Lymphatic System

By Jenna Hanson and

Rachel Gaddis

Word Bank:

tonsils

spleen

thymuslymph node

Lymph vessels

What is the lymphatic system? The lymphatic system is a collection of cells and biochemicals that

travel in lymphatic vessels, and the organs and glands that produce them.

The lymphatic system is also known as the immune system.

What does the lymphatic system do?

Transports fluidsCarries away excess fluid from interstitial spacesDestroys foreign particles (Immunities)Destroys toxins and cancerous cells

Lymphocytes Type of white blood cell (leukocyte) Two types: T-cells and B-cells Determines immune response

*Lymphocytes must be activated in order to respond to antigens!*

T and B cells

Lymph Nodes Contain large numbers of lymphocytes and macrophages that fight invading

organisms Vary in diameter from 1/25 to 1 inch Located along lymphatic vessels Approximately 500-700 lymph nodes in the adult human body

Lymphatic PathwaysPrevent backflow of lymphBegin as lymphatic capillariesTurn into larger lymphatic vessels

Spleen(Superior abdomen, Upper left quadrant)

Functions of the spleen

Filters blood (immune system)Helps to fight certain kinds of bacteriaRecycles red blood cells

Thymus(Thoracic Cavity, between lungs, connects w/ trachea)

Functions of the thymus

Transform lymphocytes into T-cellsT-cells in the thymus help to fight disease and infection

*The thymus grows less functional with age and is eventually replaced almost entirely by adipose (fat) tissue*

Lymph Movement

Body DefensesInnate (nonspecific)

Species resistant: the development of diseases unique to that organism.Mechanical barriers: Prevent entry of infectious agents, in areas such as the

respiratory, urinary and reproductive systems (Skin and mucus membranes, and sweat).

Chemical barriers: Enzymes in body fluid that provide the barrier to the pathogens. Lymphocytes produce hormone like peptides called interferons. (Viruses/ tumor cells).

Fever: the raise in temperature cause the spleen and liver to take away iron in the blood which is needed for bacteria/fungi as the temp rises.

Inflammation: blood flow to region of infection increases to isolate and destroy the infection, however this is painful

Body defenses cont.Adaptive (Specific)/ Immunity

Antigens: Usually located on cells surface; with the help of lymphocytes detect foreign antigens.

Lymphocyte Origins: During fetal development, release lymphocytes into the circulation with later turn to T and B cells.

Types of antibodies Immunoglobulin G (IgG): in plasma and tissue fluids, effective against

bacteria, viruses and toxins.Immunoglobulin A (IgA): Found in exocrine gland secretions (breast

milk, tears, nasal fluid, gastric juices, intestinal juice, bile and urine).Immunoglobulin M (IgM): Develops in blood plasma in response to

contact with certain antigens in food or bacteria. Immunoglobulin D (IgD): Found on surface of most B cells. Important

in activating B cells. Immunoglobulin E (IgE): Found in exocrine secretions. Associated with

allergic reactions.

Immune ResponsesPrimary response:

Cells release antibodies (IgM, then IgG)Antibodies are then transported to blood and throughout body

Secondary response:Following a PR, B cells produce a ‘memory’ cell.More vigorous of a response than PR.

Autoimmune responsesSometimes, the immune system accidentally produces

autoantibodies, T cells that attack and damage tissues and organs.The condition of cells attacking oneself is called autoimmunity

Common auto immune disordersType 1 DiabetesRheumatoid arthritisLupus

Allergic ReactionsAllergic responses are immune attacks against a non-harmful substanceAllergic reactions can vary from inflammation and fever to the closing

of the throat, resulting in inability to breathe.

Common allergens:PeanutsGrassDairy (Lactose intolerance)Shellfish

DiseasesMultiple Sclerosis (MS):

Causes pain, blindness, weakness, poor coordination, and muscle spasmsImmune system destroys myelin sheaths in neurons, damaging nerve tissueCan be suppressed but no treatment

AIDS: Acquired Immune Deficiency Syndrome. Virus that weakens the immune systemFinal stage of HIVOften Flu like symptomsLife-threateningTransmitted through sexual intercourse, contaminated needles, birth and receiving

infected blood (transfusion)No treatment