Lymphoid Tissue (Exam II) Flashcards
Lymphoid tissue organized into discrete structures or organs
Dense lymphoid tissue
Lymph nodes, spleen, thymus, & tonsils are all examples of:
Dense lymphoid tissue
Lymphoid tissue located throughout the body, associated with mucus membranes
Diffuse lymphoid tissue
Dense and diffuse tissue both contain a large number of ______ cells
Lymphocytes
Diffuse tissue is commonly seen in respiratory and digestive tracts as:
MALT
Lymphoid tissue where B and T cells acquire surface receptors
Primary lymphoid tissue
In primary lymphoid tissue, the B cells are located in the _____ while the T-cells are located in the _____
B cells—-> bone marrow
T cells ——> thymus
Mature B and T cells that secondarily migraine to all other lymphoid tissue are refferred to as:
Secondary lymphoid tissue
Malignant tumors of the immune system are refferred to as ____ when they involve solid organs and as _____ when they involve the blood
Lymphomas; leukemia
Circulating immune cells that are neoplastic
Leukemia
Network of blind ended vessels in connective tissue:
Lymphatic vessels
Lymphatic vessels provide a route which allows cells and large molecules in the ECS to:
Re-enter bloodstream
Lymphatic vessels assist circulation of _____, and concentrate _____ for elimination within lymph nodes
Lymphocytes; concentrate antigen
Encapsulated aggregates of lymphocytes & lymphoid tissue, distributed throughout the body
Lymph nodes
Lymph nodes are arranged in _____ or ____ along vessels of lymphatic origin
Chains or clusters
Areas where we find lymphnodes:
Submandibular, cervical , axillary, femoral, popliteal, and hilar
What are the 4 functions of lymph nodes:
- Non specific filtering of particulate matter and microorganisms form lymph
- Interaction of circulating lymphocytes with antigen in lymph
- Aggregation, activation, and proliferation of B cells with subsequent antibody production
- Aggregation & proliferation of T cells and induction of cytotoxic immunity
Due to the presence of macrophages, lymphnodes are:
Self-cleaning
Lymphocytes of all types, derived from the bone marrow:
Lymphoid cells
Lymphoid cells enter the lymph node via:
Bloodstream
Antigen presenting cell found within the lymph node:
Immune accessory cell
Immune accessory cells include:
Macrophages, B-cells, T-cells
Immune accessory cells (macrophages, B-cells, T-cells) originate in the:
Bone marrow
Immune accessory cell- macrophages at the periphery of germinal centers; antigen-presenting cells:
Follicular dendritic cells
Immune accessory cell- primarily found in germinal center that possess numerous phagocytic vesicles
Tingible body macrophage
Fibroblasts and reticular cells (fibroblasts like cells with phagocytic capability)
Stromal cells
What forms the connective tissue skeleton of lymph nodes?
Stromal cells and extracellular products
The lymph node contains an outer, fibrous _____ of dense irregular connective tissue
Capsule
Grossly, lymphnodes have dense, outer, cellular ______ and a less cellular inner _____
Cortex; medulla
What type of cells are found in the outer cellular cortex of lymph nodes?
B-cells, T-cells, & plasma cells
The medulla of lymph node is less cellular than the _____.
Cortex
Extensions of cortical tissue into the medulla of the lymph node
Medullary cords
The medullary cords of the lymph node are separated by broad lymphatic channels called:
Medullary sinuses
Interspersed throughout the cortex of the lymph node are very thin, collagenous:
Trabeculae
Blood vessels enter and leave the lymph node at the:
Hilus
Process of B- cells and T-cells leaving the blood stream and entering the lymph node
Diapedesis
Diapedesis is facilitated by complimentary:
Adhesion molecules
The complementary adhesion molecules that facilitate diapedesis of b and t-cells:
Addressins
Adressins are present on both:
Endothelial cells and lymphocytes
During diapedesis, the b and T cells migrates across the walls of specialized:
Post-capillary venules
Post capillary venules are considered:
High endothelial venules
Post capillary venules are lined by:
Cuboidal to columnar endothelium
Post capillary venules are located in the deep inner cortex of the lymph node at the ____ junction or _____ zone.
Corticomedullary junction or paracortical zone
Space beneath the capsule where numerous afferent lymph vessels drain into:
Cortisol/subcapsular sinus
The lymphatic vessels that drain into the cortical or subcapsular sinus are _____ lymph vessels
Afferent
In the lymph node: The endothelium of sinus on the side adjacent to the capsule is ______ to prevent leakage, but _____ on the side adjacent to the parenchyma.
Continuous; discontinuous
The lymphatic sinuses are not open spaces like blood sinuses, but rather are filled with:
Reticular fibers and macrophage processes
The sinuses of the lymph nodes that are located in the cortex:
Cortical sinuses, trabecular sinuses, peritrabecular sinuses
broad lymphatic channels in the inner, less cellular medulla:
Medullary sinuses
The medullary sinuses contain what type of cells?
Lymphocytes, plasma cells, monocytes
The medullary sinuses converge on the:
Hilus
Lymph drains from the hilus of the node via:
Single efferent lymph vessel
Eventually, lymph returns to the bloodstream via the:
Thoracic duct or right lymphatic ducts
Lymphatic drainage to regional lymph node is important in:
Metastasis of tumor cells
Within the cortex of the lymph node are densely packed, highly cellular:
Lymphoid follicles
Lymphoid follicles can also be called:
Lymphatic nodules or primary follicles
Lymphoid follicles may contain a paler, less dense ______.
Germinal center
If a germinal center is present in a lymphoid follicle, the follicle is considered:
Secondary follicle
A secondary follicle (germinal center present) indicates the node is:
Responding to antigen
Lymphocytes respond to antigen by increasing antibody production via:
Clonal expansion
secondary follicles are sites of _____ .
B-cell proliferation
secondary follicles (sites of b-cell proliferation) can be referred to as:
Secondary hemopoiesis
What cells are present at sites of B-cell proliferation (secondary hemopoiesis): (4)
Lymphoblasts, macrophages, immature b & T cells
Proliferation of lymphocytes (within the lymph node) results in:
Englarment and swollen lymph node
The dark staining rim around the germinal center of the lymph node is called the:
Mantle zone
The mantle zone of the germinal center of the lymph node is the region of:
Antigen presentation
The organization of lymphocytes in the cortex of the lymphnode is NOT:
Uniform
The secondary follicle of lymph node is light staining due to:
Lots of cytoplasm
Lobular lymphatic organ located in the mediastinum:
Thymus
The thymus is embryologically derived from:
Epithelial outgrowth of 3rd pharyngeal pouch
Important hematopoietic organ during fetal development
Thymus
the thymus is similar in appearance to the lymph node but lacks ____ and the medulla lacks _____
Lymphoid follicles ; medullary cords and sinuses
The thymus has a ______ of dense, irregular connective tissue:
Thin capsule
The thymus contains slender _____ or _____ that divide the thymus into lobules
Interlobular septa or trabeculae
The thymus has a darker staining ____ and a paler _____.
Cortex ; medulla
The functions of the thymus: (4)
- Production of mature immunocompetent Th (helper T cell) and Tc cells (cytotoxic T cells)
- Clonal proliferation of cytotoxic T cells
- Clonal deletion of self antibodies
- Secretion of hormones regulating T cell development and maturation
The clonal deletion of self antibodies of the thymus aids in the development of:
Immunologic self tolerance