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Flashcards in Blood and blood cells Deck (16):

what are the 6 main functions of the blood?

- transport
- heat distribution
- immunity
- haemostasis
- support
- maintain homeostasis


what are the 4 major components of blood?

- plasma
- red blood cells
- white blood cells
- platelets


what is the importance of haemoglobin?

transport of oxygen to tissue cells and transport of carbon dioxide to lungs


what is the basic structure of haemoglobin?

- 4 polypeptides each with a haem group
- 2 alpha chains, 2 beta chains
- each haem group contains Fe2+ which binds to an oxygen


what does haemoglobin carry carbon dioxide in conjunction with?

carbonic anhydrase


what adaptation does haemoglobin have in foetuses?

higher affinity for oxygen to take oxygen from the mother's blood


what are the essential features and functions of the erythrocyte?

- transport oxygen and carbon dioxide
- biconcave disk
- no organelles
- 120 day lifespan
- removed by macrophages
- dependent upon dietary iron
- produced in bone marrow
- production is stimulated by erythropoietin release from kidneys


define anaemia

low blood haemoglobin concentration


what are the major subclasses and causes of anaemia?

- microcytic (small MCV): ion deficiency - menstruation, GIT lesions, cancers
- normocytic (normal MCV): acute blood loss
- macrocytic (large MCV): vitamin B deficiency, folic acid deficiency during pregnancy


what are the major functions of leukocytes?

fight infections:
- lymphocytes produce antibodies
- neutrophils and monocytes are phagocytic
- eosinophils are involved in allergic responses
- basophils produce heparin


what are the major functions and main features of T-lymphocytes?

- cellular immunity
- produced in bone marrow and "educated" in thymus
- activated lymphocytes produce chemotaxins, lymphotoxin and interferon
- sub-groups include regulatory cells, helper cells and cytotoxic cells


what are the major functions and main features of B-lymphocytes?

- humoral immunity (antibody production)
- primary response occurs after a dormant period where it peaks then falls
- secondary response is greater, quicker and longer due to memory cells
- passive immunity can be acquired from injected antibody


what are the main features of monocytes?

- appear later
- become macrophages in tissue
- stimulate repair
- ingest, store and modify antigens and present them to lymphocytes


what are the main features of platelets?

- many organelles but no nuclei
- granules
- surface receptors initiate activation
- adhere to exposed collagen
- release granules to recruit and activate platelets
- involved in clot formation
- involved in haemostasis (prevention of blood loss)


what are the major functions of plasma?

- carrying cells
- carrying other key components: nutrients (glucose, lipids, amino acids), hormones (thyroxine, cortisol, erythropoietin), proteins (clotting factors, albumin, globulins), inorganic ions (Na+, K+, Ca2+), products of metabolism (urea, lactic acid)


in what ways do antibodies reduce infection

- precipitation: assist phagocytosis
- agglutination: clump cells together
- opsonisation: coat pathogen in antibody and mark for destruction by phagocytes
- neutralisation: prevent attachment of microorganisms to tissue