Human Anatomy Mc Kinley O Loughlin Chapter 18

Human Anatomy Mc. Kinley & O'Loughlin Chapter 18 Blood 1

New Dates: n n n Mar Mar Mar 15 -16: 19 -22: 21 -22: 26 -27: 28 -29: Blood-Heart-vessels Vessels-Lymph. Lec quiz 4 Lymph-Resp Exam 4: Cardio-Resp 21 -2

Blood n Why is Blood Red? n Average adult has ___pints of blood? n Blood Types: U. S. Average n n n A = 34% B = 9% AB = 3% a- 6% b- 9% ab- 1% 21 -3

Blood n Blood is a Connective Tissue Because…… n n it contains cells, a liquid ground substance (called plasma), dissolved protein fibers. Blood is also: n n n four times more viscous (or thicker) than water. 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. n n n blood is withdrawn from a vein and collected in a centrifuge tube is placed into the centrifuge, which then spins it in a circular motion for several minutes rotational movement separates the blood into n Liquid & Cellular components 21 -4

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Components of Blood(3) n 1. Erythrocytes (or red blood cells) n n n 2. Buffy coat n n form the lower layer of the centrifuged blood typically make up about 44% of a blood sample makes up the middle layer thin, slightly gray-white layer composed of cells called leukocytes (or white blood cells) and cell fragments called platelets forms less than 1% of a blood sample 3. Plasma n n straw-colored liquid that rises to the top generally makes up about 55% of blood 21 -6

Components of Blood n Erythrocytes and the components of the buffy coat are called the formed elements. n not “cells, ” merely fragments broken off from a larger cell Formed elements and the liquid plasma compose whole blood. So…. . n Formed Elements = RBC’s + buffy coat(WBC’s + platelets) n Formed elements + Plasma = whole blood 21 -7

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Functions of Blood 1. Transportation n Transports numerous elements and compounds throughout the body. n n erythrocytes carry oxygen from the lungs to body cells and then transport carbon dioxide from the cells back to the lungs for expulsion from the body blood plasma n n n transports nutrients that have been absorbed from the GI tract hormones secreted by the endocrine organs to their target cells plasma n carries waste products from the cells to organs such as the kidneys, where these waste products are removed 21 -9

Functions of Blood 2. Regulation of Body Temp. n Regulates body temperature. n n n plasma absorbs and distributes heat throughout the body for cooling the blood vessels in the dermis dilate and dissipate the excess heat through the integument when the body needs to conserve heat, the dermal blood vessels constrict, and the warm blood is shunted to deeper blood vessels in the body 21 -10

Functions of Blood 3. Regulation of p. H Levels n Blood plasma p. H is continuously regulated at a value of 7. 4 the p. H level required for normal cellular functioning. n p. H is a measure of how alkaline or acidic a fluid is. n Neutral p. H is measured at exactly 7. n Acidic fluids ( orange juice) are between 0 and 7. n Alkaline fluids ( milk) are between 7 and 14. n Blood plasma contains compounds and ions that may be distributed to the fluid among tissues (interstitial fluid) to help maintain normal tissue p. H. 21 -11

Functions of Blood 4. Maintenance of Fluid Levels n Maintains normal fluid levels in the cardiovascular system. n n n IF… too much fluid is absorbed in the blood, n n Prevents fluid loss. Constant exchange of fluid between the blood plasma and the interstitial fluid. High Blood Pressure results If too much fluid escapes the bloodstream and enters the tissues, may drop to unhealthy low levels, and the tissues swell with excess fluid. n Blood Pressure Drops 21 -12

Functions of Blood – 5. Protection n Leukocytes (white blood cells) help guard against infection n n Plasma n n mounting an immune response if a pathogen or an antigen is found. transports antibodies, which are molecules that can immobilize antigens until a leukocyte can completely kill or remove the antigen. Platelets and blood proteins n protect the body against blood loss by forming blood clots on damaged vessels. 21 -13

Components of Plasma n n n Complex mixture of water, proteins, and other solutes. When the proteins are moved from plasma, the remaining fluid is termed serum. Water makes up about 92% of plasma’s total volume. n water facilitates the transport of materials in the plasma 21 -14

Plasma Proteins (4) n n The next most abundant materials in plasma are the plasma proteins. Make up about 7% of the plasma. n n 6 and 8 grams of protein in a volume of 100 milliliters of blood (referred to as g/dl) The plasma proteins include: n n albumins globulins fibrinogen regulatory proteins 21 -15

Plasma Proteins 1. Albumins n Smallest and most abundant of the plasma proteins. n n n make up approximately 58% of total plasma proteins Regulate water movement between the blood and interstitial fluid. Albumins act as transport proteins that carry ions, hormones, and some lipids in the blood. 21 -16

Plasma Proteins 2. Globulins n n Second largest group of plasma proteins, forming about 37% of all plasma proteins. Smaller alpha-globulins and the larger beta-globulins primarily bind, support, and protect certain waterinsoluble or hydrophobic molecules, hormones, and ions. Also called immunoglobulins or antibodies. Produced by some of our defense cells to protect the body against pathogens that may cause disease. 21 -17

Plasma Proteins 3. Fibrinogen n Makes up about 4% of all plasma proteins. Responsible for blood clot formation. Following trauma to the walls of blood vessels, fibrinogen is converted into long, insoluble strands of fibrin, which is the essence of a blood clot. 21 -18

Plasma Proteins 4. Regulatory Proteins n Form a very minor class of plasma proteins. n n <1% of total plasma proteins Include enzymes to accelerate chemical reactions in the blood and hormones being transported throughout the body to target cells. 21 -19

Formed Elements in the Blood n Erythrocytes n n n Leukocytes n n n make up more than 99% of formed elements primary function is to transport respiratory gases in the blood make up less than. 01% of formed elements contribute to defending the body against pathogens Platelets n n make up less than 1% of formed elements and help with blood clotting 21 -20

Hematocrit n n n Percentage of erythrocytes in the blood. Values vary slightly and are dependent on age and sex. Adult males n n Females n n range between 42% and 56%. range from 38% to 46%. Altitude can affect the hematocrit. n body compensates by making more erythrocytes n more erythrocytes in the blood can carry more oxygen to the tissues 21 -21

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Erythrocytes n n Mature erythrocytes lack nuclei. n Lack of nuclei enables them to carry respiratory gases more efficiently The “job” of these erythrocytes is to Transport oxygen and carbon dioxide to and from the tissues and the lungs. 21 -23

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Hemoglobin in Erythrocytes n n n Every erythrocyte is filled with approximately 280 million molecules of a red-pigmented protein called hemoglobin. Transports oxygen and carbon dioxide, and is responsible for the characteristic bright red color of arterial blood. Hemoglobin that contains no oxygen has a deep red color that is perceived as blue because the blood within these veins is observed through the layers of the skin and the subcutaneous tissue. 21 -25

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Antibodies n n n An antibody interacts with a specific antigen. The ABO blood group has both anti-A and anti-B antibodies that react with the surface antigen A and the surface antigen B, respectively. The antibodies in your blood plasma do not recognize the surface antigens on your erythrocytes. 21 -28

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Leukocytes n Leukocytes are true “cells” because…. n they contain a nucleus and cellular organelles. Leukocytes help initiate an immune response and defend the body against invading pathogens. n Leukocytes also differ from erythrocytes in that they are about 1. 5 to 3 times larger, and they do not contain hemoglobin. 21 -31

Leukocytes Granulocytes (3) n 1. Neutrophil n n 2. Eosinophils have reddish, or pink-orange granules in their cytoplasm. n n n 60– 70% of the total number of leukocytes constitute about 2– 4% of the total number of leukocytes nucleus usually has two lobes, which are connected by a thin strand 3. Basophils are n n 1. 5 times larger than erythrocytes least numerous of the granulocytes constitute about 0. 5– 1% of the total number of leukocytes always exhibit a bilobed nucleus and abundant blue-violet granules in the cytoplasm 21 -32

Leukocytes Agranulocytes (2) n n Agranulocytes are leukocytes that have such small granules in their cytoplasm that they are frequently overlooked upon casual observation—hence the name agranulocyte. Agranulocytes include n 4. lymphocytes n 5. monocytes. 21 -33

Leukocytes – Agranulocytes Lymphocytes n T-lymphocytes (T-cells) n n n B-lymphocytes (B-cells) n n manage and direct an immune response some directly attack foreign cells and virusinfected cells stimulated to become plasma cells and produce antibodies Natural killer cells (NK cells) n attack abnormal and infected tissue cells 21 -34

Leukocytes – Agranulocytes Monocytes n n Up to three times the diameter of an erythrocyte. Constitute about 3– 8% of all leukocytes. Nucleus is kidney-shaped or U-shaped. Their job is…. . n Macrophages phagocytize bacteria, cell fragments, dead cells, and debris. 21 -35

Platelets n n n Irregular, membrane-enclosed cellular fragments that are about 2 micrometers in diameter (less than one-fourth the size of an erythrocyte). In stained preparations, they exhibit a dark central region. Sometimes called thrombocytes. Continually produced in the red bone marrow by cells called megakaryocytes. Severe trauma to a blood vessel causes the blood to coagulate, or clot. Components in the plasma produce a web of fibrin that traps erythrocytes and platelets in the web to halt blood flow. 21 -36