Submitted by: Submitted by simplieme94
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Category: Science and Technology
Date Submitted: 11/06/2012 06:50 AM
Lymphatic System:
1. Function:
a. Defend against pathogens-bacteria, viruses
b. Transport Fluids
c. Absorb Fats
2. Pathway: Lymph is fluid from a tissue
a. One way system
b. Only flows toward heart
c. Flows from high to low pressure
d. Pump-less
e. Propelled by breathing and muscle contractions
f. Through lymphatic: capillaries-vessels-nodes-trunks-collecting ducts-subclavian vein
3. Lymphatic organs:
a. Lymph nodes-kidney shaped masses of lymphatic tissue.
Lymph moves very slowly to allow time for protection,
Macrophages-eat bacteria, viruses, cancer cells
Lymphocytes-respond to foreign substances- like pollen and bacteria
i. B- lymphocytes-release antibodies
ii. T- lymphocytes
b. Spleen-largest lymphatic organ, found below diaphragm in upper left abdominal cavity, contains white and red blood cells
c. Thymus gland-located between throat and heart and decreases in size with age
d. Tonsils, by pharynx and function to trap bacteria
e. Pyers Patches- found on wall of small intestine and function to catch bacteria
f. Appendix-macrophages remove a few pathogens, vestigial in humans
4. Defense against infection: presence of a pathogen
a. Nonspecific reactions-
i. mechanical barriers like skin, mucous membranes-first line of defense
ii. Chemical barriers-2nd line of defense-enzymes in tears have an antibacterial function, enzymes in the stomach have a low pH, salt from perspiration
b. Interferons-purpose to kill virus or tumor cells
c. Fever-high fever causes iron depletion which kills bacteria; pyrogens increase with fever and increase metabolic rates
d. Inflammation-pus formation and clotting inhibit pathogens
e. Complement- includes 20 plasma proteins that circulate in the blood when they attach to a foreign object they produce MAC (membrane attack complexes)...