What Are The Body Defences Against Disease?

What are the body’s three defenses?

The Immune System has 3 Lines of Defense Against Foreign Pathogens:Physical and Chemical Barriers (Innate Immunity)Nonspecific Resistance (Innate Immunity)Specific Resistance (Acquired Immunity).

What are the 4 phases of the immune response?

This can be broken down into four stages: the lag, exponential, steady state, and declining phases. This is the time from initial antigen exposure to when antibodies are detected in the blood, and takes about a week. In this time, specialized B and T cells are activated by contact with the antigen.

How do humans defend themselves against disease?

In general, your body fights disease by keeping things out of your body that are foreign. Your primary defense against pathogenic germs are physical barriers like your skin. You also produce pathogen-destroying chemicals, like lysozyme, found on parts of your body without skin, including your tears and mucus membranes.

What are skin Defences?

Skin. The skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier.

What is the first line of defense?

The first line of defence (or outside defence system) includes physical and chemical barriers that are always ready and prepared to defend the body from infection. These include your skin, tears, mucus, cilia, stomach acid, urine flow, ‘friendly’ bacteria and white blood cells called neutrophils.

What does interferon mean?

Interferons (IFNs, /ˌɪntərˈfɪərɒn/) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses.

What chemical Defences does the body have against pathogens?

Chemical barriers against infection include enzymes in tears, saliva and mucus that break down the surface of bacteria. The acid in sweat and in the stomach kills cellular pathogens and there are anti-bacterial proteins in semen (the fluid that contains male sperm).

What are non specific Defences of the human body?

Some nonspecific defenses exist independently of infection (e.g., genetic factors, anatomic barriers, nonspecific inhibitors in body fluids, and phagocytosis). Others (e.g., fever, inflammation, and interferon) are produced by the host in response to infection.

What is the 1st 2nd and 3rd line of defense?

The first line of defense are the physical and chemical barriers, which are considered functions of innate immunity. … The third line of defense is specific resistance, which is considered a function of acquired immunity.

How do tears act as barriers?

To stop eye infections we have evolved chemicals within our tears called lysozymes . These are enzymes that destroy bacterial cells by breaking down their cell walls. Lysozymes are found in saliva, breast milk and mucus, as well as in tears.

What is an example of a specific immune response?

Specific immunity, also known as adaptive immunity, is specialized immunity for particular pathogens. Helper T-cells, cytotoxic T-cells, and B-cells are involved in specific immunity. The non-specific cells, like macrophages, tell the T- and B-cells that an intruder is present.