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What does the lymphatic system involve
a set of vessels that transports tissue fluid back into the blood stream & a set of organs that are involved in immune system
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What are lymph vessels?
collect lymph tissue fluid arising from fluid that has leaked from capillaries (proteins also leak & are returned to blood stream by lymph vessels)
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What does the immune system also collect?
lipids from digestive tract involved in exposing pathogens to immune system
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What are lymph capillaries?
one cell layer thick made up of endothelial cells permeable to tissue fluid, proteins, bacteria, & viruses
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What are lacteals?
lymph capillaries in small intestine permeable to lipids
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What are lymphatic collecting vessels?
these vessels connect to capillaries & carry fluid away
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What are lymph nodes?
organs along lymphatic collecting vessels acumulating the pathogens carried by lymph (area highly concentrated with lymphocytes ready to activate an immune response)
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What are lymph trunks?
a conversion of lymphatic collection vessels resulting in vessel of larger diameter draining large areas of the body.
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What are the five major locations of lymph trunks?
lumbar trunks, intestinal trunks, bronchomediastinal trunks, subclavian trunks, jugular trunks
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What are lymph ducts?
larger vessel into which lymph trunks empty
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Where is the thoracic duct found?
in everyone but only some people have right lymphatic duct that empties into neck veins
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Where does the thoracic duct empty?
into left internal jugular veins & left subclavian veins
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What may be the first response to infectious organisms entering the body within lymphocytes & other cells of immune system?
inflammation
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The cells involved in an immune response are what?
macrophages & lymphocytes including T & B cells
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What give rise to lymphocytes?
lymphoid stem cell in bone marrow
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Where do lymphocytes mature and where do they travel?
in the thymus (T-Cell) or bone marrow (B-cell) and travel through body until they encounter an antigen once they mature
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What is activated and sends signals to activate lymphocytes?
t-helper cell is activated once presented with antigen & sends signals to activate other T-cells and B-cells
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What happens to the lymphocytes (the cells) when activated?
once activated, the cells produce effector cells that fight pathogen & memory cells
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What are effector cells?
fight pathogen & memory cells
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What are memory cells?
guard against subsequent infections
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What is a lymphoid tissue?
designed to collect pathogens for purpose to destroying them (often infected & is located throughout body)
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What happens at the site of infection with lymphoid tissue?
multiple lymphocytes collect to fight infection & memory cells reside
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What do lymphoid organs do and what are they?
easily collect pathogens
lymph nodes, spleen, thymus, tonsils, and aggregated lymphoid follicles & appendix
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What are lymph nodes
organs that filter lymph fluid before it has an opportunity to enter back into blood vessels
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What is the spleen?
largest lymphoid organ almost the size of the heart designed to remove blood born pathogens & aged/damaged RBCs & also stores platelets
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What are the 2 areas of the spleen?
areas indentified as white (pymphoid tissue) and red pulp (vacular tissue).
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What is the thymus?
site to T-cell development & also releases hormones
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What is thymus gradually replaced by as one ages?
fibrous tissue
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What are tonsils?
simplest lymphoid organs with 4 groups (palatine, lingual, pharyngeal, & tubal)
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What are the 4 groups of tonsils that humans have and what do they do
palatine, lingual, pharyngeal, tubal-gather pathogens entering through nose & mouth
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What are aggregated lymphoid follices & appenedix?
densely packed units of lymphoid tissue forming lymphoid nodules
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What does HIV transmitted through?
bodily secretions such as blood, semen, & viginal secretions.
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What happens if the HIV fluid is exposed to air?
dries, virus dies, & cannot be infectious
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What can allow virus entry if one is exposed to an infected body fluid?
any microscopic tear in the body or via a needle or blood transfusion (rare)
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What does the virus target and what happens?
T-helper cells & destroy them. also affects microglia cells & immune system cells
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What are microglia cells?
brain tissue
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What are immune system cells?
dendritic & macrophages
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What are the infection stages?
1. acuite stage 2 weeks (first infected presels flu-like systems, fever, rash, fatique, heaeache, muscle/joint pain, diarrhea, swollen lymphnodes),
2. asymptomic period-up to 10 years (no obvious systems, but immune system is silently fighting HIV virus),
3. AIDS-time varies resulting in death (persons immune system declines & body is invaded by oppertunistic organisms)
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What is the fourth leading cause of death world wide?
AIDS
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Where are AIDS most severe spread in?
Asia, eastern europe, & africa
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What % of US is infected that does not know they are?
25%
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