Unit 13 - lymphatic system

- lymph nodes along the vessel network cleanse lymph as it passes through them (contain T & B lymphocytes that clean)

- one way network of lymphatic vessels (which collect 10% of the extracellular fluid the leaked out from cardriovascular capillaries and returns this fluid (called lymph) to venous blood)

- its a fluid found outside of cells

- blood plasma (5% body weight), fluid in blood, sometimes leave capillaries to form ISF

- ISF (interstitial fluid, 15% body weight) fluid between cells within the body (except blood cells, that's plasma between), some moves into lymphatic capillaries to form lymph

- lymph (1% body weight), fluid inside lymphatic vessels, returned to blood plasma

- intracellular fluid (found within cells, 40% of body weight)

lymphatic capillaries -> lymphatic collecting vessels (with valves) -> lymphatic ducts -> subclavian veins

- lymph enters lymphatic capillaries (closed ended vessels that project into cardiovascular capillary beds)

- lymphatic capillaries in the small intestine also play a role in fat absorption

- lymphatic capillaries connect to larger lymphatic collecting vessels that have one-way valves

- lymph nodes along collecting vessels filter lymph for bacteria & debris

- transports lymph fluid away from tissues towards either:

right lymphatic duct or thoracic duct

- lymph from right side of the head, chest and arm

- drains into right subclavian vein to re-enter blood circulation

- lymph from below the ribs and the entire left side of body

- collecting vessels from below the ribs converge to an enlarged lymph vessel (cisterna chyli, most inferior portion of thoracic duct)

- thoracic duct drains into the left subclavian vein to re-enter blood circulation

- fluid flows through lymphatic collecting vessels mostly because of body movements that move fluid towards the heart

- one-way valves in the collecting vessels prevent back flow of blood

- contain many lymphocytes and play a key role in the body's immune system

- primary lymphoid organs and tissues (mature lymphocytes leave here and move into the blood to migrate towards secondary)

- secondary lymphoid organs and tissues

- locations where lymphoid stem cells divide and mature (become immunocompetent) which includes:

- red bone marrow: all lymphocyte stem cells arise here, site of B lymphocyte proliferation (mitosis) maturation

- thymus gland (early in dev (fetal stage) lymphocyte stem cells migrate here, site of T lymphocyte proliferation (mitosis) maturation

- where lymphocytes detect and remove pathogens

- locations where lymphocytes are activated and proliferated further

- includes: lymph nodes, spleen, and mucosal associated lymphoid tissue (MALT)

- small masses of lymphoid tissue along the lymphatic collecting vessels

- high concentrations of lymph nodes are located in: cervical (neck), axillary (armpit), inguinal (groin), intestinal, pelvic regions

- located in the left side of abdominal cavity, just below diaphragm next to stomach

- filters (cleans) blood by removing pathogens (organisms that can cause disease like bacteria or viruses), old and defective blood, and cellular debris

- traps and removes pathogens at points of entry into the body

- includes tonsils, appendix, and other lymphoid tissues on mucous membranes

- lingual (1) bumpy nodules on posterior part of tongue

- palatine (2) in oropharynx, these are you tonsils

- pharyngeal (1) in posterior nasopharynx (refered to adenoids when swollen)