Immune System Flashcards
The Skin
physical barrier of dead skin. It contains chemicals (acids and oils) that inhibit the growth of micro-organism
immune system
- Body’s first line of defense against intruders.
- It consists of several nonspecific obstacles to infections
Sweat, saliva and tear
all contain lysozomes which are enzymes that attack the cell wall of bacteria
Stomach’s gastric juices
kill most bacteria swallowed with food
cilia
hair like projections on cells lining the respiratory system that filter incoming air cells
Nonspecific defensive cells
neutrophils, monocytes, macrophages, natural killer cells
Antimicrobial proteins
attack microorganisms directly or impede reproduction. They include interferons and complement. They also include histamine-proteins which causes blood vessels to dilate thus allowing blood and phagocytes (white blood cells) to enter the infected area
The inflammatory response
there is an increase in the temperature of the infected area. This is caused by a group of proteins called pyroproteins. An increase in temperature impedes the reproduction of the micro-organisms. The inflammatory response can be localized or systemic (this produces a fever)
Immune system
recognizes and defends against specific kinds of invasive microbes and cancer cell
Antigen-
a molecule that elicits an immune response
Pathogens
a disease causing agent (include viruses, bacteria, fungi, protozoa and parasitic worms.)
Antibody
a plasma protein that attaches to one particular kinds of antigen and helps counter its effects
Portal of exit
vehicle by which a pathogen leaves the body of an infected host
Portal of entry
vehicle by which a pathogen enters the body of an un-infected host
Infective dosage
the concentration of pathogen needed to cause an infection
Lymphocytes
white blood cells –2 types: •B lymphocytes •T lymphocytes (3 types) –T-helper –T-killer –T-suppressor
Immune response
- Macrophage engulfs the pathogens and displays the pathogen’s antigenic determinants on its surface.
- This stimulates the productions of T helper cells.
- T-helper cells begin to secrete the protein, lymphokines
HUMORAL IMMUNITY
As the levels of lymphokines increase, this activates the productions of B cells and T killer cells.
•The B cells begin to secrete antibodies which are specific for the pathogen. These antibodies will neutralize free floating pathogen.
CELL-MEDIATED IMMUNITY
T killer cells begin to destroy infected cells
As a result of this process, there are B and T memory cells circulating in the blood stream which will cause a quicker response if you are infected with the same pathogen.
•Immunological failures cause several diseases
Autoimmune diseases
results when the immune system turns against the body’s own molecules
–Example: insulin-dependent diabetes, rheumatoid arthritis, systemic lupus, and multiple sclerosis
Immunodeficiency diseases
diseases that are caused by the lack of one or more of the components of the immune system. As a result, the individual are susceptible to infections that would ordinarily not cause a problem
–Example: SCID (severe combined immunodeficiency-where both T and B cell are absence or inactive.
AIDS
acquired immune deficiency syndrome-where the T helper cells are destroyed
Allergies
abnormal sensitivities to antigen. They can range from seasonal problems to severe, life threatening responses (anaphylactic shock)
Immunity
mmunity-resistance to specific invaders
•Two types of immunity
–Activity immunity-when an antigen enters the body naturally or artificially, the body is stimulated to produce antibodies in its own defense
Passive immunity
antibodies are made somewhere else and are injected or passed to another individual.
Specific immune response
This is activated only when the nonspecific defense mechanisms have failed.
