What are 5 different natural defenses of the body?

Answer 1

Five natural defenses used by the body are:

The Skin: The skin is the body's first line of defense and includes the mucus membranes and enzymes/acids found on the surface. The skin acts as a barrier and prevents most pathogens from entering the body.

Mucus membrane: Found in lungs and nasal passages, the mucus membrane along along with the hair lined in the nasal cavity helps to collect debris that has entered the respiratory system.

Acids and Enzymes: Highly corrosive hydrochloric acid found in the stomach along with enzymes in the digestive tract destroys microorganisms that enter the digestive system.

Inflammation: This is the second line of defense. When the wound allows pathogens to pass through the first line of defense, the body will isolate the infected area by shrinking the capillaries in that area in one side so that the blood flowing can flush the region. This causes edema, or redness in that area, and the inflamed area can push on pain receptors, which can cause pain. On some occasions, it can also cause fevers to prevent reproduction of the pathogens. The area will be cleaned to a lymph node where phagocytes can take care of the pathogens.

Cell-mediated immunity: The third and last line of defense, there are several white blood cells that contribute to this defense.

The B cells come in two varieties, one type produces antibodies to neutralize microbes in the bloodstream so that the phagocytes can destroy them. The other, known as memory B cells, help to remember the pathogen in case the same one attacks. This type of immunity is known as specific immunity because only certain antibodies can attach to a certain microbe.

The T cells first need to mature within the thymus, where it grows to be an effective lymphocyte. There are several types of T cells, but the main ones are helper T cells, memory T cells, and cytotoxic T cells. The memory T cells, like memory B cells, helps to identify the pathogen in case of a second infection. The helper T cells activate B cells and macrophages for faster immune response. The cytotoxic is non-specific and destroys any pathogens that it comes across.