Immunity Overview and Responses

A helper T cell activates the B cell.

B cells produce plasma cells that produce antibodies and memory cells for future responses.

Eater cells preferentially engulf intruders that are marked with antibodies.

<p>Natural immunity is the non-specific defense mechanism that helps the body resist infections through pre-existing functions.</p> Signup and view all the answers

<p>Memory cells facilitate a faster and more effective immune response upon re-invasion by the same intruder.</p> Signup and view all the answers

<p>Properdin enhances bactericidal and virucidal effects in the presence of C3 and magnesium.</p> Signup and view all the answers

<p>Phagocytosis is initiated by physical contact between the phagocytic cell and the microorganism due to tissue damage or microbial multiplication.</p> Signup and view all the answers

<p>Chemotaxis refers to the directed movement of the phagocytic cell towards the site of infection, surrounding the microorganism.</p> Signup and view all the answers

<p>Complement receptors and laminin receptors are involved in the adherence phase of phagocytosis.</p> Signup and view all the answers

<p>The rapid release of reactive oxygen species is triggered by the presence of pathogens or tissue damage.</p> Signup and view all the answers

<p>Natural killer cells serve as the first line of defense against tumor cells and virus-infected cells.</p> Signup and view all the answers

<p>The markers characteristic of natural killer cells are CD 16 and CD 56.</p> Signup and view all the answers

<p>Dendritic cells are efficient antigen-presenting cells that act as a bridge between innate and acquired immunity.</p> Signup and view all the answers

<p>Interleukin 2 aids in the lysis of tumor cells by activating lymphokine-activated killer cells.</p> Signup and view all the answers

<p>Pathogen-associated molecular patterns (PAMPs) are recognized by pattern-recognition receptors (PRRs) on innate immune cells.</p> Signup and view all the answers

<p>Natural killer cells comprise about 10 to 15% of the lymphocyte population.</p> Signup and view all the answers

<p>Antibody-dependent cytotoxic cells specifically kill cancer cells and can lyse antibody-coated target cells.</p> Signup and view all the answers

<p>Lymphokine-activated killer cells initiate acquired immune responses while also participating in phagocytosis.</p> Signup and view all the answers

<p>The formation of a phagolysosome involves the fusion of cytoplasmic granules with the membrane of the phagosome, allowing the contents to be emptied into this space.</p> Signup and view all the answers

<p>Chemotaxis directs phagocytes to move toward areas of injury or infection in response to chemical stimuli called chemotaxins.</p> Signup and view all the answers

<p>In Job's syndrome, phagocytes have normal random activity but show abnormal chemotactic activity, while in Lazy leukocyte syndrome, both random and chemotactic activities of phagocytes are abnormal.</p> Signup and view all the answers

<p>Exocytosis is the process by which the contents of the phagolysosome are expelled from the cell to the exterior environment.</p> Signup and view all the answers

<p>Chemotaxins stimulate the movement of neutrophils and other white blood cells to the injured area, facilitating an immune response.</p> Signup and view all the answers

<p>Active immunity involves the individual's own immune system generating antibodies after exposure to an antigen, while passive immunity involves the transfer of pre-formed antibodies from another host.</p> Signup and view all the answers

<p>Natural immunity is non-specific, provided by external and internal components without memory, whereas acquired immunity is specific and involves the generation of memory after repeated infections.</p> Signup and view all the answers

<p>An advantage of active immunity is long-term resistance, while a disadvantage is the requirement for prolonged and repeated exposure to an antigen.</p> Signup and view all the answers

<p>T lymphocytes are involved in cell-mediated immunity, while B lymphocytes produce antibodies, which provide humoral immunity.</p> Signup and view all the answers

<p>Colostrum is significant as it provides newborns with antibodies that offer immediate protection against infections before their own immune system develops.</p> Signup and view all the answers

<p>Diapedesis is the process where white blood cells emigrate from capillaries to tissues. It is crucial for the immune response as it allows WBCs to reach sites of infection or injury.</p> Signup and view all the answers

<p>Positive chemokines attract white blood cells towards the source of stimulation, while negative chemokines repel them away. This differentiation guides immune cell movement appropriately during immune responses.</p> Signup and view all the answers

<p>Opsonins enhance phagocytosis by coating particles to make them more recognizable to phagocytic cells. This increases the efficiency of the immune response against foreign invaders.</p> Signup and view all the answers

<p>The phagolysosome is where phagocytes fuse engulfed particles with hydrolytic enzymes for digestion. This compartment is crucial for breaking down pathogens and preventing infections.</p> Signup and view all the answers

<p>Integrins enhance cell-to-cell interactions and are essential for the adhesion of immune cells during inflammation. They facilitate the recruitment of leukocytes to sites of injury.</p> Signup and view all the answers

<p>Neutrophils are the main cells present during the acute phase, mobilized by chemotaxins to mitigate infection. They perform initial phagocytosis and recruitment of additional immune cells.</p> Signup and view all the answers

<p>Factors that enhance phagocytosis include opsonins, integrins, and complement proteins like C3b. These elements make pathogens easier targets for phagocytes.</p> Signup and view all the answers

<p>The signs of inflammation include rubor (redness), tumor (swelling), calor (heat), dolor (pain), and functio laesa (loss of function). Each indicates the body's reaction to injury.</p> Signup and view all the answers

<p>Acute inflammation is characterized by the rapid influx of neutrophils, while chronic inflammation features a prolonged presence of monocytes/macrophages. Chronic inflammation often leads to pus formation.</p> Signup and view all the answers

<p>Cytopepsis refers to the active amoeboid motion used by phagocytes during engulfment. It is essential for the effective capture and digestion of pathogens.</p> Signup and view all the answers

<p>Nitric oxide, produced by activated macrophages, is toxic to microorganisms and helps kill pathogens during the immune response. It plays a part in the inflammatory process.</p> Signup and view all the answers

<p>A granuloma is formed by the accumulation of T-cells and macrophages typically due to delayed hypersensitivity reactions. It represents a chronic inflammatory response to persistent antigens.</p> Signup and view all the answers

<p>C3b is considered the most potent opsonin because it enhances the interaction between phagocytic cells and antibody-coated particles, facilitating effective engulfment of pathogens.</p> Signup and view all the answers

<p>Tissue repair involves fibroblast proliferation to replace damaged cells, leading to complete or partial restoration of function. In healing, fibrinogen also helps form a clot.</p> Signup and view all the answers