Lymphatic system part 2

many layers provides a formidable physical barrier to the entrance of microbes.  In addition  periodic shedding of the epidural cells helps remove microbes at the skin surface

the epithelial layer of these which line body cavities, secretes fluids called mucous that lubricates and moistens the cavity surface. Mucous traps many microbes and foreign substances

the mucous membrane of the nose have these which trap and filter microbes, dust and pollutants from inhaled air

the mucous membrane of the upper respiratory tract contains these.  The waving action of these propels inhaled dust and microbes that have become trapped in mucous toward the throat

of the eyes manufactures and drains away tears in response to irritants

contained in tears is an enzyme capable of breaking down the cell walls of certain bacteria.  It is also present in saliva, perspiration, nasal secretions and tissue fluids

washes microbes from the surface of the teeth and from the mucous membrane of the mouth, much as the tears wash the eyes.

cleansing of the urethra, retards microbial colonization of the urinary system

sebaceous oil glands of the skin secrete this, that forms a protective film over the surface of the skin.  The unsaturated fatty acids inhibit the growth of certain pathogenic bacteria and fungi

helps flush microbes from the surface of the skin

produced by glands of the stomach, is a mixture of hydrochloric acid, enzymes and mucous.  The strong acidity destroys many bacteria and most bacterial toxins

second line of defence. These proteins produced by infected lymphocytes, macrophages and fibroblasts. Once released by virus infected cells these diffuse to uninfected neighbouring cells where they induce synthesis of antiviral proteins that interfere with viral replication

a second line of defence. a group of normally inactive proteins in blood plasma and on plasma membranes makes up this system.  When activated these proteins enhance certain immune reactions.  It causes cytolysis (bursting) of microbes, promotes phagocytosis and contributes to inflammation

5-10% of lymphocytes in the blood are these.  they lack the membrane molecules that identify B and T cells, but they have the ability to kill a wide variety of infected body cells and certain tumour cells.  They attack any body cells that display abnormal or unusual plasma membrane proteins

the binding of Natural killer cells to a target cell causes the release of granules containing toxic substances.  Some granules contain this protein.  It inserts into the plasma membrane of the target cell and creates channels in the membrane as a result extracellular fluid flows into the target cell and the cell bursts

specialized cells that ingest microbes or other particles such as cellular debris

types of phagocytes. when an infection occur these travel to the infected area.

a chemically stimulated movement of phagocytes to a site of damage

attachment of the phagocyte to the microbe or foreign material

the plasma membrane of the phagocyte extends projections that engulf the microbe

the phagosome enters the cytoplasm and merges with lysosomes to form a single larger structure

the chemical onslaught provided by lysozyme, digestive enzymes, and oxidants within a phagolysosome quickly kills many types of microbes