Immunology LO1

What is the first line of defense in the body's immune system?

The first line of defense consists of external defenses like skin and mucous membranes that block access to portals of entry for pathogens.

What role does keratin play in the skin?

Keratin is an insoluble protein that compacts and cements epithelial cells together, providing a tough barrier against pathogen entry.

How do sweat glands protect the body from pathogens?

Sweat glands produce organic acids like lactic acid and fatty acids that lower pH, inhibiting the growth of harmful organisms.

What is the function of normal flora in the body?

Normal flora protect the body by competing with potential pathogens and can alter the pH to hinder microbial growth.

What are mucous membranes and where are they found?

Mucous membranes line all body cavities open to the external environment, such as the respiratory, gastrointestinal, urinary, and reproductive tracts.

What are the main components of innate immunity (second line of defense)?

Phagocytosis, inflammatory response, complement system, natural killer cells, and acute phase plasma proteins.

What are the three main types of phagocytes?

Polymorphonuclear Neutrophils, Macrophages, Dendritic Cells.

What triggers the inflammatory response?

The inflammatory response is triggered by tissue damage, leading to signs such as redness, heat, pain, swelling, and loss of function.

What is the role of cytokines in the immune response?

Cytokines are chemical messengers that help regulate immunity by influencing the functions of various immune cells.

What is the difference between MHC Class I and Class II molecules?

MHC Class I molecules present endogenous antigens to cytotoxic T cells, while Class II molecules present exogenous antigens primarily to helper T cells.

What is humoral immunity primarily responsible for?

Humoral immunity is responsible for fighting extracellular pathogens, such as viruses, bacteria, and fungi present in body fluids.

What triggers the activation of T cells?

T cells are activated when they encounter an antigen presented by MHC molecules on antigen presenting cells.

What are the six acute phase plasma proteins?

C-Reactive Protein (CRP), Haptoglobin, Fibrinogen, Alpha-1 Antitrypsin, Ceruloplasmin, Serum Amyloid A.

What characterizes cellular immunity?

Cellular immunity involves direct cell-to-cell interactions and is primarily mediated by T lymphocytes against intracellular pathogens.

What is the function of natural killer cells?

Natural killer cells are the first line of defense against virally infected cells and tumor cells, functioning without prior exposure to the target.

What happens during clonal expansion of lymphocytes?

When activated, B and T cells multiply and differentiate into clones, some of which become memory cells for quicker future responses.

What is the key feature of adaptive immunity?

Adaptive immunity is specific, recognizes and remembers pathogens, and has a lag period that decreases with subsequent exposures.

What are antigen presenting cells (APCs)?

APCs process and present antigens to T cells, including macrophages, dendritic cells, and B lymphocytes.

How do vaccines provide immunity?

Vaccines stimulate the adaptive immune system by inducing an active immune response, leading to memory cell formation against specific pathogens.