immune system pt 2

leukopoiesis, lymphatic system, lymphoid organs, lymph nodes

define leukopoiesis

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)