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Lymphatic system consist of what two semi independent parts:
network of lymphatic vessels and lymphoid tissues and organs
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returns interstitual body fluid and leaked plasma proteins back to the blood, absorbs fat in small intestines, filters/destroys foriegn antigens
lymphatic system
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interstitual fluid once it has entered lymphatic vessels; contains many protiens, microbes, cancer cells, about 3 L lymph return/day; relies on skeletal and respiratory pumps to move
lymph
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§Similar to blood
capillaries, yet more permeable with endothelial minivalves that remain open and withstand pressure
lymphatic capillaries
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Allow interstitial fluid to enter, but not to
escape from lymph capillaries
Keeps lymph flowing in a one-way direction
valves in lymphatic capillaries
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can absorb cell debris, pathogens, and cancer cells durign inflammation
lymphatic capillaries
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§Have thinner walls, with more internal valves than veins and more anastomoses
lymphatic collecting vessels
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travel with arteries/veins
collecting vessels
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nutrients are supplied from branching_______________
vasa vasorum
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are formed by the union
of the largest collecting vessels
lymphatic trunks
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Major trunks include:
paired lumbar, intercostal, bronchiomediastinal, subclavian, and jugular trunks and a single intestinal trunk
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Lymph is ultimately
drained into one of two large ducts:
right lymphatic duct or thoracic duct
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drains the right upper
arm and the right side of the head and thorax
right lymphatic duct
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arises from the cisterna chyli and drains the rest of the body
thoracic duct
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Parasitic worms clog up lymph vessels,
leading to enormous swelling (edema).
elaphantitis
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scattered reticular tissue elements in every body organ with
many macrophages and lymphocytes
diffuse lymphatic tissue
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diffuse lymphatic tissue includes:
- mucosa-associated
- lymphatic tissues (MALT)
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solid, spherical bodies consisting of tightly packed reticular elements
and cells
lymphatic nodules
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Have a germinal center composed of maturing B cells
lymphatic nodules
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Peyer’s Patches, Tonsils is an example of:
lymphatic nodules
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isolated clusters of lymphoid tissue, similar to
tonsils, found in small intestine (esp. ileum)
peyers patches
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Destroy bacteria and preventing them from breaching the intestinal wall
peyers patches
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Located in oro/nasopharynx, filters aiire and removes foreign materials
tonsils
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three types of tonsils:
pharyngeal (adenoids), paletine, lingual
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in nasopharynx (near auditory tube)
pharyngeal tonsils
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located on either side
of oral cavity
palatine tonsils
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located at root of tongue
lungual tonsils
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the principal lymphoid
organs of the body
lymp nodes
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occur near the body
surface in thoracic, abdominal, intestinal/mesenteric, popliteal, inguinal, axillary, and cervical regions of the body
aggregations of nodes
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swell with infection or cancer
lymph nodes
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The cortex contains follicles with germinal centers, heavy with maturing B cells, The deep cortex houses T cells in transit
lymph nodes
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largest lymph node organ
spleen
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Site of B lymphocyte production, Cleanses the
blood, Stores products of RBC breakdown for later reuse, macrophages salvage and store iron for later use by bone marrow, Site of fetal erythrocyte production (normally ceases after birth), Stores blood platelets
spleen
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Surrounded by a fibrous capsule, it has trabeculae that extend inward and contains lymphocytes, macrophages, and
huge numbers of erythrocytes
spleen
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two distinct areas of the spleen are:
white pulp and red pulp
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area containing mostly
lymphocytes suspended on reticular fibers and involved in immune functions
(lymphocyte maturation
white pulp
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remaining splenic tissue concerned with disposing
of worn-out RBCs and bloodborne pathogens
red pulp
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A bilobed organ that secrets hormones (thymosin) that cause maturation of T lymphocytes, size varies with age, stops growing during adolescense then eventually atropies, important in development of the entire immune system
thymus
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red bone marrow forms in children in:
medullary cavity of long bones
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red bone marrow forms in adults :
axial skeleton and proximal heads of humerus and femurs
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site of lymphocyte and macrophage development
red bone marrow
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Contains sinusoids with macrophages that destroy
malformed blood cells
red bone marrow
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responds quickly; results in same response with each exposure
to pathogen; consists of first line of defense and second line of defense
innate immunity
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physical barrier: intact skin and mucosa to prevent entry of microorganisms
Includes: skin and mucous membrane’s defenses (sebum, acidity, lysozyme/defensins, mucus)
first line of defense
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internal defenses: antimicrobial chemicals, phagocytes, and other cells, Inhibits spread of invaders throughout the body, Inflammation is its hallmark and most
important mechanism
second line of defense
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adaptive (specific) immunity includes:
includes third line of defense
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mounts attack against particular foreign substances, Takes longer to react than the innate system, Works in
conjunction with the innate system, Results from exposure to a pathogen (acquired), Memory Cells
are produced that reduce response time upon 2nd exposure to pathogen
Two Types:
Humoral (aka Antibody Mediated) and Cellular (aka Cell-Mediated)
Immunity
third line of defense
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anti body mediated
humoral
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cell mediated
cellular immunity
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§Antibodies bind to extracellular pathogens (antigens on bacteria, bacterial
toxins, venoms, allergens, and free viruses) and present them to phagocytes and
complement
humoral immunity
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Employs
B-Lymphocytes (made/mature in bone marrow)
which become either memory cells or plasma cells (that secrete antibodies
humoral immunity
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examples of anitbodies
IgD, IgM, IgA (in breast milk), IgG (crosses placenta), IgE (allergic rxns)
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four ways to acquire humoral immunity:
active natural, active artificial, passive natural, passive artificial
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antibodies
produced in response to natural exposure to pathogen
active natural
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antibodies
produced in response to vaccination;
may require “booster.”
active artificial
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person
produces own antibodies; long lasting
active immunity
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antibodies
come from outside source; temporary
passive immunity
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antibodies passed from mother to fetus
across placenta or in breast milk.
passive natural
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antibodies injected from serum (e.g. gamma globulin, antivenom, antitoxins for tetanus,rabies).
passive artificial
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Lymphocytes attack intracellular pathogens (viral-infected cells and
parasite-infected cells) or diseased host cells (cancer cells and foreign
tissue graft cells).
Employs T Lymphocytes
(made in bone marrow; mature in thymus)
which either become memory cells or become Helper T cells,
Cytotoxic T cells, Memory T cells, and
Suppressor T Cells (among others).
Attack and Lyse “Foreign” Cells.
cellular (cell mediated) immunity
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