components of the blood Flashcards
blood is made up of what?
plasma - that contains red blood cells, white blood cells and platelets. also contains lots of clotting factors e.g. fibrinogen
once clotting factors are removed from the blood what is left?
- serum
what does serum contain?
- glucose
- electrolytes e.g. sodium and potassium
- proteins e.g. immunoglobulins and hormones
blood cells develop in what?
- bone marrow
in an adult where is bone marrow found?
pelvis, vertebrae, ribs and sternum
what is a pluripotent haematopoietic stem cell?
- undifferentiated cells that have potential to transform into a variety of blood cells
what do pluripotent haematopoietic stem cells become?
- myeloid stem cells
- lymphoid stem cells
- dendritic cells - via various intermediate stages
red blood cells development?
myeloid stem cells -> reticulocytes
what are reticulocytes?
immature red blood cells
how long do RBCs survive for?
- up to 3 months
platelet development?
myeloid stem cells -> megakaryocytes
how long do platelets last for?
- 10 days
how long do platelets last for?
- 10 days
platelet function
- role is to clump together and plug gaps where blood clots need to form
white blood cell development?
myeloid stem cell -> myeloblast -> promyelocytes that can then become
- monocytes - then macrophages
- neutrophils
- eosinophils
- mast cells
- basophils
lymphocyte development?
lymphoid stem cell -> B cells or T cells
B cells mature where?
in bone marrow
what do B lymphocytes differentiate into?
- plasma cells
- memory B cells
T lymphocytes mature where?
- thymus gland
what do T cells differentiate into?
- CD4 cells (T helper cells)
- CD8 cells (cytotoxic T cells)
- natural killer cells
what is a blood film used for?
- used to examine blood using a microscope to check for abnormal shapes, sizes and contents of cells and note abnormal inclusions in blood
anisocytosis refers to what?
- variation in size of the RBCs. these can be seen in myelodysplasic syndrome as well as some forms of anaemia
target cells?
- central pigmented area surrounded by a pale area, surrounded by a ring of thicker cytoplasm on outside. makes it look like a bull’s eye target
-> can be seen in iron deficiency anaemia and post-splenectomy
Heinz bodies?
- individual blobs seen inside red blood cells caused by denatured globin.
-> can be seen in G6PD and alpha-thalassaemia
Howell-Jolly bodies?
- individual blods of DNA material seen inside red blood cells
- normally DNA material is removed by spleen during circulation of red blood cells
-> can be seen in post-splenectomy and in patients w severe anaemia where the body is regenerating red blood cells quickly
reticulocytes?
- immature red blood cells that are slightly larger than standard erythrocytes (RBCs) and still have RNA material in them
- RNA has a reticular ‘mesh like’ appaearance inside the cell
how many RBCs consist of reticulocytes? and what happens when this % goes up?
- 1%
- when there is a rapid turnover of red blood cells -> haemolytic anaemia.
- demonstrating the bone marrow is active in replacing lost cells
schistocytes?
- fragments of RBCs
- indicate RBCs are being physically damaged by trauma during their journey through blood vessels
what can schistocytes indicate?
- networks of clots in small blood vessels caused by
- HUS
- DIC (disseminated intravascular coagulation)
- thrombotic thrombocytopenia purpura
- can also be present in replacement metallic heart valves and haemolytic anaemia
what are sideroblasts?
- immature red blood cells that contain blobs of iron
- they occur when the bone marrow is unable to incorporate iron into the haemoglobin molecules.
what can sideroblasts indicate?
- myelodysplasic syndrome
what are smudge cells?
- immature red blood cells that contain blobs of iron
- they occur when bone marrow is unable to incorporate iron into the haemoglobin molecules
what can smudge cells indicate?
- chronic lymphocytic leukaemia
what are spherocytes?
- spherical red blood cells without normal bi-concave disk space
what can spherocytes indicate?
- autoimmune haemolytic anaemia or hereditary spherocytosis
myeloid stem cells become?
megakaryocytes -> platelets
reticulocytes -> RBCs
promyelocytes -> monocytes - macrophages, neotrophils, eosinophils, mast cells, basophils
megakaryocytes are?
- large cells
- big lobulated nucleus
- produce platelets
- essential for blood clotting
reticulocytes are?
- immature red bloodcells
- remnant RNA material called reticulum in cytoplasm
- released from bone marrow
- normally 1% of RBCs are reticulocytes
- higher % indicates rapid turnover of blood e.g. acute blood loss, haemolysis
- loose reticulum after few days and become RBCs
RBCs contain?
- large quantities of haemoglobin and carry oxygen from lungs to tissues
- survive about 3 months
macrophages?
- monocytes that have entered tissues and differentiated into macrophages
- live in most tissues in body
- have ‘toll-like receptors’
- recognise pathogen-associated molecular patterns ‘PAMPs)
- kill pathogens and abnormal cells by phagocytosis
- release cytokines that initiate inflammatory response
- activate other cells of immune system
neutrophils
- circulate through blood and lymphatic system
- migrate to areas of inflammation
- kill pathogens and abnormal cells by phagocytosis
eosinophils?
- important in responding to parasites
- sit waiting in tissues
- contain granules with - proinflammatory cytokines, chemicals toxic to pathogens e.g. ‘major basic protein’
they have 2 functions
- exocytosis of their granules
- phagocytosis - but less than neutrophils and macrophages
mast cells and basophils?
mast cells are fixed in place in tissues
basophils circulate through blood
contain cyotplasmic granules
degranulation releases pro-inflammatory cytokines
B lymphocytes
- also called B cells
- mature in bone marrow
- cell surface lined w antibodies
- each B cell has a specific type of antibody for a specific antigen
- b cells can only recognise antigens that match their antibodies
- once activated become either - plasma cell or memory b cell
what do plasma cells do?
- secrete antibodies - also called immunoglobulins
what do memory b cells do?
- await a later infection w same pathogen
T lymphocytes?
- also called T cells
- pro-thymocytes leave the bone marrow and travel to thymus gland
- mature there into T cells
- cell surface lined w T cell receptors
- each T cell has specific type of T cell receptor (TcR) for specific antigen
CD4 cells have what kind of receptor?
- MHC class 2 receptors
CD8 cells have what kind of receptor?
- MHC class 1 receptor
CD4 cells become what when activated?
- T helper cells
- help other cells become activated including CD8 cells
CD8 cells become what when activated?
- cytotoxic T cells
-> destroy infected cells via granule exocytosis causing destruction of the cell, activating the Fas pathway causing cell apoptosis
