Chapter 11 Blood PDF

hapter 11 C BLOOD SEELEY'S ESSENTIALS OF ANATOMY AND PHYSIOLOGY, 9TH EDITION. Created by: Johmel De Ocampo  Created by: Johmel De Ocampo BLOOD FUNCTIONS OF BLOOD Blood...

hapter 11 C BLOOD SEELEY'S ESSENTIALS OF ANATOMY AND PHYSIOLOGY, 9TH EDITION. Created by: Johmel De Ocampo  Created by: Johmel De Ocampo BLOOD FUNCTIONS OF BLOOD Blood helps maintain homeostasis in several ways: 1. TRANSPORT OF GASES, NUTRIENTS, AND WASTE PRODUCTS. Oxygen enters the blood in the lungs and is carried to cells. Carbon dioxide, produced by cells, is carried in the blood to the lungs, from which it is expelled. The blood transports ingested nutrients, ions, and water from the digestive tract to cells, and the blood transports the waste products of the cells to the kidneys for elimination. 2. TRANSPORT OF PROCESSES MOLECULES. Many substances are produced in one part of the body and transported in the blood to another part, where they are modified. For example, the precursor to vitamin D is produced in the skin and transported by the blood to the liver and then to the kidneys for processing into active vitamin D. Then the blood transports active vitamin D to the small intestine, where it promotes the uptake of calcium. Another example is lactate produced by skeletal muscles during anaerobic respiration. The blood carries lactate to the liver, where it is converted into glucose 3. TRANSPORT REGULATORY MOLECULES. The blood carries many of the hormones and enzymes that regulate body processes from one part of the body to another. 4. REGULATION OF PH AND OSMOSIS. Buffers, which help keep the blood’s pH within its normal limits of 7.35–7.45, are found in the blood. The osmotic composition of blood is also critical for maintaining normal fluid and ion balance. 5. MAINTENANCE OF BODY TEMPERATURE. Warm blood is transported from the interior of the body to the surface, where heat is released from the blood. This is one of the mechanisms that helps regulate body temperature. 6. PROTECTION AGAINST FOREIGN SUBSTANCES. Certain cells and chemicals in the blood constitute an important part of the immune system, protecting against foreign substances, such as microorganisms and toxins. 7. CLOT FORMATION. When blood vessels are damaged, blood clotting protects against excessive blood loss. When tissues are damaged, the blood clot that forms is also the first step in tissue repair and the restoration of normal function  Created by: Johmel De Ocampo BLOOD FUNCTIONS OF BLOOD The primary function of blood is to deliver oxygen and nutrients to and remove wastes from body cells, but that is only the beginning of the story. The specific functions of blood also include defense, distribution of heat, and maintenance of homeostasis. Nutrients (Digestive > Absorbed in Digestive Tract > Transport Directly to Liver) (O2 > Lung > Bloodstream > Heart > Body Parts) Defense WBC Maintenance of Homeostasis Blood > Vessels of the skin > heat dissipated to environment > blood goes back to body core, it would be cooler ERYTHROCYTES BUFFY COAT Red blood cells Leukocytes Carry oxygen and carbon white blood cells dioxide Platelets Make up 45% of your total blood helps with blood clotting volume PLASMA ELECTROLYTES They are positively-charged About 55% of your blood volume cations It is 90% water, and the 10% Ca, Na, K consists of electrolytes, Negative-charged anions hormones, gases, proteins, Phosphate, Sulfate, waste products Bicarbonate  Created by: Johmel De Ocampo BLOOD COMPOSITION OF BLOOD Blood is a type of connective tissue that consists of a liquid matrix containing cells and cell fragments. The liquid matrix is the plasma (plaz′ m̆), and the cells and cell fragments are the formed elements. The plasma accounts for slightly more than half of the total blood volume, and the formed elements account for slightly less than half. The total blood volume in the average adult is about 4–5 liters (L) in females and 5–6 L in males. Blood makes up about 8% of total body weight. PLASMA Plasma is a pale yellow fluid that consists of about 91% water, 7% proteins, and 2% other components, such as ions, nutrients, gases, waste products, and regulatory substances. Unlike the fibrous proteins found in other connective tissues, such as loose connective tissue, plasma contains dissolved proteins. Plasma proteins include albumin, globulins, and fibrinogen.  Created by: Johmel De Ocampo BLOOD Albumin (al-b̄′min) makes up 58% of the plasma proteins. Globulins (glob′̄-linz; globule) account for 38% of the plasma proteins. Some globulins, such as antibodies and complement, are part of the immune system. Fibrinogen (fı-brin′̄-jen) is a clotting factor that constitutes 4% of plasma proteins. Activation of clotting factors results in the conversion of fibrinogen to fibrin (fi′brin), a threadlike protein that forms blood clots Serum (ser′um) is plasma without the clotting factors. Plasma volume and composition remains relatively constant. Normally, water intake through the digestive tract closely matches water loss through the kidneys, lungs, digestive tract, and skin. Oxygen enters the blood in the lungs, and carbon dioxide enters the blood from tissues. Other suspended or dissolved substances in the blood come from the liver, kidneys, intestines, endocrine glands, and immune tissues, such as the lymph nodes and spleen. The concentration of these substances in the blood is also regulated and maintained within narrow limits.  Created by: Johmel De Ocampo BLOOD FORMED ELEMENTS OF BLOOD  Created by: Johmel De Ocampo BLOOD HEMATOPOEISIS  Created by: Johmel De Ocampo BLOOD PRODUCTION OF FORMED ELEMENTS The process of blood cell production is called hematopoiesis (h̄′m̆-t̄-poy-̄ ′sis; hemato-, blood + poiesis, making). In the fetus, hematopoiesis occurs in several tissues, including the liver, thymus, spleen, lymph nodes, and red bone marrow. After birth, hematopoiesis is confined primarily to red bone marrow, but some white blood cells are produced in lymphatic tissues. All the formed elements of blood are derived from a single population of cells called stem cells, or hemocytoblasts. These stem cells differentiate to give rise to different cell lines, each of which ends with the formation of a particular type of formed element. The development of each cell line is regulated by specific growth factors. That is, growth factors determine the types of formed elements derived from the stem cells and how many formed elements are produced. RED BLOOD CELLS Normal red blood cells are disk-shaped, with edges that are thicker than the center of the cell. The biconcave shape increases the cell’s surface area compared to a flat disk of the same size. The greater surface area makes it easier for gases to move into and out of the red blood cell. In addition, the red blood cell can bend or fold around its thin center, decreasing its size and enabling it to pass more easily through smaller blood vessels. During their development, red blood cells lose their nuclei and most of their organelles. Consequently, they are unable to divide. Red blood cells live for about 120 days in males and 110 days in females. One-third of a red blood cell’s volume is the pigmented protein hemoglobin (h̄-m̄-gl̄′bin), which is responsible for the cell’s red color.  Created by: Johmel De Ocampo BLOOD  Created by: Johmel De Ocampo BLOOD WHITE BLOOD CELLS White blood cells are spherical cells that lack hemoglobin. When the components of blood are separated from one another, white blood cells as well as platelets make up the buffy coat, a thin, white layer of cells between plasma and red blood cells. White blood cells are larger than red blood cells, and each has a nucleus. Two functions of white blood cells are (1) to protect the body against invading microorganisms and other pathogens and (2) to remove dead cells and debris from the tissues by phagocytosis. Each white blood cell type is named according to its appearance in stained preparations. Those containing large cytoplasmic granules are granulocytes, an those with very small granules that cannot be seen easily with the light microscope are agranulocytes. There are three kinds of granulocytes: neutrophils, basophils, and eosinophils. There are two kinds of agranulocytes: lymphocytes and monocytes. NEUTROPHILS the most common type of white blood cells, have small cytoplasmic granules that stain with both acidic and basic dyes. Their nuclei are commonly lobed, with the number of lobes varying from two to four. Neutrophils usually remain in the blood for a short time (10–12 hours), move into other tissues, and phagocytize microorganisms and other foreign substances. Dead neutrophils, cell debris, and fluid can accumulate as pus at sites of infections. BASOPHILS the least common of all white blood cells, contain large cytoplasmic granules that stain blue or purple with basic dyes. Basophils release histamine and other chemicals that promote inflammation. They also release heparin, which prevents the formation of clots  Created by: Johmel De Ocampo BLOOD EOSINOPHILS contain cytoplasmic granules that stain bright red with eosin, an acidic stain. They often have a twolobed nucleus. Eosinophils are involved in inflammatory responses associated with allergies and asthma. In addition, chemicals from eosinophils are involved in destroying certain worm parasites. LYMPHOCYTES are the smallest of the white blood cells. The lymphocytic cytoplasm consists of only a thin, sometimes imperceptible ring around the nucleus. There are several types of lymphocytes, and they play an important role in the body’s immune response. Their diverse activities involve the production of antibodies and other chemicals that destroy microorganisms, contribute to allergic reactions, reject grafts, control tumors, and regulate the immune system MONOCYTES are the largest of the white blood cells. After they leave the blood and enter tissues, monocytes enlarge and become macrophages, which phagocytize bacteria, dead cells, cell fragments, and any other debris within the tissues. In addition, macrophages can break down phagocytized foreign substances and present the processed substances to lymphocytes, causing activation of the lymphocytes  Created by: Johmel De Ocampo BLOOD PLATELETS Platelets are minute fragments of cells, each consisting of a small amount of cytoplasm surrounded by a cell membrane. They are produced in the red bone marrow from megakaryocytes, which are large cells. Small fragments of these cells break off and enter the blood as platelets, which play an important role in preventing blood loss. PREVENTING BLOOD LOSS When a blood vessel is damaged, blood can leak into other tissues and interfere with normal tissue function, or blood can be lost from the body. The body can tolerate a small amount of blood loss and can produce new blood to replace it. But a large amount of blood loss can lead to death. Fortunately, when a blood vessel is damaged, loss of blood is minimized by three processes: vascular spasm, platelet plug formation, and blood clotting. VASCULAR SPASM Vascular spasm is an immediate but temporary constriction of a blood vessel that results when smooth muscle within the wall of the vessel contracts. This constriction can close small vessels completely and stop the flow of blood through them. Damage to blood vessels can activate nervous system reflexes that cause vascular spasm. Chemicals also produce vascular spasm. For example, platelets release thromboxanes (throm′bok-z̄nz), which are derived from certain prostaglandins, and endothelial (epithelial) cells lining blood vessels release the peptide endothelin (en-d̄-th̄′lin).  Created by: Johmel De Ocampo BLOOD PLATELET PLUG FORMATION A platelet plug is an accumulation of platelets that can seal up a small break in a blood vessel. Platelet plug formation is very important in maintaining the integrity of the blood vessels of the cardiovascular system because small tears occur in the smaller vessels and capillaries many times each day. People who lack the normal number of platelets tend to develop numerous small hemorrhages in their skin and internal organs. BLOOD CLOTTING Blood vessel constriction and platelet plugs alone are not sufficient to close large tears or cuts in blood vessels. When a blood vessel is severely damaged, blood clotting, or coagulation, results in the formation of a clot. A clot is a network of threadlike protein fibers, called fibrin (fı′brin), that traps blood cells, platelets, and fluid. The formation of a blood clot depends on a number of proteins found within plasma, called clotting factors.  Created by: Johmel De Ocampo BLOOD Clot formation is a complex process involving many chemical reactions, but it can be summarized in three stages. 1. The chemical reactions can be started in two ways: (a) Inactive clotting factors come in contact with exposed connective tissue, resulting in their activation, or (b) chemicals, such as thromboplastin, are released from injured tissues, causing activation of clotting factors. After the initial clotting factors are activated, they in turn activate other clotting factors. A series of reactions results in which each clotting factor activates the next until the clotting factor prothrombinase, or prothrombin activator, is formed. 2. Prothrombinase converts an inactive clotting factor called prothrombin to its active form, thrombin. 3. Thrombin converts the plasma protein fibrinogen to fibrin.  Created by: Johmel De Ocampo BLOOD BLOOD GROUPING ABO BLOOD GROUP AGGLUTINATION REACTION  Created by: Johmel De Ocampo BLOOD COMPLETE BLOOD RED BLOOD COUNT COUNT A complete blood count (CBC) Blood cell counts are usually is an analysis of blood that performed electronically with a provides much useful machine, but they can also be information. A CBC consists done manually with a of a red blood cell count, microscope. hemoglobin and hematocrit A normal red blood count (RBC) measurements, and a white for a male is 4.6–6.2 million red blood cell count. blood cells per microliter (μL) of blood; for a female, a normal RBC count is 4.2–5.4 million per HEMOGLOBIN μL of blood. (A microliter is equivalent to 1 cubic millimeter MEASUREMENT [mm3] or 10−6 L, and one drop The amount of hemoglobin in a of blood is approximately 50 given volume of blood is usually μL). expressed in terms of grams of The condition called hemoglobin per 100 mL of blood. erythrocytosis (̆-rith′r̄ -sı-t̄′sis) The normal hemoglobin is an overabundance of red measurement for a male is 14–18 blood cells grams (g) per 100 mL of blood, and for a female 12–16 g per 100 mL of blood. An abnormally low hemoglobin measurement is an indication of anemia, which is either a reduced number of red blood cells or a reduced amount of hemoglobin in each red blood cell.  Created by: Johmel De Ocampo BLOOD HEMATOCRIT MEASUREMENT The percentage of the total blood volume that is composed of red blood cells is the hematocrit. One way to determine hematocrit is to place blood in a capillary tube and spin it in a centrifuge. The formed elements, which are heavier than the plasma, are forced to one end of the tube. Of these, the white blood cells and platelets form the buffy coat between the plasma and the red blood cells. WHITE BLOOD COUNT A white blood count (WBC) measures the total number of white blood cells in the blood. There are normally 5000–9000 white blood cells per microliter of blood. Leukopenia is a lower than normal WBC resulting from decreased production or destruction of the red marrow. Radiation, drugs, tumors, viral infections, or a deficiency of the vitamins folate or B12 can cause leukopenia. Leukocytosis is an abnormally high WBC. Bacterial infections often cause leukocytosis by stimulating neutrophils to increase in number. Leukemia, cancer of the red marrow characterized by abnormal production of one or more of the white blood cell types, can cause leukocytosis. However, the white blood cells do not function normally. Because these cells are usually immature or abnormal and lack normal immunological functions, people with leukemia are very susceptible to infections. The excess production of white blood cells in the red marrow can also interfere with the formation of red blood cells and platelets and thus lead to anemia and bleeding.  Created by: Johmel De Ocampo BLOOD DIFFERENTIAL WHITE BLOOD COUNT A differential white blood count determines the percentage of each of the five kinds of white blood cells. Normally, neutrophils account for 60–70%, lymphocytes 20–25%, monocytes 3–8%, eosinophils 2–4%, and basophils 0.5–1% of all white blood cells. Much insight into a patient’s condition can be obtained from a differential white blood count. For example, if a bacterial infection is present, the neutrophil count is often greatly increased, whereas in allergic reactions, the eosinophil and basophil counts are elevated. CLOTTING The blood’s ability to clot can be assessed by the platelet count and the prothrombin time measurement. PLATELET COUNT A normal platelet count is 250,000–400,000 platelets per microliter of blood. In the condition called thrombocytopenia (throm′b̄-sıt̄-p̄′n̄-̆), the platelet count is greatly reduced, resulting in chronic bleeding through small vessels and capillaries. It can be caused by decreased platelet production as a result of hereditary disorders, lack of vitamin B12 (pernicious anemia), drug therapy, or radiation therapy. PROTHROMBIN TIME MEASUREMENT Prothrombin time measurement calculates how long it takes for the blood to start clotting, which is normally 9–12 seconds. Prothrombin time is determined by adding thromboplastin to whole plasma. Thromboplastin is a chemical released from injured tissues that starts the process of clotting. Prothrombin time is officially reported as the International Normalized Ratio (INR), which standardizes the time it takes to clot on the basis of the slightly different thromboplastins used by different labs. Because many clotting factors have to be activated to form fibrin, a deficiency of any one of them can cause the prothrombin time to be abnormal. Vitamin K deficiency, certain liver diseases, and drug therapy can increase prothrombin time.  Created by: Johmel De Ocampo BLOOD BLOOD CHEMISTRY The composition of materials dissolved or suspended in the plasma can be used to assess the functioning of many of the body’s systems. For example, high blood glucose levels can indicate that the pancreas is not producing enough insulin; high blood urea nitrogen (BUN) is a sign of reduced kidney function; increased bilirubin can indicate liver dysfunction; and high cholesterol levels can signify an increased risk of cardiovascular disease. A number of blood chemistry tests are routinely done when a blood sample is taken, and additional tests are available. DISEASES AND DISORDERS  Created by: Johmel De Ocampo SUMMARY FUNCTIONS OF BLOOD 1. Blood transports gases, nutrients, waste products, processed molecules, and regulatory molecules. 2. Blood regulates pH as well as fluid and ion balance. 3. Blood is involved with temperature regulation and protects against foreign substances, such as microorganisms and toxins. 4. Blood clotting prevents fluid and cell loss and is part of tissue repair. COMPOSITION OF BLOOD 1. Blood is a connective tissue consisting of plasma and formed elements. 2. Total blood volume in an average adult is approximately 5 L. PLASMA 1. Plasma is 91% water and 9% suspended or dissolved substances. 2. Plasma maintains osmotic pressure, is involved in immunity, prevents blood loss, and transports molecules. FORMED ELEMENTS The formed elements are cells (red blood cells and white blood cells) and cell fragments (platelets). PRODUCTION OF FORMED ELEMENTS Formed elements arise (hematopoiesis) in red bone marrow from stem cells. RED BLOOD CELS 1. Red blood cells are disk-shaped cells containing hemoglobin, which transports oxygen and carbon dioxide. Red blood cells also contain carbonic anhydrase, which is involved with carbon dioxide transport. 2. In response to low blood oxygen levels, the kidneys produce erythropoietin, which stimulates red blood cell production in red bone marrow. 3. Worn-out red blood cells are phagocytized by macrophages in the spleen or liver. Hemoglobin is broken down, iron and amino acids are reused, and heme becomes bilirubin that is secreted in bile. WHITE BLOOD CELLS 1. White blood cells protect the body against microorganisms and remove dead cells and debris. 2. Granulocytes contain cytoplasmic granules. The three types of granulocytes are neutrophils, small phagocytic cells; basophils, which promote inflammation; and eosinophils, which defend against parasitic worms and influence inflammation. 3. Agranulocytes have very small granules and are of two types: Lymphocytes are involved in antibody production and other immune system responses; monocytes become macrophages that ingest microorganisms and cellular debris.  Created by: Johmel De Ocampo SUMMARY PLATELETS Platelets are cell fragments involved with preventing blood loss. PREVENTING BLOOD LOSS VASCULAR SPASM Blood vessels constrict in response to injury, resulting in decreased blood flow. PLATELET PLUG FORMATION 1. Platelet plugs repair minor damage to blood vessels. 2. Platelet plugs form when platelets adhere to collagen, release chemicals (ADP and thromboxanes) that activate other platelets, and connect to one another with fibrinogen. BLOOD CLOTTING 1. Blood clotting, or coagulation, is the formation of a clot (a network of protein fibers called fibrin). 2. There are three steps in the clotting process: activation of clotting factors by connective tissue and chemicals, resulting in the formation of prothrombinase; conversion of prothrombin to thrombin by prothrombinase; and conversion of fibrinogen to fibrin by thrombin. 3. Anticoagulants in the blood, such as antithrombin and heparin, prevent clot formation. 4. Clot retraction condenses the clot, pulling the edges of damaged tissue closer together. 5. Serum is plasma without clotting factors. 6. Fibrinolysis (clot breakdown) is accomplished by plasmin. BLOOD GROUPING 1. Blood groups are determined by antigens on the surface of red blood cells. 2. In transfusion reactions, antibodies can bind to red blood cell antigens, resulting in agglutination or hemolysis of red blood cells. ABO BLOOD GROUP 1. Type A blood has A antigens, type B blood has B antigens, type AB blood has A and B antigens, and type O blood has neither A nor B antigens. 2. Type A blood has anti-B antibodies, type B blood has anti-A antibodies, type AB blood has neither anti-A nor anti-B antibodies, and type O blood has both anti-A and anti-B antibodies. 3. Mismatching the ABO blood group can result in transfusion reactions. DIAGNOSTIC BLOOD TEST TYPE AND CROSSMATCH 1. Blood typing determines the ABO and Rh blood groups of a blood sample. 2. A crossmatch tests for agglutination reactions between donor and recipient blood.  Created by: Johmel De Ocampo SUMMARY COMPLETE BLOOD COUNT The complete blood count consists of the red blood count (million/μL), the hemoglobin measurement (grams of hemoglobin per 100 mL of blood), the hematocrit measurement (percent volume of red blood cells), and the white blood count (million/μL). DIFFERENTIAL WHITE BLOOD COUNT The differential white blood count determines the percentage of each type of white blood cell. CLOTTING Platelet count and prothrombin time measurement determine the blood’s ability to clot. BLOOD CHEMISTRY The composition of materials dissolved or suspended in plasma (e.g., glucose, urea nitrogen, bilirubin, and cholesterol) can be used to assess the functioning and status of the body’s systems. REFERENCE Seeley's Essentials of Anatomy and Physiology, 9th Edition. No Copyright Intended.