The Lympathic System
Terms
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- Define Hodgkins disease.
- Malignancy of lymph nodes; contains Reed-Sternberg cells.
- Define Lymphoma.
- Any neoplasm (tumor) of the lymphoid tissue, benign or malignant.
- What is Mononucleosis?
- Viral disease (aka Kissing disease) common in adolescents and young adults; Caused by the Epstein-Barr virus, which attacks B lymphocytes.
- Define Non-Hodgkins lymphoma.
- Includes all cancers of lymphoid tissues except Hodgkins disease. Involves uncontrolled multiplication and metastasis of undifferentiated lymphocytes; 5th most common cancer.
- What is the sentinel node?
- The 1st node that receives lymph drainage from a body area suspected of being cancerous.
- Which two ducts receive lymph from the body?
- Right lymphatic duct and thoracic duct
- How is lymphatic flow maintained?
- By skeletal muscle contraction, pressure changes in thorax. Backflow prevented by valves.
- What type of cells may spread through the body via the lymphatic stream?
- Pathogens and cancer cells.
- What type of cells are found in lymphoid tissues?
- Lymphocytes (T cells or B cells), plasma cells, macrophages and reticular cells that form the lymphoid tissue stroma.
- What type of tissue is contained in lymphoid tissue?
- Reticular connective tissue.
- What is the function of lymphoid tissue?
- To house macrophages and lymphocytes.
- What are lymph nodes?
- Principal lymphoid organs that are discrete encapsulated structures containing reticular tissue. Lymph nodes filter lymph and help activate immune system.
- What makes up a lymph node?
- Fibrous capsule, cortex and medulla.
- What type of cells are found in the cortex?
- Lymphocytes
- What type of cells are found in the medulla?
- Macrophages
- How does lymph circulate within lymph nodes?
- Lymph enters on convex side via afferent lymphatic vessels, enters subcapsular sinus that goes through cortex, medulla. Exits at hilus via efferent vessels.
- What are the 2 functions of lymph nodes?
- To filter microorganisms entering lymph, preventing them from being delivered to the blood, and to help activate immune system.
- What type of cells do the spleen, thymus, tonsils, and Peyers patches contain?
- Macrophages and lymphocytes.
- Where is the spleen located within the body?
- On the left side of the abdominal cavity just beneath the diaphragm, it curls around the anterior aspect of the stomach.
- How does the spleen get blood?
- From the large splenic artery and vein, which enter and exit the hilus.
- What are some functions of the spleen?
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- extracting aged, defective blood cells and platelets from blood
- its macrophages remove debris and foreign matter from blood - What are 3 additional functions of the spleen?
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Storing breakdown products of RBCs for later reuse and releasing others to blood for processing by liver.
Site of erythrocyte production in fetus.
Stores blood platelets. - What is white pulp?
- Areas composed mostly of lymphocytes suspended on reticular fibers.
- What is red pulp?
- All remaining splenic tissue, that is, the venous sinuses (blood sinusoids) and the splenic cords, regions of reticular connective tissue exceptionally rich in macrophages.
- What is the purpose of white pulp?
- Immune functions of the spleen.
- What is the purpose of red pulp?
- Disposing of worn-out RBCs and bloodborne pathogens.
- What type of tissue does the thymus develop from?
- Endoderm
- What hormones does the thymus secrete?
- Thymosin and Thymopoietin.
- What is an important function of the thymus?
- It causes T lymphocytes to become immunocompetent (function against specific pathogens in the immune response).
- Describe the thymus functional changes during aging.
- During childhood, increases in size when most active. During adolescence, growth stops and starts to atrophy. By old age, replaced by fibrous, fatty tissue.
- How does the thymus differ from other lymphatic organs?
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Is only lymphoid organ that doesn't fight antigens.
Second, the thymus' stroma consists of epithelial cells. - Where are the palatine tonsils located?
- On either side at the posterior end of the oral cavity.
- What two things should you know about palatine tonsils?
- Largest tonsils and ones most often infected.
- Where are the lingual tonsils located?
- At the base of the tongue.
- Where are the pharygeal tonsils located?
- In the posterior wall of the nasopharynx.
- What are Peyer's patches?
- Large isolated clusters of lymphoid follicles, (similar to tonsils), located in wall of distal portion of the small intestine.
- Name the lymphoid organs.
- Lymph nodes, tonsils, spleen, thymus, and Peyer's patches of the intestine.
- What is the function of T cells?
- To manage immune response and directly attack and destroy foreign cells.
- What is the function of B cells?
- B cells protect the body by producing plasma cells.
- Afferent lymphatic vessels
- Vessels leading toward lymph nodes.
- Subcapsular sinus
- Large, baglike sinus leading into a number of smaller sinuses.
- Hilus
- Indented region on concave side of node leading into efferent vessels.
- Efferent lymphatic vessels
- Vessels going away from lymph nodes.
- What type of tissue does all lymphoid organs (except thymus) develop from?
- Mesenchymal cells of mesoderm.
- What is an antigen?
- Anything the body perceives as foreign (bacteria, viruses, cancer cells).
- Mucosa-Associated Lymphatic Tissue (MALT)
- Small lymphoid tissues found in digestive and respiratory tracts.
- The function of MALT is:
- Protects digestive and respiratory tracts from attacks of foreign matter entering mucosa-lined cavities.
- The function of Peyer's patches is:
- To destroy bacteria in appendix and generate Memory lymphocytes for long term memory in intestine.
- The function of tonsils is:
- Guard throat by "inviting" bacteria into lymphatic system to destroy them.
- What is the first lymphoid organ to appear in human development?
- The thymus.
- The function of the spleen is:
- To provide a large, blood-filled site for lymphocyte proliferation and immune surveillance and response; cleanse blood.
- What are plasma cells?
- Daughter cells that secrete antibodies into the blood.
- What immunocompetent cell produces plasma cells?
- B cells (or B lymphocytes)
- The lymph node has 2 histologically distinct regions; name them.
- The cortex and medulla.
- Entry of lymph into lymphatic capillaries is promoted by what?
- ONe-way minivalves formed by overlapping endothelial cells.
- What are lateals?
- Highly specialized lymphatic capillaries that absorb digested fats from intestine.
- What channels (small to large) does lymph flow through?
- Lymphatic capillaries, collecting vessels, trunks, ducts.
- Lymph nodes are found in which body regions?
- Cervical, inguinal, axillary (under arms).
- What are the components of MALT (mucosa-associated lymphatic tissue)?
- Peyer's patches, appendix, tonsilslymphoid follicles in bronchi.