Cardiovascular System Handouts PDF

CARDIOVASCULAR SYSTEM HANDOUTS i. INFERIOR AND SUPERIOR VENA OUTLINE: CAVA HEART ii. PULM...

CARDIOVASCULAR SYSTEM HANDOUTS i. INFERIOR AND SUPERIOR VENA OUTLINE: CAVA HEART ii. PULMONARY ARTERY STRUCTURES OF THE HEART iii. PULMONARY VEIN a. PERICARDIUM iv. AORTA i. FIBROUS PERICARDIUM g. BLOOD FLOW (SYSTEMIC AND PULMONARY ii. SEROUS PERICARDIUM CIRCULATION) 1. PARIETAL LAYER h. CORONARY CIRCULATION 2. VISCERAL LAYER 1. CORONARY ARTERY 3. PERICARDIAL CAVITY 2. CORONARY SINUS 4. PERICARDIAL FLUID i. CARDIAC CONDUCTION b. HEART WALL i. PROPERTIES OF THE HEART i. EPICARDIUM 1. EXCITABILITY ii. MYOCARDIUM 2. AUTOMATICITY iii. ENDOCARDIUM 3. CONDUCTIVITY c. HEART CHAMBERS 4. CONTRACTILITY i. UPPER ATRIAL CHAMBERS ii. ELECTRICAL IMPULSES ii. LOWER ATRIAL CHAMBERS 1. SA NODE d. HEART VALVES 2. AV NODE i. ATRIOVENTRICULAR VALVES 3. BUNDLE OF HIS 1. TRICUSPID VALVE 4. RIGHT AND LEFT BUNDLE 2. BICUSPID OR MITRAL 5. PURKINJE FIBERS VALVE j. ELECTROCARDIOGRAM ii. SEMILUNAR VALVE i. P WAVE 1. PULMONARY VALVE ii. QRS COMPLEX 2. AORTIC VALVE iii. ST SEGMENT e. HEART SOUNDS iv. T WAVE f. GREAT VESSELS k. CARDIAC CYCLE FUNCTION: PARTS: HEART BLOOD VESSELS BLOOD THE HEART FUNCTION - to pump blood and oxygen around the body and deliver waste products (carbon dioxide) back to the lungs to be removed LOCATION: - is a hollow, four-chambered muscular organ approximately the size of a fist. - It is positioned obliquely in the middle compartment of the mediastinum of the chest, just behind the sternum. - Approximately two-thirds of the heart lies to the left of the midline of the sternum between the 2nd through the 6th ribs. - The apex of the heart is formed by the tip of the left ventricle and lies just above the diaphragm at the level of the 5th intercostal space to the left. - The base of the heart is formed by the atria and projects to the right, lying just below the 2nd rib. - Posteriorly, the heart rests on the bodies of the 5th to the 8th thoracic vertebrae STRUCTURES OF THE HEART: PERICARDIUM - The heart resides within a loose, membranous sac called the pericardium. TWO LAYERS: 1. FIBROUS PERICARDIUM 2. SEROUS PERICARDIUM (2 LAYERS) a. parietal layer- Inner lining of the fibrous pericardium b. visceral layer- Covering the outer surface of the heart and great vessels c. Pericardial cavity - the space between the parietal layer and visceral layer. d. Pericardial fluid - prevent frictions e. CONDITIONS: i. Decreased pericardial fluid → inflammation → PERICARDITIS ii. Increased or abnormal amount of pericardial fluid → PERICARDIAL EFFUSION  iii. Large pericardial effusion → CARDIAC TAMPONADE → compromised cardiac functioning →decreased cardiac output → decreased blood flow → shock → death iv. CARDIAC OUTPUT = HEART RATE X STROKE VOLUME (CO= HR X SV) 1. Normal value: 500 ml/min or 5L/min 2. CARDIAC OUTPUT: the amount of blood pumped by the heart minute. 3. HEART RATE: the number of times your heart beats per minute. 4. STROKE VOLUME: the amount of blood ejected from the ventricle with each cardiac cycle. a. Factors determine cardiac stroke volume i. Ventricular preload ii. Ventricular afterload iii. Ventricular contractility b. Formula of stroke volume i. Stroke volume = end-diastolic volume - end systolic volume (SV = EDV-ESV) HEART LAYERS The heart wall consists of three layers: (1) the outer epicardium (2) the middle myocardium (3) the inner endocardium. HEART CHAMBERS A. UPPER HEART CHAMBERS (ATRIA) - reservoir. received blood from the body or lungs - right and left atria → separated → interatrial septum - walls → not very thick → dont have to generate much force. B. LOWER HEART CHAMBERS (VENTRICLES) - Serve as pumps, receiving blood from the atria → pump → lungs or body - Right and left ventricles → separated → interventricular septum - Walls are thicker compared to atria → they have to generate much force. - Walls →Left ventricles are thicker than the right ventricle. HEART VALVES → PREVENT BACKFLOW → BLOOD A. ATRIOVENTRICULAR VALVES a. Right AV valve “TRICUSPID VALVE’’ i. Prevent backflow from the right ventricle to the right atrium. b. Left AV valve “MITRAL OR BICUSPID VALVE’’ i. Prevent backflow from the left ventricle to the left atrium. B. SEMILUNAR VALVES → separate the ventricles from their arterial outflow tracts. → OPENING of the → semilunar valves→ occurs → when the pressures in the ventricles exceed those in the aorta and pulmonary artery within 0.05 second. → CLOSING of the → semilunar valves → occurs when the pressure in the arteries exceed those in the ventricles. a. Pulmonary valve i. Prevents backflow from the pulmonary artery to the right ventricle. b. Aortic valve i. Prevents backflow from the aorta to the left ventricle. - VENTRICLES RELAXED → AV VALVE →OPEN AND SEMILUNAR VALVE→CLOSE - VENTRICLES CONTRACTED → AV VALVE → CLOSE AND SEMILUNAR VALVE → OPEN NOTE: COMMON CONDITIONS: - REGURGITATION→ is the backflow of blood through an incompetent or a damaged valve. - STENOSIS→ pathologic narrowing → valve - Example : mitral stenosis → backflow of the blood from the left ventricle to the left atrium back to your lungs → lead to → pulmonary edema → “INCREASED PULMONARY CONGESTION” HEART SOUNDS A. NORMAL HEART SOUNDS: use diaphragm → stethoscope 1. S1 (FIRST HEART SOUND) → closing → AV VALVES → high pitched 2. S2 (SECOND HEART SOUND) → closing → SEMILUNAR VALVES → high pitched B. ABNORMAL HEART SOUNDS: use bell → stethoscope 3. S3 → Heart → fluid → impede → low pitched 4. S4→ ventricle resistance → low pitched 5. Murmurs → valve defect/problem → low pitched a. AORTIC AREA → 2nd ICS, right sternal border b. PULMONIC AREA → 2nd ICS, left sternal border c. TRICUSPID AREA → 4th ICS, left sternal border  d. MITRAL AREA → 5TH ICS, left midclavicular line (APEX → HEART) GREAT VESSELS → PATHWAY → BLOOD → TRAVELS a. INFERIOR VENA CAVA → carries → deoxygenated blood from Lower part →BODY → INFERIOR VENA CAVA → TO → RIGHT ATRIUM → 1ST LARGEST VEIN b. SUPERIOR VENA CAVA → carries → deoxygenated blood from Upper part –BODY → SUPERIOR VENA CAVA → TO RIGHT ATRIUM c. PULMONARY ARTERIES → ONLY ARTERIES in the body → CARRIES → DEOXYGENATED BLOOD → deoxygenated blood from RIGHT VENTRICLE → PULMONARY ARTERIES → LUNGS d. PULMONARY VEINS → ONLY VEINS in the body → CARRIES → OXYGENATED BLOOD → oxygenated blood from LUNGS → PULMONARY VEIN → LEFT ATRIUM e. AORTA → FIRST AND LARGEST → ARTERY in the body. → carries→ nutrients and oxygen → deliver → body tissue. → oxygenated blood from LEFT VENTRICLE → AORTA → BODY → 3 PARTS: 1. ASCENDING AORTA 2. AORTIC ARC 3. DESCENDING AORTA → The major arteries that stem from the arch are: i. Brachiocephalic artery → 1st first arteries to branch off the ascending aorta. ii. Left carotid artery iii. Left subclavian artery “BLOOD FLOW” RIGHT SIDE → HEART “ DEOXYGENATED BLOOD” ➔ SUPERIOR INFERIOR VENA CAVA (FROM THE UPPER AND LOWER BODY) ➔ RIGHT ATRIUM “ right upper chamber” ➔ TRICUSPID VALVE “prevent backflow from the right ventricle to the right atrium” ➔ RIGHT VENTRICLE “ right lower chamber” ➔ PULMONARY VALVE “prevent backflow from pulmonary artery to the right ventricle” ➔ PULMONARY ARTERY →TO → LUNGS →gas exchange LEFT SIDE → HEART “ OXYGENATED BLOOD” → PULMONARY VEINS → FROM → LUNGS → LEFT ATRIUM “left upper chamber” → MITRAL OR BICUSPID VALVE “prevent backflow from the left ventricle to the left atrium’’ → LEFT VENTRICLE “left lower chamber” → AORTIC VALVE “ prevent backflow from the aorta to the left ventricle” → AORTA → supplies the BODY. CORONARY CIRCULATION 1. CORONARY ARTERIES → deliver oxygenated blood from the ascending aorta → to → myocardium → during → VENTRICULAR RELAXATION. a. RIGHT CORONARY ARTERY i. Posterior descending artery ii. Right marginal artery b. LEFT CORONARY ARTERIES i. Anterior descending coronary artery ii. Circumflex coronary artery 2. CORONARY SINUS → responsible for draining most of the deoxygenated blood leaving the myocardium to the Right atrium. VENTRICULAR RELAXATION → OXYGENATED BLOOD → AORTA → ASCENDING AORTA → CORONARY ARTERY → LEFT AND RIGHT CORONARY ARTERY → RIGHT ( right ventricle, right atrium, inferior third of interventricular septum) and LEFT (left ventricle, left atrium, anteroposterior two-thirds of interventricular septum) RECEIVES BLOOD(DEOXYGENATED BLOOD) FROM → EPICARDIAL VENTRICULAR VEINS → CORONARY SINUS → RIGHT ATRIUM CARDIAC CONDUCTION → cardiac muscle → unique → why? → it doesn’t depend upon stimulation by extrinsic nerves to contract. RATHER → it contains → special pacemaker cells → that ALLOW → to contract spontaneously → an ability called → AUTOMATICITY, AUTOMATICITY OR INHERENT RHYTHMICITY → is the unique ability of the cardiac muscle to initiate a spontaneous electrical impulse. ALSO → because the heart beats REGULARLY → it is said to have RHYTHMICITY. ALTHOUGH → the extrinsic nerves don’t cause the heart to beat→ the nervous system and certain hormones can affect the heart’s rate and rhythm. PROPERTIES OF THE HEART (4 KEY PROPERTIES) 1. EXCITABILITY → the ability of cells to respond to electrical, chemical, or mechanical stimulation. → electrolyte imbalances and certain drugs → increase myocardial excitability and produce abnormalities in electrical conduction → lead to → CARDIAC ARRHYTHMIAS. 2. INHERENT RHYTHMICITY OR AUTOMATICITY → Unique ability of the cardiac muscle to initiate a spontaneous electrical impulse. → any source other than a normal pacemaker is considered abnormal → CARDIAC ARRHYTHMIAS. 3. CONDUCTIVITY → is the ability of myocardial tissue to spread and conduct electrical impulses. → abnormal conductivity can affect the timing of chamber contractions and decrease cardiac efficiency. 4. CONTRACTILITY →in response to an electrical impulse, is the primary function of the myocardium. THE ELECTRICAL IMPULSES → generated by the heart follow a very specific route → THROUGH → the MYOCARDIUM: 1. Normal cardiac impulses arise in the SINOATRIAL (SA) NODE from its spot in the wall of the right atrium just below the opening of superior vena cava → 2. An interatrial bundle of conducting fibers rapidly conducts the impulses to the left atrium, and BOTH ATRIA BEGIN TO CONTRACT → 3. The impulse travels along three internodal bundles to the ATRIOVENTRICULAR (AV) VALVE (located near the right AV valve at the lower end of the interatrial septum). → there, the impulse slows considered to allow the atria time to contract completely and the ventricles to fill with blood. → the heart’s skeleton insulates the ventricles → ensuring that only impulses passing through the AV node can enter. →4. After passing through the AV node, the impulse picks up speed. → it then travels down the BUNDLE OF HIS also called the ATRIOVENTRICULAR (AV) BUNDLE. → 5. The AV bundle soon branches into RIGHT AND LEFT BUNDLE BRANCHES → 6. PURKINJE FIBERS → conduct the impulses throughout the muscle of both VENTRICLES→ causing them to CONTRACT. SINOATRIAL (SA) NODE → ATRIOVENTRICULAR (AV) NODE → BUNDLE OF HIS → RIGHT AND LEFT BUNDLE BRANCHES → PURKINJE FIBERS NOTE: SA NODE : HEART’S PRIMARY PACEMAKER IF the SA node FAILS TO FIRE → pacemaker cells in the AV node or Purkinje fibers can initiate the impulses → although at a slower rate. PACEMAKERs other than SA node are called “ECTOPIC” pacemakers. The heart’s pacemakers, and their firing rates when the heart is at rest, are as follows: - SA NODE: fires at 60 to 80 beats per minute “PRIMARY PACEMAKER” - AV NODE: has a firing rate of 40 to 60 beats per minute “BACKUP” or secondary pacemaker. - PURKINJE FIBERS: have a firing rate of 20 to 40 beats per minute FAST FACT: Because the signals triggering the heart’s contractions originate within itself, even if the heart is removed from the body, it will continue to beat for hours as long as it’s kept in a protected environment. ELECTROCARDIOGRAM - Cardiac impulses generate electrical currents in the heart → these currents spread through surrounding tissue and can be detected by electrodes placed on the body’s surface. → the record of these signals is called an ELECTROCARDIOGRAM (ECG). - ECG → records the electrical activity or impulses; it does NOT record the heart’s contractions. - → an ECG that appears normal is called NORMAL SINUS RHYTHM → meaning that the impulse originates in the SA NODE. - → an IRREGULAR heartbeat is called an ARRHYTHMIA. SUMMARY: DEPOLARIZATION “CONTRACTION” REPOLARIZATION “RELAXATION” P WAVE → ATRIAL DEPOLARIZATION QRS COMPLEX → VENTRICULAR DEPOLARIZATION T WAVE → VENTRICULAR REPOLARIZATION CARDIAC CYCLE The series of events that occur from the beginning of one heartbeat to the beginning of the next is called the cardiac cycle. The cardiac cycle consists of two phases: systole (contraction) and diastole (relaxation). Both atria contract simultaneously; then, as the atria relax, both ventricles contract. The vibrations produced by the contraction of the heart and the closure of the valves produce the “lub-dub” heart sounds that can be heard with a stethoscope. The first heart sound (S1) is louder and longer; the second sound (S2) is a little softer and sharper. Here’s what happens during one heartbeat: PREPARED BY: ARUFAIDA H. ENRIQUEZ,RTRP REFERENCES: EGANS THOMPSON ANATOMY AND PHYSIOLOGY GOOGLE