Anatomy Lymph Notes

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)...