of viruses?
Viruses are small infectious agents made of genetic material (DNA or RNA) enclosed in a protein coat. They require a host cell to replicate and cannot carry out metabolic processes on their own.
