Natural History NICEA pt 1

What are the functions of the lymphatic system?

collects extra tissue fluid (plasma) and liquid in small intestine and returns it to circulation

mounts immune response.

How do lymphatic vessels work?

Overlapping cells act as one-way valves. Pumped through muscle and respiratory contraction.

What are the lymphatic organs?

Lymph nodes, tonsils (3 types), spleen, thymus,

What are the two kinds of immunity? What do they involve?

Innate immunity: fast, nonspecific, no memory.

Adaptive immunity: slower, specific, memory.

What is a pH extreme?

very acidic or very basic: kills bacteria and viruses.

What is an antigen?

An antigen is any molecule that can be specifically recognized as foreign.

Innate Immune system: 1st line of defense.

Skin: mechanical and chemical barrier (lysozyme).

Mucous Membranes: mechanical and chemical barrier.

Fluids: Chemical barrier. (tears, saliva, perspiration, snot)

Innate Immune System: 2nd line of Defense

Interferons: chemicals released by infected cells that warn other cells

Complement System: poke holes in bacteria

Phagocytes: eating cells (neutrophils and monocytes)

What is inflammation?

Tissue damage releases histamine, → vasodilation. allows antibodies to enter → clotting. phagocytes monch bacteria then die → pus

What is pus?

dead leukocytes.

What are some of the traits of ADAPTIVE immunity?

specifically directed against a particular invader, self-tolerant, B and T lymphocytes make and mount B or T receptors (antigen receptors)

Adaptive immunity respones?

Cell-mediated: Killer T Cells use chemicals to slaughter

Antibody-mediated: B Cells become plasma → produce antibodies (flag antigens for death)

What is an antibody?

An antibody is a y-shaped "eat me" protein-sticker, draws phagocytes in. Each antibody attaches to a different kind of antigen.

What is an MCH?

The molecular ID card

What is an ACP?

An ACP (antigen presenting cell) is a phagocyte that devours an invader and processes the antigen, then presents it to the T cells so that they can recognize it as an invader.

ACPs include B cells, dendritic cells, and macrophages.

How does the body trigger an adaptive response?

The body must first recognize a foreign antigen. B cells can detect antigens without processing or presenting ACPs. T cells, on the other hand, need processed and presented antigens through the work of ACPs.

When do T cells respond to an invasion?

Either an antigen-MHC complex or cytokines bind to them.

What do cytokines do?

Cytokines help activate killer T cells, help activate B cells to make antibodies, and attract and stimulate phagocytes.

What do killer T cells do?

Killer T cells produce chemicals that destroy microbes

What do memory T cells do?

Memory T cells are on stand-by for the same antigen

What do B cells do?

hang out in lymph nodes, bind and respond to matching antigens, become plasma cells, and secrete antibodies, retain some memory B cells

What are the functions of antibodies?

N: Neutralize antigens on each pathogen

I: Immobilize pathogens

C: Clump pathogens

E: Enhance phagocytes

A: Activates complements

What is primary response?

the first exposure to an antigen. slow, peaks at 7 to 10 days.

What is secondary response?

The second exposure to the same antigen. quick, peaks at 3 to 5 days

What is active immunity?

body's own response to antigens, including vaccines.

What is passive immunity?

Borrowed immunity, including immunity via placenta, breastfeeding, and booster injections of antibodies.

What is the difference between antigen receptors and antibodies?

antigen-receptors are tethered to a cell membrane, an antibody is free-floating

What is a fever?

Interleukin inhibits pathogen growth, and stimulates interferon and body repair