Leucocytes Flashcards
What are leucocytes?
White blood cells
Define the term Haematopoeisis
The production of blood cells
Define the term Leucopoeisis
The production of leucocytes
Explain the journey from a stem cell to blood cells
Haematopoeisis: Stem cells undergoes differentiation.
This leads to increased specialisation(commitment) but decreased plasticity
This forms a mature cell ( erythrocyte, leucocyte and platelets) which leaves the bone marrow and enters the bloodstream
A family tree of cell division is called?
Lineage
List the 2 major leucocyte lineage with explanation
- Lymphoid(Lymphocytes)- small bland looking cells, e.g B cell, T cell and NK cell
- Myeloid- larger cells. They have cytoplasmic granules called granulocytes
List the haematopoiesis lineage
1.Haematopoietic stem cell
into
2. Lymphoid progenitor and 3.Myeloid progenitor
Lymphoid progenitor splits into 4. B cells 5. T cells 6. NK Cells
Myeloid progenitor splits into 7. Granulocytes/monocyte/ precursor mast cell and 8. Erythrocytes progenitor/ Megakaryocyte
Granulocytes differentiates to form neutrophils, eosinophils and basophils
Monocyte forms macrophage
Precursor mast cell forms mast cell.
Erythrocyte progenitor forms erythrocyte
Megakaryocyte forms platelets
Plasma cells are formed from B cells
Give 5 examples of Lymphoid Tissue (Collection of leucocyte cells)
- Tonsil
- Right + left subclavian vein
- Lymph node
- Thymus
- Heart
- Kidney
- Spleen
- Appendix
- Bone Marrow
List 3 functions of macrophage cells
- Phagocytosis
- Antigen presentation
- Activation of Bactericidal mechanism
List 2 functions of dendritic cells
- Antigen uptake in peripheral sites
2. Antigen presentation in lymph nodes
List 2 functions of neutrophil
- Activation of bactericidal mechanism
- Phagocytosis
Side note: Neutrophil has one nucleus but it is multiload
1 Function of Eosinophil
Killing of anti-body coated parasites
1 Function of Mast cell
Release of granules containing histamines
3 types of Lymphocytes
- B- cells- produces antibodies
- T- Cells- CD4 helper T cells and CD8 killer T cells
- Natural Killer(NK) Cells
What are Cytokines
Cytokines are small proteins released by cells that have an effect on another cell
List 3 actions of Cytokines
- Autocrine
- Paracrine
- Endocrine
What are Chemokines
Chemokines are small proteins released by cells. They have different protein structure/receptors to Cytokines.
They are involved in Spatial organisation. E.g CXCL8 attracts neutrophils to sites of infection
What is Juxtacrine signalling
Cell-cell contact communication between 2 cells
What are the 5 cardinal features of inflammation
- Calor (Heat)
- Dalor (Pain)
- Rubor (Redness)
- Tumor (Swelling)
- Lack of function
After successful breach of the skin barrier. What leucocyte cell first approaches the pathogen?
Tissue Macrophage
Engulfs and kills the pathogen by phagocytosis.
Then undergoes Antigen presentation
What 2 type of cells can perform phagocytosis?
- Macrophage
2. Neutrophils
Describe the process of Phagocytosis
- Pathogen is phagocytosed into a phagosome.
- Phagosome fuses with low pH(acidic) lysosome digestive enzyme to form phagolysosome
- This produces toxic free radicals and hydrogen peroxide
Phagocytosis causes the release of soluble mediators. List the 2 main soluble mediators
- Cytokines
2. Chemokines
List 3 examples of Cytokines
- Tumour Necrosis Factor (TNF- alpha)
- Interleukin-1 (IL-1)
- Interleukin-6 (IL-6)
Give an example of Chemokines
- CXCL8
Besides the attraction of neutrophils,
List 3 effects soluble mediators has on blood vessels
- Vasodilation
- Increased Permeability - junction between endothelial cell widens.
- Increased adhesion molecules on blood vessel endothelium
Define local inflammation
The response is present in the site of infection.
Define systemic inflammation
The response has spread beyond the original site of infection to other parts of the body
Cause of systemic inflammation
During more serious infections. Cytokines are released into the bloodstream and can have an effect on distant tissues
Symptoms/Features of Systemic inflammation
Fever, fatigue, muscle pain, anorexia
prolonged systemic inflammation can lead to loss of muscle and fat
List 4 organs cytokines effect during a systemic inflammation
- Liver - activation of opsonisation
- Bone marrow - causes neutrophil mobilization for phagocytosis
- Hypothalamus 4. Fat and Muscle - both causes an increase in temperature. Pathogen replication decreased/Increased antigen processing+ specific immune response
List 4 outcomes of acute inflammation
- Resolution- insult removed, tissue heals completely
- Fibrosis- insult removed, but tissue is scarred
- Chronic- insult cannot be removed
- Abscess Formation
3 advantages of inflammation
- Amplifies the immune response- small stimulus creates large local and systemic response
- Focuses the immune response - bring in specific cells that are needed
- Activates the next stages - B cells/T cells
3 disadvantages of inflammation
- Healthy tissue may be damaged- bystander damage
- May be activated inappropriately (without an infection)
- May be activated in an uncontrolled manner e.g meningitis
