The complement system in microorganisms

What Are the Components of the Immune System? The human immune system is a very complex system build up of numerous functional parts. To understand how the immune system works it is essential to know the functional parts and their rolle in the system therefore we will list you the functional parts and what rolle they play in the immune system.

The complement system in microorganisms

Physical and Chemical Barriers Innate Immunity 2.

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Nonspecific Resistance Innate Immunity 3. Specific Resistance Acquired Immunity Physical and Chemical Barriers Innate Immunity Physical and chemical barriers form the first line of defense when the body is invaded.

Physical Barriers The skin has thick layer of dead cells in the epidermis which provides a physical barrier. Periodic shedding of the epidermis removes microbes. The mucous membranes produce mucus that trap microbes. Hair within the nose filters air containing microbes, dust, pollutants Cilia lines the upper respiratory tract traps and propels inhaled debris to throat Urine flushes microbes out of the urethra Defecation and vomiting -expel microorganisms.

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Chemical Barriers Lysozyme, an enzyme produced in tears, perspiration, and saliva can break down cell walls and thus acts as an antibiotic kills bacteria Gastric juice in the stomach destroys bacteria and most toxins because the gastric juice is highly acidic pH Saliva dilutes the number of microorganisms and washes the teeth and mouth Acidity on skin inhibit bacterial growth Sebum unsaturated fatty acids provides a protective film on the skin and inhibits growth Hyaluronic acid is a gelatinous substance that slows the spread of noxious agents Nonspecific Resistance Innate Immunity The second line of defense is nonspecific resistance that destroys invaders in a generalized way without targeting specific individuals: Phagocytic cells ingest and destroy all microbes that pass into body tissues.

For example macrophages are cells derived from monocytes a type of white blood cell. Macrophages leave the bloodstream and enter body tissues to patrol for pathogens.

When the macrophage encounters a microbe, this is what happens: The microbe attaches to the phagocyte. The vesicle merges with a lysosome, which contains digestive enzymes. The digestive enzymes begin to break down the microbe.

The phagocyte uses any nutrients it can and leaves the rest as indigestible material and antigenic fragments within the vesicle. The phagocyte makes protein markers, and they enter the vesicle. The indigestible material is removed by exocytosis. The antigenic fragments bind to the protein marker and are displayed on the plasma membrane surface.

The macrophage then secretes interleukin-1 which activates the T cells to secrete interleukin 2, as described below under specific resistance. Inflammation is a localized tissue response that occurs when your tissues are damaged and in response to other stimuli.

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Inflammation brings more white blood cells to the site where the microbes have invaded. The inflammatory response produces swelling, redness, heat, pain Fever inhibits bacterial growth and increases the rate of tissue repair during an infection.

Specific Resistance Acquired Immunity The third line of defense is specific resistance. This system relies on antigens, which are specific substances found in foreign microbes.

Most antigens are proteins that serve as the stimulus to produce an immune response. Here are the steps in an immune response: When an antigen is detected by a macrophage as describe above under phagocytosisthis causes the T-cells to become activated.

The activation of T-cells by a specific antigen is called cell-mediated immunity. The body contains millions of different T-cells, each able to respond to one specific antigen. The T-cells secrete interleukin 2. Interleukin 2 causes the proliferation of certain cytotoxic T cells and B cells.

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From here, the immune response follows 2 paths: Cytotoxic T Cell Pathway The cytotoxic T cells are capable of recognizing antigens on the surface of infected body cells.

The cytotoxic T cells bind to the infected cells and secrete cytotoxins that induce apoptosis cell suicide in the infected cell and perforins that cause perforations in the infected cells.

Both of these mechanisms destroys the pathogen in the infected body cell. Click here for an animation on cytotoxic T cells. The animation is followed by practice questions. Click here for even more practice questions.

Activation of a helper T cell and its roles in immunity: T Cell Pathway T-cells can either directly destroy the microbes or use chemical secretions to destroy them.

The complement system in microorganisms

At the same time, T cells stimulate B cells to divide, forming plasma cells that are able to produce antibodies and memory B cells. If the same antigen enters the body later, the memory B cells divide to make more plasma cells and memory cells that can protect against future attacks by the same antigen.

When the T cells activate stimulate the B cells to divide into plasma cells, this is called antibody-mediated immunity.The immune system is a host defense system comprising many biological structures and processes within an organism that protects against function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy many species, the immune system .

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The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's cell is part of the innate immune system, which is not adaptable and does not change over the .

Immune System (March ). Introduction. Fluid Systems of the Body. The Blood System. The Lymph System. Innate Immunity. Surface Barriers or Mucosal Immunity. Complement tests, most commonly C3 and C4, are used to determine whether deficiencies or abnormalities in the complement system are causing, or contributing to, a person's disease or condition.

Complement CH50 is a blood test that helps us determine whether protein abnormalities and deficiencies in the complement system are responsible for any increase in autoimmune activity.

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