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32 terms

Lymphatic System

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Compare and contrast circulatory system and the lymphatic system?
Lymph vessels travel one-way, back to the heart, venous route; has similar structure to veins including tunics and valves (?); structural difference includes the lymph vessel's need to diffuse bigger molecules; lymph transport slower and has lower pressure and speed than veins
What is the main function of the lymphatic system?
To bring back lost fluid and plasma proteins to the circulatory system to ensure that there is sufficient blood volume
What dictates what get forced outside the capillaries?
Blood pressure
Name a few things that the lymph vessels carry.
Fat molecules, pathogens, lymphocytes
Where do the fluids get forced out of the circulatory system?
Capillaries
What does interstitial mean?
Outside the cell, tissues, or organs
Lacteal
Lymphatics located in the villi of small intestines that absorb fat molecules that are too big to be absorbed by blood vessels of the intestines
Where are fat molecule taken once absorbed by lacteals?
They bypass the liver and are carried directly to the heart
How many liters of fluid are not returned to the circulatory system?
3 liters remain in the interstitial tissues
Where is lymph introduced back into the circulatory system?
Right and left subclavian/internal jugulars, then right atrium
Lymph
Clear, colorless fluid similar to blood plasma; contains macrophages, bacteria, viruses, cancer cells
What is it called when cancer cells are present in the lymph?
Metastasizing
Main components of the lymph system?
Lymph, vessels, tissues, organs
Where are the lymphatic vessels located?
Woven between the tissue cells and blood capillaries in loose connective tissue
Edema
Lymph not returned to blood vessels as normal; fluid back-up
How is draining reestablished?
Lymph vessels will regrow
What increases the rate at which lymph returns to the heart?
Exercise
Elephantiasis
A worm transmitted by a mosquito clogs a lymph vessel; usually affects lower extremities
Name the major lymphoid cells
T lymphocytes, B lymphocytes, dendritic cells, reticular cells, natural killer cells
T-lymphocytes
mature in the thymus, manage immune response, and some directly attack and destroy pathogens
B-lymphocytes
mature in the bone marrow, can differentiate into plasma cells, which produce antibodies
What are antibodies?
They bind to antigens in order to immobilize them
Dendritic cells
APCs, found in areas open to the external environment, has long extensions to catch pathogens, engulf via receptor mediated endocytosis
Reticular fibers
produces fiber to make the framework to support other cell types lymphoid organs; specifically, found in spleen and lymph node
Natural killer cell
large lymphocyte, directly attacks and destroys pathogens nonspecifically, involved in innate immunity, also targets transplanted cells, host cells infected with viruses or cancerous cells
Diffuse lymphoid tissue
loose aggregation of lymphocytes
Nodule
tight aggregation of lymphocytes with a definite structure
Describe lymph vessel drainage.
Capillaries pick up the lost fluid, drain into lymph vessels, vessels drain into 6 lymph ducts, and the ducts drain into 2 collecting vessels
Lymphatic trunks
Formed by the union of the largest lymph vessels
Name the 6 trunks.
Paired lumbar, bronchomediastinal, subclavian, jugular, intestinal trunk, intercostal
Right lymphatic duct
Drains the right arm, right side of head and thorax and dumps into the right subclavian
Thoracic duct
Collects from the rest of the body including lower extremities and dumps into the left subclavian vein