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Cardiovascular System: Blood Chapter 14. Cardiovascular System 3 components –Blood, heart, and blood vessels Transports substances to and from body cells.

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Presentation on theme: "Cardiovascular System: Blood Chapter 14. Cardiovascular System 3 components –Blood, heart, and blood vessels Transports substances to and from body cells."— Presentation transcript:

1 Cardiovascular System: Blood Chapter 14

2 Cardiovascular System 3 components –Blood, heart, and blood vessels Transports substances to and from body cells Hematology: branch of science concerned w/study of blood, blood-forming tissues

3 Blood The only liquid connective tissues with three functions 1. Transportation –Blood transports oxygen from lungs to cells throughout body –Carries nutrients from GI tract to body cells, waste products away from cells, hormones from endocrine glands to other body cells 2. Regulation –pH of body fluids 3. Protection –Blood clots in response to injury, which protects against excessive blood loss –Helps protect against disease Ex. White blood cells

4 Blood Denser and more viscous (sticky) than water pH ranges from % of total body weight Hematocrit: the percentage of total blood volume occupied by red blood cells 2 parts –1. blood plasma –2. formed elements

5 Blood Plasma Liquid that contains dissolved substances Contains plasma proteins –Albumins: help maintain proper blood osmotic pressure, important in exchange of fluids across capillary walls –Globulins: defensive proteins Antibodies or immunoglobulins –Fibrinogen Key protein in formation of blood clots

6 Formed Elements Cells and cell fragments Red blood cells White blood cells Platelets

7 Formation of Blood Cells Hemopoiesis: the process by which the formed elements of blood develop Before birth: occurs in the yolk sac of embryo and later in liver, spleen, thymus, and lymph nodes of fetus 3 rd trimester: red bone marrow becomes site for hemopoiesis

8 Red Bone Marrow: highly vascularized connective tissue located in the microscopic spaces b/w trabeculae of spongy bone tissue Red bone marrow cells come from pluripotent stem cells (have capacity to develop into many different types of cells) –Generate myeloid stem cells (develop. in red bone marrow and develop into diff. kinds of cells) and lymphoid stem cells (begin develop. in red bone marrow but complete in lymphatic tissue)

9 Red Blood Cells (RBCs) or erythrocytes Protein called hemoglobin: carries oxygen and gives its red color Mature RBCs are without a nucleus or organelles, cannot divide or do extensive metabolic activities

10 RBC life cycle Live for 120 days 1. Macrophages in spleen, liver, and red bone marrow phagocytize ruptured and worn-out red blood cells, break apart globin and heme of hemoglobin 2. globin amino acids which can be used by body to create proteins 3. iron removed from heme and associates with transferrin (acts as transporter) 4. iron-transferrin complex red bone marrow, RBC precursors use it in hemoglobin synthesis –Iron needed for heme –Amino acids for globin –Vitamin B 12 needed for hemoglobin (stomach produces intrinsic factor for absorption of B 12

11 5. Erythropoiesis in red bone marrow RBCs, enter circulation 6. When iron removed from heme: –Biliverdin: a green pigment Bilirubin: a yellow-orange pigment –Bilirubin enters blood liver secreted by liver cells into bile passes into small intestine and large intestine 7. large intestine, bacteria convert bilirubin urobilinogen some absorbed into blood urobilin excreted in urine Most urobilinogen eliminated in feces –Brown pigment stercobilin

12 RBC Production Formation of just RBCs is called erythropoeisis Near end of process: RBC precursor ejects nucleus reticulocyte (biconcave shape of red blood cell) Negative feedback loop Regulated by amount of oxygen in blood Erythropoiesis and destruction of RBCs at same pace If erythrop. cant keep up with RBC destruction, erythro. increases

13 RBC Production Hypoxia: deficiency of oxygen stimulates release of erythropoietin (EPO) which is hormone made by kidneys EPO thru blood red bone marrow stimulates erythropoeisis Cyanosis: bluish-purple skin coloration due to prolonged hypoxia Anemia: low # of RBCs or low hemoglobin

14 White Blood Cells WBCs or leukocytes Have nuclei, no hemoglobin Granular or agranular Granular: neutrophils, eosinophils, and basophils Agranular: lymphocytes and monocytes

15 WBC functions Combat microbes by phagocytosis or produce antibodies Neutrophils: respond first, phagocytosis, release enzymes such as lysozyme Then monocytes arrive –wandering macrophages –Clean up cellular debris


17 Eosinphils release enzymes that combat inflammation in allergic reactions Basophils involved in allergic reactions Lymphocytes-3 types –B cells-produce antibodies –T cells-attack viruses, fungi, transplanted cells, cancer, etc. –Natural killer cells -attack variety microbes and certain tumor cells

18 WBCs Have proteins called major histocompatibility antigens (MHC) cell identity markers Used to type tissues to identify compatibility of donors and recipients

19 WBC life spans A few days During infection, only a few hours Leukocytosis: increase in the # of WBCs –Usually indicates inflammation/infection

20 Platelets Disc shaped No nucleus When blood vessels damaged, platelets form blood clots Release chemicals that promote blood clotting Life span: 5-9 days

21 Hemostasis: a sequence of responses that stops bleeding when blood vessels are injured Hemorrhage: the loss of a large amount of blood from the vessels Hemostatic response must be quick, localized, and carefully controlled Three mechanisms: –1. vascular spasm –2. platelet plug formation –3. blood clotting (coagulation)

22 1. Vascular Spasm smooth muscle contracts quickly causing a spasm Reduces blood loss vasoconstriction which further reduces blood loss

23 2. Platelet Plug Formation Platelets come together to form a platelet plug 1. platelet adhesion 2. b/c of adhesion, platelets change and enter the platelet release reaction –sustain vascular spasm 3. chemical release makes other platelets sticky platelet aggregation forming a platelet plug

24 3. Clotting (Coagulation) Liquid part of blood: serum Gel portion: clot –fibrin Clotting (coagulation): is a series of chemical reactions that culminates in the formation of fibrin threads If blood clots to easily thrombosis can occur (clotting in an unbroken blood vessel)

25 Clotting With the use of clotting factors 3 stages: –1. Prothrombinase is formed –2. Prothrombinase converts prothrombin (liver) enzyme thrombin –3. Thrombin converts soluble fibrinogen (liver) insoluble fibrin. Fibrin forms threads of clot.

26 Two pathways for clotting 1. Extrinsic Pathway –Occurs rapidly –Damaged tissue cells release tissue factor (TF) into blood from OUTSIDE blood vessels –Tissue eventually converted into prothrombinase 2. Intrinsic Pathway –Occurs more slowly –Activators in direct contact with blood or within blood

27 Clot Retraction Clot retraction: consolidation or tightening of the fibrin clot plasminogen –This can be activated to plasmin clot is dissolved by digesting fibrin threads Small clots dissolve in a process called fibrinolysis

28 Clotting Clots can form within blood vessels –Roughened vessel surface as a result of atherosclerosis, trauma, or infection Thrombosis: clotting in an unbroken blood vessel Thrombus embolus

29 Emboli form in veins b/c slower blood rate Pulmonary embolism: when embolus gets lodged in lungs –Ventricular failure or death –Blocking artery blocks blood flow to brain, kidney, or heart stroke, kidney failure, or heart attack

30 Blood Groups and Blood Types Isoantigens (agglutinogens): an assortment of glycolipids and glycoproteins on the surface of red blood cells blood groups and within a blood group there may be different blood types –2 major blood groups ABO and Rh

31 ABO blood group Based on 2 isoantigens –Antigens A and B –Type A (A antigen) and Type B (B antigen) blood, Type AB or O (no antigens) Isoantibodies (agglutinins) –React with A and B antigens if mixed –Anti-A antibody (reacts with antigen A) –Anti-B antibody (reacts with antigen B) –So, If you have type A blood, you have A antigens on RBC surfaces, and anti-B antibodies in your plasma

32 Rh Blood Group Rh+ or Rh- Important in blood transfusions Ex. Person with type A blood receives type B blood –1. The anti-B antibodies of recipient bind to B antigens of donor blood causing hemolysis –2. anti-A antibodies of donor plasma can bind to A antigens on recipients RBC, not serious though

33 People with type AB blood = universal recipients Type O blood= universal donors

34 Common Disorders Anemia: oxygen carrying capacity of blood is reduced due to decreased RBCs or amount of hemoglobin Sickle Cell Disease: has abnormal type of hemoglobin (Hbs). When this gives up oxygen, bend the erythrocyte into a sickle shape Hemophilia: inability to produce blood clots Leukemia

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