Circulation & Cardiovascular Systems

Chapter 32: pp. 593-612 Circulation & Cardiovascular Systems Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Leukemia SEM 5,270 (Normal): Yorgos Nikas/Getty Images; (Leukemia): SPL/Photo Researchers, Inc. 1

Outline Transport in Invertebrates Open versus Closed Circulatory Systems Transport in Vertebrates Transport in Humans Heartbeat Vascular Pathways Blood Pressure Cardiovascular Disorders Blood Components Clotting 2

Transport in Invertebrates Small aquatic animals with no circulatory system May rely on external water in gastrovascular cavity to service cells Roundworms and other pseudocoelomates Use a fluid filled body cavity as a means of transporting substances Fluid filled cavity can also act as a hydrostatic skeleton Animals that have a rigid skeleton May still rely on body fluids for the purpose of locomotion Bivalves pump hemolymph into the foot for digging into mud 3

Aquatic Organisms Without a Circulatory System Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. food mouth undigested waste products enzymes gastrovascular cavity food nutrient uptake by endocytosis a. Hydra 7 b. Flatworm coelomic fluid 4 c. Red sea star, Mediastar a: CABISCO/Visuals Unlimited; b: B. Runk/S. Schoenberger/Grant Heilman Photography; c: Randy Morse, GoldenStateImages.com;

Open vs. Closed Invertebrate Circulation Two types of circulatory fluids: Blood contained within blood vessels Hemolymph flows into hemocoel Open Circulatory System Heart pumps hemolymph via vessels Vessels empty into tissue spaces Closed Circulatory System Heart pumps blood to capillaries Gases and materials diffuse to and from nearby cells Vessels return blood to heart without it contacting tissues 5

Open vs. Closed Circulatory Systems Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. dorsal aorta ostia tubular heart heart ventral blood vessel dorsal blood vessel lateral vessel valve pump ostia pump hemolymph hemocoel 6 a. Open circulatory system b. Closed circulatory system

Transport in the Vertebrates All vertebrates have a closed cardiovascular system Vertebrate heart: Atrial chamber(s) of heart receive blood from general circulation Ventricle chamber(s) of heart pump blood out through blood vessels Vertebrate vessels: Arteries Carry blood away from heart Arterioles Lead to capillaries Capillaries Exchange materials with tissue fluid Venules Lead to veins Veins Return blood to heart 7

Transport in Vertebrates Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Outer layer fibrous connective tissue Middle layer smooth muscle elastic tissue Inner layer endothelium a. Artery endothelium b. Capillary Outer layer fibrous connective tissue Middle layer smooth muscle elastic tissue Inner layer endothelium closed valve 8 c. Vein

Anatomy of a Capillary Bed Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. artery arteriole O 2 -rich blood flow precapillary sphincter arteriovenous shunt venule O 2 -poor blood flow vein 9

Comparison of Circulatory Circuits in Vertebrates Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. pulmonary capillaries pulmonary capillaries gill capillaries pulmonary circuit pulmonary circuit heart ventricle atrium right atrium ventricle heart left atrium right atrium right ventricle left atrium left ventricle aorta systemic circuit systemic capillaries aorta systemic circuit systemic capillaries aorta a. systemic capillaries b. c. 10

Comparison of Circulatory Pathways Fish Blood flows in single loop Single atrium and single ventricle Amphibians Blood flows in double loop Two atria with single ventricle Other vertebrates Blood flows in a double loop Heart divided by septum into separate sides 11

Transport in Humans Human Heart Fist sized Cone shaped Very muscular organ (special cardiac fibers) Lies within a fluid filled sac (the pericardium) 12

Human Heart: Gross Anatomy Septum separates heart into left & right halves Each half has two chambers Upper two chambers are the atria Thin walled Receive blood from circulation Lower two chambers are the ventricles Thick walled Pump blood away from heart 13

External Heart Anatomy Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aortic arch aorta left pulmonary artery pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins lung sternum left atrium left cardiac vein right atrium right coronary artery b. pericardium heart left ventricle right ventricle Inferior vena cava apex 14 a. b: SIU/Visuals Unlimited

Internal View of the Heart Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. left subclavian artery left common carotid artery brachiocephalic artery superior vena cava aorta left pulmonary artery cardiac muscle cell mitochondrion intercalated disk pulmonary trunk left pulmonary veins right pulmonary artery right pulmonary veins semilunar valve left atrium right atrium atrioventricular (bicuspid) valve atrioventricular (tricuspid) valve chordae tendineae papillary muscles b. gap junction right ventricle septum left ventricle inferior vena cava a. b: Dr. Don W. Fawcett/Visuals Unlimited; 15

Human Heart: Valves Valves open and close to control blood flow through heart Atrioventricular valves Tricuspid Bicuspid Semilunar valves Pulmonary Aortic 16

Transport in Humans Blood returning to heart from systemic circuit Enters right atrium Right atrium pumps through tricuspid valve to right ventricle Right ventricle pumps blood through pulmonary valve to the pulmonary circuit Blood returning to heart from pulmonary circuit Enters left atrium Left atrium pumps through mitral valve to left ventricle Left ventricle pumps blood through aortic valve to the systemic circuit Oxygen poor blood never mixes with oxygen rich blood (in humans) 17

Heartbeat Systole Contraction of heart chambers Diastole Relaxation of heart chambers Pulse Two part pumping action that takes about a second Blood collects in atria, the atria contract Pushes blood through tricuspid and mitral valves into the resting lower ventricles This phase (the longer of the two) is called the diastole Second part begins when ventricles fill Ventricles contract This is called systole After blood moves into the pulmonary artery and aorta, the ventricles relax 18

Stages in the Cardiac Cycle Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. pulmonary vein aorta semilunar valves superior vena cava semilunar valves close ( dub ) aortic semilunar valve bicuspid valve right atrium left atrium right atrium a. left ventricle inferior vena cava c. right ventricle aorta pulmonary vein d. b. atrioventricular (AV) valves close ( lub ) represents contraction 19 d: Biophoto Associates/Photo Researchers, Inc.

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Conduction System of the Heart Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. R SA node P T AV node Q branches of atrioventricular bundle Purkinje fibers b. Normal ECG S a. c. Ventricular fibrillation d: David Joel/MacNeal Hospital/Getty Images d. Recording of an ECG 22

Heartbeat Rhythmic contraction due to cardiac conduction system Sinoatrial node (SA) keeps the heartbeat regular Atrioventricular node (AV) signals ventricles to contract Purkinje Fibers Electrocardiogram (ECG) A recording of electrical changes that occurring in myocardium during cardiac cycle When SA node triggers an impulse, the atrial fibers produce an electrical charge (P wave) 24

Vascular Pathways Human cardiovascular system includes two major circular pathways: Pulmonary Circuit Takes oxygen poor blood to the lungs and returns oxygen rich blood to the heart Systemic Circuit Takes blood throughout the body from the aorta to the vena cava 26

Path of Blood Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. jugular vein (also subclavian vein from arms) CO2 head and arms O2 carotid artery (also subclavian artery to arms) CO2 O2 O2 CO2 pulmonary artery superior vena cava lungs pulmonary vein aorta heart inferior vena cava hepatic vein mesenteric arteries hepatic portal vein liver digestive tract renal artery renal vein Iliac vein kidneys iliac artery 27 CO2 O2 trunk and legs

Velocity and Blood Pressure Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. ariteries ariterioles capillaries venules veins blood pressure total cross-sectional area of vessels Magnitude velocity Blood Flow 28

Cross Section of a Valve in a Vein Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. to heart to heart a. Contracted skeletal muscle pushes blood past open valve. b. Closed valve prevents backward flow of blood. 29

Blood Pressure The beat of the heart supplies pressure that keeps blood moving in the arteries Systolic Pressure results from blood forced into the arteries during ventricular systole Diastolic Pressure is the pressure in the arteries during during ventricular diastole Skeletal muscle contraction pushes blood in the veins toward the heart Blood pressure Normally measured with a sphygmomanometer on the brachial artery Expressed in the form: Systolic over Diastolic 30

Cardiovascular Disorders Hypertension High blood pressure Atherosclerosis Accumulation of fatty materials in inner linings of arteries Stroke Cranial arteriole bursts or is blocked by an embolus Heart attack (Myocardial infarction) Coronary artery becomes partially blocked Angina pectoris Painful squeezing sensation from myocardial oxygen insufficiency 31

Coronary Arteries and Plaque Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. coronary artery ulceration lumen of vessel fat cholesterol crystals atherosclerotic plaque Biophoto Associates/Photo Researchers, Inc. 32

Blood: Homeostasis Functions Transports substances to and from capillaries for exchange with tissue fluid Guards against pathogen invasion Regulates body temperature Buffers body ph Maintain osmotic pressure Clots prevent blood/fluid loss 33

Red Blood Cells Small, biconcave disks Lack a nucleus and contain hemoglobin Hemoglobin contains Four globin protein chains Each associated with an iron containing heme Manufactured continuously in bone marrow of skull, ribs, vertebrae, and ends of long bones 34

White Blood Cells Most types larger than red blood cells Contain a nucleus and lack hemoglobin Important in inflammatory response Neutrophils enter tissue fluid and phagocytize foreign material Lymphocytes (T Cells) attack infected cells Antigens cause body to produce antibodies 35

Composition of Blood Blood Plasma 46-63% Formed Elements 37-54% Plasma Protein 7% Water 92% Other Solutes 1% Platelets WBC RBC 99.9% Albumin Globulin Eg. Electrolytes Monocytes Basophils Neatrophils Fibrinogen Lymphocytes Eosinophils Regulatory Proteins 36

Platelets Platelets Result from fragmentation of megakaryocytes Involved in coagulation Blood clot consists of: Platelets Red blood cells All entangled within fibrin threads 37

Blood Clotting Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. red blood cell fibrin threads 1. Blood vessel is punctured. platelet plug 2. Platelets congregate and form a plug. fibrin threads 3. Fibrin threads form and trap red blood cells. Eye of Science/Photo Researchers, Inc. 38

Capillary Exchange Capillaries very narrow Tiny RBCs must go through single file Wall of capillaries very thin to facilitate diffusion of nutrients, gases, and wastes Oxygen and nutrients exit a capillary near the arterial end Carbon dioxide and waste molecules enter a capillary near the venous end 39

Blood Type Determined by the presence or absence of surface antigens (agglutinogens) Antigens A, B and Rh (D) Antibodies in the plasma (agglutinins) Cross reactions occur when antigens meet antibodies 40

Blood Type 41

Agglutination Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. antigen 500 Type A blood of donor binding Agglutination anti- A antibody of type B recipient clumping 42

Blood Type During pregnancy, if the mother is Rh negative and the father is Rh positive, the child may be Rh positive. Rh positive red blood cells may leak across the placenta The mother will produce anti Rh antibodies. Antibodies may attack the embryo in a subsequent pregnancy 43

Review Transport in Invertebrates Open versus Closed Circulatory Systems Transport in Vertebrates Transport in Humans Heartbeat Vascular Pathways Blood Pressure Cardiovascular Disorders Blood Components Clotting 44