How do lymphatic vessels differ from vascular capillaries?
- larger diameter
- thinner walls
- anchoring filaments
- flat, irregular
- greater permeability
Why are the walls of lymphatic capillaries thinner thann the walls of vascular capillaries?
because it is not continuous with the basal lamina
What is the function of the anchoring filaments in lymphatic capillaries?
keeps passageways open when ISF pressure goes up
Why do lymphatic capillaries have a greater permeability?
because of overlapping endothelial cells
Where are lymphatic capillaries found?
- in connective tissue deep to skin
- in mucous membranes
- in digestive tract
- ** not in CNS
What are lacteals? their function?
- lymphatic capillaries in the small intestine
- they transport lipids absorbed by the digestive tract
How do lymphatics differ from veins?
- thinner walls
- wider lumens
- no clear layers
What is lymphodema and how is it caused?
- swollen area because lymph drainage is disturbed in a compressed or damaged vessel
- ISF pressure goes up causes edema
Where do lymphatic ducts take lymph?
to the venous system
Where does the thoracic duct get lymph from?
entire lower body under diaphragm and L side above the diaphragm
What is the origin of the thoracic duct?
Where does the lymphatic duct get lymph from?
R upper body
What do lymphocytes respond to?
- invading organisms (bacteria and viruses)
- abnormal body cells (cancer cells)
- foreign proteins (toxins)
What do T cells attack? how?
- foreign cells or infected body viruses
- through direct contact
What do helper T cells and suppressor cells do?
assist in regulation and coordination of immune response
How are memory T cells produced?
produced by division of activated T cells
What is the function of memory T cells?
on reserve to get activated only when same antigen appears again
What do B cells differentiate into? When?
- into plasmocytes
- when they exposed to antigens
What is the function of plasmocytes?
produce and secrete antibodies
What is an antigen?
part or product of a pathogen
What is the goal of immune response?
destruction or inactivation of pathogens, abnormal cells, and foreign molecules
What are the methods that the immune response uses to fulfill its goal?
- cell- mediated immunity
- antibody- mediated immunity
What is cell-mediated immunity?
direct contact (T cells)
What is antibody-mediated immunity?
attack my circulating antibodies that are released by plasmocytes with B cells
What is lymphopoiesis? Where does it occur?
- lymphocyte production
- in the bone marrow and thymus
What is the function of pluripotential lymphoid stem cells?
produce lymphatic stem cells that either stay in the bone marrow or migrate to the thymus
What is the function of the lymphatic stem cells that stay in the bone marrow?
- divide to produce NK cells and B cells, which go to peripheral tissues
- NK cells circulate throughout
- B cells go to lymph node, spleen, or lymphatic organs
What is the function of the lymphatic stem cells that go to the thymus?
repeatedly divide and produce daughter cells that mature into T cells, which go to spleen, bone marrow, and lymphoid organs
What is so special about the success of immunity?
the ability to increase the number of specific types of lymphocytes
What is the germinal center?
pale central zone of of lymphoid nodule with activated lymphocytes
What are tonsils?
large nodules in wall of pharynx
What is the function of tonsils?
remove pathogens that enter pharynx in food and air
What are the 5 tonsils?
- 1pharyngeal tonsil
- 2palatine tonsil
- 2lingual tonsil
What are peyer's patches? Where are they found?
- aggregated lymphoid nodules
- in mucosal lining of small intestines