Med-Surg Assignment 
Name: Ezenwosu Adaobi Pamela 
Matric no:17/mhs07/010
Department:Nursing 
Level:300

1)Explain the role of the immune system?
The role of the immune system is to protect our body from any foreign matters that might cause any damage or homeostatis imbalance. The success of the immune system depends on its ability to discriminate between foreign(non self) and host(self) cells.

2)Describe the two types of immunity .
A) Innate Immunity
Plants and animals have what is called innate immunity. Innate immunity is the first line of defense against pathogens. Innate immunity refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. It involves several cell types, proteins, and even an organ. The organ involved is your skin.It protects you and prevents pathogens from getting inside your body. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body. The innate immune response is activated by chemical properties of the antigen
B) Adaptive immunity
Adaptive immunity refers to antigen-specific immune response. The adaptive immune response is more complex than the innate. The antigen first must be processed and recognized. Once an antigen has been recognized, the adaptive immune system creates an army of immune cells specifically designed to attack that antigen. Adaptive immunity also includes a "memory" that makes future responses against a specific antigen more efficient. Adaptive immunity works slower than innate, and is more specific. There are two types: passive and active.
—Passive immunity occurs when antibodies are passed from one person to another, as through transfusion for example.
 —Active immunity involves two types of white blood cells - T-cells and B-cells. Dendritic cells, after they have eaten and digested the pathogen, present the pathogen pieces to T-cells, which activates (turns on) the T-cells.

3)Explain the different types of antibodies and their roles.
a)IgG is the antibody isotype that most people think of when they're talking about antibodies. It is the antibody that is built by immunization. It activates an immune cascade that can eliminate some forms of infection. IgG can also neutralize certain toxins.

b)IgA is the antibody isotype that is found in usually mucosal areas, such as the mouth and the vagina. It can also be found in saliva, tears, and breast milk. IgA is formed by two Ig subunits bound together. When IgA binds to a target, it can stimulate inflammation. In mucosal areas, IgA can also keep pathogens from sticking to epithelial cells.The production of IgA against inappropriate targets is associated with certain autoimmune diseases, such as celiac disease.
	•	c)IgM is one of the first types of antibody to be produced after a pathogen has entered the body.Since it is made up of five Ig subunits bound together, it has very high avidity. In other words, it sticks very strongly to its target. IgM is very important in the early stages of an infection. IgM sometimes appears when an infection becomes reactivated, such as with a herpes outbreak. It can also appear when someone is reexposed to a disease they've previously gotten rid of.
	•	d)IgE is the antibody that is responsible for the allergic response.It is mostly found in the lungs, skin, and mucous membranes. When IgE binds to an allergen, it starts the histamine reaction. It's the histamine reaction that causes the symptoms of an allergy attack. This single subunit antibody also helps to protect the body from parasitic worms.
	•	e)IgD is important in the early stages of the immune response. Bound to B cells, it does not circulate.Instead, it signals those cells to become active. This can help to stimulate inflammation. IgD is the least understood type of antibody, and its functions are still being discovered.