Hematopoietic System Flashcards
What is the hematopoietic system?
The system in the body involved in creation of cells of blood. The system consists of organs + tissues, primarily bone marrow, spleen, tonsils + lymph nodes involved in production of blood
What is blood?
Fluid connective tissue constituting about 7% of our total body weight
What is blood’s functions?
Transports substances
Helps regulate life processes
Affords protects against diseases
What are the primary components of blood?
Plasma
Erythrocytes (RBCs)
Leukocytes (WBCs)
Platelets
Describe erythrocytes
Biconcave discs
Lack nucleus + other organelles
Plasma membrane, cytosol + haemoglobin
What does cytosol contain?
Haemoglobin
What is the function of erythrocytes?
Transport respiratory gases
Nucleate
Haematopoiesis
Describe haemoglobin
Composed of 4 protein globin chains
Each centred around haem group
Each haem group consists of porphyrin ring with Fe2+ centre
What does an adult haemoglobin contain
2 alpha chains + 2 beta chains
What does Fe2+ allow?
Binding of O2
What are reticulocytes?
Less mature erythrocytes
Up to 2 days old
Where are RBCs released from?
Bone marrow into peripheral circulation
What do reticulocytes contain?
Residual ribonucleoprotein particles
= bluish hue to cell
What are the different types of WBCs?
Neutrophils Eosinophils Basophils Monocytes Lymphocytes
What is WBC name?
Leukocytes
What are granulocytes?
Neutrophil, eosinophil + basophil
= contain bacteria-combating granules
What are the agranulocytes?
Lymphocyte + monocyte
= no granules
Describe neutrophils
Biggest
Most numerous
Prominent nucleus segmented into 2
What do less mature neutrophils look like?
Non-segmented nucleus
What does cytoplasm of neutrophils contain?
Glycogen, numerous filaments + microtubules
Describe the action of neutrophils
Microbe —-> chemotaxis of phagocyte to microbes —-> ingestion —-> killing be enzymes + other chemicals —-> elimination (exocytosis)
Describe eosinophils
Same size as neutrophils
Contain bilobed nucleus
What does cytoplasm of eosinophils contain?
Specific granules that contain dense filamentous core of major basic protein
What does matrix of granules in eosinophils contain?
Lysosomal enzymes
Describe basophils
Smaller
Nucleus = 2-3 lobes
Similar to mast cells
Why can basophils be hard to distinguish?
Have large, dark-staining granules
What do basophil granules contain?
High conc of heparin, histamine, leukotrienes, serotonin + chemotic factor
What do basophils do?
Mediate hypersensitivity
= bind to IgE antibody
What do eosinophils do?
Phagocytose antigen-antibody complexes in active leukotrienes
Describe monocytes
Largest cell in blood
Large nucleus - ovoid, kidney shaped
Cytoplasm pale
What do monocytes do?
Ingest + remove tissue debris + infectious agents
Describe lymphocytes
Relatively big
Contain single, deeply-stained, spherical nucleus
Contain few granules
What are the different types of lymphocytes?
T cells, B cells + neutral killer cells (NK)
What do lymphocytes do?
Plasma cells produce antibodies
What are the platelets called?
Thrombocytes
Describe thrombocyte
Non-nucleated flat, biconvex, round or ovoid disc
What are thrombocytes derived from?
Bone marrow megakaryocytes
What are thrombocytes involved in?
Haemostasis
What do thrombocytes promote?
Coagulation to form blood clots
Describe megakaryocyte
Platelets are components
Edges break off to form platelets
Describe bone marrow
Soft tissue that fills centre of bones
Richly vascularized connective tissue
Most rapidly replicating tissue in body
What is myeloid tissue?
Blood forming tissues identified as “red marrow” of bones
What is lymphoid tissues?
Elements of larger lymphatic system; some lymphoids arise from proliferation within lymphoid tissues
Where does haematopoiesis happen at embryonic stage?
Synthesis of blood cells in spleen, liver + bone
marrow
Where does haematopoiesis happen at birth stage?
Bone marrow
What is the development of erythrocytes regulated by?
Hormone erythropoietin
What is general stages of haemostasis?
Vasoconstriction
Temporary clot
Coagulation
Describe what happens in haemostasis
Blood flow + pressure decreased
Exposed collagen binds + activates platelets
Release of platelet factors
Factors attract more platelets
Platelets aggregate into platelet plug
Associated with activation of fibrin protein mesh
What is blood type?
Classification of blood based on presence + absence of antibodies + inherited antigenic substances on surface of RBCs
What are the 4 main types?
A
B
AB
O
What does Rh factor do?
Present either + or -
eg. A-, A+ …
What antigen + antibody does A have?
A
B
What antigen + antibody does B have?
B
A
What antigen + antibody does AB have?
A+B
NONE
What antigen + antibody does O have?
NONE
BOTH
DONORS
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