Ch 21 lymphatic system Part 1 Flashcards
Circulation of lymphatic vessels
Fluid flows through lymph nodes towards large veins above the heart and then empties into the blood stream
Where does lymph empty into?
The subclavian veins
Function of primary lymphatic organs
Provide environment for stem cells to divide and mature into B and T lymphocytes
Functions of the lymphatic system
1) fluid recovery
2) immunity
3) lipid absorption
Lacteal function
- are at the end of each villi
- absorb dietary lipids that are not absorbed by the blood capillaries (in the small intestine)
What gives rise to mature B cells?
Red bone marrow
Where does the maturation of pre-T cells from red bone marrow occur?
In the thymus
Function of secondary lymphatic organs and tissues
Site where most immune responses occur (lymph nodes, spleen, and lymphatic nodules)
Structure of the cortex of a lobule in the thymus gland
Tightly packed lymphocytes and macrophages
Function of the medulla of a lobule in the thymus gland
Reticular epithelial cells produces thymus hormones
Size and location of lymph nodes
- bean-shaped, 1 in long
- located along lymphatic vessels
- scattered throughout body but concentrated near mammary glands, axillae and groin
What is lymph?
Fluid containing white blood cells that circulate through lymphatic vessels that keep all the parts of the body clean
Flow of lymph through lymph nodes
Afferent vessels lead in, sinuses lead to efferent vessels that exit at hilus (only nodes filter lymph)
What is white pulp?
Lymphatic tissue (lymphocytes and macrophages) around branches of splenic artery
What is red pulp?
Venous sinuses filled with blood and splenic tissue (splenic cords)
Cell-mediated response
- killer cells attack antigens
- helper cells costimulate T and B cells
- directed against intracellular pathogens
Antibody-mediated response
- Plasma cells form antibodies
- directed against extra cellular pathogens, such as bacteria
4 steps of phagocytosis
1) chemotaxis
2) adherence
3) ingestion
4) digestion and killing
Chemotaxis
Attraction to chemicals from damaged tissues, complement proteins, or microbial products
Adherence
Attachment to plasma membrane of phagocyte
Ingestion
Engulf by pseudopods to form phagosome
Digestion and killing
- merge with lysosome containing digestive enzymes and form lethal oxidants
- exocytosis residual body
