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Pluripotent stem cells
Blood Stem Cells
differentiation of pluripotent stem cells
Hematopoiesis in a foetus outside of the bone marrow
Hematopoiesis after birth inside of the bone marrow
- Small fragments of large cells called Megakaryocytes
Splits into platelets
Forms platelets from Pluripotent stem cells
Too few platelets, leading to bleeding problems and blood loss
Too many platelets, leading to excessive clotting and thrombi/emboli
Hematopoietic system components
- Blood (cells and plasma)
- Bone marrow
- Production of RBCs by differentiation of stem cells via the stimulation of bone marrow by Erythropoietin
a hormone formed mainly in the kidneys, but somewhat in the liver.
Destruction of RBCs. Average lifespan is 120 days.
Hematocrit / RBC count / Hemoglobin concentration
- Hematocrit: Packed cell volume of RBCs in blood (i.e. the % of RBCs in blood). Usually ≈ 40% - 52%
- RBC count: Number of RBCs per cubic mm of blood. Usually ≈ 4.2 - 6.0 million/mm³
- Hemoglobin concentration: grams of Hb per decilitre of whole blood | Usually ≈ 12-15 g/dL in ♂ | Usually ≈ 10.5-14 g/dL in♀
White Blood Cells:
- Healthy pt will have ≈ 5,000 - 9,000 WBC per microlitre (µL)
- Infections can raise this number to >16,000
Large % of total WBCs which attach to blood vessel walls waiting for action.
Marginated leukocytes detach from blood vessle walls
WBCs travel through the lining of a blood vessel
WBCs follow chemical signals to an infection site
WBCs engulf and destroy invaders
Production of WBCs by differentiation of stem cells
- Absorb basic stains and have blue granules
- Primarily involved in allergic reactions.
- Their granules contain Histamines and Heparin
Released in allergic reactions
Break down blood clots
- formed from Lymphoblasts
- Primary cells involved in immune response
- No granules or staining
- Highly specialized with surface receptors specific to a single antigen
- Have two forms: T- and B-cells
- Called that because they mature in the Thymus gland within the mediastinum
- Part of the Cell mediated immunity response
- Are able to induce apoptosis in body cells displaying foreign antigen on their surface,
- Once an antigen activates them, they stimulate the production of other cells called Effector cells (aka plasmocytes) (aka B Cells)
- Originate in Bone marrow and migrate to peripheral lymphatic tissue.
- Some B cells are maintained in the body after an attack, giving the body a `memory` of the previous infection
- Once exposed to an antigen, they produce large volumes of the specific antibodies necessary to defend against the invader, an effect called Humoral immunity
- B-cell mediated
- Because protective function of immunization is found in the humor (cell-free bodily fluid/serum)
- Absorb acidic stains and have red granules
- They can inactivate the chemical mediators of acute allergic reactions, thus modulating the anaphylactic response.
- Their granules contain:Major Base Protein (MBP) - A protein released in conjunction to an antibody used against parasitic infections
Major Base Protein (MBP)
A protein released in conjunction to an antibody used against parasitic infections
Contain granules & have 3 forms: Basophils, Eosinophils, and Neutrophils
Dormant form of WBC that can mature when needed into: Macrophages
- 'Garbage collectors' which engulf foreign invaders, dead neutrophils, and remove damaged or abnormal RBCs
- Attack tumors
- Involved in tissue repair
- Secrete growth factors that stimulated production of Granulocytes and RBCs
- Some are bound to tissues and form part of the; Reticuloendothelial system
Macrophages, after engulfing foreign bodies or infectious agents, stimulate Lymphocyte production in an immune response
- Type of Granulocyte
- Absorb neither acidic or base stains, and contain pale blue and pink granules
- Primarily used to fight infection by phagocytosis
- If the neutrophil count is low then you have Neutropenia
- neutrophil count is low
- Where the infection may overwhelm and kill the pt.
- can be => of bone marrow disorders
the process of programmed cell death
- aka an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses.
- The antibody recognizes a unique part of the foreign target, termed an antigen
- Each tip of the "Y" of an antibody contains a 'lock' that is specific for one particular antigen 'key'
- Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly (e.g. by blocking a part of a microbe that is essential for its invasion and survival).
Cell mediated immunity
- aka cellular immunity because protective function of immunization is associated with cells
- is an immune response that does not involve antibodies, but rather involves the activation of various cells including Macrophages and antigen-specific T cells