PTAT 2 Cardiovascular Anaphysiology Lecture Notes PDF

S4 (Abnormal) Pericardium 4TRIAL GALLOP Covering of the heart Heard after S1, late diastole Compose of 2 layers: MI 1. Fibrous HTN...

S4 (Abnormal) Pericardium 4TRIAL GALLOP Covering of the heart Heard after S1, late diastole Compose of 2 layers: MI 1. Fibrous HTN 2. Serous Heart auscultations LANDMARKS: 1. Aortic area - R 2nd ICS 2. Pulmonic area - L 2nd ICS 3. Tricuspid area - L 4th ICS 4. Mitral area - L 5th ICS, midclavicular 5. Erb’s pont - L 3rd ICS 1. Fibrous pericardium Outermost layer Composed of tough inelastic, dense irregular connective tissue Its open end is fused to the connective tissues of the blood vessels entering and leaving the heart. – Function: CARDIOVASCULAR ANAPHYSIO ○ Prevents overstretching of the Heart heart Shape ○ provides protection ○ Cone-shaped structure ○ anchors the heart in the ○ Relatively small same size as mediastinum closed fist 2. Serous pericardium Rest Innermost layer ○ Diaphragm Is a thinner, more delicate membrane Location that forms a double layer around the ○ mediastinum heart Orientation 2 layers of serous pericardium: ○ Apex: Anteriotly directed, Left, A. Parietal Layer of the serous (PSP) inferior (ALI) ○ outermost layer ○ Base: Posteriorly directed, B. Visceral layer of the serous (VSP) Right, Superior (PRS) ○ Aka the epicardium Landmarks ○ Innermost layer ○ Apex: L 5th ICS Pericardial fluid (PF) ○ Base: 2-3 costal cartilage Function: decreases friction in the heart N amount: 15 to 50 ml Fiona Erica Peji & Fhelomenarose Verzosa 5  Between the parietal & visceral layers of Forms most of the anterior surface of the the serous pericardium is a thin film of a heart lubricating serous fluid Inside RV contains a series of ridges ○ The space that contains PF is formed by raised bundles of cardiac mm kown as pericardial cavity fibers called “trabeculae carneae” Condition related to amount of PF Posterior surface (+) decrease PF - Pericardial friction rub Aka base surface (+) Increase PF - Cardiac tamponade Chamber: 1. Right atrium 2. Left atrium Forms most of the base of the heart Inferior surface Aka diaphragmatic surface Chamber: 1. Right Ventricle 2. Left Ventricle Chambers of the heart Surfaces of the heart 1. Anterior 2. Posterior 3. Inferior Anterior surface Aka Sternocostal surface Chambers in anterior surface includes: 1. R atrium Atrium: receiving chamber Receives blood from THREE veins Ventricle: pumping chamber ○ SVC 1. Right Atrium ○ IVC Describe as rough due to the presence of ○ Coronary sinus pectinate muscles in the inside of AVG thickness: 2-3 mm posterior wall of RA The insides of posterior and anterior Receives blood from THREE veins (aka walls of RA are different; openings) Ant wall of R atrium: rough due to ○ SVC presence of mm ridges “Pectinate mm”; ○ IVC Post wall of R atrium: smooth ○ Coronary sinus 2. R ventricle AVG thickness: 2-3 mm AVG thickness: 4-5 mm Fiona Erica Peji & Fhelomenarose Verzosa 6  2. Left Atrium Valves of the heart (+) pulmonary veins Function: prevents backflow of the ○ It receives blood from the lungs blood through FOUR pulmonary veins Atrioventricular valves (inlet valves) ○ Anterior wall of left atrium is ○ Right AV valve - tricuspid valve also smooth ○ Left AV valve - mitral/ bicuspid ○ Blood passses from left atrium valve into the left ventricle through Semilunar valves (outlet valves) the bicuspid valve ○ Right - pulmonic valve Interatrial Septum ○ Left - Aortic valve Divides the atrial region into a right atrium and left atrium Foramen ovale ○ Before birth, this structure allows most blood entering the righ tatrium pass into the left atrium (+) Fossa ovalis ○ Remnant of foramen ovale ○ Is formed by septum primum and septum secundum. Blood flow inside of the heart ○ Closed version ni foramen ovale (NORMAL) ○ Once the foramen closed after the first breath of the baby (yung iyak) 3. Ventricles (+) cardiac mm fiber (ridges) ○ Pectinate mm (+) papillary mm Trabeculae Carneae ○ Ridges and folds of the myocardium in the ventricles ○ Their contraction pulls on the chordae tendineae, preventing inversion of the mitral (bicuspid) and tricuspid valves towards the atrial chambers. Cordae Tendinae ○ are attached to the leaflets on to the ventricular side and prevent the cusps from swinging back into the atrial cavity during systole. (tortora) Fiona Erica Peji & Fhelomenarose Verzosa 7  The left side of the heart pumps oxygenated blood into the systemic circulation to all tissues of the body except the air sacs (alveoli) of the lungs. The right side of the heart pumps deoxygenated blood into the pulmonary circulation to the air sacs. (accdg to tortora, 15th ed) Branches of Aorta 2. Conduction system Autorhythmic fibers in the SA node, located in the right atrial wall (a), act as the heart’s pacemaker, initiating cardiac action potentials Autorhythmic fibers: (tortora, 15th ed, p.711) - An inherent and rhythmical electrical Heart Sounds activity is the reason for the heart’s lifelong beat. The source of this electrical activity is a network of specialized cardiac muscle fibers called autorhythmic fibers (auto-=self) because they are self-excitable. - repeatedly generate action potentials that trigger heart contractions 2 important fxn of Autorhythmic fibers Great Control Center of the Heart 1. act as a pacemaker 1. Autonomic Nervous System (ANS) 2. forms the cardiac conduction system The conduction system ensures that the chambers of the heart contract in a coordinated manner. Fiona Erica Peji & Fhelomenarose Verzosa 8  1. SA node Natural pacemaker: autorhythmic fibers in the Cardiac excitation normally begins in SA node would initiate an AP about every 0.6 the sinoatrial (SA) node second, or 100 times per minute located in the right atrial wall just inferior and lateral to the opening of the Summary: SVC SA node cells do not have a stable resting potential, but repeatedly depolarize The spontaneous depolarization is called pacemaker potential: triggers action potential Each action potential from the SA node Coronary Artery - BS of the Heart propagates throughout both atria via gap junctions in the intercalated discs of atrial muscle fibers. Following the action potential, the two atria contract at the same time. 2. AV node By conducting along atrial muscle fibers, the action potential reaches the atrioventricular (AV) node located in the interatrial septum, just anterior to the opening of the coronary sinus action potential slows considerably as a result of various differences in cell structure in the AV node This delay provides time for the atria to empty their blood into the ventricles. 3. Atrioventricular (AV) bundle aka bundle of His only site where action potentials can conduct from the atria to the ventricles 4. Right and Left bundle branches extend through the interventricular Cardiac Action Potential septum toward the apex of the heart 5. Purkinje fibers rapidly conduct the AP beginning at the apex of the heart upward to the remainder of the ventricular myocardium ventricles contract, pushing the blood upward toward the semilunar valves Fiona Erica Peji & Fhelomenarose Verzosa 9 (Action potential in a ventricular contractile Hemodynamics fiber. The resting membrane potential is about Systolic – Highest arterial pressure −90 mV.) (_mmHg) Diastolic – Lowest arterial pressure (_mmHg) Pulse Pressure – Difference between the systolic and diastolic (SBP – DBP) End Diastolic Volume – Amount of blood left after diastole (ventricular relaxation) ○ Normal – 120ml – preload – (initial stretching of the heart) End Systolic Volume - Amount of Skeletal muscle vs. Heart muscle blood left after systole (ventricular contraction) ○ Normal – 50ml Stroke Volume – Amount of blood pumped by ventricles per contraction ○ Normal – 70ml Cardiac Output – Amount of blood pumped by ventricles per minute Cardiac Cycle ○ Normal – 4-6L Pumping action of the Heart Mean Arterial Pressure – Arterial Diastole: Ventricular relaxation pressure with respect to time Systole: Ventricular contraction ○ DBP + 1/3 PP ECG Reading Normal electrocardiogram (ECG). P wave = atrial depolarization; QRS complex = onset of ventricular depolarization; T wave = ventricular repolarization. Fiona Erica Peji & Fhelomenarose Verzosa 10  The analysis of an ECG involves measuring time spans between waves, known as intervals or segments. The P–Q interval measures the time from the start of the P wave to the beginning of the QRS complex, indicating the conduction time from atrial to ventricular excitation. ○ Lengthening of this interval can occur due to scar tissue from conditions like coronary artery disease. The S–T segment, from the end of the S wave to the start of the T wave, reflects the depolarization of ventricular contractile fibers ○ can be elevated in acute myocardial infarction or depressed with insufficient oxygen The Q–T interval, from the start of the QRS complex to the end of the T wave, represents the duration of ventricular depolarization and repolarization ○ can be prolonged by myocardial damage, ischemia, or conduction issues Fiona Erica Peji & Fhelomenarose Verzosa 11 Fiona Erica Peji & Fhelomenarose Verzosa 12