440 likes | 596 Views
Blood. Transport Gases Nutrients metabolic wastes hormones Regulate pH temperature fluid Defense blood loss infectious agents. O 2 and CO 2 Carbs, proteins, fats urea and uric acid Estrogen, testosterone, ADH, insulin Between 7.45 to 7.48
E N D
Transport Gases Nutrients metabolic wastes hormones Regulate pH temperature fluid Defense blood loss infectious agents O2 and CO2 Carbs, proteins, fats urea and uric acid Estrogen, testosterone, ADH, insulin Between 7.45 to 7.48 Acts as a heat resevoir to distribute it tissues get fluid from blood Has ability to stop blood loss Defend against foreign invaders Blood Functions
Blood Composition Cells = Formed Elements (not all are technically cells) Erythrocytes aka RED blood cells count ~ 5.0 million/drop Leukocytes aka White blood cells count ~ 4,000 – 11,000/drop Platelets aka Thrombocytes count 250,000 – 500,000/drp
Blood Composition Matrix = Plasma 90% Water 8% Proteins albumin globulins fibrinogen 2% Other gases nitrogenous wastes nutrients electrolytes
Biconcave discs Lack nucleus Lack mitochondria Contain hemoglobin Carry oxygen and some carbon dioxide ERYTHROCYTES
HEME PORTION Has central Fe atom that carries one oxygen molecule Each Hemoglobin is like a 4 passenger TAXI HEMOGLOBIN
GLOBIN PORTION 4 protein chains *each chain has one heme *each RBC carries 250 million hemoglobin molecule *Therefore each RBC carries ONE BILLION O2 HEMOGLOBIN
HEMOGLOBIN • When oxygen is bound to hemoglobin it is called oxyhemoglobin. • When oxygen is NOT bound to hemoglobin it is called deoxyhemoglobin • 20% of CO2 is transported in hemoglobin, but does not compete with oxygen site of heme
Hematopoiesis Erythropoiesis: formation of erythrocytes Formation of blood • Starts with hemocytoblasts • Occurs in red bone marrow
Stem cell Hemocytoblast Committed cell Proerythroblast Ribosome production Early erythroblast Late erythroblast Hemoglobin production When hemoglobin content reaches ~35%, organelles get ejected. Eventually nucleus gets ejected. Normoblast Reticulocyte Gets released into blood stream Erythrocyte Mature cell
Time it takes for erythropoiesis Hemocytoblasts Total time to replace RBCs is about ONE week 3 to 5 days Reticulocytes 2 days more Erythrocytes
Erythropoietin (EPO) • Regulates RBC production • Normal rates 2 million/sec • Kidneys control production of EPO
IMBALANCE Homeostasis: Normal blood oxygen levels mechanism for regulating erythropoiesis 1 Stimulus: Hypoxia (low blood O2- carrying ability) due to • DecreasedRBC count • Decreased amountof hemoglobin • Decreasedavailability of O2 IMBALANCE
IMBALANCE Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia (low blood O2- carrying ability) due to • DecreasedRBC count • Decreased amountof hemoglobin • Decreasedavailability of O2 IMBALANCE Kidney (and liver toa smaller extent)releaseserythropoietin. 2
IMBALANCE Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia (low blood O2- carrying ability) due to • DecreasedRBC count • Decreased amountof hemoglobin • Decreasedavailability of O2 IMBALANCE 2 Kidney (and liver toa smaller extent)releaseserythropoietin. Erythropoietinstimulates redbone marrow. 3
IMBALANCE Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia (low blood O2- carrying ability) due to • DecreasedRBC count • Decreased amountof hemoglobin • Decreasedavailability of O2 IMBALANCE Enhancederythropoiesisincreases RBCcount. 4 2 Kidney (and liver toa smaller extent)releaseserythropoietin. 3 Erythropoietinstimulates redbone marrow.
IMBALANCE Homeostasis: Normal blood oxygen levels 1 Stimulus: Hypoxia (low blood O2- carrying ability) due to • DecreasedRBC count • Decreased amountof hemoglobin • Decreasedavailability of O2 O2- carryingability of bloodincreases. 5 IMBALANCE 4 Enhancederythropoiesisincreases RBCcount. 2 Kidney (and liver toa smaller extent)releaseserythropoietin. 3 Erythropoietinstimulates redbone marrow.
Induced Polycythemia Increasing the number of red blood cells in circulation • Training at higher altitudes • Blood doping
Hemoglobin Aged and damaged red blood cells are engulfed by macrophages of liver, spleen, and bone marrow; the hemoglobin is broken down. Heme Globin Bilirubin Amino acids Iron stored In liver Iron is released to blood from liver as needed for erythropoiesis. Fate and destruction of RBCs Bilirubin is picked up from blood by liver, secreted into intestine in bile, metabolized by bacteria, and excreted in feces. Urine gets its color from urochrome (comes from bilirubin) Circulation Food nutrients are absorbed from intestine and enter blood. Raw materials are made available in blood for erythrocyte synthesis.
Fate and destruction of RBCs Circulation
Erythrocyte disorders Anemias = abnormally LOW oxygen carrying capacity • low RBCs – blood loss, RBC destruction, defective bone marrow • low Hemoglobin content – low iron, B12 deficiency • abnormal hemoglobin – sickle cell Polycythemia = abnormal excess of RBCs • increases blood viscosity • increases blood pressure Can be due to disease, high altitude or blood doping
Leukocytes • Granulocytes = have cytoplasmic granules • Basophils – release histamine (inflammation); contain heparin (anticoagulant) • Neutrophils – phagocytize bacteria • Eosinophils –role in allergies and asthma • Agranulocytes = lack cytoplasmic granules • Monocytes – phagocytize foreign invaders • Lymphocytes– involved in immune response
Leukopoiesis – formation of WBCs Leukemia – abnormally high WBC count of abnormal WBCs Leukopenia – low WBC count
Thrombocytes aka Platelets • Responsible for Blood Clotting
Hemostasis Stoppage of blood flow
Step Vascular spasm • Smooth muscle contracts,causing vasoconstriction. 1
Step Vascular spasm • Smooth muscle contracts,causing vasoconstriction. 1 Step Platelet plug formation • Injury to lining of vesselexposes collagen fibers;platelets adhere. 2 Collagenfibers
Step Vascular spasm • Smooth muscle contracts,causing vasoconstriction. 1 Step Platelet plug formation • Injury to lining of vesselexposes collagen fibers;platelets adhere. • Platelets release chemicalsthat make nearby plateletssticky; platelet plug forms. 2 Collagenfibers Platelets
Chemicals that aid platelet plug formation • Serotonin • Enhances vasoconstriction • Thromboxane • Enhances vasoconstriction • Attracts platelets to the wound What is aspirin, and how does it work? Inhibits thromboxane increases bleeding time
Step 1: Vascular spasm •Smooth muscle contracts, causing vasoconstriction. Step 2: Platelet plug formation •Injury to lining of vessel exposes collagen fibers; platelets adhere. Collagen fibers •Platelets release chemicals that make nearby platelets sticky; platelet plug forms. Step 3: Coagulation •Fibrin forms a mesh that traps red blood cells and platelets, forming the clot. Platelets Fibrin
Inactive Clotting Factors Becomes The catalyst Collagen exposure Ca+2 Prothrombin Activator Active Clotting Factors Becomes The catalyst Prothrombin Thrombin Fibrinogen Fibrin
Fibrin Platelets RBC Figure 17.15
Clot Retraction • Platelets contract within 30–60 minutes • Platelets pull on the fibrin strands pulling ends of wound together
Fibrinolysis • Clot dissolving • Takes several days to occur