2 - Cells and Tissues of the Immune Response Flashcards
What cell gives rise to all the cells of the immune system in bone marrow
Mulipotential hematopoietic stem cell
What cells do common lymphoid progenitor give rise to
- NK cells
- Small lymphocytes
↳ T OR B lymphocytes
What do B lymphocytes give rise to
Plasma cell
What cells do common myeloid progenitor give rise to
- Megakaryocytes (–> thrombocytes)
- Erythrocyte
- Mast cell
- Myoblast
What cells do myoblasts give rise to
- Granulocytes
- Monocytes (–> macrophage)
Granulocytes
- Basophil
- Neutrophil
- Eosinophil
Neutrophil
- Multilobed nucleus
- Are phagocytes
Mast cell
Granules filled with histamine and other mediators that act on blood vessels to promote increased blood flow and delivery of plasma proteins and leukocytes into the tissue
Basophil
Defend against allergens, pathogens and parasites
Eosinophil
- Anti parasitic and bactericidal
- Allergy responses
- Inflammation
Tissue resident macrophages
- Develop in foetal life from hematopoietic precursors in the yolk sac, foetal liver and bone marrow
- Derived from bone marrow postnatally
Dendritic cells
- Arise from myeloid lineage in bone marrow and differentiate into subsets
- Detect antigen in skin and mucosa and migrate to lymph nodes
What are the major subsets of dendritic cells
- Classical DCs (cDCs)
- Plasmacytoid DCs (pDCs)
- Monocyte derived DCs (moDCs)
Unique feature lymphocytes
Only cells that express clonally distributed antigen receptors, each specific for a different antigenic determinant
Classes of lymphocytes
- B lymphocytes
- Helper T lymphocyte
- Cytotoxic T lymphocyte
- Regulatory T lymphocyte
Functions of B lymphocytes
Neutralisation of microbe, phagocytosis, complement activation
Function of helper T cells
- Activation of macrophages
- Inflammation
- Activation of B lymphocytes
Function of cytotoxic T lymphocyte
Killing of infected cell
Function of regulatory T lymphocyte
Suppression of immune response
function of primary lymphoid organs
- Where B and T cells mature
- Learn how to differentiate between host cells and foreign pathogens
function of secondary lymphoid organs
Involved in the presentation of foreign antigens to T and B cells to activate adaptive immune system
Maturation of lymphocytes
Fully mature T cells leave the thymus, but immature B cells leave the bone marrow and complete maturation in secondary lymph nodes
Naive lymphocytes
May respond to foreign antigens in secondary lymphoid tissues or return by lymphatic drainage to the blood and recirculate through other secondary lymphoid organs
What happens to naive lymphocytes that are not activated by an antigen
Die by apoptosis and are replaced by new cells that have arisen in the generative lympoid organs
Lymphatic system
- Drainage and filtration system that enables interstitial fluid and plasma proteins to flow back into blood
- Allows lymphocyte circulation and antigen presentation
- Lymphatic fluid flows one direction due to pressure from muscle action and one way valves
What occurs to the thymus with age
- Atrophy beginning within the cortex
- Naive T cell generation is reduced but amount of memory T cells increases
Lymph nodes
Encapsulated, Vascularised secondary lymphoid organs with anatomic features that favour the initiation of adaptive immune responses to antigens carried from tissues by lymphatics
Functions of the spleen
- Remove aging and damaged blood cells and particles (immune complexes and opsonized microbes) from circulation
- Initiate adaptive immune responses to blood borne antigens
- Site where B cells finally mature
Where do all immune cells originate
Bone marrow
