What is the body's third line of defense

What is the function of third line of Defence in the body? The body has three lines of defense: i) Physical (skin and mucous membranes) and chemical barriers that prevent entry by pathogens, ii)Non- specific defensive cells (phagocytes, eosinophils, and natural killer cells) and proteins. Innate immunity essentially helps slow the progress of the. These are three lines of defense , the first being outer barriers like skin, the second being non-specific immune cells like macrophages and dendritic cells, and the third line of defense being the. There are two basic types of lymphocyte and both are made in bone marrow.

The third line of defence depends on lymphocytes.

One type, the T cells, mature after having first migrated from the bone marrow to the thymus gland. The other type, B cells, migrate to and then mature in either the bone marrow or in the foetal liver or spleen. This type of immunity is long lasting due to the production of memory cells. 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. Non-specific response-Includes phagocytosis of pathogen, inflammation of tissues, vasodilation (increased blood flow to area), and swelling. Specificity of 3rd Line of Defense. To protect the body against pathogens, the immune system relies on a multilevel network of physical barriers, immunologically active cells, and a variety of chemicals.

Host Defense: Lines of Defense.

First: Any barrier, Nonspecific. Second: Protective cells and fluids, inflammation and phagocytosis, Nonspecific. But sometimes, the first line of defense is not enough and our body must use its second line of defense. A type of white blood cells , called Phagocytes, are released.

It incorporates a specific response for each specific pathogen, resulting in adaptive immunity that is mediated by specialist Lymphocytes (cell mediated immunity) or antibodies (humoral immunity). The first and second lines of defense are physical barriers whereas the third line of defense is a chemical barrier The first and second lines of defense are cell-mediated but the third line of. The final defense : adaptive immune system. All this may not be enough to stop pathogen invasion.

In such case, the body mobilizes its third line of defense , so called adaptive immune system. Unlike innate immune cells, those adaptive do specialize for specific pathogens, by. The cells of the immune The cells of the immune system are able to distinguish between different kinds of pathogens. These responses react to the presence of any pathogen, regardless of which species it is.

White blood cells are involved in most of these responses. This line of defence is also non-specific. The immune cells involved in allergic reactions, especially in the lining of the nasal passages, causing sneezing and runny noses _______.

When a microbe invades the body , the immune system makes antibody against it. It is then a battle between the antigen ( intruder) against the antibody (immune system). Once the intruder has been destroyed , the immune response winds down.

REVIEW QUESTIONS – THE BODY’S DEFENSES 1. Describe the body’s first line of defense against pathogens. Complete the table to show the three different ways the body keeps out pathogens: How It Works Skin Breathing passages Mouth Stomach 3. The second line of defense in the body is called the _____. The immune system is closely tied to the lymphatic system, with B and T lymphocytes being found primarily within lymph. There are many cells and proteins that fight dangerous invaders in the nonspecific line of defense. When it gets to the third line of defense , antibodies are created which helps T and B cells target the enemy.

In the Three Lines of Defense model, management control is the fi rst line of. The skin, nails and hair form the integumentary system, which stops dirt and pathogens from entering the body. It involves non-specific responses to pathogens that have invaded the internal environment of the organism.