Studied by 6 peopleleukopoiesis, lymphatic system, lymphoid organs, lymph nodes
define leukopoiesis
production of WBCs
what type of molecule stimulates leukopoiesis
chemical messengers
list two chemical messengers that stimulate leukopoiesis
interleukins, colony-stimulating factors (CSFs)
chemical messengers stimulate the production of WBCs. where are they released from (2)
red bone marrow and mature WBCs
which stem cell do all leukocytes originate from
hemocytoblast stem cells
which two pathways emerge from hemocytoblast stem cells (ie list the two cells)
lymphoid and myeloid stem cells
what do lymphoid stem cells produce
lymphocytes
what do myeloid stem cells produce
all other formed elements: RBCs, platelets, basophils, eosinophils, neutrophils, monocytes
on the path to granulocytes, name the list of cells that arise starting from the stem cells
myeloblasts, promyelocytes, myelocytes, band cells, mature granulocytes
which cell in the pathway to granulocyte production develops lysosomes
promyelocytes
which cell in the pathway to granulocyte production develops granules
myelocytes
which cell in the pathway to granulocyte production has a curved nuclei
band cells
what happens to nuclei in mature granulocytes (during the pathway of granulocyte formation from stem cells)
they become segmented
in the pathway to granulocyte production, what change happens in promyelocytes
they accumulate lysosomes
in the pathway to granulocyte production, what change happens in myelocytes
they accumulate granules
where are mature granulocytes mostly stored
bone marrow
mature granulocytes are mostly stored in the bone marrow, but where else can they be found
blood
where does granulocyte production occur
bone marrow
list the cells in the pathway to monocyte production (which is an agranulocyte)
hemocytoblast stem cell, myeloid stem cell, monoblast, promonocyte, monocyte
how long can monocytes live for
several months
list the cells in the pathway to lymphocyte production (which is an agranulocyte)
hemocytoblast stem cell, lymphoid stem cell, lymphocyte precursors (T and B), lymphocytes (T and B)
what cells to T lymphocyte precursors give rise to
immature T lymphocytes
where do T lymphocytes mature
thymus
what cells do B lymphocyte precursors give rise to
immature B lymphocytes
where do B lymphocytes mature
bone marrow (which is where they were formed)
how long do lymphocytes live
a few hours to decades
list 2 advantages of the lymphatic system
transport hormones/nutrients/waste, continuous screening of pathogens through circulating fluid
which immune cells circulate through lymph and blood
T and B cells
describe the role of T and B cells circulating through blood and lymph
detect circulating pathogens and then travel to the site of injury/infection to neutralize them
what happens to excess interstitial fluid
enters the lymphatic system
by which structure does excess interstitial fluid enter the lymphatic system
lymphatic capillaries
what is the name for the fluid circulating through the lymphatic system
lymph
where do lymphatic vessels carry lymph from + where do they take it
peripheral tissues to the venous system
what are lymphatic trunks
the largest collecting vessels in the lymphatic system that drain large areas of the body
name the 5 lymphatic trunks
lumbar, bronchomediastinal, subclavian, jugular, intestinal
which of the 5 lymphatic trunks are paired
lumbar, bronchomediastinal, subclavian, jugular
which of the 5 lymphatic trunks are UNpaired
intestinal
from any of the lymphatic trunks, where is lymph delivered to (2)
either the right lymphatic duct or the larger thoracic duct of the thoracic region
what parts of the body does the right lymphatic duct receive lymph from
drains from the right upper limb and the right side of the head and thorax
what parts of the body does the thoracic duct duct receive lymph from
rest of the body (everything except the right upper limb, head, and thorax areas)
list the 2 functional categories of lymphoid organs
primary and secondary
what are primary lymphoid organs (describe them)
areas where T and B cells mature
give 2 examples of primary lymphoid organs
red bone marrow, thymus
what are secondary lymphoid organs (describe them)
areas where mature lymphocytes first encounter their antigen and become activated
list 3 secondary lymphoid organs
lymph nodes, spleen, MALT
what is the full name of MALT
mucosa-associated lymphoid tissue
what does MALT form (3)
tonsils, Peyer’s patches in the small intestine, appendix
which type of membranes are MALT found in
mucous
purpose of MALT
protection from pathogens that seek to enter the body
why do we need a high concentration of lymphoid tissue in the respiratory and GI tract?
these are both open to the environment, so it’s easy for pathogens to enter the body through these tracts
what shape are lymph nodes
bean
list the 2 distinct regions of the lymph node
cortex and medulla
which is interior: cortex or medulla
medulla
which is exterior: cortex or medulla
cortex
what structure surrounds the lymph node
capsule
describe how the capsule of the lymph node dictates the internal structure
capsule fibers extend into the node as trabeculae. this divides the node into compartments (each with a cortex and medulla)
what cells are predominant in the cortex of lymph nodes
B cells
what are B cells doing in the cortex of lymph nodes
dividing
what cells are deep in the cortex of lymph nodes
T cells
what are the T cells of lymph nodes doing
continuously circulating among blood, lymph nodes, and lymph
what cells does the medulla of lymph nodes contain (3)
B, T, and plasma cells
plasma cells are differentiated __ cells
B
how do plasma cells arise
when a B cell interacts with an antigen
what can plasma cells do that B cells can’t
produce antibodies for an antigen
what term is used to describe the spaces within lymph nodes that allow for the movement and drainage of lymphatic fluid?
lymph sinuses
describe the structure of lymph sinuses within lymph nodes
large lymphatic capillaries that lay underneath a crisscrossing network of reticular fibers
which cell type resides on the reticular fibers of lymph nodes
macrophages
role of macrophages within lymph nodes
check for any foreign matter and phagocytose it
main function of a lymph node
purification of lymph
lymph nodes purify lymph before it returns to ____ circulation
venous
list some things that lymph nodes remove from lymph to purify it (3)
debris, pathogens, antigens
T or F: lymph nodes start the immune response once infections reach vital organs
false; they start the immune response BEFORE infection reaches vital organs
where is the thymus located
mediastinum
which cells mature in the thymus
T cells
mature T cells leave the thymus into the ____ or ____
lymph or blood
what is the largest lymphatic organ
spleen
what two structures does the spleen contain
white and red pulp
what type of tissue is the white pulp of the spleen
lymphatic tissue
role of the white pulp of the spleen
initiates the immune response by B and T cells
role of red pulp within the spleen
removes old/damaged RBCs and other blood components
how does white pulp initiate the immune response (via _____)
via B and T cells
by which mechanism does red pulp remove old/damaged RBCs
phagocytosis
other than B and T cells, list two other lymphoid immune cells
macrophages and dendritic cells
what do macrophages do in the lymphatic system (2)
phagocytose foreign substances and help activate T cells
what do dendritic cells do in the lymphatic system (2)
capture antigens and deliver them to lymph nodes, and they help activate T cells
give an example of a supporting lymphoid cell
reticular cells
what are reticular cells
fibroblast-like cells
what do reticular cells produce
reticular fiber
what is the reticular fiber of lymphoid cells called
stroma
what is the stroma (describe it)
the network that supports the other cell types in lymphoid organs/tissues (acts as scaffolding)
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