医学英语 血液

Blood is withdrawn from a vein
Blood composition
• Transport nutrients absorbed from GI tract; hormones; waste • Regulate body temperature • Contains ions and compounds that may be distributed to the fluid among tissues (interstitial fluid) to help maintain normal pH (7.4) • Contains clotting factors • Immunity (immunoglobulin)
FORMED ELEMENTS
Physiology of red blood cells
Erythropoiesis
• In red bone marrow (all hematopoiesis) • Hemocytoblast Reticulocyte (nucleated) • Last stage = erythrocytes (lost nucleus)
Hematology and blood disease
• Blood diseases affect the production of blood and its components, such as blood cells, hemoglobin, blood proteins, the mechanism of coagulation, etc
Temperature of blood is about 1°C higher than measured body temperature. Can be broken down into its liquid and cellular components by a machine called a centrifuge.
Up to three times the diameter of an erythrocyte. Constitute about 3–8% of all leukocytes. Nucleus is kidney-shaped or Ushaped. Macrophages phagocytize bacteria, cell fragments, dead cells, and debris. Important in fighting chronic infection Take longer to get to site of infection, but arrive in larger numbers Become wandering macrophages, once they leave the capillaries Destroy microbes and clean up dead tissue following an infection
BLOOD
Study Guide SUMC 2011-2012
Blood Facts
The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight.
Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell.
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Natural killer cells attack many different microbes & some tumor cells destroy foreign invaders by direct attack
Platelets (thrombocytes)
• Are smallest of formed elements • lack nucleus • Are fragments of megakaryocytes; (fragments of cytoplasm) • Constitute most of mass of blood clots • Release serotonin to vasoconstrict & reduce blood flow to clot area • Secrete growth factors to maintain integrity of blood vessel wall • Survive 5-9 days, 200 000-400 000 mm3 • aged and dead platelets are removed by fixed macrophages in the spleen and liver.
• • • • • Sickle-cell anemia thalassemia Heamophilia Lymphoma Leukemia
White Blood Cells
Neutrophils
• • • • • • • • • 60% of WBCs Lobed nucleus Light staining granules – Digestive enzymes Function – Phagocytize & destroy bacteria First cells to respond to infection Secrete antibacterial chemicals Direct actions against bacteria release lysozymes which destroy/digest bacteria release proteins that act like antibiotics & poke holes in bacterial cell walls destroying them
Blood Facts
Considered a connective tissue because it contains cells, a liquid ground substance (called plasma), and dissolved protein fibers. About four times more viscous (or thicker) than water.
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release strong oxidants (bleach-like, strong chemicals ) that destroy bacteri1-4% of WBCs Lobed nucleus Eosin-staining granules Secrete anti-histamine Attack parasites
Basophils
0.5% of WBCs Lobed nucleus Large granules stained dark purple Histamine – creates inflammation in allergic reaction
lymphocytes
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Monocytes