Chapter 17 Blood PDF

https://www.newscientist.com/definition/blood/ Chapter 17 Blood  Circulation Exits the heart via arteries Arteries branch into capillaries Oxygen and nutrients diffuse across capill...

https://www.newscientist.com/definition/blood/ Chapter 17 Blood  Circulation Exits the heart via arteries Arteries branch into capillaries Oxygen and nutrients diffuse across capillary walls and into organs Carbon dioxide and waste from organs enter bloodstream Oxygen deficient blood leaves capillary bed and flows into veins Veins return to heart  Outline Blood Composition and Functions Blood Plasma Formed Elements Homeostasis Transfusion and Blood Replacement Diagnostic Blood Tests Developmental Aspects of Blood  Outline Blood Composition and Functions Blood Plasma Formed Elements Homeostasis Transfusion and Blood Replacement Diagnostic Blood Tests Developmental Aspects of Blood  Blood Composition Blood – Fluid connective tissue – Plasma – non-living fluid matrix – Formed elements – living blood "cells" suspended in plasma Erythrocytes (red blood cells, or RBCs) Leukocytes (white blood cells, or WBCs) Platelets (cell fragments)  Blood Composition Spun tube of blood yields three layers – Plasma on top (~55%) – Erythrocytes on bottom (~45%) – WBCs and platelets in Buffy coat (< 1%) Hematocrit – Percent of blood volume that is RBCs – 47% ± 5% for males; 42% ± 5% for females  Figure 17.1 The major components of whole blood. Slide 2 Withdraw 1 blood and place in tube. © 2013 Pearson Education, Inc.  Figure 17.1 The major components of whole blood. Slide 3 Withdraw Centrifuge 1 2 blood the and place in tube. blood sample. © 2013 Pearson Education, Inc.  Figure 17.1 The major components of whole blood. Slide 4 Plasma 55% of whole blood Least dense F component o r m Buffy coat e Leukocytes and platelets d 2 million RBCs made per second Balance between RBC production and destruction depends on – Hormonal controls – Adequate supplies of iron, amino acids, and B vitamins Hormonal Control of Erythropoiesis Hormone Erythropoietin (EPO) – Direct stimulus for erythropoiesis – Always small amount in blood to maintain basal rate High RBC or O2 levels depress production – Released by kidneys (some from liver) in response to hypoxia Dialysis patients have low RBC counts Hormonal Control of Erythropoiesis Causes of hypoxia – Decreased RBC numbers due to hemorrhage or increased destruction – Insufficient hemoglobin per RBC (e.g., iron deficiency) – Reduced availability of O2 (e.g., high altitudes) Hormonal Control of Erythropoiesis Effects of EPO – Rapid maturation of committed marrow cells – Increased circulating reticulocyte count in 1– 2 days Some athletes abuse artificial EPO – Dangerous consequences Testosterone enhances EPO production, resulting in higher RBC counts in males  Figure 17.6 Erythropoietin mechanism for regulating erythropoiesis. Slide 2 I MB AL A NC E Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia I MB (inadequate O2 AL A NC delivery) due to E Decreased RBC count Decreased amount of hemoglobin Decreased availability of O2 © 2013 Pearson Education, Inc.  Figure 17.6 Erythropoietin mechanism for regulating erythropoiesis. Slide 3 I MB AL A NC E Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia I MB (inadequate O2 AL A NC delivery) due to E Decreased RBC count Decreased amount of hemoglobin Decreased availability of O2 2 Kidney (and liver to a smaller extent) releases erythropoietin. © 2013 Pearson Education, Inc.  Figure 17.6 Erythropoietin mechanism for regulating erythropoiesis. Slide 4 I MB AL A NC E Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia I MB (inadequate O2 AL A NC delivery) due to E Decreased RBC count Decreased amount of hemoglobin Decreased availability of O2 2 Kidney (and liver to a smaller extent) releases 3 erythropoietin. Erythropoietin stimulates red bone marrow. © 2013 Pearson Education, Inc.  Figure 17.6 Erythropoietin mechanism for regulating erythropoiesis. Slide 5 I MB AL A NC E Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia I MB (inadequate O2 AL A NC delivery) due to E Decreased RBC count Decreased amount of hemoglobin Decreased Enhanced availability of O2 4 erythropoiesis increases RBC 2 Kidney (and liver to count. a smaller extent) releases 3 erythropoietin. Erythropoietin stimulates red bone marrow. © 2013 Pearson Education, Inc.  Figure 17.6 Erythropoietin mechanism for regulating erythropoiesis. Slide 6 I MB AL A NC E Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia O -carrying I MB 5 2 AL A (inadequate O2 ability of NC E delivery) due to blood Decreased rises. RBC count Decreased amount of hemoglobin Decreased Enhanced availability of O2 4 erythropoiesis increases RBC 2 Kidney (and liver to count. a smaller extent) releases 3 erythropoietin. Erythropoietin stimulates red bone marrow. © 2013 Pearson Education, Inc.  Dietary Requirements for Erythropoiesis Nutrients—amino acids, lipids, and carbohydrates Iron – Available from diet – 65% in Hb; rest in liver, spleen, and bone marrow – Free iron ions toxic Stored in cells as ferritin and hemosiderin Transported in blood bound to protein transferrin Vitamin B12 and folic acid necessary for DNA synthesis for rapidly dividing cells (developing RBCs)  Fate and Destruction of Erythrocytes Life span: 100–120 days https://www.diabetesselfmanagement.com/ – No protein synthesis, growth, division diabetes-resources/definitions/hba1c/ Old RBCs become fragile; Hb begins to degenerate Get trapped in smaller circulatory channels especially in spleen Macrophages engulf dying RBCs in spleen  Fate and Destruction of Erythrocytes Heme and globin are separated – Iron salvaged for reuse – Heme degraded to yellow pigment bilirubin – Liver secretes bilirubin (in bile) into intestines Degraded to pigment urobilinogen Pigment leaves body in feces as stercobilin – Globin metabolized into amino acids Released into circulation  Figure 17.7 Life cycle of red blood cells. Slide 1 Low O2 levels in blood stimulate 8 kidneys to produce erythropoietin. 2 Erythropoietin levels rise in blood. Erythropoietin and necessary 3 raw materials in blood promote erythropoiesis in red bone marrow. 4 New erythrocytes enter bloodstream; function about 120 days. Aged and damaged 5 red blood cells are engulfed by macrophages of spleen, liver, and bone marrow; the hemoglobin is broken down. Hemoglobin Globi Heme n Iron is Amino Bilirubin is stored acids picked up as ferritin or by the liver. hemosiderin. Iron is bound to transferrin and released to blood from liver as needed for erythropoiesis. Bilirubin is secreted into Circulatio intestine in bile where n it is metabolized to stercobilin by bacteria. Raw materials are 6 made available in blood for erythrocyte synthesis. Food nutrients (amino acids, Fe, Stercobilin B12, and folic acid) is excreted are absorbed from in feces. intestine and © 2013 Pearson enter blood. Education, Inc.  Erythrocyte Disorders Anemia – Blood has abnormally low O2-carrying capacity – Sign rather than disease itself – Blood O2 levels cannot support normal metabolism – Accompanied by fatigue, pallor, shortness of breath, and chills  Causes of Anemia Three groups – Blood loss – Low RBC production – High RBC destruction Causes of Anemia: Blood Loss Hemorrhagic anemia – Blood loss rapid (e.g., stab wound) – Treated by blood replacement Chronic hemorrhagic anemia – Slight but persistent blood loss Hemorrhoids, bleeding ulcer – Primary problem treated  Causes of Anemia: Low RBC Production Iron-deficiency anemia – Caused by hemorrhagic anemia, low iron intake, or impaired absorption – Microcytic, hypochromic RBCs – Iron supplements to treat  Causes of Anemia: Low RBC Production Pernicious anemia – Autoimmune disease - destroys stomach mucosa – Lack of intrinsic factor needed to absorb B12 Deficiency of vitamin B12 – RBCs cannot divide macrocytes – Treated with B12 injections or nasal gel – Also caused by low dietary B12 (vegetarians)  Causes of Anemia: Low RBC Production Renal anemia – Lack of EPO – Often accompanies renal disease – Treated with synthetic EPO  Causes of Anemia: Low RBC Production Aplastic anemia – Destruction or inhibition of red marrow by drugs, chemicals, radiation, viruses – Usually cause unknown – All cell lines affected Anemia; clotting and immunity defects – Treated short-term with transfusions; long- term with transplanted stem cells  Causes of Anemia: High RBC Destruction Hemolytic anemias – Premature RBC lysis – Caused by Hb abnormalities Incompatible transfusions https://socratic.org/questions/what-are-the-functions-of-human-red-blood- cells Infections  Causes of Anemia: High RBC Destruction Usually genetic basis for abnormal Hb Globin abnormal – Fragile RBCs lyse prematurely  Causes of Anemia: High RBC Destruction Thalassemias – Typically Mediterranean ancestry – One globin chain absent or faulty – RBCs thin, delicate, deficient in Hb – Many subtypes Severity from mild to severe https://www.news-medical.net/health/Thalassemia-Pathophysiology.aspx  Causes of Anemia: High RBC Destruction Sickle-cell anemia – Hemoglobin S One amino acid wrong in a globin beta chain – RBCs crescent shaped when unload O2 or blood O2 low – RBCs rupture easily and block small vessels Poor O2 delivery; pain https://www.whattoexpect.com/first-year/sickle-cell-anemia.aspx  Sickle-cell Anemia Black people of African malarial belt and descendants Malaria – Kills 1 million each year Sickle-cell gene – Two copies = Sickle-cell anemia – One copy  Sickle-cell trait; milder disease; better chance to survive malaria  Figure 17.8 Sickle-cell anemia. Val His Leu Thr Pro Glu Glu … 1 2 3 4 5 6 7 146 Normal erythrocyte has normal hemoglobin amino acid sequence in the beta chain. Val His Leu Thr Pro Val Glu … 1 2 3 4 5 6 7 146 Sickled erythrocyte results from a single amino acid change in the © 2013 Pearson beta chain of hemoglobin. Education, Inc.  Erythrocyte Disorders Polycythemia vera – Bone marrow cancer 🡪 excess RBCs – Severely increased blood viscosity Secondary polycythemia – Less O2 available (high altitude) or EPO production increases 🡪 higher RBC count – Blood doping  Leukocytes Make up