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Blood. Blood. The only fluid tissue in the human body Classified as a connective tissue Components of blood Living cells Formed elements : basophils, eosinophils , erythrocytes, lymphocytes, megakaryocytes, monocytes, neutrophils Non-living matrix
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Blood • The only fluid tissue in the human body • Classified as a connective tissue • Components of blood • Living cells • Formed elements: basophils, eosinophils, erythrocytes, lymphocytes, megakaryocytes, monocytes, neutrophils • Non-living matrix • Plasma: primarily water, non-cellular; the fluid matrix of blood
Blood • If blood is centrifuged 1. Erythrocytes sink to the bottom (45% of blood, a percentage known as the hematocrit) 2. Buffy coat contains leukocytes and platelets (less than 1% of blood) • Buffy coat is a thin, whitish layer between the erythrocytes and plasma 3. Plasmarises to the top (55% of blood) 1 31 2 11
Plasma • Found in Plasma • Nutrients: • Glucose, fatty acids • vitamins • amino acids • Gases: • O2 , CO2 • Ions: • Sodium • Potassium • Calcium
Formed Elements • Three major categories of • Formed Elements: • Erythrocytes • Leukocytes • Platelets Figure 10.1 (2 of 2)
Physical Characteristics of Blood • Color range • Oxygen-rich blood is scarlet red • Oxygen-poor blood is dull red • pH must remain between 7.35–7.45 • Blood temperature is slightly higher than body temperature at 100.4°F • In a healthy man, blood volume is about 5–6 liters or about 6 quarts • Blood makes up 8% of body weight
Blood Plasma • Composed of approximately 90% water • Includes many dissolved substances • Nutrients • Salts (electrolytes) • Respiratory gases • Hormones • Plasma proteins • Waste products
Blood Plasma • Plasma proteins • Most abundant solutes in plasma • Most plasma proteins are made by liver • Various plasma proteins include • Albumin—regulates osmotic pressure • Clotting proteins—help to stem blood loss when a blood vessel is injured • Antibodies—help protect the body from pathogens
Blood Plasma • Acidosis • Blood becomes too acidic • Alkalosis • Blood becomes too basic • In each scenario, the respiratory system and kidneys help restore blood pH to normal
Formed Elements • Erythrocytes • Red blood cells (RBCs) • Leukocytes • White blood cells (WBCs) • Platelets • Cell fragments
Questions • Which body organ plays the main role in producing blood proteins? • What are the three major categories of formed elements? • What determines whether blood is bright red (scarlet) or dull red? • What is the blood volume of an average-sized adult? • Name as many different categories of substances carried in plasma as you can. • Define formed elements. Which category is most numerous? Which makes up the buffy coat?
Photomicrograph of a Blood Smear Figure 10.2
Formed Elements • Erythrocytes (red blood cells or RBCs) • Main function is to carry oxygen • Anatomy of circulating erythrocytes • Biconcave disks • Essentially bags of hemoglobin • Anucleate (no nucleus) • Contain very few organelles • 5 million RBCs per cubic millimeter of blood
Formed Elements • Hemoglobin • Iron-containing protein • Binds strongly, but reversibly, to oxygen • Each hemoglobin molecule has four oxygen binding sites • Each erythrocyte has 250 million hemoglobin molecules • Normal blood contains 12–18 g of hemoglobin per 100 mL blood Hemoglobin transports oxygen in the blood as well as a small amount of carbon dioxide.
Formed Elements • Homeostatic imbalance of RBCs • Anemia is a decrease in the oxygen-carrying ability of the blood • Sickle cell anemia (SCA) results from abnormally shaped hemoglobin • Polycythemia is an excessive or abnormal increase in the number of erythrocytes
Formed Elements Table 10.1
Formed Elements Figure 10.3
Formed Elements • Leukocytes (white blood cells or WBCs) • Crucial in the body’s defense against disease • These are complete cells, with a nucleus and organelles • Able to move into and out of blood vessels (diapedesis) • Can move by ameboid motion • Can respond to chemicals released by damaged tissues • 4,000 to 11,000 WBC per cubic millimeter of blood
Formed Elements • Abnormal numbers of leukocytes • Leukocytosis WBC count above 11,000 leukocytes/mm3 Generally indicates an infection • Leukopenia • Abnormally low leukocyte level • Commonly caused by certain drugs such as corticosteroids and anticancer agents • Leukemia • Bone marrow becomes cancerous, turns out excess WBC
Formed Elements • Types of leukocytes • Granulocytes • Granules in their cytoplasm can be stained • Possess lobed nuclei • Include neutrophils, eosinophils, and basophils • Agranulocytes • Lack visible cytoplasmic granules • Nuclei are spherical, oval, or kidney-shaped • Include lymphocytes and monocytes
Formed Elements • Easy way to remember this list • Never • Let • Monkeys • Eat • Bananas • List of the WBCs from most to least abundant • Neutrophils • Lymphocytes • Monocytes • Eosinophils • Basophils
Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Basophils Erythrocytes Platelets Eosinophils Lymphocytes Monocytes Neutrophils Formed Elements Figure 10.4
Hemocytoblaststem cells Formed Elements Figure 10.4, step 1
Hemocytoblaststem cells Lymphoidstem cells Secondary stem cell Formed Elements Figure 10.4, step 2
Hemocytoblaststem cells Lymphoidstem cells Secondary stem cell Lymphocytes Formed Elements Figure 10.4, step 3
Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Lymphocytes Formed Elements Figure 10.4, step 4
Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Basophils Erythrocytes Platelets Eosinophils Lymphocytes Monocytes Neutrophils Formed Elements Figure 10.4, step 5
Formed Elements • Types of granulocytes • Neutrophils • Multilobed(3-7 lobes) nucleus with fine granules • Act as phagocytes at active sites of infection • Name means “neutral-loving” • Eosinophils • Large brick-red cytoplasmic granules • Found in response to allergies and parasitic worms
Formed Elements • Types of granulocytes (continued) • Basophils • Have histamine-containing granules • Initiate inflammation • Releases a vasodilator; least abundant WBC
Formed Elements • Types of agranulocytes • Lymphocytes • Nucleus fills most of the cell • Play an important role in the immune response • Monocytes • Largest of the white blood cells • Function as macrophages • Important in fighting chronic infection • Phagocyte in chronic infections
Formed Elements • Platelets • Derived from ruptured multinucleate cells (megakaryocytes) ancestral cell of platelets • Needed for the clotting process • Normal platelet count = 300,000/mm3
Questions • What is the role of hemoglobin in the red blood cell? • Which white blood cells are most important in body immunity? • If you had a severe infection, would you expect your WBC count to be closest to 5,000, 10,000 or 15,000/mm3. • Little Lisa is pale and listless. What disorder of erythrocytes might she be suffering from? • Define anemia, and give three possible causes. • Name the granular and agranular WBCs. Give the major function of each type in the body.