Lymphatic sys #7 Flashcards
Functions of lymphatic system
- Pick up excess tissue fluid and cleanse it from bacteria and toxins out of the system and return it to the heart
- Provides site of surveillance for immune system cells
1st component of lymphatic system and its characteristics
Lymphatic vessel,
Lymph flows only towards heart(one system way),mini valves- to prevent backflow, unidirectional, permeable to large molecules-dissolved proteins and bacteria, absorbs leaked tissue fluid, fluid flow along pressure gradient
2nd component of lymphatic sys part a)
Lymph node and organs& tissues
lymph node: protect body by removing foreign matter from the lymphatic system contain macrophage(ingest ,engulf bacteria and foreign substances) and lymphocytes(respond to foreign substances), fluid flows slowly to allow macrophage and lymphocyte to carry out function,
2nd component of lymphatic sys part b)
other organs
1) spleen; blood rich organ–> filters and cleanses blood of bacteria and debris
destroys worn out erythrocytes and return breakdown product(iron) to liver, stores platelets, act as blood reservoir
2)Thymus gland; located low in the throat overlying the heart, produces hormone(thymosin) and others which is required in the programming of lymphocytes so that they can carry out their function
3)Tonsils, rings the pharynx, traps and prevents any bacteria and pathogen entering the mouth inflammation of tonsils: tonsillities
4) peyer’s patches located in the walls of the small intestine, destroys bacteria and microorganism prevents it from penetrating through the wall
What activates body defense system?
- pathogens(disease causing agents)
- antigens(non self antigen)
Body defenses- innate
Protects body from all foreign substances
Prevents the entry and spreading of bacteria and pathogen
responds immediately
cannot differentiate between foreign substances
what are the different barrier layers and its features
1st barrier: skin,mucous membrane,
2nd barrier: inflammatory response
3rd barrier: antibodies,macrophage
surface membrane barrier features:
PH acid of skin inhibits bacteria
sticky mucus traps and prevents micro-org and bacteria from entering mouth and nose
Ciliated mucosa in respiratory tract prevents dust and bacteria from entering lungs
acidic enzymes secretion from stomach juice kill bacteria
cells involved in innate immunity
phagocytes
-macrophage and neutrophils phagocytose foreign particles that escape mechanical barrier
NK cells
found in blood and lymph node
kills all cell types, non-selective
lyse and kill cancer cells and virus infected cells
kills cells instead of engulfing
Series of events to describe innate immunity
Injurious agents–>cells damaged–>release kinins , histamines
blood vessels dilate capillaries are
leaky, fluid
accumulates at
tissue spaces, pain,
temporary
limitation in movement,
blood clotting protein,
fibrin barrier, healing
(redness,heat)
increased metabolic rate
of repair of tissue and oxygen
nutrients to area,healing
Antimicrobial properities(innate immunity)
Complement- group of plasma protein that complements the actions of defense system
cytokines- protein produced by immune cells in response to antigens, serves to communicate between innate and adaptive immunity
Adaptive immunity characteristics
-protects body from most bacteria,virus
-differentiates foreign sub( intial exposure neccessary)
-targets a particular foreign matter
2 divsions of adaptive immunity.Describe
Humoral and cellular immunity
Cellular immunity- t lymphocytes
cytotoxins- binds and inserts toxic chemical in cell and destroys them(rupture)
helper t cells-stimualte activation and function of t and b cells
suppressor t cells-inhibits t and b cells activities, after antigen is destroyed, response stops
Humoral-Activated b cells divides into plasma (synthesis and secrete antibodies into interstitial fluid)memory b cells(responds to next infection)
B cells activation
-B cells bind to antigen of foreign substances through receptor mediated endocytosis
-Antigen broken down and presented to B cell plasma membrane as MHC antigen-presenting complex.
-T cells binds and recognise complex
t and b cells exchange keys signals
activation of b cells, differentatiate into plasma and memory b cells
Types of acquired immunity
Naturally and artificially
Naturally- active expose to viral infection
b cells encounter antigen and produces them
passive-b cells arent challenged to produce antibodies and dont produce memory cells
fetus through mother by placenta
Artificially-
active, given weakened living pathogen, vaccines, booster shot needed
passive-immune serum containing antibodies given
