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56 terms

A&P 2- Chapter 20

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How many liters of fluid are returned to circulation by the lymphatic system per day?
3 Liters
What will happen to BV and BP if lymphatic system doesn't return fluids?
BV and BP will drop
What helps with fat absorption in the lymphatic system?
Lacteals
Where are the lacteals located?
Villi of intestines
What is the primary job of the lacteals?
Absorb fats from food we eat
What is responsible for the defense of the lymphatic system?
Immune functions
Where are lymph capillaries interspersed?
Throughout tissues
What kind of endothelial connections do they have?
Loose endothelial connections; these are very permeable compared to regular capillaries
Is it hard or easy for fluid to get into lymph capillaries?
Easy
Lymph capillaries collect that fluid that is NOT captured by the
Venous end of the capillaries (about 3L a day) and returns it to the venous circulation
What is the fluid called that the lymph capillaries collect because it is not captured by the venous end of the capillaries?
Lymph
What is the composition of lymph?
Primarily water, has electrolytes, proteins, etc.
What do the lymph vessels run along with?
Deeper arteries and veins
How are lymph vessels formed?
Formed by the coalescence of capillaries
What kind of valves do the lymph vessels contain?
Valves to facilitate 'one way' movement of lymph back into general circulation
What is the structure of lymph vessels?
Same 3 layered structure as veins, but much thinner
Where is the beginning of the thoracic duct?
Cisterna chyli in the thorax
What does cisterna chyli mean?
Well or hole
What does the thoracic duct drain?
The legs, abdomen, left half of the thorax, left arm and left half of the head
Where does the thoracic duct empty into?
The left subclavian vein
What is the function of the right lymphatic duct?
It returns lymph from the right half of the thorax, the right half of the head and the right arm
Which side of the lymphatic system is smaller?
Right side
Where does the right lymphatic duct enter?
The right subclavian vein
What shape are lymph nodes?
Round or bean shaped
What kind of outer capsule do lymph nodes have?
Fibrous outer capsule
What divides up the inside of lymph nodes into compartments?
Fibrous trabeculae
*What kind of lymphocytes does the outer cortex of lymph nodes have?
B-cell lymphocytes
*What kind of lymphocytes does the deeper medulla of lymph nodes have?
Both B and T-cell lymphocytes
Where are large clusters of lymph nodes found?
Close to the surface in cervical (head and neck), axillary, cubital and inguinal (groin) areas of the body
Kids have many ______________ lymph nodes
Inguinal
The lymph node acts as a collection point for several....
Afferent (incoming) lymph vessels
Usually only one or two of these will exit the lymph nodes...
Efferent (outgoing) lymph vessels
What kind of cells are found within the nodes?
Lymphocytes, macrophages, and reticular cells
What happens when a foreign cell invades a node?
Lymphocytes undergo rapid proliferation at the germinal centers to deal with them
Where is the spleen located?
In the extreme upper left quadrant of the abdominal cavity
What does the spleen do?
Filters, cleanses and destroys foreign substances in the blood
What kind of cells does the spleen destroy?
Worn out RBCs
What part of hemoglobin does the spleen recycle?
Heme
What does the spleen do with iron
Stores it for later use to make hemoglobin
What does the spleen act as a reservoir for, and what does it store?
Reservoir for blood and stores platelets
What is white pulp mainly made of?
Lymphocytes
What is red pulp made of?
Venous sinuses and capillaries; deals with RBC destruction
Where is the thymus located
In the superior mediastinim, inferior to thyroid gland
When does the thymus increase/decrease in size?
Increases in size until puberty then decreases until unnoticeable in adults
What kind of cells does the thymus house and mature?
T-cell lymphocytes
What does the thymus-blood barrier do?
Prevents pathogens from invading the thymus gland and prematurely stimulating T-cell lymphocytes
How does the thymus aid in developing immune system, especially in neonates
It releases hormones
What will happen if you remove an infant's thymus
They will die because they never develop an immune system
Thymosin
STimulates blood barrier to create t-lymphocytes which recognize foreign antigens on the surface of invading cells
What does SCID stand for?
Severe Compromised Immune Disease
What is SCID?
WHen you take out a child's thymus and they don't have immunity (and die)
What do the tonsils form around the entrance to the pharynx?
A ring of lymphatic tissues
Which tonsils are most often removed?
Palantine tonsils
What are the pharyngeal tonsils AKA?
Adenoids
What is elphantiasis caused by?
A parasite
How does elphantiasis occur?
The worms usually infect the inguinal lymph nodes and block drainage.