Term
| Definition: Lymphoid tissue |
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Definition
-tissue in which lymphocytes are found in high numbers
-can include bone marrow, thymus, Peyer's patches, lymph nodes, spleen, hemolymph nodes, and diffuse lymphid tissues |
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Term
| Briefly, how does the immune system work for the purposes of this class? |
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Definition
-it helps the body defend itself against antigens
Workings: antigen-presenting cells process and present antigen=> contact with lymphocytes=> stimulates lymphocytes to divide and become antibody-secreting plasma cells=> antibodies bind antigen, thus inactivatind and removing it
-other lymphocytes develop ability to killll malignant/ viral-infected cells |
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Term
| What type(s) of cell(s) included in the immune system? |
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Definition
| -consists of lymphocytes and antigen-presenting cells such as macrophages and dendritic cells |
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Term
| Lymphocytes are derived from ____ cells in the _________ |
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Definition
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Term
| ___ lymphocytes complete their maturation in the bone marrow and ___ lymphocytes to the thymus to mature |
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Definition
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Term
Definition: Diffuse lymphoid tissue
=>encapsulated or nonencapsulated? |
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Definition
-lymphocytes scattered throughout the CT of many organs, especially tubular organs that open to exterior (eg gastro-intestinal tract, respiratory tract, repro tract)
=>nonencapsulated |
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Term
Definition: Lymphoid nodule
=>encapsulated or nonencapuslated? |
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Definition
-discrete aggregations of lymphocytes, usually in loose CT
=>nonencapsulated |
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Term
| Definition: germinal center |
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Definition
| -regions in the lymphoid nodule where lymphocytes are proliferating as the result of contact with a foreign material |
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Term
| True or False: Lymphoclasts are the type of lymphocytes that proliferate in a germinal center as the result of contact with foreign material. |
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Definition
FALSE; lymphoblasts are the proliferating cells
-larger, larger nuclei, paler staining |
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Term
| What is the term used to describe the region of a lymphoid nodule that is not the germinal center? |
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Definition
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Term
| True or False: Lymphoid nodules increase or decrease in size depending on the exposure of the animal to antigens |
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Definition
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Term
| Multiple nodules that are close to each other and whose margins merge are termed ________ |
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Definition
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Term
| Describe the epithelium of the Tonsils |
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Definition
-stratified squamous or respiratory
-has crypts which penetrate the tonsil
-has nodules with germinal centers |
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Term
| True or False: a layer of CT separates the tonsil from the underlying tissue, acting much like a parietal capsule |
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Definition
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Term
| Definition: Peyer's patches |
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Definition
| -aggregated nodules in the wall of the ileum |
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Term
|
Definition
-mucosa-associated lymphoid tissue
-a lymphoid organ near the lumen of the respiratory, gastrointestinal, and urogenital systems |
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Term
| What is special about MALT's epithelium? |
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Definition
| -it is specialized to deliver antigens from the lumen to the deeper lymphocytes |
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Term
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Definition
| -small encapsulated organs composed predominantly of lymphocytes |
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Term
| Lymph/lymphocytes are collected in the body, pass through _______ vessels, and enter one side of a lymph node via an ________. The exit via an _____ |
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Definition
-lymphatic vessel
-afferent lymphatic vessel
-efferent lymphatic vessel |
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Term
| Describe the shape of a lymph node and its capsule |
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Definition
-bean-shaped
-eclosed in a dense CT capsule which sends trabeculae into the node to compartmentalize it |
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Term
| In a lymph node: afferent lymphatic vessels enter/exit the capsule at one/sevral point(s) on the convex/concave side |
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Definition
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Term
| In a lymph node: efferent lymphatic vessels, arteries, and veins, are found on the convex/concave side |
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Definition
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Term
| In a lymph node, the concavity is called what? |
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Definition
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Term
| Outline the lymphatic vascular system |
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Definition
lymph channels enter on convex side
pierce capsule=> dilate into subcapsular sinus (underlies entire convex side of capsule)=> runs alongside septa as trabecular sinuses OR medullary sinuses in medulla=> sinusoidal branches=> towards hilus=> efferent lymphatic vessel at hilus |
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Term
| Outline the blood supply of a lymph node |
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Definition
| -Outer cortex: afferent arteriole=> capillaries=> venules=> high endothelial venule> collect into single vein=> leave node at hilus |
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Term
| What makes high endothelial venuales structurally special? What about functionally? |
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Definition
-S: endothelium is cuboidal (not typical squamous)
-F: endothelium has cell surface markers which lymphocytes use as a sign to exit from the blood vessel into the perenchyma of the node |
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Term
| True or False: The lymph node has a capsule and trabeculae of dense CT |
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Definition
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Term
| What kind of CT spans the space between blood vessels and lymph sinuses in a lymp node? |
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Definition
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Term
| Describe Lymph Node Parenchyma |
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Definition
-mostly lymphocytes
-some macrophages and everything normally found in loose CT |
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Term
| The _____ (layer) of a lymph node has a higher concentration of lymphocytes as the ____ is occupied by the ____ sinuses |
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Definition
-cortex
-medulla
-medullary
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Term
| The cortex of a lymph node contains what? |
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Definition
-lymphoid follicles/nodules
-some have germinal centers and marginal zones |
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Term
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Definition
| -the region between and deep to the lymphoid follices in the cortex of a lymph node |
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Term
| Circuating lymphocytes enter the lymph node bie the incoming ___ or ____ vessels. |
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Definition
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Term
| Circulating lymphocytes that enter the lymph node via the blood vascular systen leave the blood through the ______ |
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Definition
| -the wall of the post-capillary venule |
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Term
| Circulating lymphocytes exit the lymph node how? |
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Definition
| -via efferent lymphatic vessels |
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Term
| True or False: the lymph node is not a site of proliferation of lymphocytes and development into plasma cells |
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Definition
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Term
| How does the positioning of a lymphocyte in a lymph node change as it differentiates into an antibody-secreting plasma cells? |
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Definition
| -moves toward the medulla and leave the node to settle into the CT compartment to secrete antibodies |
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Term
| What is the primary role of lymph nodes? |
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Definition
| -to act as immunologic filters of the lymph and are designed to bring the lymh in close contact with lymphocytes |
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Term
| What general class of animal are hemal nodes and hemolymph nodes found? |
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Definition
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Term
| What is special about a Hemal node? What other structure is it functionally similar to? |
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Definition
-look like typical lymph nodes, but are blood filter, not lymph filters
-spleen, NOT lymph nodes
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Term
| True or False: the sinuses of hemal nodes are filled with lymphocytes |
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Definition
| FALSE, filled with blood cells |
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Term
| Where are hemal nodes found in the body? |
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Definition
-in RUMINANTS
-along the vertebral column and on some visceral organs |
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Term
| What is a hemolymph node? |
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Definition
| -sturctured like a lymph node, but blood AND lymph mix together in the sinuses |
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Term
| True or False: the speen has a dense CT capsule that gives rise to numerous trabeculae |
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Definition
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Term
| What is the purpose of the spleen's capsule? |
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Definition
| -gives rise to trabeculae which support the contents of the spleen and subdivide it into communicating compartments |
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Term
| In the spleen, _____ CT supports the parenchyma |
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Definition
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Term
| Moacroscopically, where are the major blood vessels found on the spleen? |
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Definition
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Term
| Compare/Contrast: White Pulp and Red Pulp |
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Definition
-Compare: both found in spleen
-Contrast: White is rich in lymphoid cells and Red has blood in large sinuses and free in extravascular space |
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Term
| The spleen serves as an _______ of the blood, similar that the lymph nodes monitor the lymph. To do this. it has masses if ______ tissue in the white pulp. |
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Definition
-immunologic monitor
-lymphoid |
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Term
| The lymphoid tissie in the white pulp of the spleen is housed in what kind of stroma? |
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Definition
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Term
| What are the two major functions of the spleen? |
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Definition
| -immunologic monitor of the blood and the destruction of old RBCs |
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Term
| Outline blood flow of the Spleen |
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Definition
| large vessels enter at hilus=> subdivide while still in capusle and trabeculae (trabecular arteries=> leave trabeculae and enter white pulp as small muscular arteries or large arterioles=>small branches of central arter leave white pulp=> branch into sheathed capillaries=> splenic sinuses=> veins=> out os spleen |
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Term
| Upon leaving the trabeculae to enter the white pulp in the spleen, the artery is ensheathed by what? |
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Definition
-Peri-arterial lymphoid sheath (PALS): a thich layer of lymphocytes
-this structure contains lymphoid germinal centers |
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Term
| What comprises the white pulp of the spleen? |
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Definition
| -Peri-arterial lymphoid sheath and its germinal centers |
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Term
| What are sheathed capillaries and where are they found? |
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Definition
-found in spleen
-small branches of central artery leavh white pulp=> branche into sheathed capillaries
-surrounded by a network of reticular fibers, reticular cells, and macrophages
=>appear ellipsoid in cross section |
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Term
| What kind of basal laminae do sheathed capillaries have? What functional impact does this have? |
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Definition
-discontinuous, thus gaps between endothelial cells
-blood can flow out into the surrounding tissue |
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Term
| The red pulp of the spleen contains large ___-filled spenic sinuses. The tissue between the sinuses is called ______. |
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Definition
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Term
| Describe the walls of the splenic sinuses of the red pulp? What is its functional purpose? |
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Definition
-porous
-to allow blood cells to pas through tem |
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Term
| Becuase the ______ and ______ are so leaky, much blood leaves the blood vessels and enter the splenic cords and other extravascular space in the red pulp of the spleen. |
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Definition
-sheathed capillaries
-splenic sinuses |
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Term
| In which part of the spleen do cells of the imuune system (give 2 examples) inspect the blood for foreign material? What else happens here? |
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Definition
-macrophages and lymphocytes
-splenic sinuses in red pulp
-macrophages remove aged RBCss |
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Term
| In what 3 locations are old RBCs degraded by macrophages? |
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Definition
-splenic sinuses of the red pulp of the spleen
-bone marrow
-liver |
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Term
| True or False: The spleen has an afferent lymphatic vessels but no efferent lymphatic drainage. |
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Definition
| FALSE; the spleen does NOT have afferent lymphatic vessel but there is efferent lymphatic drainnage |
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Term
| The spleen is a _____ of the blood/lymph. It is designed to bring the ____ in close cntact with lymphocytes. |
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Definition
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Term
| The thymus is the site for maturation of what? |
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Definition
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Term
| Outline the life journey the T lymphocytes |
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Definition
| bone marrow=> Pre-T lymphocytes leave bone marrow=> enter blood stream=> exit into thymus=> mature into T lymphocytes=> re-enter bloodstream=> waner periphery of the body |
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Term
| Describe the macroscopic structure of the thymus |
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Definition
-divided into two lobes and enclosed in a capsule of dense CT
-further divded into lobules by septa that arises from the capsule |
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Term
| What special cells are part of the stroma of the thymus? |
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Definition
| -epithelial reticular cells |
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Term
| True or False: Like the bone marrow, the thymus is a filter through which lymph percolates and thus has an afferent lymphatic vessel. |
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Definition
| FALSE; like the bone marrow, the thymus is NOT a filter through whichlymph percolates and has NO afferent lymphatic vessels |
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Term
| What is the funcition of the thymus and how is it specialized for this function? |
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Definition
| -protected from antigens and consitutes a special protected microenvironment in hwich T cell differentiation can occur under the influence of hormones secreted by the thymus cells |
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Term
| The thymus has two regions. What are they are descrbie their macroscopic histological appearances. |
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Definition
-cortex: dark-staining= more lymphoocytes
-medulla: light-staining |
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Term
| Describe Epithelial Reticular Cells Histologically, Functionally, and Structurally |
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Definition
-H: pale-staining
-S: elongated, branching, and connected to each other
-form a meshworl crisscrossing the organ and form an adventitial coat that lines the inside of the capsule, septa, and blood vessels in the cortex of the spleen
-F: reduce permeability of the corticla blood vessels, forming part of a blood-thymus barrier |
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Term
| True or False: In the thymus, the pale-staining medulla is a germinal center as there are many germinal centers found in the thymus. |
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Definition
| FALSE; the medulla is NOT a germinal center and there are NONE found in the thymus |
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Term
| What is the function of the immune system? |
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Definition
| -identifies and protects against disease-causing organisms and foreign substances (recognizes antigens that are not normally present) |
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Term
| What composes the immune system? |
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Definition
-Lymphoid organs: lymph nodes, spleen, thymus
-Lymphoid tissues: mucosa-associated lymphoid tissue (MALT), aggregated lymphoid nodules, diffuse lymphoid tissue
-Cells: lymphocytes, antigen-presenting cells (dendritic cells and macrophages) |
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Term
| How are lymphocytes involved in immune defense? |
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Definition
-lymphocytes have a central role in immune defense
-circulate b/n lymphoid tissues and organs through blood and lymph: constant movement b/n tissues and systemic circulation, provide ongoing immune surveillance |
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Term
| Where do B-lymphocytes mature? |
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Definition
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Term
| What do B-lymphocytes mature into? What are they responsible about it? |
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Definition
-plasma cells that secrete immunoglobulin
-some become memory cells
-responsible for humoral immune response |
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Term
| Where do T-lymphocytes mature? What are the two types? What are they responsible for? |
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Definition
-mature in thymus
-T-helper cells (TH cells)
-Cytotoxic T-cells (TC cells)
-responsible for cell-mediated immunity |
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Term
Definition: Primary lymphoid tissues
Examples? |
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Definition
-where lymphocytes mature and become able to recognize antigen
-Ex: Bone marrow (B-cells) and Thymus (T-cells) |
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Term
Definition: Secondary lymphoid tissues
Examples? |
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Definition
-where lymphocytes are activated in response to antigen
-Ex: spleen, lymph nodes. MALT |
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Term
| All lymphocytes arise in the bone marrow from ___________ cells |
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Definition
| -hematopoietic stem cells |
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Term
| Outline the path of a T-cell |
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Definition
| come from hematopoietic stem cells in bone marrow=> bloodstream=> mature in thymus=> go out via bloodstream to organs |
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Term
| Outline the path of a B-cell |
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Definition
| "born" from hematopoietic stem cell cells in bone marrow=> remain here to mature=> exit via bloodstream to go out into body |
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Term
| In birds, where do B-cells mature? |
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Definition
| -bursa of Fabricius/ cloacal bursa |
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Term
| Describe the selection process of T-lymphocytes in the thymus |
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Definition
-immature T-lymphocytes come here from the bone marrow, mature here
-those that react to self antigens die |
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Term
| What happens to T-cells after maturation in the thymus? |
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Definition
| -after maturation, T-cells re-enter the bloodstream and patrol the body, in circulation and peripheral (secondary) lymphoid tissue |
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Term
| How does a young thymus differ from an old thymus? During puberty? |
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Definition
| -thymus is large in young, largest at puberty, then regresses to mainly adipose tissue with age |
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Term
| Describe the stroma of the thymus. What is special about the stroma of the thymus? |
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Definition
-has a collagenous CT capsule that dives as trabeculae to divide its two lobes into smaller lobules
-has a Blood-thymus Barrier that creates a special environment for T-cell maturation, protects them from exterior antigens |
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Term
| Where is the thymus located? |
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Definition
| -located in cranial mediastinum, thoracic inlet and ventral cervical region |
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Term
| True or False: The thymus behaves as a lymph filter and thus has afferent lymphatics. |
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Definition
| FALSE, the thymus is NOT a lymph filter |
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Term
| Compare/contrast the cortex and medulla of the thymus (eg components, histologically, etc) |
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Definition
-Cortex: peripheral and darker staining
-contains mostly T-lymphocytes (aka "thymocytes")
-has few epithelial reticular cells: helps form blod-thymus barrier by lining septa, capsule, and blodd vessels
-Medulla: central and light staining
-more epithelial reticular cells are more numerous and make loosely, arranged network
-fewer T-cells than in cortex
-Hassall's corpuscles: degenerating epithelial reticular cells |
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Term
| What is the function of epithelial reticular cells? |
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Definition
-line septa, capsule, and blood fells to help form blood-thymus barrier
-helps support lymphocyte proliferation and maturation (structural framework and hormone secretion) |
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Term
| _______ is a histological marker for epithelial reticular cells |
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Definition
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Term
Definition: Secondary Lymphoid Tissue
How they are specialized for their function?
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Definition
-lymphocyte-rich tissues/organs in whic lymphocytes are activated in response to antigens
-strategically positioned at sites of antigen entry, antigens are transported via blood or lymph thus associated with mucosal surfaces
-contain antigen-presenting cellls to aid in inducing an immune response |
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Term
| What broad categories of lymphoid tissues are examples of nonencapsulated secondary tissues? More specifically? |
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Definition
-Diffuse lymphoid tissue
-Aggregated lymphoid nodules: Tonsils, lymphoid nodules, MALT |
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Term
| Give some examples of encapsulated secondary lymphoid tissues |
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Definition
-Lymph nodes
-Hemal nodes
-Hemalymph nodes
-Spleen |
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Term
| Definition/Location: Diffuse lymphoid tissu |
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Definition
-Definition: nnonencapsulated, composed of lymphocytes scattered through CT of organs
-Location: GI tract, resp tract, urogenital tract |
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Term
| In diffuse lymphoid tissue, where are lymphocytes found? Plasma cells? |
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Definition
-lymphocytes found in lamina propria and epithelium
-plasma cells found in lamina propria |
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Term
Definition: Lympoid nodules
Examples and their locations? |
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Definition
-nonencapsulated, discrete aggregates of lymphocytes (usually in loose CT)
-Ex: tonsils/pharynx, eyer's patches/SI, Mucosa-associated lymphoid tissues: (BALT= resp tract, GALT= GI tract, urigenital tract) |
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Term
| Do lymphoid nodules ever change size? Why or why not? Do they contain germinal centers? |
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Definition
-YES, inc or dec in size dep on antigen exposure and immune-stimulation
-some may have germinal centers |
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Term
| What are tonsils? Why is their location functionally important? |
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Definition
-dense aggregates of lyphoid tissue
-located in pharynx to aid in local antibody production and generalized immune response |
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Term
| The tonsils are separated from lumen by a layer of epithelium/endothelium that is ____(type)____. |
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Definition
-epi
-stratified squamous or respiratory epi |
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Term
| What two structures in tonsils are functionally significant? Does it have a capsule? |
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Definition
-Lymphoid follices with germinal centers and crypts
-KINDA, has a dense CT on deep surface that acts as a partial capsule |
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Term
| Definition: Peyer's patches |
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Definition
| -dense aggregates of lymphoid tissue in the wall of the ileum (SI) |
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Term
| Describe to the structure of Peyer's patches |
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Definition
-dense aggregates of lymphoid tissue
-separated from intestinal lumen by specialized epi: has scattered low-cuboidal M cells
-contains lymphoid follicle(s) with germinal centers |
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Term
| What are M cells and where are they found? |
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Definition
-specialized low cuboidal epi cells in intestinal lumen superficial to Peyer's patches
-specialized for transytosis of Ag from lumen into underlying Peyer's patch |
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Term
| Definition/Location: Lymphoid Follicles |
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Definition
-nodular collections of densely-packed lymphocytes with central, paler germinal center
-found in cortex of lymph nodes, tonsils, and other nonencapusulated dense lymphoid tissues |
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Term
| When are germinal centers present? What are they? |
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Definition
-form when an immune response has been stimulated
-regions where lymphocytes are proliferating as a result of antigenic stimulation (B-cells) |
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Term
| Germinal center is _____-staining while the surrounding ________ is darker. The germinal center contains _______ cells while the surrounding region contains ________ cells. |
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Definition
-pale
-mantle zone
-dividing B-cells
-resting B-cells, some memory B-cells, few T-helper cells, dendritic cells, macrophages |
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Term
| How are antigens presented to lymphocytes in lymphoid follicles? |
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Definition
| -follicular dendritic cells present antigen to lymphocytes |
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Term
| Definition/Macroscopic Structure/Function: Lymph Node |
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Definition
-Definition: small encapsulated lymphoid organs, composed predominantly of lymphocytes
-Macroscopic Structure: bean-shaped with concave and convex surfaces organized into cortex and medulla
-Function: acts as an "in-line filter" of LYMPH |
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Term
| What is collected by lymphatics? |
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Definition
| -interstitial/extracellular fluid |
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Term
| Outline the Lymph flow in lymph nodes |
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Definition
| afferent lymphatics=> subcapsular sinus=> trabecular sinus=> medullary sinus => efferent lymphatics |
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Term
| Where are lymph nodes located in general? |
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Definition
| -located along lymphatic vessels, occur in groups where lymphatics converge |
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Term
| Describe the stroma of the lymph node. Parenchyma? |
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Definition
Stroma: dense irregular CT capsule and trabeculae and meshwork of reticular CT throughout node
-Parenchyma: moslty lymphocytes with many macrophages |
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Term
| The subcapsular sinus of a lymph node contains what kind(s) of cell(s)? |
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Definition
| -reticular cells, fibers, and sinus macrophages |
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Term
| Compare/contrast the cortex and medulla of lymph nodes (eg histologically, contents, etc) |
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Definition
Cortex: darker staining outer layer (b/c more lymphocytes)
-has lymphoid follicles with germinal centers and mantle zones
-contains paracortex/paracortical region b/n and deep to follicles
Medulla: lighter staining central region
-medullary cords composed of plasma cells
-medullary sinuses contain macrophages
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Term
| In lymph nodes, lymhoid follicles and germinal centers are composed of ____cells and the paracortex is composed of ___cells. |
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Definition
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Term
| Immature lymphocytes _________ in primary lympoid tissue. |
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Definition
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Term
| What structurally happens to lymphocytes in primary lymphoid tissue? How is this functionally significant? |
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Definition
-antigen receptors develop to determine shape and charge of receptor on lymphocytes
-enables lymphocytes to recognize and react to antigens (lymphocytes that react to self-antigen are eliminated) |
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Term
| What is the difference b/n a matura and naive lymphocyte? |
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Definition
-Mautre: able to bind and react with antigen
-Naive: not yet exposed to antigen, not yet activated |
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Term
| What does afferent lymph carry? |
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Definition
-antigen presenting cells: dendritic cells and macrophages
-free antigens: infectious agents
-lymphocytes from mucosal surfaces and site inflammation |
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Term
| Describe what happens to lymphocytes in the lymph nodes |
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Definition
-naive lymphocytes that neet the appropriate antigen in lymph nodes become activated and proliferate
-B-cells=> plasma cells or memory B-cells
-T-cells=> cytotoxic T-cells or helper T-cells |
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Term
| Describe the lymph node blood supply |
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Definition
| blood vessels ener node at the hilus=> in outer cortex, arterioles divide into capillaries=> give rise to venules (high endothelial venules)=> venules collect into single vein=> vein exts node at hilus |
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Term
| Location/Structure/Function: High endothelial venules (HEV) |
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Definition
-Location: in paracortical region of lymph node cortex
-Structure: lined by cuboidal endothelium
-Function: endothelium has cell surface markers that signal lymphocytes to exit bloodstream into parenchyma of lymph node
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Term
| Outline T-lymphocyte Circulation |
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Definition
| Naive T-cells enter lymph node from blood via HEV=> exposed to antigen-presenting cells=> leave cia lymphatics and continue patrolling OR proliferate and differentiate into efffector cells=> migrate to lymphoid tissues or sites of infection |
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Term
| Outline B-lymphocyte Circulation |
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Definition
| naive B-cells enter lymph node from blood via HEV=> exposed to antigen-presenting cells=> stay in node or exit thru efferent lymphatics OR proliferate and differentiate into effector cells=> memory B-cells->stay in node or exit thru efferent lymphatics OR plasma cells-> medullary cords of lymph nodes OR bone marrow or other tissues |
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Term
| True or False: Antigens frommucosal surfaces can stimulate immune-response in nonencapsulated nodular lymphoid tissue and germinal centers may form in response to antigenic activation. |
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Definition
| TRUE, see mucosa-associated lymphoid tissue |
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Term
| Where do activated/effector lymphocytes migrate? |
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Definition
| -to regional lamina propria of tubular organs or regional lymph nodes via circulation |
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Term
| How do lymph nodes in pigs vary from normal lymph nodes? |
|
Definition
-lymphoid follicles in central region
-medullary cords are at periphery
-cortical and medullary compnents function similar to other species
-direction of lymph flow is similar to that of other species |
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|
Term
| What general class of animal has hemal and hemolymph nodes? Where in the animal are they located |
|
Definition
-ruminants
-Hemal nodes: along vertebral column and on some visceral organs
-Hemolymph nodes: in perirenal and lumbar regions of ruminants |
|
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Term
| How are hemal nodes different from lymph nodes? |
|
Definition
-dark red color
-DO NOT HAVE LYMPHATIC VESSELS
-BLOOD filters, NOT lymph filters
-sinuses contain blood rather than lymph |
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|
Term
| What is the function of of hemolymph nodes? |
|
Definition
|
|
Term
|
Definition
| -large lymphoid organ that filters blood |
|
|
Term
| Describe the stroma of the spleen |
|
Definition
--thich, dense CT capsule contianing smooth muscle and elastic fibers
-capsule gives rise to trabeculae that supports contents of spleen an dsubdivides it into compartments
-reticular CT also supports parenchyma |
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|
Term
| In the spleen, blood vessels enter and exit via the ______ |
|
Definition
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Term
| Compare/contrast the white pulp and red pulp of the spleen |
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Definition
-White pulp: pale, nodular foci rich in lympoid cells
-Red pulp: deep red areas that contain blood in large sinuses and free in extravascular space |
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Term
| What is/are the function(s) of the spleen? |
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Definition
-immunologic monity of the BLOOD
-major site of destruction of old (senescent) RBCs |
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Term
| Outline Splenic Blood Flow |
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Definition
| large blood vessels at hilus=> subdivide while in capsule and trabeculae as trabecular arteries=> enter white pulp as central arteries=> branch into penicilliary=> end as sheathed capillaries ensheathed by PALS=> flows into splenic sinuses=> moves into veins=> exits spleen at hilus |
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Term
| White Pulp of Spleen= _________ + __________ |
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Definition
| PALS + lymphoid follicles +/- germinal centers = white pulp |
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Term
| In the spleen, what kind of lymphocytes are in Peri-arterial Lymphoid Sheaths (PALS)? Lymphoid follicles? Germinal centers? |
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Definition
-PALS= T-cells (especially T-helper cells)
-LF= B-cells
-GC= B-cells |
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Term
| How are sheathed capillaries structurally special? How is this functionally relevant? |
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Definition
-NO endothelium, instead surrounded by macrophages
-blood passes from sheathed capillaries through macrophages and into venous sinuses of red pulp |
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Term
| Sheathed capillaires act as filter for _____. How? |
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Definition
-blood
-antigen exposed-presented to lymphocytes
-old RBCs removed from circulation |
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Term
| True or False: The spleen acts as an immunological monitor of blood and lymph, thus it has afferent and efferent lymphatics. |
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Definition
| FALSE, blood only and NO afferent lymphatics |
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Term
| What kind of tissue lies between splenic sinuses? |
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Definition
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Term
| The leakiness of _______ and _______ in the spleen allows blood to come into contact with lymphocytes and macrophages in spenic cords. How is this functionally relevant? |
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Definition
-splenic sinuses
-sheathed capillaries
-allows old RBCs to be removed by macrophages and blood to be inspected for foreign material |
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Term
| Describe the parenchyma of splenic red pulp. Venous sinuses? |
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Definition
-contains macrophages of sheathed capillaries and blood cells in transit
-contain RBCs that will be exiting the spleen through splenic vein, wall are discontinuous with gaps b/n endothelial cells |
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Term
_______ + _______= white pulp of spleen
_______ + ______ = red pulp of spleen |
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Definition
PALS + lymphoid follicles +/- germinal centers= white pulp
splenic sinuses + splenic cords= red pulp |
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Term
| What constitutes the stroma of the spleen? Parenchyma? |
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Definition
-Stroma: capsule, trabeculae, and reticular framework
-Parenchyma: B-cells, T-cells, plasma cells, dendritic cells, etc |
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