Immune System Flashcards
Brief overview of what the immune system includes
Primary lymphoid organs
Secondary lymphatic tissues
Various cells in the innate + adaptive immune system
What comes under the primary lymphoid organs of the immune system
Thymus
Bone marrow
What comes under the secondary lymphatic tissues
Spleen
Tonsils
Lymph vessels
Lymph nodes
Adenoids
Skin
Liver
What comes under innate leukocytes (WBC)
Phagocytes
Mast cells
Eosinophils
Basophils
Natural killer (NK) cells
INNATE LEUKOCYTES
What comes under phagocytes?
Macrophages
Neutrophils
Dendritic cells
Functions of innate leukocytes
Identify + eliminate pathogens
Mediators in the activation of the adaptive immune system
What are MHC I molecules?
Proteins on the surfaces of all nucleated cells that help the immune system distinguish between “self” (body cells) and “non-self” (foreign cells).
What do MHC I mol do if the cell is infected?
MHC I mol displays fragments of proteins from the infectious agents to T-cells.
Do healthy cells display MHC I molecules?
No so are ignored by the immune system.
What happens to cells identified as “non-self” by foreign proteins?
Will be attacked by the immune system.
PRIMARY LYMPHOID ORGAN
Role of the Thymus
Provides an env for the development of T cells from heamatopoietic progenitor cells.
PRIMARY LYMPHOID ORGAN
When is the Thymus its largest + most active?
During the neonatal + pre-adolescent period of development.
PRIMARY LYMPHOID ORGAN
By what stage in life does the thymus begin to atrophy and what else happens?
Early teens
Thyme stroma is replaced by adipose tissue
When does T-lymphopoiesis occur?
All through life.
PRIMARY LYMPHOID ORGAN
Role of the bone marrow
RBC prod in the heads of long bones.
Red bone marrow is a key element in the lymphatic system as it generates lymphocytes from immature hematopoietic progenitor cells.
What do the PRIMARY LYMPHOID ORGANS have to do with lymphocytes?
They’re involved in the prod + early selection of lymphocytes.
What are lymphatic vessels?
Network carrying lymph fluid unidirectionally towards the heart.
Functions of the lymphatic system
Transportation of WBC to + from lymph nodes into bones
Transportation of antigen-presenting cells to the lymph nodes where an immune response is stimulated.
What does the spleen act as?
A blood filter
- Removes antibody-coated bacteria + anti-body coated blood cells through blood + lymph node circulation
What does the spleen synthesise??
Antibodies
Lymph nodes are widely distributed throughout the body, give some examples of where they can be found
Armpit
Stomach
What are lymph nodes linked by?
Lymphatic vessels
Purpose of lymph nodes
Act as filters for foreign particles
Important in the functioning of the immune system
What are lymph nodes packed tightly of?
WBCs called lymphocytes + macrophages.
What in the skin is part of the adaptive immune system?
Langerhans cells
What does the reticuloendothelial system of the liver contain?
Immunologically active cells acting as a sieve for antigens carried to it via the portal system.
What do leukocytes (WBCs) do?
Defend body vs disease + foreign material.
List the innate leukocytes
Phagocytes
Mast cells
Eosinophils
Basophils
Natural killer (NK) cells
INNATE LEUKOCYTES
Name the types of phagocytes that invade pathogens
Neutrophils
Macrophages
INNATE LEUKOCYTES
Phagocytes that invade pathogens - Neutrophils
Where are neutrophils normally found?
In bloodstream
INNATE LEUKOCYTES
What is the most abundant type of phagocyte?
Neutrophils
INNATE LEUKOCYTES - PHAGOCYTES
What do neutrophils do at the acute phase of inflammation?
They migrate towards the site of inflammation + are the 1st cells to arrive at the scene of infection.
INNATE LEUKOCYTES - PHAGOCYTES
Where do macrophages reside?
In tissues + produce chemicals.
INNATE LEUKOCYTES - PHAGOCYTES
What do macrophages do?
Get rid of worn-out cells in the body
Act as antigen-presenting cells that activate the adaptive immune system.
What are dendritic cells?
Phagocytes in tissues in contact w/ the external env + are located mainly in skin, nose, lungs, stomach + intestines.
What do dendritic cells serve as?
A link between bodily tissues + the innate + adaptive immune system due to presenting antigens to T-cells.
INNATE LEUKOCYTES - MAST CELLS
Where are they located?
Connective tissues
Mucous membranes
INNATE LEUKOCYTES - MAST CELLS
Purpose
Regulate inflammatory response
INNATE LEUKOCYTES - MAST CELLS
What are they associated with?
Allergy + anaphylaxis
INNATE LEUKOCYTES - BASOPHILS + EOSINOPHILS
What do they do?
Secrete chemical mediators involved in defending against parasites
Also play a role in allergic reactions.
CELLS OF THE ADAPTIVE IMMUNE SYSTEM
What are they?
Lymphocytes (special types of leukocytes)
CELLS OF THE ADAPTIVE IMMUNE SYSTEM
Major types of lymphocytes
B cells
T cells
CELLS OF THE ADAPTIVE IMMUNE SYSTEM
Where are lymphocytes derived from?
Hematopoietic stem cells in the bone marrow
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
T cells
What do they focus on?
Specific foreign particles rather than attacking just any antigens.
They circulate until they encounter their specific antigen.
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
T cells
What do they do?
Directly kill infected host cells, activating other immune cells, prod cytokines + regulate the immune response.
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
T cells
What are the 2 major subtypes?
Killer T cells
Helper T cells
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
T cells
Killer T cells
Kill cells infected w/ the virus
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
T cells
Helper T cells
Reg innate + adaptive immune responses
Help determine which response the body makes according to the pathogen present.
CELLS OF THE ADAPTIVE IMMUNE SYSTEM - LYMPHOCYTES
B cells
Antigen-specific receptor is an antibody mol on the B cell surface which recognises whole pathogens w/out any need for antigen processing.
What is innate immunity?
Natural resistance through physical, chemical + cellular approaches.
What are natural killer cells a part of?
Innate immune response
What do NK cells do as a part of the innate immune response??
Recognise abnormal MHC I mol on infected/tumour cells + kills them.
They identify + destroy cells infected by pathogens.
What does a NK cell do if it detects an infected or tumour cell?
Granules of perforin are secreted from its cytoplasm.
Perforin = Destructive protein creating a pore in target cell.
Granzymes are released in the immunological synapse.
Granzymes = Induces a target cell to undergo apoptosis.
== Phagocytic cells digest cell debris left behind.
What are NK cells an effective mechanism for?
Controlling pot infections + preventing cancer progression.
