Ch. 43 Ap Biology

The immune system is made up of several types of cells that work together to fight infections. Lymph cells (called lymphocytes) are the main type of cell in the adaptive immune system. There are 2 types of lymph cells: T cells and B cells. When B cells respond to an infection, they change into plasma cells. The plasma cells are found mainly in the bone marrow—the soft, inner part of some bones. The plasma cells

11. Define the following: Genetic drift: unpredictable fluctuations in allele frequencies, reduces genetic variation over time through such losses of alleles

An antigen is anything in the body the is non self which could include bacteria, viruses, chemicals or abnormal cell growth.

The immune system depends on the body’s structures to help it function. For instance, the skin acts as the “body’s first line of defense.” If a pathogen finds a breach in the skin barrier, it is the circulatory system that must now signal the immune system of the invader. Shortly after, white blood cells will be notified of the infection and will target and destroy the pathogen.

One defence mechanism of the human body is that when a person gets ill or is infected the person will get a fever, this is a method of notifying the person. This is a bodily defence mechanism produced by the immune system, its main purpose is to make it difficult for the virus to multiply prepare for the virus. The body’s pH level will also change to make it less optimal for the virus. The immune system’s mechanism will change depending on the body’s condition. If the body gets cut the immune system will causes inflammation, this will cause red blood cells to come to the

The body’s protection against viruses, bacteria and other types of invasions is our immune system (Tortora, 2014).

They are harmless variant or derivative of a pathogen that stimulates a host’s immune system to mount defenses against the pathogen

a. This function is mediated by T cells and B cells (memory cells) in our body via adaptive immunity. The adaptive immune system evolved in early vertebrates and allows for a stronger immune response as well as immunological memory, where each pathogen is “remembered” by a signature antigen. The adaptive immune response is antigen-specific and requires the recognition of specific “non-self” antigens during a process called antigen presentation. Antigen specificity allows for the generation of responses that are tailored to specific pathogens or pathogen-infected cells. The ability to mount these tailored responses is maintained in the body by memory cells. Should a pathogen infect the body more than once, these specific memory cells are used to quickly eliminate it. So basically killer T cells will identify antigens present on foreign cells. These antigens are not found in any of the cells inside our body. Therefore, T cells will identify them and kill them.

The immune system consists of a defense system that guards the body against invasion from infections and other diseases. Normally, a healthy person's immune system has the capability to differentiate between its own cells and cells that represent threats to the health of the body. (Craft and Kanter, 2002). Autoimmune disease refers to a broad range of over 80 acute, long-lasting diseases that affect nearly every organ in the body. (Wrong Diagnosis.com, 2000).

Active-Natural immunity happens when a person is exposed to a live pathogen, such as chicken pox, develops that disease, and the body creates an immune response to that specific pathogen. Active immunity is often called acquired immunity.

Innate immunity refers to nonspecific defence mechanisms that respond to an antigen's presence in the host 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.

The body has two immune systems: the innate immune system and the adaptive immune system.

This is called an immune response. Vaccination is an attempt to manipulate the immune system to provide protection from disease caused by a pathogen without subjecting the person to the actual disease. The cowpox virus was sufficiently similar to the smallpox virus that if an individual were exposed to cowpox, the person would develop antibodies that would subsequently attack and disable the smallpox virus. This basic principle discovered by Jenner over two hundred and fifty years ago is used today to develop the dozens of vaccines we take for granted.

Normally the body is protected by the immune system. When the immune system detects an unwelcome visitor such as fungi, bacteria and or viruses

If a pathogen breaches barriers: innate immune response result into an immediate effect of non- specific response. All Innate immune systems derived from plants and animals, when a pathogen evades the innate response, a third layer of protection is possessed by vertebrates in which activation of adaptive immune system takes place. The immune system response adopts itself within an infection and pathogen recognition is improved. As a result of the improved response, its then retains itself when the pathogen is eliminated in form of an immunological memory and allows the adaptive immune system to mount faster and stronger when pathogen is encountered each time.