Lymphatic & Immune Systems Flashcards
Lymphatic System is a ___ system that begins with ___ which merge to form ___ which merge to form ___
One way
Lymphatic capillaries
Lymphatic vessels
Lymphatic ducts
Lymphatic systems acts as a suction pump to retrieve ___, ___ and ___ from ___
Water, proteins and WBC from the tissues
Lymph
Fluid in the lymphatic vessels
Lymph nodes
Lymph filters
Lymph nodes role in the immune system
Contain WBC which initiate immune response against foreign bodies picked up by the lymph
Large lymphatic ducts merge to form the _____ which is the
Thoracic duct
Largest lymphatic vessel found in the chest
Role of the thoracic duct
Empty into a large vein near the neck
Also lymphatic vessels from the intestines dump dietary fats into the thoracic duct
Innate immunity
General, non-specific protection the body provides against various invaders
Simplest = skin
Innate immunity core components:
- Skin
- Tears, saliva and blood contain _____ which is:
- _____ of stomach destroys many pathogens
- Macrophages and neutrophils ________
- _______ is a group of 20 blood proteins which can __________, leading to their destruction
- Skin
- Tears, saliva and blood contain Lysozyme which is an enzyme that kills bacteria by destroying cell walls
- Extreme acidity of stomach destroys many pathogens
- Macrophages and neutrophils INDISCRIMINATELY phagocyte micro-oganisms
- Complement system is a group of 20 blood proteins which can nonspecifically bind to the surface of foreign cells, leading to their destruction
Humoral immunity
Specific protection by antibodies aka immunoglobulins
Antibodies structure
Light and heavy chain components joined by disulfide bonds
Constant region and variable (antigen binding) region
Antigen function
Binds to microorganisms that have been specifically recognized leading to their destruction and removal from the body
Immunoglobiulins/antibodies are differentiated by their:
Most of the antibodies circulating in the plasma is the ____ class
Constant region
IgG class
Molecule that an antibody binds to is the
Antigen
Small site in which an antibody recognizes within a larger antigen is called an
Epitope
Protein enabling the production of antibodies is called the ___ and the molecule becoming antigenic is called the ___
Carrier
Hapten
When an antibody binds to an antigen any of the following happens to initiate removal from the body:
- Binding directly inactivates antigen
- Binding can induce phagocytosis by macrophages or neutrophils
- Presence of antibodies on the surface of the cell can activate the complement system to form holes in the cell membrane and lyse the cell
Antibodies are produced by
B cells
Antigen produced by a cell can recognize ___
But B cells can produce ___
Only one type of antigen
All types of antibodies to recognize their antigen
When antigen binds to the antibody of the specific immature B cell, the cell is stimulated to proliferate and differentiate into two kinds of cells:
Plasma cells: produce and secrete antibody protein into plasma
Memory cells: Produced from the same clone and have same variable regions but don’t secrete antibody., just are pre-activated B-cells that wait for the same antibody to appear before activation
If activation of the memory cell occurs
Start producing antibody very quickly, so quickly that no symptoms of illness appear (Clonal selection)
Clonal selection
B cells memory cells target antigens already seen by the immune system
Primary immune response
Can take a week or more for B cells to proliferate and secrete significant levels of antibody on the first exposure
Too slow to prevent symptoms from occuring
Secondary immune response
Second exposure to specific antibody is stronger and swifter and symptoms don’t develop
“Immunity” due to presence of memory cells
Vaccination
Used to improve response to infections by exposing the immune system to an antigen associated with a disease so that the secondary immune response builds up before pathogen is encountered in the future
IgM antibody location and function
Blood and B cell surface
Initial immune response, structure of blood, structure of B cell as antigen receptor
IgG antibody location and function
Blood
Ongoing immune response, majority antibody in blood, can cross placenta
IgD antibody location and function
B cell surface
Serves IgM as antigen receptor on B cells
IgA antibody location and function
B cell surface
Serves with IgM as antigen receptor on B cells
IgE antibody location and function
Blood
Allergic reactions
Two types of T cells: T helpers (CD4) T killers (CD8) What are their roles?
CD4: Activate B cells, T killer cells and other immune cells
-Central controller of immune response
CD8: Destroy abnormal host cells
T helpers communicate with otters cells by releasing ___ and ___
special hormones called lymphokines and interleukins
T helper cell is the host of the virus
HIV
T killer role to destroy abnormal host cells such as
Virus-infected host cells
Cancer cells
Foreign cells such as skin graft given by incompatible donor
“T” in T-cell stands for :
Thymus
They develop in the thymus gland during childhood in bone marrow
T cell receptor
Protein on the T-cell surface that can bind antigen
How do T-cells recognize. an antigen?
Bind to the proteins on its surface for examination
Major histocompatibility complex
Cell-surface proteins so that immune system can keep an eye on whats going on inside every cell
Two kinds of major histocompatibility complexes (MHCs) are ___ and ____
Where are they found?
MHC I: on surface of every nucleated cell in the body
MHC II: only certain special cells have them
Function of MHC I
Randomly pick up peptides from the inside of the cell and display them on the surface allowing T-cells to monitor cellular contents
EX: cell with protein gets piece of protein exposed by MHC I and T-killer cell comes to destroy it
Function of MHC II
Antigen presenting cells (APCs) that phagocyte proteins or cells and display fragments using the MHC II display system when T helpers then recognize and bind to
Antigen presenting cells
MHC II and macrophages and B cells
MHC II Display System alerts T-helpers and they bind to the cell
T-helper will activate B-cells that are specific for that antigen and stimulate proliferation of T-killer cells
Activated B-cells mature into plasma cells and secrete antibodies specific for the antigen
Full activation of T cells only occurs when
T cell binds to both antigen and the MHC molecule
Bone Marrow
Site of synthesis of all the cells of blood from stem cells
Spleen
Filters the blood and is a site of immune cell interactions like lymph nodes
Destroys aged RBC
Thymus
Site of T cell maturation
Shrinks in size in adults because the maturation of the immune system and T cells are most active in children
Tonsils
Masses of lymphatic tissue in the back of the throat which help catch pathogens that enter the body via respiration or ingestion
Not required for survival, removed if infected
Appendix
Found near the beginning of the large intestine
Mass of lymphatic tissue which helps catch pathogens that enter the body
Not required for survival, removed if infected
Tolerance of the immune system
Ideally, the immune system should only destroy foreign antigens, not its normal proteins and cell structures
Self antigens
Antigens destroying normal cells
How does the body deal with the production of self-antigens
B-cells and T-cells must go through a selection process in order to eliminate self-reactive cells
B-cells the selection process to prevent self-antigens occurs in the
Bone Marrow and lymph nodes
B-cells whose surface receptors bind to normal cell surface proteins are
B-cells whose surface receptors bind to normal soluble proteins
Induced to die through apoptosis
Become unresponsive or anergic
T cells the selection process to prevent self-antigens occurs in the
Thymus or lymph nodes
Immature T-cells whose receptors bind normal proteins become
Anergic
Clone selection is. response to antigen recognition process in T-cells vs B-cells
Same
Autoimmune reaction
Immune system attacks normal body cells or proteins
i.e., diabetes, arthritis, Grave’s disease, myasthenia graves and celiac disease
Autoimmune diseases are often treated with
Immuno-suppresant drugs with steroids to reduce inflammatory response
