Chapter 20 Blood PDF

1 BLOOD Blood is a specialized fluid connective tissue Functions: 1. Transportation of dissolved gases 2. Distribution of nutrients 3. Transportation of metabolic wastes 4. Delivery of enzymes and hormones 5. Stabilization of pH and electrolyte composition 6. Prevention of fluid lo...

1 BLOOD Blood is a specialized fluid connective tissue Functions: 1. Transportation of dissolved gases 2. Distribution of nutrients 3. Transportation of metabolic wastes 4. Delivery of enzymes and hormones 5. Stabilization of pH and electrolyte composition 6. Prevention of fluid loss 7. Defense against toxins and pathogens 8. Stabilization of body temperature Composition of Blood: 1. Plasma- the liquid matrix of the blood, density slightly greater than water containing dissolved proteins. 2. Formed elements- Blood cells and cell fragments that are suspended in the plasma a. Red Blood cells- transports oxygen and CO2 b. White blood cells- components of the immune system c. Platelets- small membrane enclosed packets of cytoplasm that contain enzymes and other factors involved in clotting  Whole blood is a mixture of plasma and formed elements  Average 5-6 liters of whole blood in the adult male  4-5 Liters in the adult female  Blood Volumes: Hypovolemic, Hypervolemic, Normovolemic Plasma and its composition  ~55% volume of whole blood  H2O accounts for 92% of plasma volume  Plasma proteins account for 7% of the plasma compositions. 3 major classes 1. Albumins- 60%  Contribute to osmotic pressure  important in the transport of fatty acids, steroid hormones etc.  smallest plasma protein 2. Globulins -35% of plasma proteins  Immunoglobulins- antibodies- attack foreign proteins and pathogens  Transport proteins- bind small ions, hormones or compounds that are either soluble or might be filtered out by the blood or kidneys. 3.Fibrinogen- 4%  Participates in clotting reactions  Can interact with fibrin which provides framework for clotting, which removes clotting proteins leaving fluid known as serum.  The liver is responsible for synthesizing and releasing more than 90% of the plasma proteins Formed Elements 1. RBC- Erythrocytes  Biconcave disc with a thin central region and a thick outer margin. Diameter ~ 7 microns  Lifespan 120 days  Obtains energy via anaerobic metabolism  Lacks nucleus  Hemoglobin- makes up 95% of RBC protein. Red pigment responsible for the cells ability to transport O2 and CO2 Blood types- determined by specific components on RBC cell membrane (surface antigens or agglutinogens).  2 A, B, AB, O RH + and RH- among a few. 2. WBC- Leukocytes 2 major classes: 1. Granular 2. Agranular 1. Granulocytes a. Neutrophils- 70% of circulating WBC  Cytoplasm packed with neutral staining granules containing enzymes and bacteriocides  Very dense contorted nucleus divided into lobes (beads on a string)  First to appear at a site of injury- phagocytic also known as PMNs- polymorphonucleocytes b. Eosinophils- 2-4%  Granules stains acid red  Bilobed nucleus  Phagocytic  Increase during allergic reactions c. Basophils- ~ 1%  Numerous granules stain basic- deep purple or blue  Granules contain histamine- increase during inflammation  Attracts other WBCs to the other 2. Agranular Leukocytes a. Monocytes- 2-8%  largest WBC, normally spherical in shape  large oval or fidney bean shaped nucleus  bloodstream- free macrophage  CT- fixed macrophage  Arrives to injury site attracts and stimulates other phagocytic cells as well as fibroblasts b. Lymphocytes 20-30%  Very little cytoplasm  Purple staining nucleus  Responsible for specific immunity  Responds 3 ways 1. T cells- enter peripheral tissues and attacks foreign cells directly 2. B cells- differentiate into plasma cells that secrete antibodies 3. NK cells (large granular lymphocytes) immune surveillance- destruction of abnormal tissue cells- prevents cancer 3. Platelets (thrombocytes)- not cells but membrane enclosed packets of cytoplasm Megakaryocytes- enormous cells in the bone marrow that release platelets in the blood Clotting response iincludes: 1. transports chemicals needed for clotting 2. Forms a temporary patch in the walls of damaged blood vessels 3. Causes contraction after a clot has formed to reduce the size of the break in the vessel wall.