Mod 3 Flashcards
Lymphatic vessels are connected to many lymph nodes. The 3 main types of white blood cells found in lymph nodes are…
Macrophages- engulf pathogen and other material found in lymph (filter)
B & T cells can be exposed to pathogens in the lymph nodes and become activated to fight infections.
What does the lymphatic system lack?
What are the 3 components of it?
RBC’s and Albumin
Fluid balance: Return tissue fluid to the blood stream
Immune Defense
Transportation of lipids absorbed in the digestive tract. Lipids enter the lymphatic vessels & are transported to the blood through the lymphatic sys.
Lymph Nodes
As lymph moves toward the blood stream through lymphatic vessels it passes through lymph nodes. Lymph nodes contain white blood cells: macrophages, B-cells, T-cells
Lymph Nodules
Accumulations of lymphatic tissue closely associated with the mucus membranes and referred to as MALT: Tonsils that surround the opening to the pharynx are lymph nodules. When in the intestine it’s called peyers patches.
Nodules are NOT connected to lymphatic vessels & lymph does NOT flow through them.
Do have macrophages, B-cells & T-cells
Macrophages
engulf pathogens or other material found in the lymph and filter it through endocytosis. Enzymes from lysosomes digest material: phagocytosis and leaves through exocytosis to be used as nutrients
Spleen
Blood reservoir, Immune response to foreign blood (B & T-cells), destroys defective RBC’s (macrophages)
Thymus
For t-cell maturation (thymosin), made in bone marrow
Physical Barriers
Epidermis: superficial layers are made of dead cells filled with a protein called keratin. Sebum-secretion- lowers pH <5 & kills pathogens, nonpathogenic bacteria called normal flora out compete pathogens.
Mucous membranes that line the digestive but are living. Goblet cells produce mucus
respiratory and urinary tracts.
Inflammation
From tissue damage and infection, responds by stimulating the inflammatory response- histamine is released into the tissue causing dilation= more blood flow to inflamed tissues & loosening of junctions of epithelial cells of capillary walls allowing more fluid to leave the blood into the tissues
Phagocytes
Specialized white blood cells such as neutrophils & macrophages carry out phagocytosis. Neutrophils are most abundant WBC
Complement proteins
Produced by the liver and released into the blood inactive. Bacteria activate it and these activated proteins increase inflammation and bind to bacterial cells to stimulate phagocytosis of the cells. Can also cause formation of pores in the plasma membrane= death to bacterial cell
Fever
Chemicals released from WBC’s . Fever boosts efficiency of immune sys. WBC’s become more active at fighting infections at higher temps.
Last line of defense: name 3 specifc defenses
Helper T-cells
Cytotoxic T-cells
B-cells
Produced in the bone marrow and released into blood inactive. Are naive. Once activated divide rapidly producing many more activated cells of the same type to help destroy bacterial or viral pathogens that have entered the body’s tissues
These cells recognize specific elements of pathogens called antigens- foreign molecules that activate T- cells etc for an immune response
Helper T-cell
Help cytotoxic t-cells and B-cells become activated to fight infections. Macrophages present eaten pathogens antigens on their plasma membrane and the naive helper t-cell comes in contact, activated and divides and produces many new activated cells to activate Cytotoxic t-cells and B-cells.
HIV- when helper t-cells are not able to help
AIDS- when helper t-cells population is too low
Cytoxic T-cell
1) Recognize antigens bound to the surface of other cells and become 2) activated by a chemical- cytokines. Will take antigens from virus and place them on the surface of the cell so cytotoxic t-cells can recognize cancerous cells or viruses. Release toxins
B-cells
Produce antibodies that can bind to antigens but specific to 1 antigen and carry out phagocytosis. Antigens are now on its body for helper t-cells to recognize.
Antibodies have 3 effects
Enhancing phagocytosis- macrophages are much more effective when antigen is coated with antibodies
Activating complement- activated to destroy antigen (most antigens are proteins found on surface of bacterial cells & viruses. Carbs can also be antigens
Neutralizing the antigen- the effect of the antigen is neutralized by coating it
Immunological memory
5-10 days to respond and destroy the antigen for a first time exposure and Primary Response
Secondary Responser: 24 hours many more helper t-cells, cytotoxic T-cells and B-cells become activated to destroy the antigen as long as it has the same antigens.
Can get a cold many times because multiple viruses cause same symptoms
Memory Cells
On a 2nd exposure to antigen, cells are activated, divide rapidly to produce many new cells and will carry out that cell’s particular function in the immune sys. but some will not participate in fighting, rather will stay in a partially activated state to fight it in a later time.
How does lymph move?
Contraction of skeletal muscle
Contraction of lymph vessels
Thoracic pressure changes
Immune Response in 5 steps
Recognition: Macrophages Recruitment: monocytes, granulates Activation Elimination: Phagocytosis Repair: Fibroblasts
Vaccines
Immunizations that can help prevent a person from getting a certain disease.
A Vaccines is made of a collection of antigens that will stimulate an immune response.
Killed pathogens, rendered harmless.
Helper T-cells, cytotoxic T-cells & B-cells can become activated & produce memory cells
Antibody
IgA 5-15
Can be secreted onto mucus membranes to provide additional protection against infections
Antibody
IgD <1
Main antigen receptor bound to the plasma membrane of B-cells
