Lymphatic and Immune System
Lymphatic and Immune System
Anatomy of the Lymphatic System
are vessels that carry lymph from throughout the body towards the heart. Lymph Vessels resemble veins because they both have three vessel tunics and have valves to stop back flow.
small, round encapsulated structures that are located along the pathway of lymph vessels. Their function is to monitor for and remove unwanted substances.
, mucous associated lymphatic tissue, it is located in the GI, respiratory, urinary and reproductive tracts and aids in the defense against foreign substances that come into contact with the mucosal membranes found in the organs of these systems
is located inferior to the diaphragm in the left upper quadrant of the abdomen and functions in monitoring the blood for bacteria and other possibly harmful substances (this is done by white pulp) and then eliminating these substances via phagocytosis (this is done by red pulp).
is a bilobed organ that is located anterior to the heart and functions in the maturation of T Lymphocyte cells. This organ shrinks and holds almost no function after puberty.
The lymphatic system lacks a pump and instead relies on smooth muscle contractions to move lymph towards the heart
Innate Body Defenses
provides a physical, chemical and biological barrier of body structures that are exposed to the external environment.
is a thick secretion that helps trap microbes and also contains antimicrobial substances.
Nonspecific internal defenses
are the chief phagocytic cells, these cells wander throughout a region searching for cellular debris
Natural Killer Cells
can lyse and kill a wide variety of harmful cells. They kill target cells by releasing cytolitic chemicals that will also kill uninfected cells
are molecules that stimulates neighboring cells to activate genes for PKR to block viral reproduction in the neighboring cells. They also help activate macrophages and mobilize natural killer cells.
proteins provide a major mechanism for destroying foreign substances in the body by amplifying the inflammatory response and killing bacteria and some other cell types
is triggered whenever body tissues are damaged, it is used to prevent the spread of damaging agents and disposes of cell debris. The four signs of inflammation are
redness, heat, swelling and pain
is a surge of fluids into a tissue space to help dilute the harmful substances and to bring large quantities of oxygen and nutrients to that area
is an abnormally high body temperature in response to invading microorganisms. Moderate fever can be beneficial because it raises you metabolic rate.
) provides a physical, chemical and biological barrier for the bodies surface.
secrete sebum creating a slightly acidic skin pH that interferes with the growth of microbes.
Sweat Gland Secretion
help to wash away microbes and also contain antibacterial and antifungal substances
Saliva and Lacrimal Fluid
contain lysozyme, and enzyme that lyse bacteria.
Adaptive Immune Defenses
, developed response
, humoral response, is antibody mediated immunity are created and mature in the bone marrow. If stimulated the B cells begin to clone rapidly.
secrete specific antibodies at a very fast rate, these antibodies are used to mark antigens on foreign material for destruction by either an innate or adaptive defense mechanism.
are clonal B cells that did not differentiate into plasma cells that can activate an immediate immune response to future exposures of the the same antigen.
Active Humoral Immunity
is when B-Cells encounter antigens and produce antibodies against them, this can be
through a bacterial or viral infection or
Passive Humoral Immunity
is a short term immunity in which B cells are not challenged by antigens and immunological memory does not occur, this can be
from the mother to her fetus or
through injection of serum.
, cellular response are created in the bone marrow and mature in the thymus under negative and positive selection pressures.
Negative selection eliminates the T cells that are strongly anti-self
Positive selection selects t cells with weak response to self-antigens, which then become immunocompetent and self-tolerant.
T cells are activated by soluble proteins secreted by macrophages and dendritic cells. Once activated the T cells release chemicals that increase mobilization of dendritic cells and production of macrophages
Helper T cells
function mainly in coordinating the immune response and help both cell-mediated and humoral- mediated immune response
Cytotoxic T Cells
release chemicals that destroy cells.
engulf foreign particles and present fragments of antigens embedded on their own surfaces to be recognized by T and B cells. Major APCs are dendritic cells!
Antigens and Antibodies
are substances that can mobilize the immune system to start an immune response. Most immune responses target large molecules that are nonself, or not usually found in the body.
are able to stimulate proliferation of specific lymphocyte and antibody production and are able to react with products of activated lymphocytes. These can include foreign protein, nucleic acids, some lipids and large polysaccharides.
are small molecules, like peptides, nucleotides and hormones that lack the immunogenic property of complete proteins but are still reactive when liked up with body's proteins. They are "incomplete antigens".
are self proteins that are found on our cells, they are not antigenic to us but are to others.
Class I MHC
are found on all body cells.
Class II MHC
are found on cells involved in immune response
, also called immunoglobulins, are produced by plasma cell, a clonal B-cell, they bind to free antigens on foreign material and mark the antigens for destruction.
-the antibodies bind and block specific sites on the virus to prevent these antigens from binding to receptors cells
- the antibodies bind to more than one cellular antigen making them clump together
the antibodies cross link soluble molecules to form larger insoluble complexes