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Circulation and Defense 1 Circulatory System 2 Background Closed system vs. open systems 3 4 Blood Vessels Arteries Veins Capillaries 5 6 Blood Vessels Arteries - away from heart -Thick elastic walls – why? - withstand pressure - Branch into arterioles - smaller arteries 7 Specific Arteries Aorta - largest artery – 2.5cm in diameter - extends from left ventricle of heart Carotid - from aorta to head - internal to brain, external to face - have chemoreceptors to detect pH 8 Specific Arteries cont’d Coronary - branch off aorta & lead back to heart muscle Brachial - extends from aorta to arms Hepatic - from aorta to liver Femoral - from aorta to legs Renal - from aorta to kidneys 9 Veins To heart Thinner walls w/ some elastic Valves to prevent backflow Venules branch from capillaries to veins 10 11 Specific Veins Inferior Vena Cava - from lower body to right atrium - all veins from lower body lead here - 3cm in diameter Superior Vena Cava - from head to rt. atrium 12 Specific veins cont’d Jugular veins - from brain & face to superior vena cava 13 Capillaries One cell thick Site of gas exchange b/w cells & blood Fluids from tissues re-enters blood due to hypertonicity (increased plasma protein concentration) Edema – swelling of tissue – water retention 14 15 16 The Heart 2 pathways of circulation - pulmonary circulation - b/w heart & lungs blood becomes oxygenated at lungs - systemic circulation b/w heart & all body parts blood drops off O2, picks up CO2 Path of blood through heart – see diagram 17 18 19 20 Features of the Heart Made of cardiac muscle (cross striated) Heartbeat has 2 parts 1. Systole - contracting of muscle - ventricles push blood out 2. Diastole - relaxed - atria filling up 21 Heart action Both atria fill simultaneously - A-V valves closed - semilunars closed A-V valves open as atria contract Ventricles fill and A-V valves forced shut Semilunars open as ventricles contract Blood pushed into arteries semilunars forced to close Lub-dupp sound is closing of valves 22 23 Regulation of Heartbeat Heart beats w/o control from CNS Contractions coordinated by sinoatrial node(S-A node) AKA pacemaker - located in rt. atrium - made of cells that spontaneously initiate electrical impulses 24 Steps of heart beat - Pacemaker initiates impulse - Electric current spreads across both atria causing them to contract - A-V node in rt. Atrium hit by impulse - A-V node stimulates ventricles to contract 25 Regulation of Pacemaker Medulla sends messages (hormones) to change heart rate - epinephrine aka adrenaline causes heart rate - temperature causes heart rate 26 27 Regulation of blood flow Flow is not even to all parts Smooth muscles in arterioles constrict & relax thus changing blood flow Vasodilation - muscles relax & dilate thus blood flow Vasoconstriction – muscles contract & constrict the arteriole thus blood flow i.e. - after eating 28 Blood Pressure Greater the pressure the greater the flow Negative feedback regulates pressure Stretch receptors in aorta & carotids If pressure the heart rate should & blood vessels should dilate If pressure the heart rate should & vessels should constrict 29 Blood Pressure cont’d Hypertension – high blood pressure - dilation doesn’t occur - medication helps dilate vessels 30 Functions of Blood Transport - O2 - CO2 and other wastes - nutrients, hormones, electrolytes Regulates pH Regulates temperature 31 Components of Blood 2 parts of whole blood 1. Plasma – liquid 55% 2. Cellular part – solid 45% 4-6 L in ave. person 32 33 Plasma 90% water 10% - substances moving from place to place ie, nutrients, hormones - electrolytes – dissolved ions osmotic balance & pH balance (7.4) 34 Plasma cont’d Plasma proteins - enzymes - immunoglobulins – antibodies - fibrinogens – clotting - when these proteins are gone the plasma is called serum 35 Red Blood Cells Aka erythrocytes Most numerous Made in bone marrow Carries O2 - hemoglobin binds w/iron No nucleus when mature 36 White Blood Cells 1 WBC for every 1,000 RBC Larger than RBC’s Defends against foreign particles Made in bone marrow Mature in spleen, thymus, tonsils, adenoids & lymph nodes 37 WBC’s cont’d Different types of WBC’s - macrophages – eating phagocytes - T lymphocytes - B lymphocytes 38 39 Platelets Chips of cells, no nucleus Smaller than RBC’s Blood clotting 40 The Lymphatic System Some fluid (plasma) leaks out at capillaries & doesn’t return Lymph system returns this fluid (now called lymph) to the circulatory system Lymph nodes filter lymph and attack viruses & bacteria System also functions in fat absorption See diagram pg. 934 41 42 The Body’s Defense 43 Two Mechanisms Nonspecific Specific 44 Nonspecific 1st line skin mucous membranes secretions like lysosyme 45 Nonspecific cont’d - 2nd line a. phagocytic WBC’s (eat & use digestive enzymes) - 3 kinds 1. Neutrophils - attracted by chemicals (chemotaxis) - amoeboid movements - short life b/c self destruct 46 Phagocytic WBC’s cont’d 2. Monocytes which become macrophages have long pseudopods & long life 3. Eosinophils – defend against lg. parasites like fluke 47 2nd line cont’d b. Natural Killer Cells - destroy bodies own cells that are infected by virus or may cause tumors - not phagocytic but cause lyseing 48 2nd line cont’d c. Inflammatory response pg. 935 - wounded cells release histamine - local vasodilation (capillaries dilate) causing more leaks - signals phagocytic WBC’s - more WBC’s to area (pus is dead phagocytes & fluids) - local temperature - fever 49 50 2nd line cont’d d. Antimicrobial proteins * Interferon - emitted from virus infected cell - warns neighbors - neighbors block entry by changing cell proteins - prevents cell proliferation 51 2nd line cont’d * Complement system - 20 proteins interact in steps resulting in lysis of invader - some work w/chemotaxins 52 53 Specific Defense – 3rd line Also known as the immune system Utilizes lymphocytes & antibodies Four features of immune system 1. Specificity 2. Diversity 3. Self/nonself recognition 4. Memory 54 Specificity Recognizes & eliminates antigens Antigens are any foreign invader that trigger an immune response - antibody generating 55 56 Diversity Responds to millions of types of invaders 57 Self/Nonself Recognition Is a problem for transplants A breakdown here is an Autoimmune Disorder & results in attacking self cells 58 Memory Remembers antigens previously encountered Responds quicker & more effectively on 2nd or 3rd exposure 59 Acquired Immunity Active Immunity Body builds its own antibodies to fight invader 2 types 1. Natural as in chickenpox 2. Stimulated by a vaccine 60 Acquired Immunity Passive Antibodies given from one organism to another 2types 1. Take antibiotics 2. From mother to child Immunity persists only as long as the antibodies are present 61 How specific immunity arises Lymphocytes provide the specificity & diversity 1. originate from stem cells in marrow – mature elsewhere ie. T-cells in thymus B-cells in bone marrow 62 63 2. Travel through lymph vessels & concentrate in nodes & spleen 3. Antigen receptors on cell membrane 64 Antigens interact w/lymphocytes inducing immune response & memory (clonal selection) Fig. 43.14 pg. 934 65 66 67 Immune Responses – 2 types 1. Humoral Immunity - works on free bacteria, viruses & toxins - produces antibodies - uses B-cells 68 Immune responses cont’d 2. Cell – Mediated Immunity - works on bacteria, viruses inside of cells - also on Protists, parasites, worms, transplants, cancer cells (nonself cells) - uses direct action of lymphocytes - uses T-cells Diagram pg 942 69 70 71 72 73 74 Role of Helper T Cells 75 76 77 78 79 80 Antigen/Antibody Antigen – macromolecule that causes immune response Antibody - Y-shaped quaternary protein 1. Called immunoglobulins 2. Antigen binding sites at tips – pg. 937 3. Types – IgM, IgA, IgG, IgB, IgE 81 82 83 Rh Factor Protein on RBC’s Rh+ means you have this protein Rh-means you don’t have it Important during pregnancy – Why? 84 Disorders of Immune System Autoimmune disease - fails to recognize self - lupus - rheumatic fever 85 Disorders cont’d Allergies - hypersensitivity of defense - similar to defense against some parasitic worms - hayfever – IgE recognizes pollen as invader 86 Disorders cont’d Immunodeficiency - Depressed humoral or cell-mediated response - Causes a. cancer – Hodgkin's b. genetic – need bone marrow transplant c. AIDS Acquired Immunodeficiency Syndrome 87 Disorders cont’d - AIDS a. infects cells with CD4 receptors - T-cells (including helper T’s) - some B-cells - some macrophages 88 89 AIDS cont’d b. Immune system responds ok at first then as more HIV’s accumulate imm. sys. can’t keep up c. See graph pg 951 HIV T-cells d. Eventually imm. sys. can’t fight off invaders 90