Innate Immune system Flashcards
Non-specific (Innate)
Cells
-Phagocytes
-Inflammatory cells
-Cytotoxic cells
Physical barriers
-Skin
-Mucus membranes
Chemical mediators
-cytokines
-lysosomes
-Interferon
-The complement system
Physical barriers - define
Physical barriers prevent entry of pathogens
Physical barriers - individual example (3)
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 .
Physical barriers - Respiratory system
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.
Physical barriers - digestive system
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.
Cells (theyre all white blood cells btw) - phagocytes
Phagocytes: recognise and kill microbes by phagocytosis. Include
neutrophils and macrophages
Cells - Cytotoxic
Cytotoxic cells: recognise and kill infected body cells. Natural Killer cells (NK
cells)
Complement system
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
Cells - Inflammatory
Inflammatory cells: Release chemicals that recruit phagocytes, antibody- secreting cells, and cytotoxic cells to the infected area. Include mast cells and basophils.
Inflammation
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.
Role of cytokines in immune response
Cytokines are the chief communication signals of your T cells.
Cytokines include interleukins, growth factors, and interferons
Role of lymphocytes
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.
Role of interferon
Interferons are naturally occurring cytokines that may boost the
immune system’s ability to recognize cancer as a foreign invader
Phagocytes
Phagocytes are a type of immune cell that can surround and kill microorganisms, ingest foreign material, and remove dead cells.
Natural Killer Cells
Natural Killer Cells are white blood cells that destroy infected cells and cancer cells in your body
