ch 22 lymphatic Flashcards
What are the 3 functions of the lymphatic system?
- fluid balance
- lipid absorption: by lacteals (lymphatic vessels in digestive tract lining)
- defense
What is chyle?
The lymph in the digestive tract. It is white in color due to high lipid content
Name the parts of the lymphatic system
lymph, lymphatic vessels, lymphatic tissue, lymphatic organs, and lymphocytes.
How is lymph formed?
Excess fluid passes through the tissue spaces and enters lymphatic capillaries to become lymph.
What makes lymphatic capillaries different from blood capillaries? Why is it easy for fluid and other substances to enter a lymphatic capillary, but impossible for it to go back out?
They are dead ended, lack a basement membrane. The cells of the simple squamous epithelium slightly overlap. This facilitates their function in two ways: First everything can enter. Second, the overlapping cells act as one-way valves so nothing can flow back out.
What is the function of valves in lymphatic vessels? Name three mechanisms responsible for moving lymph through the lymphatic vessels.
prevent lymph from back flow.
3 mechanisms for moving lymph:
- contraction of lymphatic vessels
- contraction of skeletal muscles
- thoracic pressure changes when breathing
name the lymphatic vessels from small to large. What is the largest vessel? What drains into it?
- Lymphatic capillaries
- Lymphatic vessels (have valves, looks like beads)
- Lymphatic trunks (drain lymph from major portions of body)
- Lymphatic ducts.
Thoracic duct is largest. It drains lymph from the right side of the body inferior to the thorax and the entire left side of the body
What is lymphatic tissue comprised of?
What differentiates a lymphatic organ from lymphatic tissue and what are the lymphatic organs?
lymphocytes, macrophages, dendritic cells, reticular cells, and other cell types.
Lymphatic organs are encapsulated and diffuse lymphatic tissue is not. Organs are thymus, spleen and lymph nodes.
What are the functions of lymphocytes and reticular fibers in lymphatic tissue?
the network of reticular fibers in the lymphatic tissue traps microorganisms and other particles and lymphocytes can come consume them.
What is mucosa-associated lymphoid tissue (MALT)? In what way is the location of MALT beneficial?
non-encapsulated lymphatic tissue found in and beneath the mucous membranes lining the digestive, respiratory, urinary, and reproductive tracts (all open to outside of body). Prime locations to intercept microorganisms as they enter the body.
what is the difference between encapsulated and non-encapsulated lymphatic tissue?
Encapsulated is within a connective tissue capsule. It forms most lymphatic organs (spleen, thymus, lymph nodes). Non-encapsulated lacks the capsule and is often associated with other organ systems.
Distinguish among lymphatic tissue, lymphatic nodules, Peyer patches, and lymphatic follicles.
Lymphatic tissue: lymphocytes, macrophages, and other cells. Can make lymphatic organs or just line areas.
Lymphatic nodules: denser arrangements of lymphocytes in compact spherical structures surrounded by diffuse lymphatic tissue.
Peyer patches: groups of lymphatic nodules in the small intestine and appendix.
Lymphatic follicles: lymphatic nodules in lymph nodes and the spleen
Describe the structure, function of the tonsils.
large groups of lymphatic nodules and diffuse lymphatic tissue in throat. 3 types: pharyngeal, 2 palatine, and lingual. Protect against pathogens entering from nose or mouth.
- What are lymph nodes?
- Where are lymph nodes found?
- Describe their structure?
- How do they work?
- If immune response is initiated, where do lymphocytes migrate to divide?
- They are lymphatic organs
- distributed along the course of the lymphatic vessels, most numerous at entrances to trunk.
- They are encapsulated with a cortex and medulla. Have trabeculae to subdivide sections (inward extensions of capsule). Lymphocytes and macrophages attach to reticular fibers.
- Lymph filters in the afferent arms-like structures. Macrophages remove debris, lymphocytes may start and immune response. Then lymph flows out the efferent arms. They are the only structures that filters lymph.
- Germinal centers.
What is a germinal center of a lymph node?
the center area of a lymphatic nodule where lymphocytes rapidly divide.
What is the structure of the spleen? Trace the pathway of blood into the spleen and back out.
- Consists of Red pulp and white pulp.
- Blood goes from splenic artery into white pulp where it is cleaned by lymphocytes. Next it goes to red pulp where macrophages eat old RBCs and debris. Finally it leaves via the splenic vein.
- What is the structure of the thymus?
2. What is its function?
- A bilobed gland that has lymphocyte compartments made by endothelial cells (rather than reticular fibers).
- It secretes thymosin stimulating T-cell maturation. T-cells which would react to self-molecules are destroyed and only the good ones are sent out to the body.
What is immunity?
The ability to resist damage by foreign substances. Divided into innate immunity and adaptive immunity
Whats the difference between innate and adaptive immunity? Which one is unique to vertebrates?
Innate aka non-specific immunity: response we are born with. Same response w/ ea exposure. No memory. Not specific. All organisms have this
Adaptive Immunity aka specific immunity: occurs when innate immunity is breached. Responses acquired thru life. Response is remembered and is stronger/faster ea time. Unique to vertebrates.
What are the 4 components of innate immunity?
- physical barriers: skin, tears, saliva, mucus membranes
- Chemical Mediators: Chemicals that kill or block pathogens. Cytokines, histamines, sebum, lysozyme, and complement proteins.
- White Blood Cells
- The inflammatory Response
what are cytokines and what roles do cytokines play as chemical mediators?
Are chemicals released by one cell that binds to and affects the activity of another cell. Interferons are an example.
What is complement? How is it activated? How does complement provide protection?
- A chemical mediator of innate immunity. It is a series of blood proteins that destroys abnormal cells and “complements” adaptive immunity.
- Activated by a compliment cascade in either the alternative pathway or classic pathway.
- Forms MACs, opsonizes other cells, promotes inflammation, and calls other cells to help.
- What are interferons?
2. How do they protect against viral infection?
- They’re cytokines. Antiviral proteins that also protect the body against some forms of cancer.
- They cause neighboring cells (where a virus is attacking) to produce antiviral proteins. Also activates phagocytic immune cells.
What is opsonization?
one way that complement proteins kill. They attach to the surface of bacterial cells and stimulate macrophages to phagocytize the bacteria.
Define chemotactic factor, chemotaxis, and phagocytosis.
Chemotactic factor: acts as a chemical signal to attract leukocytes
Chemotaxis: the affinity of white blood cells for foreign cells. Attracted to the chemotactic factor.
Phagocytosis: phagocytic cells eating other cells and fragments.
- What are the functions of neutrophils and macrophages?
- Are these part of innate or adaptive immunity?
- What is pus?
- Neutrophils: They can phagocytize or release lysosomal enzymes to kill. They are small phagocytic cells.
Macrophages: Big pagocytic cells in immune system. Expand on neutophils’ roles.
- Innate immunity
- Pus: accumulation of dead neutrophils, dead microorganisms, debris from dead tissue, and fluid.
What effects are produced by the chemicals released from basophils, mast cells, and eosinophils? Part of Innate of adaptive immunity?
Basophils: release histamine and leukotrienes—that produce an inflammatory response or activate other mechanisms.
Mast cells: Same as basophils, but stuck in place at points of entry to body.
Eosinophils: secrete enzymes that kill parasites.
INNATE IMMUNITY
What are Natural Killer Cells? Part of Innate or adaptive immunity? What do they do?
Lymphocytes. Part of innate immunity. Kill tumors abnormal and virus infected cells.
Define antigen. Distinguish between a foreign antigen and a self-antigen.
Substances that elicit an immune response are called antigens.
Foreign antigens: are not produced by the body but are introduced from outside it. viruses, bacteria, pollen, dander, food and drugs ect. They may cause an immune response.
Self-antigens are molecules the body produces and shouldn’t cause an immune response unless there is an autoimmune disease.