Innate Immune system

Cells -Phagocytes -Inflammatory cells -Cytotoxic cells Physical barriers -Skin -Mucus membranes Chemical mediators -cytokines -lysosomes -Interferon -The complement system

Physical barriers prevent entry of pathogens

Skin - closely packed cells = barrier, skin contains sebaceous and sweat glands that secrete compounds which inhibit growth of microorganisms. Eyes - glands in the eyes produce tears removing and inhibiting growth of microorganisms Blood - contains platelets that clot the blood when a wound occurs stopping pathogens from entering .

The nose, trachea, and bronchi are lined with mucous membranes. The mucus traps pathogens and prevents growth Cilia in the respiratory tract sweep out mucus and the trapped microorganisms. Then forced out by coughing or sneezing.

Saliva contains digestive enzymes that destroy or inhibit the growth of pathogens. The stomach contains digestive enzymes, and hydrochloric acid. Bacteria naturally present in the intestinal tract, help prevent colonization by pathogens.

Phagocytes: recognise and kill microbes by phagocytosis. Include neutrophils and macrophages

Cytotoxic cells: recognise and kill infected body cells. Natural Killer cells (NK cells)

The complement system consists of more than 30 different proteins found in the blood. They function by attracting and supporting the white blood cells at the site of infections Some complement proteins destroy cell membranes and cell walls of pathogens

Inflammatory cells: Release chemicals that recruit phagocytes, antibody- secreting cells, and cytotoxic cells to the infected area. Include mast cells and basophils.

Reaction when a tissue is injured and infected by a pathogen. Histamine is released by damaged cells, and inflammatory cells this results in increased blood flow to the damaged tissue, increased permeability of the capillaries to white blood cells Also signals phagocytes and cytotoxic cells to the site of infection. The increased blood flow to the area causes swelling and redness.

Cytokines are the chief communication signals of your T cells. Cytokines include interleukins, growth factors, and interferons

Lymphocytes, including both T-cells and B-cells, secrete cytokines. Many of these cytokines are also known as interleukins because they serve as a messenger between white cells, or leukocytes.

Interferons are naturally occurring cytokines that may boost the immune system’s ability to recognize cancer as a foreign invader

Phagocytes are a type of immune cell that can surround and kill microorganisms, ingest foreign material, and remove dead cells.

Natural Killer Cells are white blood cells that destroy infected cells and cancer cells in your body