Five Infectious Agents
Single-celled organisms with a cell membrane and cytoplasm but no organized nucleus. Bind to the cells of a host organism to obtain food and support.
Substances that destroy or inhibit microorganisms, tiny living bodies invisible to the naked eye. (Antibiotic means "destructive to life")
Toxin that is secreted by bacteria during their growth.
Molecules in the walls of certain gram-negative bacteria that are released when the bacterium dies or is detroyed, causing toxic effects on body.
The systemic spread of toxins through the blood stream. (Sepsis)
An organism much smaller than bacteria. Viruses invade and live inside cells of the organism they infect. Can lie dormant for long periods of time.
Include yeasts and molds. Rarely cause human disease other than minor skin infections.
Range in sinze from single celled to large intestinal worms.
Similiar to viruses. Smaller and entirely made of proteins.
- -Anatomic Barriers- External, non-specific
- -Inflammatory Response- Internal, non-specific
- -Immune Response- Internal, specific
- -Transient (no memory)
- -Multiple protein systems
- -Multiple cell types
- -Long-term (memory)
- -One plasma protein (immunoglobulin)
- -One cell type (lymphocytes)
A marker on the surface of a cell that identifies it as self or non-self.
A substance produces by B lymphocytes in response to the prescence of a foreign antigen that combines with or detroys the antigen thus preventing infection.
A long-term condition of protection from infection or disease.
- Natural vs Acquired
- -Natural: Inborn protection against infection or disease that is part of the person's or species' genetic makeup
- -Acquired: Protection developed after exposure to an antigen. Transferred to the person from an outside source such as from the mother through placenta or breast-feeding.
- Primary vs. Secondary
- -Primary: The initial development of antibodies in response to the first exposure to an antigen in which the immune system becomes "primed" to produce faster, stronger respones to future exposures.
- -Secondary: The fast, strong response of the immune system to a repeated exposure to an antigen.
- Humoral vs. Cell-Mediated
- -Humoral: The long term immunity provided by antibodies created by B lymphocytes
- -Cell-Mediated: Short-term immunity to an antigen proided by T lymphocytes which directly attack the antigen but do not produce antibodies or memory.
Antibodies. Proteins produced in response to foreign antigens that destroy or control the antigens.
A type of leukocyte (white blood cell) that attacks foreign substances as part of the body's immune response. B and T lymphocytes.
The type of leukocyte that produces antibodies to attack an antigen. Develop a memory for the antigen and cause a fast response in future exposures. Involved in Humoral Immunity.
The type of leukocyte that does no produce antibodies but directly attacks to antigen.
Antigens which trigger an immune response. (Non-self)
Requirements to cause an immune response
- -Sufficient foreignness of antigen
- -Sufficient size of antigen
- -Sufficient complexity of antigen
- -Sufficient amounts of antigen
Molecules that do not trigger an immune response on their own but can become immogenic when combined with larger molecules.
Antigens the body recognizes as self or non-self. These are the ones that determine the response.
Major Histocompatibility Complex (MHC)
A group of genoes on chromosome 6 that provide the genetic code for HLA antigens.
Rh Blood Group
A group of antigens on the red blood cells. Rh positive or Rh negative.
An antigen in the Rh blood group that is also known as antigen D. 85 percent Rh+. 15 percent Rh-. Rh+ blood and Rh- blood are incompatible.
ABO Blood Groups
Four blood types formed by the prescence of two antigens known as A and B. Can be type A, B, AB or O (neither A or B).
Undifferentiated cells in the bone marrow from which all blood cells, including thrombocytes, erythrocytes and types of lekocytes develop.
The development by B lymphocytes the ability to recognize every possible antigen.
The process by which a specific antigen reacts with the approproiate receptors on the surface of immatures B lymphocytes activating them and prompting them to divide and create antibodies.
Cells produced by mature B lymphocytes that remember antigens and trigger a strong, fast immune respones on the second exposure.
Three effects of antibodies on antigens
- Agglutination: A soluble antibody combines with a solid antigen, causing it to clump together.
- Precipitation: The antigen-antibody complex precipitates out of the body and is carried away by body fluids.
- Neutralization: The antibody, in combining with the antigen, inactivates the antigen by preventing it from binding to receptors on the surface of body cells.
Two indirect effects of antibodies on antigens
- Enhancement of Phagocytosis: Phagocytosis is one of the chief processes of inflammation in which certain types of white blood cells ingest and digest foreign substances. The actions of antibodies can encourage phagocytosis.
- Activation of Plasma Proteins: Antibodies can activate plasma proteins of the complement system that, in turn, attack and destroy antigens.
Four Functions of Antibodies
- -Neutralization of bacterial toxins
- -Neutralization of viruses
- -Opsonization of bacteria (coats bacteria with Opsonin)
- -Activation of inflammatory processes
Classes of Immunoglobulins
- IgM: Antibody produced first during the primary immune response. Largest immunoglobulin
- IgG: Antibody which has memory and recognizes repeat invasions of an antigen. 80-85% of immunoglobulins in the blood. Has four subclasses.
- IgA: The antibody present in mucous membranes. Also present in blood. Involved in secretory immune responses.
- IgE: Least concentrated immunoglobulin. Principle antibody in anaphylactic and allergic reaction. Also principle in fighting off parasites.
- IgD: Antibody present in very low concentrations.Little is known about it. Present on the surface of B cells.
Human Antibody Classifications
- Isotypic: Same in all organisms of the same species
- Allotypic: Differ between members of the same species
- Idiopathic: Differ within same individual. (Same type, different functions)
An antibody which is very pure and specific to a single antigen.
Secretory Immune System
Lymphoid tissues beneath the mucosal endothelium the secrete sweat, tears, saliva, mucus and breast milk. AKA external immune system.
An allergic response that takes place after the elapse of some time following reexposure to an antigen.
Five Types of Mature T cells
- Memory Cells: Induce secondary immune response.
- Td Cells: Transfer delayed hypersensitivity. Secrete proteins called lymphokines that activate other cells such as macrophages.
- Tc Cells: Cytotoxic (Poisonous to cells) cells that directly attack an destroy cells that bear foreign antigens.
- Th Cells: Helper cells that ficilitate both cell-mediated and humoral immune responses. (control)
- Ts Cells: Suppressor cells that inhibit both cell-mediated and humoral immune processes. (control)
Proteins, produced by T cells that cegulate immune responses by binding with and affecting the function of the cells that produced them or of other nearby cells.
A cytokine released by a macrohage.
A cytokine released by a lymphocyte.
The recognition, ingestion, and breakdown of a foreign antigen composed of antibody and cytotoxic responses.
Antigen Presenting Cells (APCs)
Cells, such as macrophages, that express on their surface parts of the antigens they have digested. This helps activate killer T cells.
T cell receptor
A molecule on the surface of a helper cell that responds to a specific antigen. There is a specific TCR for every antigen which the human body may be exposed to.
Inflammation is a swift and nonspecific attack on cellular injury caused by disease or injury.
Phases of Inflammation
- Phase 1: Acute inflammation- healing
- Phase 2: Chronic inflammation- healing
- Phase 3: Granuloma forming- healing
- Phase 4: Healing
Four Functions of Inflammation
- -Destroy and remove unwanted substances
- -Wall off the infected and inflamed area
- -Stimulate the immune response
- -Promote healing
Large cells resembling bags of granules that reside near blood vessels. When activated by injury, chemical agents or immunological processes they activate immune response by:
- -degranulation (emptying their granules into the extracellular environment)
- -synthesis (construction of leukotrienes and prostaglandins)
A substance released during degranulation of mast cells and also by basophils. It constricts and dilates blood vessels increasing flow of blood to the injury site. Also increases the permiability of the vessel walls.
Released by platelets. Vasodilates and vasoconstricts to increase blood flow to injury site.
Chemicals that attract white cells to the site of inflammation. Called chemotaxis
Also called slow reacting substances of anaphylaxis (SRS-A). Synthesized by mast cells during inflammatory response that cause vasodilation, vascular permiability and chemotaxis.
Substances synthesized by mast cells during inflammatory response that cause vasodilation, vascular permiability and chemostaxis. Also cause pain.
Plasma Protein Systems
Complex sequences of actions triggered by proteins present in the blood. Three plasma protein systems involved in inflammation are the complement system, coagulation system, and the kinin system.
Plasma Protein Responses
- Immune: Immunoglobulins
- Inflmmation: Complement, Coagulation and Kinin
A series of actions triggered by a first action culminating in a final action. Typical in plasma protein response
A group of plasma proteins that are dormant in the blood until activated as by antigen-antibody complex formation. Involved in most events of inflammatory response. Has 11 proteins number C1-C9 plus factors B and D.
A plasma protein system, also called the clotting system, that results in formation of a protein called fibrin. Fibrin forms a network that walls off an infection and forms a clot that stops bleeding and serves as a foundation for repair and healing of a wound.
A plasma protein system which produces bradykinin, a substance which works with prostaglandins to cause pain. Also has actions similiar to Histamine such as vasodilation and bronchospasm. Slower than Histamine to react. More important in later stages of inflammation.
Any substances which penetrates the vessel walls into the surrounding tissue to help in the healing processes.
Adherence of white blood cells to vessel walls in the early stages of inflammation.
Movement of the white cells out of the blood vessels through gaps in vessel walls created during inflammatory response.
White cells with multiple nuclei and have the appearance of granule bags. Types are neutrophils, eosinophils and basophils.
White cells with a single nucleus. Largest normal blood cell. During inflammation monocytes mature and grow to several times their size becoming macrophages.
Cells that have the ability to ingest other cells and substances such as bacteria and cell debris. All granulocytes and monocytes are phagocytes.
Granular white blood cells (most numerous of the white blood cells) that are readily attracted to the site of inflammation where they quickly attack and phagocytose bacteria and other bad substances.
Large white blood cells that will ingest, destroy or partially destroy invading organisms.
Granular white glood cells that attack parasites and also help to control and limit the inflammatory response.
Granular white clood cells that similarly to mast cells, release Histamine and other chemicals that control constriction and dilation of blood vessels during inflammation.
Fragments of cytoplasm that circulate in the blood and work with compnents of the coagulation system to promote blood clotting. Platelets also release serotonin, a vasoconstrictive substance.
Chronic Inflammatory Response
More than two weeks of acute inflamation.
Cells that secrete collagen. A critical factor in wound healing.
A liquid mixture of dead cells, bits of dead tissue and tissue fluid that may accumulate in inflamed areas.
A tumor or growth that forms when foreign bodies that cannot be destroyed by macrophages are surrounded and walled off.
Outcomes of Healing
- -Resolution: Complete restoration of normal structure
- -Repair: Scar formation
The complete healing of a wound and return of tissues to their normal structure and function. The ending of inflammation with no scar formation.
Healing of a wound with scar formation
Regrowth through cell proliferation.
The cleaning up or removal of debris, dead cells, and scabs from a wound, principally through phagocytosis.
Simple healing of a minor wound with out granulation of pus formation
Complex healing of a larger wound involving sealing of the wound through scab formation, granulation or filling of the would and constriction of the wound.
Filling of a wound by the inward growth of healthy tissues from the wound edges.
Growth of epithelial cells under a scab seperating it from the wound and providing a protective covering for the healing wound.
Inward movement of wound edged during healing that eventually brings the wound edges together.
Continuing processes of wound reconstruction that may occur over a period of years after initial healing, as scar tissue is remodeled and stregthened.
When healing does not go well. Can occur in inflammation and reconstruction
An exaggerated and harmful immune response. An umbrella term for allergy, autoimmunity and isoimmunity.
Three types of hypersensitivity
- Allergy: An exaggerated immune response to an environmental antigen such as pollen or bee venom.
- Autoimmunity: A disturbance in the body's normal tolerance for self antigens. As in hyperthyroidism or rheumatic fever
- Isoimmunity: An immune reaction between members of the same species, commonly of one person against the antigens of another person, as in the reaction of a mother to her infant's Rh negative factor or in transplant reactions
Immediate Hypersensitivity Reactions
A swiftly occuring secondary hypersensitivity reaction. Immediate hypersensitivity reactions are usually more severe than delayed ones. Anaphylaxis.
Delayed Hypersensitivity Reaction
A hypersensitivity reaction that takes place after the elapse of some time follow reexposure to an antigen. Delayed reactions are usually less severe than immediate.
Four Types of Hypersensitivity Reactions
- Type 1: IgE reactions. Typical anaphylactic reaction cause.
- Type 2: Tissue-Specific.
- Type 3: Immune complex mediated reactions
- Type 4: Cell-mediated reactions
Three Hypersensitive Targets
- -Environment Antigens-Allergic responses
- -Self antigens- Targeted by autoimmune responses
- -Other person's antigens- Targeted by isoimmune responses
Two types of immune deficiency
- Congenital: inborn
- Acquired: after birth
Acquired immunodeficiency syndrom. A group of signs, symptoms and disorders that often develop as a consequence of HIV infection.
Human immunodeficiency virus. A virus that breaks down the immune defenses making the body vulnerable to a variety of infections and disorders.
A state of physical or psychological arousal to stimulus.
The stimulus or cause of stress.
General Adaptation Syndrome
- A sequence of stress response stages:
- -Stage 1: Alarm-Sympathetic nervous system is aroused and mobilized. (fight or flight). Pupils dilate, heart rate increases, brochial passages dilate. Glucouse levels rise, digestion slows, blood pressure rises and the flow of blood to the skeletal muscles increases. Endocrine system aroused releasing adrenaline.
- -Stage 2: Resistance or Adaptation- Person begins to cope with the situation. Things come back down to normal. Most times the last stage of stress.
- -Stage 3: Exhaustion- This is the stage sometimes known as burnout. Person can no longer cope with stress. Can cause physical illness.
A chemical or physical disturbance in the cells or tissue fluid produced by a change in the external environment or within the body.
Dynamic Steady State
Homeostasis. The tendency of the body to maintain a net constant composition although the components of the body's internal environment are always changing.
The continual synthesis and breakdown of body substances that results in the dynamic steady state.
The interactions of psychological, neurological/endocrine and immunological factors that contribute to the alteration of the immune system as an outcome of a stress response that is not quickly resolved.
Changes within the body initiated by a stressor.
Hormones produced in a stress response
- -Catecholamines- Norepinephrine and epinephrine
- -Beta endorphins
- -Growth hormone
A steroid hormone released by the adrenal cortex that regulates the metabolism of fats, carbohydrates, sodium, potassium and proteins. Also has an anti-inflammatory effect.