KEY CONCEPT The immune system has many responses to pathogens and foreign cells.

Many body systems work to produce nonspecific responses. Nonspecific responses are the same for every pathogen. Inflammation = Nonspecific response white blood cells move toward infection and damaged tissue capillary wall extracellular space white blood cell characterized by swelling, redness, and pain

In fever, body temperature increases. Macrophages release chemicals that signal the hypothalamus to increase the body’s temperature. Low fevers stimulate the production of interferons. Protein that prevents viruses from reproducing. Increase activity of white blood cells by increasing the rate at which they mature. High fevers (above 103) - Hypothalamus can no longer regulate body temp. can cause seizure, brain damage, and even death.

Cells of the immune system produce specific responses. Specific immune defenses = cellular level Our bodies must be able to detect healthy cells and foreign/infected cells. Specific immune responses begin with the detection of antigens. Antigens are surface proteins on pathogens. Each pathogen has a different antigen. virus antigens

There are two specific immune responses. Cellular immunity uses T cells to destroy infected body cells. pathogen antigens T cell receptors activated T cells memory T cells

There are two specific immune responses. Humoral immunity uses B cells to produce antibodies. B cell T cell pathogen memory B cells activated B cells antibodies

Both responses produce memory cells. B cell T cell specialized T and B cells provide acquired (active) immunity

The immune system rejects foreign tissues. Tissue rejection occurs in organ or tissue transplants. Tissue rejection is the result of an immune response. immune system detects protein markers on the donor tissue makes antibodies against the donor’s tissue