14 Unit 1 Chapter 14

14 Unit 1 3 components of the cardiovascular system = blood, heart, blood vessels Function of CV system = transports substances to and from body cells Hematology = branch of science that deals with study of blood, blood- forming tissues and disorders associated with them

14 Unit 1 Is a type of connective tissue Transportation- gasses (O 2 & CO 2 ), nutrients (GI tract), heat & waste, hormones (endocrine system) Regulation- pH, temperature, water balance in cells Protection- loss of blood via clotting, WBC vs. disease; production of interferons and complement

14 Unit 1 5 facts about blood 1.Blood is thicker than water 2.Temp is 38° C 3.Slightly alkaline 7.35 – % of total body weight 5.Volume = males – 5-6 liters females – 4-5 liters

14 Unit 1 Connective tissue-Two parts Plasma = straw-colored liquid with dissolved materials (~55%) Formed Elements = cells and cells fragments (~45%) 99% of the formed elements are RBCs

14 Unit 1 hematocrit (Hct) = Percent of blood volume occupied by red blood cells (RBC) Buffy coat – part made up by white blood cells (WBC) and plateletes ~1%

Figure 14.1a

Figure 14.1b

14 Unit 1 ~91% water, 7% proteins, 1.5 % other solutes Proteins: Albumin (54%)- maintains osmotic pressure; Globulins (38%)- antibodies for defense Fibrinogen (7%)- clotting Other solutes in plasma: Electrolytes, nutrients, gases, hormones, vitamins & waste products

14 Unit 1 I. Red Blood Cells II. White blood cells A. granular Leukocytes 1.Neutrophils 2.Eosinophils 3.Basophils B. Agranular leukocytes 1.T & B lymphocytes & natural Killer cells 2. monocytes III Platelets

14 Unit 1 Hemopoiesis – production of formed elements 3 months before birth and throughout life occurs in red bone marrow Contains pluripotent stem cells In response to specific hormones these develop through a series of changes to form all of the blood cells

14 Unit 1 Bone marrow contains pluripotent stem cells – cells that can develop into many different types of cells In response to specific hormones these develop into myeloid stem cells (RBC, platelets, and some WBC) and lymphoid stem cells (T and B lymphocytes)

Figure 14.2a

Figure 14.2b

14 Unit 1 AKA = Erythrocytes Contains - hemoglobin protein- carries oxygen Also carries some CO 2 Male has ~ 5.4 million cells/µl; Female has ~4.8 million

14 Unit 1 Production rate = 2 million/sec Contain no nucleus & other organelles Consists of membrane, cytosol, hemoglobin Biconcave shape provides for greater surface area for the diffusion of gas molecules into/out of a RBC

14 Unit 1 Wear out fast- live ~120 days due to wear and tear as they squeeze through capillaries Worn out and ruptured cells are cleared by macrophages (liver spleen, red bone marrow) Fe- recycled in bone marrow Carried in blood on transferrin – plasma protein acts as a transporter for iron

14 Unit 1 biliverdin  bilirubin – what the non-iron portion of heme is converted into and excreted (bile) Urobilinogen and stercobilin – by products of bilirubin; some absorbed in large intestine; ultimately excreted in urine or feces

Figure 14.3

14 Unit 1 called erythropoiesis Released as reticulocytes (almost a RBC) Mature to erythrocytes in 1-2 days Production & destruction is balanced

14 Unit 1 If O 2 carrying capacity falls, RBC productions is inc. by a negative feedback loop Low O 2 delivery (hypoxia)  erythropoietin (EPO)- kidney hormone  stimulates erythropoiesis

14 Unit 1 Cyanosis – life threatening condition caused by prolonged hypoxia; bluish-purple skin coloration Anemia – reduced O 2 carrying capacity – reduced # of RBC or ↓ amount of hemoglobin in blood; pale skin

Figure 14.4

14 Unit 1 aka = leukocytes Classified as either 1. granular which contains a chemical filled cytoplasmic granule/vesicle (neutrophils, eosinophils, basophils) or 2. agranular (lymphocytes, monocytes) Function in defense: phagocytosis or antibody production

14 Unit 1 Phagocytes: Neutrophil- first responders; release lysozomes that destroy bacteria Monocytes  slower response; become wandering macrophages (big eaters compared to neutrophils) Eosinophil- work in interstitial fluid; Involved in suppressing allergic responses; phagocitize antibody-antigen complexes and are effective against some parasitic worms Basophil- intensify allergic reactions

14 Unit 1 Phagocytes: a. Neutrophil- first responders; release lysozomes that destroy bacteria b. Monocytes  slower response; become wandering macrophages (big eaters compared to neutrophils)

14 Unit 1 Phagocytes: c. Eosinophil- phagocitize antibody-antigen complexes involved in suppressing allergic responses d. Basophil- release heparin, histamines, serotonin; intensify allergic reactions

14 Unit 1 Producing antibodies (Immune response): B-cells – plasma cells – produce antibodies to help destroy bacteria/inactivate toxins T-cells – attack viruses, fungi, cancer cells, transplanted cells, bacterial cells Natural killer (NK) cells – attack infectious microbes and some types of tumor cells

14 Unit 1 Major histocompatibility (MHC) antigens – proteins on the surface of a cells that act as “cell identity markers” that are unique for each person; used to type tissue for transplants

14 Unit 1 Number of RBC vs. WBC is 700:1; ,000 WBC /µl blood Life span is a few days normally; a few hour during an active infection; some B and T cells live for years

14 Unit 1 Leukocytosis= normal increase in WBC #’s  response to stresses; indicates inflammtion/infection Differential white blood cell count is the measure of the different types of WBC per 100 WBC (helps in diagnosis) Leukopenia = abnormally low WBC numbers; never good; radiation, shock, some chemotherapeutic agents

14 Unit 1 Myeloid stem cells  megakaryoblasts  megakaryocytes  fragments = platelets Plug damaged blood vessels Promote blood clotting Life span 5-9 days

14 Unit 1 Hemostasis = stationary blood – a series of responses that stop bleeding when blood vessels are injured 1. Vascular reactions (spasm) 2. platelet plug formation 3. blood clotting (coagulation) Hemorrhage - loss of large amounts of blood

14 Unit 1 1. Vascular spasm – contraction of smooth muscle in the walls of a damaged blood vessel; effective for several minutes to several hours; platelets at the site release chemicals to enhance vasoconstriction maintaining vascular spasm Quick reduction of blood loss

14 Unit 1 2. platelet plug formation – platelets stick to parts of a damaged blood vessel; they release chemcials to make other platelets sticky; eventually forms a platelet plug

14 Unit 1 3. blood clotting –when blood is withdrawn it separates into serum and a gel called fibrin (protein fibers that make up a clots) Clotting (coagulation) –process of clot formation; series of chemical reactions involving clotting factors Thrombosis – clotting in an unbroken blood vessel

14 Unit 1 1. prothrombinase is formed 2. prothrombinase converts prothrombin (a protein)  thrombin (an enzyme) 3. thrombin converts fibrinogen (another protein)  fibrin (fibers that form the threads of a clot)  clot

14 Unit 1 Extrinsic pathway  happens quickly; tissue factor(TF) from damaged cells makes prothrombinase Intrinsic Pathway  takes several minutes Materials “intrinsic” to blood make prothrombinase

14 Unit 1 Clot retraction- consolidation or tightening of the fibrin clot As the clot retracts damaged edges of blood vessels pull closer together Permanent repairs take place when fibroblasts form connective tissue and endothelial cells repair the vessel lining

14 Unit 1 Fibrinolysis: dissolving of unnecessary clots by activated plasmin which digests fibrin threads in a clot

14 Unit 1 Clots can be triggered by 1. Roughness on vessel wall as a result of atherosclerosis, trauma, infection 2. If the flow of blood becomes too slow clotting factors accumulate enough to trigger a clot

14 Unit 1 Thrombosis - clotting in an unbroken vessel (thrombus = clot) Blood clot, air bubble, or fat from a broken bone transported by blood= embolus and can block a small blood vessel Pulmonary embolism – blockage of blood vessel in the lungs

Figure 14.5

14 Unit 1 Agglutinogens – antigens composed of glycolipids/proteins on the surface of RBC Blood groups are categorized based on the presence or absence of various antigens >24 blood groups and >100 antigens

14 Unit 1 We will deal with ABO and Rh groups ABO blood group has two antigens A and B Your blood type is determined by which you have (if you have the A antigen you have blood type A; AB blood has both the A and B antigen; O has no antigen)

14 Unit 1 Blood usually has antibodies or agglutinins that can react with antigens e.g. anti-A antibody or anti-B antibody You don’t react with your own antigens Thus: type A has anti-B and vice versa

Figure 14.6

14 Unit 1 The Rh blood group is named after the rhesus monkey where the Rh antigen was discovered If have antigen you are Rh + Normally we don’t have anti-Rh antibodies they develop after the first exposure from transfusion

14 Unit 1 Transfusion – transfer of whole blood or blood components (plasma) If mismatched blood is given antibodies in the recipient's blood bind to the antigens on the donated RBC and causes hemolysis (rupture of RBC)

14 Unit 1 Universal recipients - Type AB has no AB antibodies so can receive any ABO type blood Universal donors - Type O have neither antigen so can donate to any other ABO type Misleading because of many other blood groups that must be matched