49. Immune system – lymphoid organs and cells involved. Innate and acquired immunity. Flashcards
Lymphoid organs
- Contain lymphocytes which divide and differentiate
Lymphoid organs
- Contain lymphocytes which divide and differentiate
Primary Lymphoid organs (aka. central lymphoid organs)
- where immature lymphocytes develop
- organs where differentiation, proliferation and maturation of stem cells into immune competent cells occurs
Primary Lymphoid organs (aka. central lymphoid organs)
- where immature lymphocytes develop
- organs where differentiation, proliferation and maturation of stem cells into immune competent cells occurs
Thymus
- where T lymphocytes are formed
- generate and select T cells that will protect the body from infection
Bone marrow
- where B cell maturation and hematopoiesis occurs
- generates important immune system cells like B cells, granulocytes, natural killer cells (NK Cells) and immature thymocytes
- produced platelets and RBC
Thymus
- where T lymphocytes are formed
- generate and select T cells that will protect the body from infection
Bone marrow
- where B cell maturation and hematopoiesis occurs
- generates important immune system cells like B cells, granulocytes, natural killer cells (NK Cells) and immature thymocytes
- produced platelets and RBC
Secondary Lymphoid organs
- where antigen is localised so it can be effectively exposed to mature lymphocytes
- initiates acquired (adaptive) immune responce
Spleen
- contains T cells, B cells, Natural killer cells, macrophages, dendritic cells and RBCs
- antibodies and activated lymphocytes are produced here, they are then delivered to blood
- filters blood, traps foreign materials (antigens), provides defence against blood-borne antigens
Lymph nodes
- distributed through out body along course of lymphatic vessel
- B cells, T cells, macrophages and dendritic cells
- immunologic filters, drain lymph from most of the body tissues - filter antigens, before allowing lymph to the system again
Secondary Lymphoid organs
- where antigen is localised so it can be effectively exposed to mature lymphocytes
- initiates acquired (adaptive) immune responce
Spleen
- contains T cells, B cells, Natural killer cells, macrophages, dendritic cells and RBCs
- antibodies and activated lymphocytes are produced here, they are then delivered to blood
- filters blood, traps foreign materials (antigens), provides defence against blood-borne antigens
Lymph nodes
- distributed through out body along course of lymphatic vessel
- B cells, T cells, macrophages and dendritic cells
- immunologic filters, drain lymph from most of the body tissues - filter antigens, before allowing lymph to the system again
Tonsils
- traps bacteria and viruses from inhaled air
Appendix
- tells lymphocytes where to go to attack infection
- enhances intestines defences
Peyer’s patches
- detect antigens (bacteria, toxins)
- tell WBCs (B cells) to produce an antibody
Tonsils
- traps bacteria and viruses from inhaled air
Appendix
- tells lymphocytes where to go to attack infection
- enhances intestines defences
Peyer’s patches
- detect antigens (bacteria, toxins)
- tell WBCs (B cells) to produce an antibody
Innate immunity
- non-specific defence mechanisms that occur immediately or with hours of an antigen entering the body
- it’s present at birth, and doesn’t have to be learned
- treats all foreign invaders in the same way
- has no memory of the encounters, no protection for the future
- activated by chemical properties of the antigen
- physical barriers: skin, chemicals in blood, immune system cells
- Phagocytosis
- WBCs involved are: monocytes -> (develop into macrophages), neutrophils, eosinophils, basophils, Natural killer cells (NK cells)
Innate immunity
- non-specific defence mechanisms that occur immediately or with hours of an antigen entering the body
- it’s present at birth, and doesn’t have to be learned
- treats all foreign invaders in the same way
- has no memory of the encounters, no protection for the future
- activated by chemical properties of the antigen
- physical barriers: skin, chemicals in blood, immune system cells
- Phagocytosis
- WBCs involved are: monocytes -> (develop into macrophages), neutrophils, eosinophils, basophils, Natural killer cells (NK cells)
The complement system
- one protein activates another, and so on…
- functions: killing bacteria directly, attaching to bacteria and making it easier for neutrophils and macrophages to identify and ingest, attracting macrophages and neutrophils to trouble spot, neutralising viruses, helping immune cells remember specific invaders, antibody formation, increasing effectiveness of antibodies, helping body get rid of dead cells
Cytokines
- messengers of immune system
- WBCs and other immune cells produce cytokines when an antigen is detected
- stimulate certain WBCs to become more effective killers, attract other WBCs to the trouble area
- inhibit activity - ending immune response
- interferons - interfere with reproduction of viruses
- participate in acquired/ adaptive immunity too
The complement system
- one protein activates another, and so on…
- functions: killing bacteria directly, attaching to bacteria and making it easier for neutrophils and macrophages to identify and ingest, attracting macrophages and neutrophils to trouble spot, neutralising viruses, helping immune cells remember specific invaders, antibody formation, increasing effectiveness of antibodies, helping body get rid of dead cells
Cytokines
- messengers of immune system
- WBCs and other immune cells produce cytokines when an antigen is detected
- stimulate certain WBCs to become more effective killers, attract other WBCs to the trouble area
- inhibit activity - ending immune response
- interferons - interfere with reproduction of viruses
- participate in acquired/ adaptive immunity too
Acquired immunity
- not present at birth, it’s learned
- as a person’s immune system encounters antigens, components of acquired immunity learn the best way to attach each antigen - and develop memory cells for that antigen
- tailors its attack for a specific antigen, learn, adapt, remember
- takes time to develop after first exposure to new antigen, after, the antigen is remembered
- responses for future infection from those antigens are quicker and more effective, than first exposure
- WBCs responsible - Lymphocytes (T cells and B cells)
- acquired immunity begins when antibodies produced by B cells, encounter an antigen
- other cells involved: dendritic cells, cytokines, complement system
Acquired immunity
- not present at birth, it’s learned
- as a person’s immune system encounters antigens, components of acquired immunity learn the best way to attach each antigen - and develop memory cells for that antigen
- tailors its attack for a specific antigen, learn, adapt, remember
- takes time to develop after first exposure to new antigen, after, the antigen is remembered
- responses for future infection from those antigens are quicker and more effective, than first exposure
- WBCs responsible - Lymphocytes (T cells and B cells)
- acquired immunity begins when antibodies produced by B cells, encounter an antigen
- other cells involved: dendritic cells, cytokines, complement system
T Cells - respond to antigens when presented by MHC proteins
B Cells - involved in humoral immune response - antibodies secreted by B cells label invading microbes for destruction
Macrophages - kill microbes by ingesting them through phagocytosis, they also engulf viruses, cellular debris and dust particles in the lung
Neutrophils - leukocytes that, like macrophages, ingest and kill bacteria by phagocytosis
Natural killer cells - kill cells of the body that have been infected with viruses, they kill by creating a hole in the plasma membrane of the target cell. They also attack cancer cells before they have had chance to develop into a detectable tumour
T Cells - respond to antigens when presented by MHC proteins
B Cells - involved in humoral immune response - antibodies secreted by B cells label invading microbes for destruction
Macrophages - kill microbes by ingesting them through phagocytosis, they also engulf viruses, cellular debris and dust particles in the lung
Neutrophils - leukocytes that, like macrophages, ingest and kill bacteria by phagocytosis
Natural killer cells - kill cells of the body that have been infected with viruses, they kill by creating a hole in the plasma membrane of the target cell. They also attack cancer cells before they have had chance to develop into a detectable tumour
