LYMPH/IMMUNE SYSTEM HONORS A&P

Lymph

Clear fluid that circulates through the lymphatic system carrying immune cells and waste products

Lymphatic vessels

Network of vessels that transport lymph throughout the body

Lymph nodes

Small bean shaped structures that filter lymph and house immune cells

Lymphatic capillaries

Tiny vessels that collect interstitial fluid and begin lymph flow

Lacteals

Specialized lymphatic capillaries in the small intestine that absorb dietary fats

Interstitial fluid

Fluid surrounding body cells that can enter lymphatic capillaries

Edema

Swelling caused by excess accumulation of interstitial fluid in tissues

Tonsils

Lymphatic tissue in the throat that helps trap and destroy pathogens entering through the mouth or nose

Thymus

Organ where T cells mature and become functional

Spleen

Organ that filters blood removes old red blood cells and helps fight infection

Bone marrow

Soft tissue inside bones where blood cells including immune cells are produced

Peyer’s patches

Clusters of lymphatic tissue in the small intestine that monitor intestinal bacteria

Appendix

Lymphatic organ that contributes to immune function and stores beneficial bacteria

Immunity

Ability of the body to resist infection and disease

Pathogen

Disease causing organism such as bacteria viruses or fungi

Antigen

Substance that triggers an immune response

Antibody

Protein produced by B cells that specifically binds to antigens

Immune response

Body’s defense reaction to foreign substances or pathogens

Innate immunity

Nonspecific defense present at birth that responds quickly to pathogens

Physical barriers

Structures like skin and mucous membranes that block pathogen entry

Chemical barriers

Substances like stomach acid and enzymes that destroy pathogens

Phagocytes

Cells that engulf and digest pathogens and debris

Macrophages

Large phagocytes that engulf pathogens and present antigens to other immune cells

Neutrophils

Most abundant white blood cells that quickly respond to infection by engulfing pathogens

Natural killer NK cells

Immune cells that destroy infected or abnormal cells

Inflammation

Local response to injury or infection causing redness heat swelling and pain

Fever

Rise in body temperature that helps fight infection

Adaptive immunity

Specific defense that develops over time and targets particular pathogens

Lymphocytes

White blood cells involved in adaptive immunity including B cells and T cells

B cells B lymphocytes

Cells that produce antibodies against specific antigens

T cells T lymphocytes

Cells that attack infected cells or help regulate immune responses

Helper T cells CD4 cells

T cells that activate other immune cells and coordinate the immune response

Cytotoxic T cells CD8 cells

T cells that directly kill infected or cancerous cells

Regulatory T cells

T cells that suppress immune responses to maintain balance and prevent autoimmunity

Memory T cells

Long lived T cells that respond quickly upon re exposure to a pathogen

Plasma cells

Activated B cells that produce large amounts of antibodies

Memory B cells

Long lived B cells that provide faster response upon future exposure to an antigen

Humoral immunity

Immunity involving antibodies circulating in body fluids

Antigen presentation

Process by which immune cells display antigens to activate T cells

Clonal selection

Process where specific lymphocytes are activated and multiply in response to an antigen

Primary immune response

Initial response to a pathogen that is slower and less intense

Secondary immune response

Faster stronger response upon second exposure to the same pathogen

Complement system

Group of proteins that enhance immune responses by destroying pathogens

Autoimmune disease

Disorder in which the immune system attacks the body’s own cells

Allergy

Overreaction of the immune system to a harmless substance

Immunodeficiency

Condition where the immune system is weakened or absent

HIV Human Immunodeficiency Virus

Virus that attacks helper T cells and weakens the immune system

AIDS Acquired Immunodeficiency Syndrome

Advanced stage of HIV infection with severe immune damage

Active immunity

Immunity developed through exposure to an antigen leading to memory cell formation

Passive immunity

Immunity gained through transfer of antibodies from another source

Vaccination

Administration of a weakened or inactive pathogen to stimulate immune memory

Herd immunity

Protection of a population when a large portion is immune reducing disease spread

Functions of the lymphatic system

Produce maintain and distribute lymphocytes and return fluid and solutes from tissues to the bloodstream

Peripheral tissues

Body tissues near the exterior such as skin and mucous membranes exposed to pathogens

Virus

Infectious particle that enters cells hijacks their machinery and replicates causing cell destruction

Interferon

Chemical released by infected cells that interferes with viral replication in other cells

Histamines

Chemicals released by injured cells that trigger inflammation and increase blood flow

Pyrogens

Substances that cause fever by acting on the hypothalamus

Phagocytic immune response

Defense involving cells that engulf and destroy pathogens

Cell mediated immune system

Immune response involving T cells that directly attack infected cells

Self vs nonself recognition

Ability of immune cells to distinguish between body cells and foreign cells

Self tolerance

Mechanism that prevents the immune system from attacking its own cells

Major Histocompatibility Complex MHC

Cell surface proteins that help immune system recognize foreign substances

Class I MHC

Molecules on all nucleated cells that present antigens to cytotoxic T cells

Class II MHC

Molecules on immune cells that present antigens to helper T cells

Cytokines

Chemical signals released by immune cells to communicate and activate responses

Interleukin 1 IL 1

Cytokine that activates helper T cells

Interleukin 2 IL 2

Cytokine that stimulates growth of B cells and cytotoxic T cells

Perforin

Protein released by cytotoxic T cells that forms pores in infected cells causing lysis

Monocytes

White blood cells that develop into macrophages

Eosinophils

White blood cells that attack large parasites

Mast cells

Cells that release histamine during inflammation

Chemokines

Chemical signals that attract immune cells to sites of infection

Vasodilation

Widening of blood vessels during inflammation to increase blood flow

Clotting response

Process that prevents spread of infection and begins tissue repair

Effector cells

Short lived immune cells that actively fight pathogens

Epitope

Specific part of an antigen recognized by an antibody

Antigen binding site

Region of antibody that attaches to a specific antigen

Neutralization

Antibodies block harmful effects of pathogens

Agglutination

Clumping of antigens to enhance destruction

Precipitation

Process where soluble antigens are cross linked and settle out

Complement fixation

Activation of complement proteins leading to pathogen destruction

Natural active immunity

Immunity developed after exposure to disease causing antigen

Artificial active immunity

Immunity developed through vaccination

Natural passive immunity

Immunity transferred from mother to fetus through placenta

Artificial passive immunity

Immunity gained through injection of antibodies from another source

Placenta

Organ through which maternal antibodies are transferred to the fetus

Thymus endocrine role

Gland responsible for T cell maturation especially important early in life