The Lymphatic And Immune System

C. interstitial fluid.

A. lymph nodes.

C. Protista

A. phagocytes

D. NK (natural killer) cells

lymph vessels/ lymphatics lymph lymph nodes

fluid in the tissues between cells

- Transports lymph and "junk" from the tissues back to the cardiovascular system. - Filters the lymph fluid in lymph nodes to destroy pathogens as part of the immune system. - Nourishes cells in the lymphatic system. (Transport fats from the small intestine)

- The lymphatic vessels provide a one-way system that carries lymph back toward the heart

- Lymph vessels (lymphatics) include the lymphatic capillaries, collecting vessels, (trunks,) and ducts.

- they are very permeable (take up cell debris, pathogens, and cancer cells) and - they have endothelial cells that overlap to form one-way minivalves, that are anchored by collagen filaments, to preventing their collapse

- have thinner walls, with more internal valves - anastomose [uh-nas-tuh-mohz] more frequently

the right upper arm and the right side of the head and thorax

the rest of the body

at the junction of the internal jugular and subclavian veins on its own side of the body

- the respiratory pump - the muscular pump

Lymphocytes

T and B cells

that manage the immune response AND attack and destroy foreign cells

that produce plasma cells which secrete antibodies

circulate for a few days in the blood. They then move to the tissues where they turn into...

Monocytes that move to the tissues that phagocytize foreign substances and help activate T cells

a type of connective tissue that is filled with reticular cells and fibers. It is filled with lymphoid cells.

- Provides a proliferation site for lymphocytes - Furnishes a surveillance vantage point. When foreign protein is picked up, it ends up in lymphatic tissue which can then defend the body against it.

filter lymph (macrophages then destroy microorganisms and debris) AND as part of the immune system, the lymphocytes are activated and mount a defensive attack

- Site of lymphocyte proliferation and immune surveillance and response - Cleanses the blood of aged cells and platelets and debris - Stores breakdown products of RBCs (e.g., iron) for later reuse - Stores blood platelets - Has a fibrous capsule and trabeculae (internal divisions) - Contains lymphocytes, macrophages, and huge numbers of erythrocytes

T (thymus) lymphocyte maturation

- Its size changes with age - Increases in size from infancy and is most active during childhood - Stops growing during adolescence and then gradually atrophies

- Simplest lymphoid organs - Form a ring of lymphatic tissue around the pharynx - Contain tonsillar crypts that trap and destroy bacteria and particulate matter. - Lymphoid cells are exposed to this material and protect us from it.

- are clusters of lymphoid follicles that are found in the wall of the distal portion of the small intestine - They destroy bacteria, and thereby prevent them from breaching the intestinal wall

Archaea Bacteria

Protista Plantae Fungi Animals

Bacteria Protista Fungi Animals

Protista (algae, slime molds, protozoans)

Plantae Fungi Animals

Plantae(Moss, ferns, conifers, flowering plants)

Fungi (yeast, Mushrooms)

Animals (sponges, worms, arthropods, vertebrates)

Prokaryote

Eukaryote

Viruses

Protozoal diseases

Fungal diseases

Animal diseases

Innate (nonspecific) defenses

surface barriers

internal cells and chemicals

Physical - Intact skin - keratin - Mucous membranes (with cilia)- on the - systems that open to the body's surface. Chemical - Enzymes - pH - Lysosomes in fluid secretions (tears, saliva, sweat, mucus with lysosomes) Biological - Native bacteria - "Good bugs"

- Necessary if microorganisms invade deeper tissues - Phagocytes - neutrophils and macrophages - Natural killer (NK) cells Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals) - Antimicrobial proteins (interferons and complement proteins) - Fever

NK cells are lymphocytes that kill virus-infected cells AND cancer cells.

They kill by secreting perforins to damage the cell membrane AND they cause apoptosis (programmed cell death.)

- chromatin condensation - nuclear fragmentation - chromosomal DNA fragmentation - blebbing (forming an irregular bulge in the plasma membrane) - cell shrinkage

- A cells that has a virus in it is dead. - Viral-infected cells are activated to secrete interferons (IFNs.) IFNs enter neighboring cells causing them to produce antiviral proteins that block viral reproduction

insert into bacterial membranes and form a pore that causes the cell to burst.

- Is specific - one specific cell will target one specific pathogen - Is systemic - Has memory - The system will also "remember" that it has encountered this pathogen before

An incomplete antigen (hapten) does not directly trigger an immune response, but does when it binds to proteins in the body. They cause hypersensitivities.

A complete antigen can trigger an immune response.

- Cells have proteins, polysaccharides, glycoproteins, and glycolipids on their surfaces. - These molecules act as antigens when they cause an immune response. - The body learns to recognize its own antigens as "self." MHC are "self" proteins. - Our body will attack cells with "non-self" antigens.

Antigenic determinants are the regions of the antigen that cause the immune system response.

(major histocompatibility complex) markers are self-antigens. These are cell surface proteins that act that the body "feels" and recognizes a cell as "self."

Bacteria and molecules in exteracellular enviroment

body cells infected by viruses abnormal or cancerous cells transplanted tissues

Bone marrow

Thymus Gland

Effector Cells Memory cells

Toxic 8 1 Cytotoxic --> CD8 --> MHC 1 Help 4 Z Helper Cells --> CD4 --> MHC 2

have not been exposed to their (non-self) antigen.

fight against the current pathogen.

"remember" the current pathogen for the next infection.

Immunocompetence and Self- Tolerance

they must be able to recognize and bind to a specific antigen

they must be unresponsive to self antigens

- engulf antigens - They then present fragments of antigens on their surface attached to MHC proteins so that they can be recognized by T cells

Macrophages B Cells

Uses lymphocytes, APCs, and specific molecules to identify and destroy nonself substances

- Recognize antigens by binding to them - Communicate with one another so that the whole system mounts a specific response

is the first encounter between an antigen and a naive immunocompetent lymphocyte.

It usually occurs in the spleen or a lymph node

- B cell is activated when antigens bind to its surface receptors and cross-link them - Receptor-mediated endocytosis of cross-linked antigen-receptor complexes occurs - Stimulated B cell grows to form a clone of identical cells bearing the same antigen-specific receptors (T cells are usually required to help B cells achieve full activation)

Lag period: three to six days Peak plasma antibodies: 10 days Antibody levels decline: after 10 days

Lag period: hours A Peak plasma antibodies: 2-3 days Antibody level decline: after weeks to months Antibodies bind with greater affinity

Immunological Memory -or- Fool me once, shame on you; fool me twice, shame on me.

acquired in the regular course of life due to exposure to a pathogen

acquired by man's means

memory cells are produced

antibodies are received

Proteins secreted by plasma cells (effector B cells) Capable of binding specifically with antigen detected by B cells

First antibody released - early infection Potent agglutinating agent Activates and fixes complement

In mucus and other secretions (saliva, sweat, intestinal fluids, milk) Helps prevent entry of pathogens

are self-antigens. These are cell surface proteins that act that the body "feels" and recognizes a cell as "self."

- Engulfing dying virus-infected or tumor cells - Importing antigens through temporary gap junctions with infected cells

Once primed by APC presentation of antigen, they Help activate T and B cells Induce T and B cell proliferation Activate macrophages and recruit other immune cells Without TH, there is no immune response

Directly attack and kill other cells Tc cell releases perforins and granzymes by exocytosis Perforins create pores through which granzymes enter the target cell Granzymes stimulate apoptosis

Virus-infected cells Cells with intracellular bacteria or parasites Cancer cells Foreign cells (transfusions or transplants)