Cells and Structure of the Immune System Flashcards
What are hematopoietic stem cells?
HSCs are self-renewing, multi potent sources of RBCs, WBCs, and platelets.
What are the niches for the HSCs?
- Osteoblasts
- Sinusoidal Endothelial Cells
What are the main two progenitor cells that are made by HSCs?
- Common Myeloid Progenitor
- Common Lymphoid Progenitor
What cells are the result of common myeloid progenitors?
Thrombocytes Erythrocytes Mast Cells Basophil Neutrophils Eosinophils Monocytes (macrophages/dendritic cells)
What cells are the result of common lymphoid progenitors?
T lymphocytes
B lymphocytes
Natural Killer Cells
What is the function of the myeloid WBCs?
They make up most of the innate immune cells and are the first defense against infection. They also present microbes to the adaptive immune cells.
What is the function of the neutrophils?
Phagocytosis and activation of bactericidal mechanisms
What is the structure of the neutrophils?
- Have 3 to 4 nuclear lobes
- Electron dense light pink staining granules
What is the function of the primary neutrophil granules?
- Direct toxic/enzymatic activity
What is the function of the secondary neutrophil granules?
- Free radical formation
What is the function of monocytes and macrophages?
Phagocytosis and activation of bactericidal mechanisms
Also have some antigen presentation
What is the structure of monocytes and macrophages?
- Large cells with eccentric vesicular nuclei
- Have abundant lysosomes
What is the function of dendritic cells?
Uptake of the antigen as well as antigen presentation.
What is the structure of the dendritic cells?
Long finger like processes to increase surface area for antigen display
Where do dendritic cells go for antigen presentation?
They migrate to the lymph nodes
What is the function of the eosinophils?
They kill antibody coated parasites
What is the structure of eosinophils?
They are bi lobed with bright pink granules.
What do eosinophils release from their granules?
Theu release highly toxic substances
What can chronic eosinophil activation cause?
It can damage tissue as seen in chronic allergic asthma
What is the function of mast cells?
Release histamine granules and granules of active agents
What is the structure of mast cells?
Large mononuclear cells with dark granules of histamine and heparin
What is the function of basophils?
Work in immunity against parasitic infection and in allergic responses.
What is the structure of basophils?
2-3 poorly defined nuclear lobes and dark basophilic granules.
What are the lymphoid WBCs?
NK Cells
T Cells
B Cells
Where are the T cells found?
Thymus
Where are the B cells found?
Bone Marrow
What is the structure of natural killer cells?
Large and mononuclear
What is the function of NK cells?
Go after cancer cells and viral infections
What is the structure of B cells?
Have varying B surface receptors that recognize specific antigens
What is the function of plasma cells?
They are the effector form of B cells and they serve to produce antibodies specific to an antigen
What is the function of T cells?
Cytotoxic T cells will kill infected cells while other T cells will orchestrate antibody and macrophage responses
What are the common molecules for myeloid cell differentiation?
IL-3 & GM-CSF
What are the common molecules for lymphoid cell differentiation?
IL-7
What are the most abundant WBCs?
Neutrophils
