Download Lymphatic System

Lymphatic System
Instructions: Read chapter 13 (pp. 254-271). While you are
reading, please complete the graphic organizer. This will serve
to help you summarize the key points of this system.
Functions:
1. Fluid Balance: pulls fluid from tissues into lymph capillaries to
avoid edema.
2.Fat Absorption – taken care of by the lymph capillaries
embedded in the intestines (fats and fat soluble vitamins)
3.Defense – WBC’s (Lymphocytes and Macrophages)
Primary Organs and their Roles:
Red Bone Marrow- in the epiphysis of long bones; area where
hemopoesis occurs and where B cells differentiate.
Thymus Gland- within the thoracic cavity; superior to the heart;
bi-lobed gland responsible for the differentiation of T cells –
also produces thymus hormones that help T cells mature. This
gland shrinks as you get older which may be why you are more
prone to disease as you age.
Secondary Organs and their Roles:
Lymphatic Vessels- contain lymph (fluid) to combat edema –
vessels and capillaries – capillaries have simple squamous -these
vessels can assist tumors in metastasis
Lymph Nodes-swollen areas of vessels contain T, B cells and
macrophages.
Spleen-located near stomach – two areas red and white pulp –
full of macrophages and lymphocytes which react to pathogens
in the blood and help to clean out old red blood cells.
Lymphatic Nodules-tonsils, peyers patches, and appendix –
concentrated area of lymph tissue.
Defense:
Nonspecific
Briefly describe the Barriers to Entry and their link to this
system.
Mechanical barriers like mucous membranes in the respiratory
system, digestive system etc block pathogens. Oil glands in the
integument block bacteria colonization and the acid pH of the
stomach kills pathogens that may enter on consumed food.
Describe the Inflammatory Reaction.
Symptoms are redness, heat, swelling, and pain. White blood
(Basophils) cells release histamine causing blood vessels to
dilate becoming permeable to fluids. Increased blood flow
results in red, warm skin. Dilated capillaries cause proteins and
fluid to enter tissues causing swelling. Swollen tissues push on
nerves resulting in pain.
Neutrophils and Monocytes (monocyte = Macrophages) are
stimulated to come to the inflamed area and phagocytose the
bacteria and dead tissue due to the trauma.
Natural Killer Cells
Lymphocytes that kill virus-infected cells and tumor cells by cell
to cell contact. May also be cells involved in the aging process –
may be involved in apoptosis (programmed cell death).
Specific Response to Antigens (Lock and Key systems)
B-cells and Antibody Immunity
B lymphocytes give rise to plasma cells that create antibodies
for specific antigens. The body has the ability to recognize its
own cells and distinguish it from trespassers. Antibodies are
proteins shaped like the antigen receptor and capable of
combining with and neutralizing specific antigens on the surfaces
of cells.
T-cells and Cell Immunity
Lymphocytes are capable of recognizing an antigen because
they have antigen receptors which are plasma membrane
proteins that combine with a specific antigen. In this way they
can target and connect to invader cells.
Induced Immunity
Define: occurs naturally through infection or is brought about
artificially through medical intervention.
Active Immunity Body creates its own antibodies in response to
antigens of invading cells. Vaccines induce this process.
Passive Immunity Individual given prepared antibodies. It is a
temporary immunity. (Breastfeeding)
Aging and the Lymphatic System
Disappearing Thymus Gland
B cells don’t form clones
Response to vaccines not as good
Questions:
1. Describe how the lymphatic system helps maintain
homeostasis in the respiratory and cardiovascular systems.
Respiratory: Non-specific defenses like mucous membranes
and cilia which trap debris and move it out of the system.
Tonsils sit superior to the respiratory passages to trap any
inhaled or ingested pathogens. Leukocytes actively create
antibodies for any inhaled pathogens which will help fight
infection. Inflammatory responses help maintain homeostasis
of the sinuses during respiratory illnesses and allergies.
Cardiovascular: Leukocytes in the blood stream identify the
foreign antigens and actively create antibodies to attack such
antigen. Histamine produced by Basophils increases
capillary permeability to allow for inflammatory responses.
Blood is moved to sites that need it due to infection.
2. Discuss how allergies, tissue rejection and auto immune
diseases result.
An allergy is a hypersensitivity to substances that normally
do not elicit a response from the body. An immediate allergic
reaction is when the body creates an inflammatory response
to the foreign antigen on the allergen (pollen).
Tissue rejection occurs because the body does not
recognize the antigens on the transplant tissue and the Tcells target the tissue killing it.
Autoimmune disease is when antibodies from a body attack
its own cells. It is unknown what causes these. Auto immune
diseases are often found in multiples in people that exhibit
them. There isn’t a cure, but many can be controlled with
drugs.
3. Describe what happens to a person who has an
autoimmune disease.
Their antibodies attack the bodies own cells as in Diabetes
where the cells in the Islets of Langerhans are destroyed by
the T-cells causing Insulin to not be made by the body.