Chapter 20: Lymphatic system and Immunity Flashcards
Define Immunity
process that protect the body from cellular injury and disease-causing cells, and pathogens
what are the two components of the lymphatic system
- lymphatic vessels (tubes)
2. lymphatic tissues and organs (clusters of lymphoid follicles, tonsils, lymph nodes, spleen, thymus
functions of the lymphatic system (3)
- regulation of interstitial fluid volume
- absorption of dietary fats
- immune functions
how many lymph trunks are there?
nine lymph trunks
intestinal trunk and lumbar trunk drain into what vessel
cisterna chyli
what does the cisterna chyli and other lymph trunks drain into?
one of two lymph ducts- thoracic duct and right lymphatic duct
How does the lymph drain?
drains into the blood through low-pressure venous circuit, returns to the heart through valves, skeletal muscles, smooth muscle walls in the lymph-collecting vessels
Describe the lymphatic capillary walls
not tightly joined together, able to flap open and close, fluid is able to leak into the blood increasing pressure in the interstitial fluid
what happens when the pressure in the interstitial fluid decreases?
endothelial cells flap shut, major role in precise control of the amount of fluid between cells
what is the predominant tissue type of the lymph system?
loose CT called reticular tissue that contains specialized cells and thin reticular fibers (traps pathogens)
What do lymphoid organs house?
leukocytes: macrophages, B lymphocytes, and T lymphocytes
What is Mucosa-Associated Lymphatic Tissue (MALT)?
loosely organized clusters of lymphoid tissue that protects the mucous membrane
Where can MALTS be found?
tonsils, Peyer’s patches, apendix
What are Lymph nodes?
small clusters of lymphatic tissues located along lymphatic vessels throughout the body
What are the functions of Lymph nodes?
- traps pathogens
- drains out through efferent lymphatic vessels
- prevents pathogens from being delivered to the blood
What is the spleen?
largest lymphoid organ in the body, protects. the body from pathogens that have entered the blood
What is the thymus?
secretes hormones that carry on the function of producing T cells
What is the first line of defense of the Immune system?
includes the cutaneous and mucous membranes that act as surface barrier to block pathogen into the body
What is the second line of defense of the immune system?
includes the responses of the cells and proteins that make up the innate immunity
What is the third line of defense in the Immune system
includes the responses of the cell and protein of adaptive immunity
Innate immunity
consists of antimicrobial proteins and certain cells that respond quickly. Main response for the first 12 hours (exist in the blood stream)
Adaptive immunity
responds to specific antigens
Natural Killer cells
- located in the blood and spleen
- main response is to activate the T cells of adaptive immunity
How does lymphatic and immune system work together?
- lymphoid organs and tissues provide a residence for cells of the immune system
- lymphoid traps pathogens for the immune system
- lymphoid organs activate cells of the immune system
Phagocytes
-includes macrophages, neutrophils, eosinophils
What are the other cells of the innate immunity?
-nonphagocytic cells include NK cells, dendritic cells, and basophils
Antimicrobial proteins
-includes complement proteins and several types of cytokines
complement
20 or more plasma proteins produced mostly by the liver
what happens when complement proteins are activated?
- cell lysis
- formation of MAC
- enhanced inflammation
- neutralization of viruses
- enhancing phagocytosis
- opsonization
- clearance of immune complexes
what are cytokines?
proteins produced by several types of immune cells that enhance immune response
What cytokines are involved in the innate immunity?
- tumor necrosis factor
- Interferons
- interleukins
What are the two stages of inflammation?
- damaged cells release inflammatory mediators
2. phagocytes arrive and clean up the damaged tissue
What are the inflammatory mediators?
- histamine
- serotonin
- cytokines
- bradykinin
- prostaglandins
- leukotrienes
What are the 4 cardinal signs of inflammation?
- redness
- heat
- swelling
- pain
Phagocyte response from inflammation
- local macrophages are activated and contain invading pathogens
- inflammatory mediators and complement proteins attract neutrophils (margination)
- increased permeability known as diapedesis
- monocytes go to the tissue
- bone marrow increases production of leukocytes
What causes a fever?
response when pyrogens are released from damaged cells or certain bacteria
Steps of class 1 MHC (4)
- cell synthesizes either a self antigen or a foreign antigen
- antigen is broken down by enzymes in the cytosol
- fragment of antigen goes through the RER and is coupled with a class 1 MHC molecule in the RER
- MHC-antigen complex leaves the RER bu a vesicle and is inserted into the plasma
Steps of class 2 MHC
- cell ingest a pathogen by phagocytosis
- phagocytic vesicle fuses with a lysosome and the antigen is fragmented
- lysosome fuses with a vesicle from the RER that contains class 2 MHC molecule
- MHC-antigen complex is inserted into the cell’s plasma
TH cells
exerts their effects through secretion of cytokines
-stimulation of macrophages, TC cells, B cells
TC cells
- kill other cells
- release protein perforin are creates pores
describe the three phases
- a B cell clone recognizing its specific antigen, which triggers it to undergo changes and secreting antibodies
- antibodies in the blood rises dramatically
- persistence of a population of B cells that are faster if another antigen is encountered
antibody structure
- basic subunit is a Y-shaped molecule formed from 4 peptide chain (2 heavy and 2 light)
- each chain has 2 types of regions
- constant region
- variable region
What are the 5 basic classes of antibody?
- IgG
- IgA
- IgM
- IgE
- IgD
What are the different actions of antibodies (ability to bind antigens)?
- agglutination
- precipitation
- opsonization
- neutralization
- complement activation
- stimulation of inflammation
