27-1 The Cardiovascular System © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-2 Introduction The cardiovascular system consists of heart, blood vessels, and blood Sends blood to Lungs for oxygen Digestive system for nutrients CV system also circulates waste products to certain organ systems for removal from the blood © 2009 The McGraw-Hill Companies, Inc. All rights reserved Functions of the Heart Generating blood pressure Routing blood Ensuring one-way blood flow Heart separates pulmonary and systemic circulations Heart valves ensure one-way flow Regulating blood supply Changes in contraction rate and force match blood delivery to changing metabolic needs © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-4 The Heart: Structures Cone-shaped organ about the size of a loose fist In the mediastinum Extends from the level of the second rib to about the level of the sixth rib Slightly left of the midline © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-5 The Heart: Structures (cont.) Heart is bordered: Laterally by the lungs Posteriorly by the vertebral column Anteriorly by the sternum Rests on the diaphragm inferiorly © 2009 The McGraw-Hill Companies, Inc. All rights reserved Size, Shape, Location of the Heart Size of a closed fist Shape Apex: Blunt rounded point at the bottom pointing towards left hip. Base: Flat part at opposite of end of cone Located in thoracic cavity in mediastinum © 2009 The McGraw-Hill Companies, Inc. All rights reserved Coverings of the Heart: Anatomy Pericardium – a double-walled sac around the heart composed of: 1. 2. A superficial fibrous pericardium A deep two-layer serous pericardium a. The parietal layer lines the internal surface of the fibrous pericardium b. The visceral layer or epicardium lines the surface of the heart They are separated by the fluid-filled pericardial cavity that helps to minimize friction during heart beats. 7 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Pericardial Layers of the Heart Figure 18.2 8 © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-9 The Heart: Structures (cont.) Heart walls: Epicardium (visceral layer) Myocardium Outermost layer Fat to cushion heart Click for Larger View Middle layer Primarily cardiac muscle Actually contracts Endocardium Innermost layer Thin and smooth Stretches as the heart pumps © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-11 The Heart: Structures (cont.) Four chambers Two atria Upper chambers Left and right Separated by interatrial septum Two ventricles Lower chambers Left and right Separated by interventricular septum Atrioventricular septum separates the atria from the ventricles Click for View of Heart © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-13 The Heart: Structures (cont.) Tricuspid valve – prevents blood from flowing back into the right atrium when the right ventricle contracts Bicuspid valve – prevents blood from flowing back into the left atrium when the left ventricle contracts Pulmonary valve – prevents blood from flowing back into the right ventricle Aortic valve – prevents blood from flowing back Click for View of into the left ventricle Heart © 2009 The McGraw-Hill Companies, Inc. All rights reserved Location of Heart Valves © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-15 Heart Valves © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-16 The Heart: Blood Flow Deoxygenated blood in from body Oxygenated blood out to body Oxygenated blood in lungs Deoxygenated blood out to lungs Atria Contract Ventricles Contract © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-17 The Heart: Blood Flow (cont.) Right Atrium Tricuspid Valve Right Ventricle Pulmonary Valve Body Lungs Aortic Semilunar Valve Left Ventricle Bicuspid Valve Left Atrium © 2009 The McGraw-Hill Companies, Inc. All rights reserved Systemic and Pulmonary Circulation © 2009 The McGraw-Hill Companies, Inc. All rights reserved Myocardial Thickness and Function Thickness of myocardium varies according to the function of the chamber Atria are thin walled, deliver blood to adjacent ventricles Ventricle walls are much thicker and stronger right ventricle supplies blood to the lungs (little flow resistance) left ventricle wall is the thickest to supply systemic circulation 19 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Thickness of Cardiac Walls Myocardium of left ventricle is much thicker than the right. 20 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Pathway of Blood Through the Heart and Lungs Figure 18.5 21 © 2009 The McGraw-Hill Companies, Inc. All rights reserved © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-23 The Heart: Cardiac Cycle One heartbeat = one cardiac cycle Atria contract and relax Ventricles contract and relax Right atrium contracts Tricuspid valve opens Blood fills right ventricle Right ventricle contracts Tricuspid valve closes Pulmonary semilunar valve opens Blood flows into pulmonary artery Left atrium contracts Bicuspid valve opens Blood fills left ventricle Left ventricle contracts Bicuspid valve closes Aortic semilunar valve opens Blood pushed into aorta © 2009 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Cycle © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-25 The Heart: Cardiac Cycle (cont.) Influenced by Exercise Parasympathetic nerves Sympathetic nerves Cardiac control center Body temperature Potassium ions Calcium ions © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-26 The Heart: Heart Sounds One cardiac cycle – two heart sounds (lubb and dubb) when valves in the heart snap shut Lubb – First sound Dubb – Second sound When the ventricles contract, the tricuspid and bicuspid valves snap shut When the atria contract and the pulmonary and aortic valves snap shut Third heart sound (occasional) Caused by turbulent blood flow into ventricles and detected near end of first one-third of diastole © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-27 The Heart: Cardiac Conduction System Group of structures that send electrical impulses through the heart Sinoatrial node (SA node) Wall of right atrium Generates impulse Natural pacemaker Sends impulse to AV node Atrioventricular node (AV node) Between atria just above ventricles Atria contract Sends impulse to the bundle of His Bundle of His Between ventricles Two branches Sends impulse to Purkinje fibers Purkinje fibers Lateral walls of ventricles Ventricles contract Link to Diagram © 2009 The McGraw-Hill Companies, Inc. All rights reserved Electrocardiogram Action potentials through myocardium during cardiac cycle produces electric currents than can be measured Pattern P wave QRS complex Atria depolarization Ventricle depolarization Atria repolarization T wave: Ventricle repolarization © 2009 The McGraw-Hill Companies, Inc. All rights reserved Heart Excitation Related to ECG Figure 18.17 30 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Arrhythmias Tachycardia: Heart rate in excess of 100bpm Bradycardia: Heart rate less than 60 bpm Sinus arrhythmia: Heart rate varies 5% during respiratory cycle and up to 30% during deep respiration Premature atrial contractions: Occasional shortened intervals between one contraction and succeeding, frequently occurs in healthy people © 2009 The McGraw-Hill Companies, Inc. All rights reserved Alterations in Electrocardiogram © 2009 The McGraw-Hill Companies, Inc. All rights reserved Events during Cardiac Cycle © 2009 The McGraw-Hill Companies, Inc. All rights reserved Mean Arterial Pressure (MAP) Average blood pressure in aorta MAP=CO x PR CO is amount of blood pumped by heart per minute CO=SV x HR SV: Stroke volume of blood pumped during each heart beat HR: Heart rate or number of times heart beats per minute Cardiac reserve: Difference between CO at rest and maximum CO PR is total resistance against which blood must be pumped © 2009 The McGraw-Hill Companies, Inc. All rights reserved Cardiac Output: Example CO (ml/min) = HR (75 beats/min) x SV (70 ml/beat) CO = 5250 ml/min (5.25 L/min) 35 Chapter 18, Cardiovascular © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-36 © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-37 Blood Vessels: Arteries and Arterioles Strongest of the blood vessels Carry blood away from the heart Under high pressure Vasoconstriction Vasodilation Arterioles Small branches of arteries Aorta Takes blood from the heart to the body Coronary arteries Supply blood to heart muscle © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-38 Blood Vessels: Veins and Venules Blood under no pressure in veins Does not move very easily Skeletal muscle contractions help move blood Sympathetic nervous system also influences pressure Valves prevent backflow Venules Small vessels formed when capillaries merge Superior and inferior vena cava Largest veins Carry blood into right atrium © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-39 Blood Vessels: Capillaries Branches of arterioles Smallest type of blood vessel Connect arterioles to venules Only about one cell layer thick Oxygen and nutrients can pass out of a capillary into a body cell Carbon dioxide and other waste products pass out of a body cell into a capillary © 2009 The McGraw-Hill Companies, Inc. All rights reserved © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-41 Apply Your Knowledge Match the following: ANSWER: C Tricuspid valve __ A. Two branches; sends impulse to Purkinje fibers __ F Bicuspid valve B. Covering of the heart and aorta __ B Pericardium C. Between the right atrium and the right ventricle __ E SA node D. In the lateral walls of ventricles __ A Bundle of His E. Natural pacemaker D Purkinje fibers __ F. Between the left atrium and the left ventricle © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-42 Apply Your Knowledge How do arteries control blood pressure? ANSWER: The muscular walls of arteries can constrict to increase blood pressure or dilate to decrease blood pressure. © 2009 The McGraw-Hill Companies, Inc. All rights reserved Gross Anatomy of Circulatory System © 2009 The McGraw-Hill Companies, Inc. All rights reserved Coronary Circulation Coronary circulation is the functional blood supply to the heart muscle itself Collateral routes ensure blood delivery to heart even if major vessels are occluded 44 Chapter 18, Cardiovascular © 2009 The McGraw-Hill Companies, Inc. All rights reserved Coronary Circulation: Arterial Supply 45 © 2009 The McGraw-Hill Companies, Inc. All Figure rights 18.7a reserved Coronary Circulation: Venous Supply 46 Chapter 18, Cardiovascular © 2009 The McGraw-Hill Companies, Inc. All Figure rights 18.7b reserved Circle of Willis = Cerebral Arterial Circle = Ring of vessels surrounding pituitary gland - supplies cerebrum and cerebellum ic Brain can receive blood from carotids or vertebrals (significance?) Fig 22.13 v © 2009 The McGraw-Hill Companies, Inc. All rights reserved Circle of Willis © 2009 The McGraw-Hill Companies, Inc. All rights reserved Pulmonary Circuit Right ventricle into pulmonary trunk to pulmonary arteries to lungs Return by way of 4 pulmonary veins to left atrium Fig 22.9 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Major Systemic Arteries The Systemic Circuit Contains 84% of blood volume Supplies entire body: except for pulmonary circuit Supplies entire body: except for Figure 21-20 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Systemic Arteries Blood moves from left ventricle: into ascending aorta © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Aorta The ascending aorta: rises from the left ventricle curves to form aortic arch turns downward to become descending aorta Branches of the Aortic Arch deliver blood to head and neck: brachiocephalic trunk left common carotid artery left subclavian artery © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Common Carotid Arteries Carry blood to head and neck Each common carotid divides into: external carotid artery-Supplies structures of: Neck, lower jaw, face internal carotid artery-Enters skull and divides into: opthalmic artery, anterior cerebral artery, middle cerebral artery © 2009 The McGraw-Hill Companies, Inc. All rights reserved Aortic Arch Left common 2 carotid Brachiocephalic 1 trunk 3 Left subclavian © 2009 The McGraw-Hill Companies, Inc. All rights reserved Descending aorta • thoracic aorta • abdominal aorta Abdominal aorta Common iliac External iliac Femoral © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Abdominal Aorta Divides at terminal segment of the aorta into: left common iliac artery right common iliac artery © 2009 The McGraw-Hill Companies, Inc. All rights reserved Descending Aorta - Thoracic Area Bronchial arteries - supply bronchi and lungs Pericardial arteries - supply pericardium Mediastinal arteries - supply mediatinal structures Esophageal arteries - supply esophagus Paired intercostal arteriesthoracic wall Superior phrenic arteries - supply diaphragm © 2009 The McGraw-Hill Companies, Inc. All rights reserved Descending Aorta - Abdominal Area Celiac trunck - 3 branches – to liver, gallbladder, esophagus, stomach, duodenum, pancreas, and spleen Superior mesenteric– to pancreas and duodenum, small intestine and colon Paired suprarenal - to adrenal glands Paired renal – to kidneys Paired gonadal – to testes or ovaries Inferior mesenteric – to terminal colon and rectum Paired lumbar – to body wall Fig 22.17 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Major Systemic Veins All Systemic Veins Drain into either: Superior vena cava (SVC) or Inferior vena cava (IVC) Figure 21-27 © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Superior Vena Cava (SVC) Returns blood to the heart from: head neck chest shoulders upper limbs © 2009 The McGraw-Hill Companies, Inc. All rights reserved Veins of the Neck Temporal and maxillary veins: drain to external jugular vein Facial vein: drains to internal jugular vein © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-62 © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-63 Superior sagittal sinus Falx cerebri Inferior sagittal sinus Straight sinus Cavernous sinus Junction of sinuses Transverse sinuses Sigmoid sinus Jugular foramen Right internal jugular vein (b) Dural Sinuses In The Cranium © 2009 The McGraw-Hill Companies, Inc. All rights reserved The Inferior Vena Cava (IVC) Returns blood to the heart from: Regions inferior to the diaphram © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-66 Dissection of the posterior abdominal wall Right Left Diaphragm Hepatic veins Inferior vena cava Renal veins Abdominal aorta Common iliac veins © 2009 The McGraw-Hill Companies, Inc. All rights reserved Placental Blood Supply Blood flows to the placenta: through a pair of umbilical arteries which arise from internal iliac arteries and enter umbilical cord Blood returns from placenta: in a single umbilical vein which drains into ductus venosus Ductus venosus: empties into inferior vena cava Figure 21-33a © 2009 The McGraw-Hill Companies, Inc. All rights reserved 68 Atrial Septal Defect Present at birth Treated naturally Surgery Or catheterization © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-69 Treatment of patent foramen oval aka “Atrial Septal Defect” © 2009 The McGraw-Hill Companies, Inc. All rights reserved Ventricular Septal Defect 70 © 2009 The McGraw-Hill Companies, Inc. All rights reserved UNDERSTANDING YOUR BLOOD PRESSURE Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc So…high blood pressure is a condition that most people willhave havehigh at some point in their lives. 65 million adults blood pressure in this country. 1 in 3 American adults have high blood pressure “Silent Killer” NEW RESEARCH STATES… that at age 55 or older, those who do not have high blood pressure have a 90% chance of developing it during their lifetimes. Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc What Is Blood Pressure? Blood is carried to all parts of your body in vessels called arteries. Blood pressure is the force of blood pushing against the arteries. What Is Blood Pressure? Each time the heart beats (about 60-70 times a minute at rest), it pumps out blood into the arteries. This is called SYSTOLIC pressure. Your blood pressure is at its highest when the heart beats, pumping the blood. 120/ 80 When the heart is at rest, between beats, your blood pressure falls. Bottom number This is called DIASTOLIC pressure. Your blood pressure is always given as these two numbers with one above or before the other. http://www.hsfpe.org/ Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc What Is Normal Blood Pressure? Category Normal Systolic (Top Number) Diastolic (Bottom Number) Less than 120 Less than 80 “Normal” blood pressure is when both numbers are lower than 120/80. Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc “Prehypertension” Prehypertension Which of the following blood pressure readings are considered “prehypertensive”? Top Number Bottom Number 120-139 80-89 138/82 118/78 128/89 This category was created to alert people to their risk of developing high blood pressure so they could make lifestyle changes that may help to avoid developing this condition. Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc “Prehypertension” If your blood pressure is in the prehypertensive range: Prehypertension 120-139 80-89 It means that you don’t have high blood pressure now, but you are likely to develop it in the future. Unless you take ACTION to prevent it! Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc What Is High Blood Pressure? When blood pressure stays elevated over a long period of time it is called high blood pressure or “hypertension”. http://diseases-explained.com/ High blood pressure is dangerous because it makes the heart work too hard and contributes to hardening of the arteries (atherosclerosis). Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc What Is High Blood Pressure? “Hypertension” A blood pressure of 140/90 is considered high blood pressure. High Blood Pressure Systolic Diastolic Stage 1 140-159 90-99 Stage 2 160 or higher 100 or higher Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc High Blood Pressure Warning Signs: 1. 2. 3. 4. Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc Why Is High Blood Pressure Important? Increases your risk for : Heart disease & Stroke – the 1st and 3rd leading causes of death for Americans. If left uncontrolled, high blood pressure can also cause: Heart failure Heart Attack Kidney disease Blindness Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc What can high blood pressure do to your body? Stroke Heart Attack High blood pressure is the most important risk factor for stroke. Very high pressure can cause a break in a weakened blood vessel, which then bleeds in the brain. This can cause a stroke. If a blood clot blocks one of the narrowed arteries, it can also cause a stroke. High blood pressure is a major risk factor for heart attack. The arteries bring oxygencarrying blood to the heart muscle. If the heart cannot get enough oxygen, chest pain, can occur. If the flow of blood is blocked, a heart attack results. Blindness High blood pressure can eventually cause blood vessels in the eye to burst or bleed. Vision may become blurred or otherwise impaired and can result in blindness. Heart failure The heart is unable to pump enough blood to supply the body's needs. Arteries Kidney disease As people get older, arteries throughout the body "harden," especially those in the heart, brain, and kidneys. High blood pressure is associated with these "stiffer" arteries. This, in turn, causes the heart and kidneys to work harder. Kidneys act as filters to rid the body of waste. High blood pressure can narrow and thicken the blood vessels of the kidneys. The kidneys filter less fluid and waste builds up in the blood. The kidneys may fail altogether. Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc The Good News is… You can take action to prevent getting high blood pressure or take steps to control it! See your doctor for regular blood pressure check ups If youMaintaining drink alcoholic beverages, a healthy weightdrink in moderation Eat a healthy diet rich in vegetables and fruits, and low Choose prepare foods with less salt fatand dairy foodsactive Get physically If you smoke, think about quitting Source: Your Guide To Lowering Blood Pressure, www.nhlbi.nih.govc 27-84 Factors that affect Blood Pressure 1. 2. 3. 4. 5. Neural factors: Sympathetic nervous system causes vasoconstriction or narrowing of blood vessels. Kidneys: release renin which triggers angiotensin a potent vasoconstrictor. Temperature: Cold is vasoconstricting Heat is the opposite. Chemicals: Medication, nicotine, alcohol Diet: salt, fat, and cholesterol balance © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-85 Blood Pressure Force blood exerts on the inner walls of blood vessels Systolic pressure Ventricles contract Blood pressure is at its greatest in the arteries Diastolic pressure Highest in arteries Lowest in veins Ventricles relax Blood pressure in arteries is at its lowest Reported as the systolic number over the diastolic number © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-86 Blood Pressure (cont.) Control is based mainly on the amount of blood pumped out of the heart The amount of blood entering should equal the amount pumped from the heart Starling's law of the heart Blood entering the left ventricle stretches the wall of the ventricle The more the wall is stretched The harder it will contract and The more blood it will pump out © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-87 Apply Your Knowledge What is the difference between the systolic pressure and diastolic pressure? ANSWER: Systolic pressure is the result of the contraction of the ventricles increasing the pressure in the arteries. Diastolic pressure is the result of the relaxation of the ventricles lowering the pressure in the arteries. Good Answer! © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-88 Apply Your Knowledge Do pulmonary arteries carry blood with high levels of oxygen or low levels of oxygen? ARTERIES: Pulmonary arteries carry oxygen-poor blood. © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-89 Diseases and Disorders of the Cardiovascular System Disease Description Anemia The blood does not have enough red blood cells or hemoglobin to carry an adequate amount of oxygen to the body’s cells Aneurysm A ballooned, weakened arterial wall Arrhythmias Abnormal heart rhythms Carditis Inflammation of the heart Endocarditis Inflammation of the innermost lining of the heart, including valves © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-90 Diseases and Disorders of the Cardiovascular System (cont.) Disease Description Myocarditis Inflammation of the muscular layer of the heart Pericarditis Inflammation of the membranes that surround the heart (pericardium) Congestive Heart Failure Weakening of the heart over time; heart is unable to pump enough blood to meet body’s needs Coronary Artery Atherosclerosis; narrowing of coronary arteries Disease (CAD) caused by hardening of the fatty plaque deposits within the arteries © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-91 Diseases and Disorders of the Cardiovascular System (cont.) Disease Description Hypertension High blood pressure; consistent resting blood pressure equal to or greater than 140/90 mm Hg Leukemia Bone marrow produces a large number of abnormal WBCs Murmurs Abnormal heart sounds Myocardial Infarction Heart attack; damage to cardiac muscle due to a lack of blood supply © 2009 The McGraw-Hill Companies, Inc. All rights reserved 27-92 Diseases and Disorders of the Cardiovascular System (cont.) Disease Description Sickle Cell Anemia Abnormal hemoglobin causes RBCs to change to a sickle shape; abnormal cells stick in capillaries Thalassemia Inherited form of anemia; defective hemoglobin chain causes, small, pale, and short-lived RBCs Thrombophlebitis Blood clots and inflammation develops in a vein Varicose Veins Twisted, dilated veins © 2009 The McGraw-Hill Companies, Inc. All rights reserved By-pass Graft 93 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Percutaneous Transluminal Coronary Angioplasty 94 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Artificial Heart 95 © 2009 The McGraw-Hill Companies, Inc. All rights reserved