Cardiovascular System Anatomy PDF

Cardiovascular System Cardiovascular What is the cardiovascular system? The cardiovascular system consists of a network of vessels that circulates blood throughout the body, motored by the action of the heart. We’ll be talking about specifics of the heart in a separate lesson, so will concentrate he...

Cardiovascular System Cardiovascular What is the cardiovascular system? The cardiovascular system consists of a network of vessels that circulates blood throughout the body, motored by the action of the heart. We’ll be talking about specifics of the heart in a separate lesson, so will concentrate here on the circulatory system. Cardiovascular Tracing the flow of blood: Pulmonary Circulation The inferior vena cava is the largest vein of the body. It carries de-oxygenated blood back from the lower part of the body to the right atrium of the heart. This blood is carrying carbon dioxide. The superior vena cava is above the heart and carries de-oxygenated blood from the head and arms to the right atrium of the heart. Cardiovascular From the right atrium, the blood flows through the tricuspid valve to the right ventricle and then onto the lungs through the pulmonary valve and pulmonary artery. In the lungs, the blood exchanges the carbon dioxide it is carrying for oxygen. Cardiovascular Cardiovascular The fully oxygenated blood now flows BACK to the left atrium of the heart through the pulmonary veins. Cardiovascular Tracing the flow of blood: Systemic circulation: The oxygenated blood leaves the left atrium through the mitral (bicuspid) valve into the left ventricle, gets pumped from the left ventricle through the aortic valve to the aorta. Cardiovascular The aorta is the largest artery of the body. The ascending aorta leaves the heart, curves in an inverted ‘U’ shape making an arch, and then descends downward. Cardiovascular At the arch of the aorta, 3 branches extend upward: 1. The brachiocephalic artery (or innominate artery) quickly divides into the right subclavian artery that supplies blood to the right arm and upper torso and the right common carotid artery that supplies the head and neck. 2. The left common carotid artery supplies the head and neck. 3. The left subclavian artery supplies the left arm and upper torso. ‘Subclavian’ means it is located below the clavicle… or collarbone. Cardiovascular The descending aortic artery leads downward through the diaphragm and chest…and into the abdomen. About 1/5 to 1/3 of the blood passes through the renal artery into the kidney. The kidney is a filter, and takes some water and waste products out of the blood. The kidneys excrete the waste products and water out of the body as urine. Cardiovascular The descending aortic artery continues downward into the abdomen. It then splits into two major branches. This split is called the aortic bifurcation; the two branches are called iliac arteries. Cardiovascular The left iliac artery supplies blood to the left pelvis and leg; the right iliac artery supplies blood to the right pelvis and leg. The iliac artery continues down into the leg as the femoral artery and its branches. Cardiovascular Cardiovascular Tracing the flow of blood: The arteries: Arteries are elastic tubes that carry blood in pulsating waves. The blood exerts pressure against the walls of the arteries as it passes through. The peak pressure occurs during the heart’s contraction, and is called systolic pressure. Cardiovascular The minimum pressure occurs between contractions when the heart expands and refills, and is called diastolic pressure. This pressure variation within the artery produces a pulse. All arteries have a pulse. Cardiovascular Common pulse sites used to check circulation are: 1. TEMPORAL (TEM por ul) - side of forehead 2 & 3. CAROTID (kuh RAH did) - neck 4. BRACHIAL (BRAY kee ul) - inside the elbow 5. RADIAL - thumb side of wrist 6. FEMORAL (FEM er all) - groin 7.POPLITEAL (pah plah TEE ul) – behind the knee 8 & 9. DORSALIS PEDIS (dor SAL us PED iss) - upper surface of foot Cardiovascular Systolic and diastolic blood pressure can be measured in the brachial artery just above the elbow with an instrument called a sphygmomanometer (sfig mō mah MOM ah ter) and a stethoscope. Two measurements are taken, and are expressed in millimeters of mercury (the chemical symbol for mercury is Hg). The two blood pressure measurements are written as a ratio… systolic over diastolic. Cardiovascular In the average adult, systolic pressure usually ranges between 100 to 140 mm Hg. Diastolic pressure usually ranges between 60 to 90 mm Hg. A typical blood pressure reading would be expressed as 120/80… 120 over 80. A reading of 140/90 would be considered ‘high’ blood pressure, and may pose health risks. Cardiovascular Cardiovascular Tracing the flow of blood: The arterioles: The arteries branch off into even smaller vessels called arterioles, and then to smaller vessels yet called capillaries. Arterioles act like adjustable nozzles in the circulatory system, so they have the greatest influence over blood pressure. Cardiovascular Tracing the flow of blood: The capillaries: The capillaries are the smallest of the blood vessels, and the walls are so thin that molecules can pass through them. They branch out from the arterioles, passing next to the organs, intestines, and through all the cellular tissue. In the cellular tissue, the capillaries provide the means of exchange, through the process of absorption. Cardiovascular Tracing the flow of blood: The venules: The capillaries, now carrying carbon dioxide and cell wastes, start merging into bigger vessels called venules (VEEN or VEN yoo als). The venules widen even further, emptying into veins. Cardiovascular Tracing the flow of blood: The veins: The veins have valves that prevent the backflow of blood. Veins lead back to the heart. Cardiovascular Veins are the vessels that are used to remove blood from the body for analysis. This procedure is called a venipuncture (VEEN ah punk chur) and the medical personnel that specializes in this procedure is called a phlebotomist (flah BOTT ah mist). Heart anatomy Cardiovascular Heart Anatomy: Approximately the size of your fist. Location: 1. Superior surface of diaphragm. 2. Left of the midline. 3. Anterior to the vertebral column, posterior to the sternum. Cardiovascular Cardiovascular Coverings of the Heart: Pericardium – a double-walled sac around the heart composed of: 1. A superficial fibrous pericardium. 2. 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. Cardiovascular Cardiovascular Cardiovascular Heart Wall: Epicardium – visceral layer of the serous pericardium Myocardium – cardiac muscle layer forming the bulk of the heart Fibrous skeleton of the heart – crisscrossing, interlacing layer of connective tissue Endocardium – endothelial layer of the inner myocardial surface Cardiovascular Cardiovascular External Heart: Major Vessels of the Heart (Anterior View) Vessels returning blood to the heart include: 1. Superior and inferior venae cava. 2. Right and left pulmonary veins. Cardiovascular External Heart: Major Vessels of the Heart (Anterior View) Vessels conveying blood away from the heart include: 1. Pulmonary trunk, which splits into right and left pulmonary arteries 2. Ascending aorta (three branches): a) Brachiocephalic. b) Left common carotid. c) Subclavian arteries. Cardiovascular External Heart: Vessels that Supply/Drain the Heart (Anterior View) Arteries – right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries. Veins – small cardiac, anterior cardiac, and great cardiac veins Cardiovascular Cardiovascular External Heart: Major Vessels of the Heart (Posterior View) Vessels returning blood to the heart include: 1. Right and left pulmonary veins. 2. Superior and inferior venae cavae. Vessels conveying blood away from the heart include: 1. Aorta. 2. Right and left pulmonary arteries. Cardiovascular External Heart: Vessels that Supply/Drain the Heart (Posterior View) Arteries – right coronary artery (in atrioventricular groove) and the posterior interventricular artery (in interventricular groove) Veins – great cardiac vein, posterior vein to left ventricle, coronary sinus, and middle cardiac vein Cardiovascular External Heart: Posterior View Cardiovascular Gross Anatomy of Heart: Frontal Section: Heart Chambers Cardiovascular Atria of the Heart: Atria are the receiving chambers of the heart. Each atrium has a protruding auricle. Pectinate muscles mark atrial walls. Blood enters right atria from superior and inferior venae cavae and coronary sinus. Blood enters left atria from pulmonary veins. Cardiovascular Ventricles of the Heart: Ventricles are the discharging chambers of the heart. Papillary muscles and trabeculae carneae muscles mark ventricular walls. Right ventricle pumps blood into the pulmonary trunk. Left ventricle pumps blood into the aorta. Cardiovascular 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. Cardiovascular Thickness of Cardiac Walls: Myocardium of left ventricle is much thicker than the right. Cardiovascular Atrial Septal Defect: Cardiovascular Ventricular Septal Defect: Cardiovascular Pathway of Blood Through the Heart and Lungs: Right atrium tricuspid valve right ventricle Right ventricle pulmonary semilunar valve pulmonary arteries lungs Lungs pulmonary veins left atrium Left atrium bicuspid valve left ventricle Left ventricle aortic semilunar valve aorta Aorta systemic circulation Cardiovascular 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. Cardiovascular Cardiovascular Coronary Circulation: Arterial Supply: Cardiovascular Coronary Circulation: Venous Supply: Heart Valves Cardiovascular Heart Valves: Heart valves ensure unidirectional blood flow through the heart. Atrioventricular (AV) valves lie between the atria and the ventricles AV valves prevent backflow into the atria when ventricles contract. Chordae tendineae anchor AV valves to papillary muscles. Cardiovascular Semilunar valves prevent backflow of blood into the ventricles. Aortic semilunar valve lies between the left ventricle and the aorta. Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk. Cardiovascular Cardiovascular Cardiovascular Microscopic Anatomy of Heart Muscle: Cardiac muscle is striated, short, fat, branched, and interconnected. The connective tissue endomysium acts as both tendon and insertion. Intercalated discs anchor cardiac cells together and allow free passage of ions. Heart muscle behaves as a functional syncytium. Cardiovascular Cardiovascular Cardiac Muscle Contraction: Heart muscle: Is stimulated by nerves and is self-excitable (automaticity). Contracts as a unit. Has a long (250 ms) absolute refractory period. Cardiac muscle contraction is similar to skeletal muscle contraction. Heart Physiology Cardiovascular Heart Physiology: Intrinsic Conduction System: Autorhythmic cells: Initiate action potentials. Have unstable resting potentials called pacemaker potentials. Use calcium influx (rather than sodium) for rising phase of the action potential. Cardiovascular Heart Physiology: Sequence of Excitation: Sinoatrial (SA) node generates impulses about 75 times/minute. Atrioventricular (AV) node delays the impulse approximately 0.1 second. Cardiovascular Heart Physiology: Sequence of Excitation: Impulse passes from atria to ventricles via the atrioventricular bundle (bundle of His). AV bundle splits into two pathways in the interventricular septum (bundle branches) 1. Bundle branches carry the impulse toward the apex of the heart. 2. Purkinje fibers carry the impulse to the heart apex and ventricular walls. Cardiovascular Heart Physiology: Sequence of Excitation: Cardiovascular Heart Excitation Related to ECG: Cardiovascular Extrinsic Innervation of the Heart: Heart is stimulated by the sympathetic cardioacceleratory center. Heart is inhibited by the parasympathetic cardioinhibitory center. Cardiovascular Electrocardiography: Electrical activity is recorded by electrocardiogram (ECG). P wave corresponds to depolarization of SA node. QRS complex corresponds to ventricular depolarization. T wave corresponds to ventricular repolarization. Atrial repolarization record is masked by the larger QRS complex. Cardiovascular Heart Sounds Cardiovascular Heart Sounds: Heart sounds (lub-dup) are associated with closing of heart valves First sound occurs as AV valves close and signifies beginning of systole (contraction). Second sound occurs when SL valves close at the beginning of ventricular diastole (relaxation) Cardiovascular Cardiac Cycle: Cardiac cycle refers to all events associated with blood flow through the heart Systole – contraction of heart muscle. Diastole – relaxation of heart muscle. Cardiovascular Cardiac Output (CO) and Reserve: Cardiac Output is the amount of blood pumped by each ventricle in one minute. CO is the product of heart rate (HR) and stroke volume (SV) HR is the number of heart beats per minute. SV is the amount of blood pumped out by a ventricle with each beat. Cardiac reserve is the difference between resting and maximal CO. Cardiovascular Extrinsic Factors Influencing Stroke Volume: Contractility is the increase in contractile strength, independent of stretch and EDV. Increase in contractility comes from: Increased sympathetic stimuli Certain hormones Ca2+ and some drugs Cardiovascular Extrinsic Factors Influencing Stroke Volume: Agents/factors that decrease contractility include: Acidosis. Increased extracellular K+. Calcium channel blockers. Cardiovascular Chemical Regulation of the Heart: The hormones epinephrine and thyroxine increase heart rate. Intra- and extracellular ion concentrations must be maintained for normal heart function. Congestive Heart Failure Cardiovascular Congestive Heart Failure (CHF): Congestive heart failure (CHF) is caused by: 1. Coronary atherosclerosis. 2. Persistent high blood pressure. 3. Multiple myocardial infarcts. 4. Dilated cardiomyopathy (DCM) – main pumping chambers of the heart are dilated and contract poorly Cardiovascular Examples of Congenital Heart Defects: Cardiovascular Age-Related Changes Affecting the Heart: Sclerosis and thickening of valve flaps. Decline in cardiac reserve. Fibrosis of cardiac muscle. Atherosclerosis. Cardiovascular Congestive Heart Failure: Causes of CHF: Coronary artery disease, hypertension, MI, valve disorders, congenital defects. Left side heart failure: Less effective pump so more blood remains in ventricle. Heart is overstretched & even more blood remains. Blood backs up into lungs as pulmonary edema. Suffocation & lack of oxygen to the tissues. Cardiovascular Congestive Heart Failure: Right side failure: Fluid builds up in tissues as peripheral edema. Coronary Artery Disease Cardiovascular Coronary Artery Disease: Heart muscle receiving insufficient blood supply: Narrowing of vessels atherosclerosis, artery spasm or clot. Atherosclerosis - smooth muscle & fatty deposits in walls of arteries. Treatment drugs, bypass graft, angioplasty, stent Cardiovascular Clinical Problems: MI = myocardial infarction Death of area of heart muscle from lack of O2. Replaced with scar tissue. Results depend on size & location of damage. Blood clot Use clot dissolving drugs streptokinase or t-PA & heparin. Balloon angioplasty. Angina pectoris Heart pain from ischemia (lack of blood flow and oxygen ) of cardiac muscle. Cardiovascular By-pass Graft: Cardiovascular Percutaneous Transluminal Coronary Angioplasty: Cardiovascular Artificial Heart: