MEDIASTINUM & CARDIOVASCULAR SYSTEM Though My Heart Is Torn © 2011 by Karen Mathison Schmidt Kaan Yücel M.D., Ph.D. 31. 10.2014 Friday

crucial organ of the human body .HEART (1)7.3 million Trapezoidal in A-P dimensions Tipped-over pyramid in 3-D crucial organ of the human body 30%

well- oxygenated (arterial) blood Right heart (Suction) poorly- oxygenated(venous) blood from the body superior vena cava & inferior vena cava right atrium right ventricle pulmonary arteries lungs Left heart (Pumping) well- oxygenated (arterial) blood from the lungs pulmonary veins left atrium left ventricle aorta the body

The four chambers of the heart right and left atria & right and left ventricles Atrium – plural atria Ventricles Discharging chambers Receiving chambers cardiac cycle Ventricular filling (diastole) Ventricular emptying (systole) Blood pressure 120-80 mm/Hg

The fibrous skeleton of the heart Keeps the orifices of the AV & semilunar valves patent prevents them from being overly distended by an increased volume of blood. Provides attachments for the valves & myocardium. Forms an electrical «insulator» separating impulses of the atria & ventricles  they contract independently surrounding and providing passage for the initial part of the AV bundle

Sulci/Grooves in the heart coronary sulcus (atrioventricular groove) between atrium & ventricles anterior & posterior interventricular (IV) sulci (grooves) between right and left ventricles

apex located inferiorly & base located superiorly Apex & base of the heart apex located inferiorly & base located superiorly Apex projects forward, downward and to the left Base faces in a posterior direction

The four surfaces of the heart Anterior (sternocostal) surface mostly of right ventricle some of the right atrium on the right some of the left ventricle on the left Diaphragmatic (inferior) surface formed mainly by the left ventricle partly by the right ventricle related to central tendon of diaphragm. Right pulmonary surface formed by the right atrium. Left pulmonary surface left ventricle & a portion of left atrium.

2.RIGHT ATRIUM forms the right border of the heart Receives venous blood from the SVC, IVC, and coronary sinus. Through the right atrioventricular orifice, discharges the poorly oxygenated blood it has received into the right ventricle.

3.RIGHT VENTRICLE forms largest part of the anterior surface of the heart a small part of the diaphragmatic surface almost the entire inferior border of the heart.

muscular and membranous parts interventricular septum (IVS) obliquely placed partition between the right and left ventricles, forming part of the walls of each muscular and membranous parts Bulges into the cavity of the right ventricle. Superiorly and posteriorly, a thin membrane, forms the much smaller membranous part of the IVS.

4.LEFT ATRIUM forms most of the base of the heart right and left pulmonary veins enter here. Tubular, muscular left auricle, Its wall trabeculated with pectinate muscles. A semilunar depression in the interatrial septum Floor of the oval fossa surrounding ridge Valve of the oval fossa

Compared to the right ventricle 5.LEFT VENTRICLE forms the apex of the heart, left (pulmonary) surface & border, most of the diaphragmatic surface. Compared to the right ventricle Walls 2-3 times thicker Trabeculae carneae finer and more numerous Cavity longer Anterior & posterior papillary muscles larger

aortic valve semilunar valve between the left ventricle & ascending aorta obliquely placed.

double-leaflet mitral valve Guards the left AV orifice. Has two cusps, anterior and posterior.

6. SEMILUNAR VALVES Semilunar cusps of the pulmonary valve anterior-right-left Seminular cusps of the aortic valve posterior-right-left concave when viewed superiorly no tendinous cords to support

7. VASCULATURE OF THE HEART coronary arteries & cardiac veins embedded in fat course across the surface of the heart just deep to the epicardium.

Arterial Supply of the Heart coronary arteries first branches of the aorta supply the myocardium and epicardium Anastomoses between the branches of the coronary arteries exist, which enables the development of the collateral circulation.

8. STIMULATING, CONDUCTING, & REGULATING SYSTEMS OF HEART 1. sinuatrial (SA) node initiates the heartbeat & coordinates contractions of the four heart chambers 2.atrioventricular (AV) node 3.bundles highly specialized conducting fibers for conducting impulses rapidly to different areas of the heart Propagation of the impluse Simultaneous contraction of the cardiac striated muscle cells

sinuatrial (SA) node pacemaker of the heart @junction of the SVC & right atrium near to the superior end of the sulcus terminalis

sinuatrial (SA) node pacemaker of the heart stimulated by sympathetic division of the autonomic nervous system to accelerate the heart rate inhibited by parasympathetic division to return to or approach its basal rate.

atrioventricular (AV) node a smaller collection of nodal tissue than the SA node in the posteroinferior region of the interatrial septum near the opening of the coronary sinus

JOURNEY OF THE SIGNAL Generated @ SA node Passed through the walls of the right atrium Propageted by the cardiac muscle Signal passed from SA node to AV node Distributed to the ventricles through the AV bundle

BUNDLES passes from the AV node AV bundle the only bridge between the atrial and ventricular myocardium passes from the AV node through the fibrous skeleton of the heart and along the membranous part of the IVS. @ junction of membranous & muscular parts of the IVS divides into : right bundle & left bundle.

BUNDLES right and left bundles proceed on each side of the muscular IVS deep to the endocardium then ramify into subendocardial branches (Purkinje fibers) extend into the walls of the respective ventricles.

Innervation of the Heart autonomic nervous system, cardiac plexus Cardiac plexus posterior to the ascending aorta and bifurcation of the pulmonary trunk

Innervation of the Heart Parasympathetic supply autonomic nervous system, cardiac plexus Parasympathetic supply presynaptic fibers of the vagus nerves Slows the heart rate Reduces the force of the contraction Constricts the coronary arteries saving energy

Innervation of the Heart sympathetic supply presynaptic fibers cell bodies in the intermediolateral cell columns (IMLs) of the superior 5 or 6 thoracic segments postsynaptic sympathetic fibers cell bodies in the cervical and superior thoracic paravertebral ganglia of the sympathetic trunks. causes increased heart rate increased impulse conduction, increased force of contraction, increased blood flow through the coronary vessels increased activity.

a closed sac with two layers 11. PERICARDIUM fibroserous membrane, covers the heart & beginning of its great vessels a closed sac with two layers fibrous pericardium serous pericardium parietal layer visceral layer –heart & great vessels .

fibrous pericardium continuous superiorly w/ tunica adventitia of the great vessels & w/pretracheal layer of deep cervical fascia Continuous inferiorly w/ central tendon of the diaphragm Attached anteriorly to the sternum by sternopericardial ligaments Site of continuity pericardiacophrenic ligament Inner surface lined by parietal layer of the serous pericardium Protects the heart against sudden overfilling.

pericardial cavity potential space between opposing layers of the parietal & visceral layers of serous pericardium contains a thin film of fluid : pericardial fluid enables the heart to move and beat in a frictionless environment.

right & left brachiocephalic veins 12. GREAT VESSELS right & left brachiocephalic veins formed by the union of internal jugular & subclavian veins posterior to the sternoclavicular (SC) joints. brachiocephalic veins unite to form the SVC. @ inferior border of the 1st right costal cartilage shunt blood from the head, neck, & upper limbs right atrium.

superior vena cava (SVC) Returns blood from all structures superior to the diaphragm except the lungs & heart. Passes inferiorly and ends by entering right atrium of the heart.

ascending aorta begins at the aortic orifice. only branches coronary arteries, arising from the aortic sinuses. ascending aorta

Arch of the aorta (Aortic arch) curved continuation of the ascending aorta begins posterior to the 2nd right sternocostal (SC) joint at the level of the sternal angle. ligamentum arteriosum remnant of the fetal ductus arteriosus root of the left pulmonary artery inferior surface of the arch of the aorta The usual branches of the arch brachiocephalic trunk left common carotid artery left subclavian artery.

brachiocephalic trunk first and largest branch of the arch of the aorta arises posterior to the manubrium. ascends superolaterally divides into right common carotid & right subclavian arteries.

left common carotId artery second branch of the arch of the aorta arises posterior to the manubrium, slightly posterior and to the left of the brachiocephalic trunk.

left subclavian artery third branch of the arch of the aorta arises from the posterior part of the arch posterior to left common carotid artery. ascends lateral to trachea & left common carotid artery. Leaves the thorax and enters the root of the neck.

monitor changes in blood pressure CAROTID BODY CN IX CN X responsible for detecting changes in blood chemistry, primarily oxygen content CAROTID SINUS monitor changes in blood pressure CN IX

Abdominal aorta

Abdominal aorta

External iliac artery Femoral artery

Anterior tibial artery Posterior tibial artery Popliteal artery Anterior tibial artery Posterior tibial artery

Anterior tibial artery Dorsal pedis artery

U Superficial