CARDIOVASCULAR SYSTEMConsists of: Pericardium Heart Arteries Capillaries VeinsHas two circulations: Systemic Pulmonary

MEDIASTINUM

PERICARDIUM Attaches to: roots of the great vessels central tendon of the diaphragm maintains the position of the heart prevents rapid over distension of the heart

SEROUS PERICARDIUM outer parietal layer and inner visceral layer lubrication allowing free movement of heart within the fibrous pericardium

HEART WALLThree layers: Epicardium Outermost Serous Adipose tissue Endocardium lines the interior heart chambers continuous with the endotheliumthe blood vessels Myocardium Thickest Cardiac muscle

HEART CHAMBERS

Comprised of four chambersTWO ON THE RIGHT Right atrium (RA) Right ventricle (RV)TWO ON THE LEFT Left atrium (LA) Left ventricle (LV)

THE CHAMBERS Internally the left and right ventricles are divided by the interventricular septumArtia Thin-walled Pectinate muscleVentricle eject blood into arteries RV thinner than LV Trabeculae carneae muscle

VALVESAtria and ventricles separated by valves One way Between atrium and ventricle Atrioventricular valve Left AV valve (bicuspid or mitral valve) Right AV valve (tricuspid valve) Tendinous cords (chordae tendinae) Papillary muscles

GREAT VESSELS Superior vena cava Inferior vena cava Aorta Pulmonary trunk

BLOOD FLOW OF THE HEART

ARTERIES AND VEINS

ARTERIES First branches of the aorta left and right coronary arteries Right coronary artery Supplies left atrium, ventricle and septum Anterior interventricular artery Ventricles

VEINS Great cardiac vein Middle cardiac vein Small cardiac vein Coronary sinus Main vein of heart Receives all major cardiac veins Drains to RA

CONDUCTING SYSTEM

BLOOD VESSELS

ArteriesConvey blood away from the heartThick tunica mediaNarrow lumenMore elastic an collagen fibres

VeinsCarry blood back to the heartThick tunica externaLarge lumenLess collagen and elastic fibres

CapillariesConnection between smallest arteries and veins

Vessel walls are composed of layers called tunics1. Tunica intima Innermost layer Endothelium2. Tunica media Middle layer Smooth muscle3. Tunica externa Outermost layer Connective tissue sheath

AORTA

Ascending aorta Coronary arteriesArch of aorta Brachlocephalic artery Left common caroid Left subclavianDescending aorta IntercostalsAbdominal aorta Celiac trunk Superior mesenteric artery Inferior mesenteric artery Renal arteries Gonadal arteriesCommon iliac arteries

VENOUS RETURN Venous return requires the aid valves and pumps to drive blood back to the heart 2 majorMuscular pumpThoracic pump

Major veins Superior vena cavaReceiving blood from head, neck and upper limb

Inferior vena cavaReceiving blood from lower limbs, pelvic organs and abdominal organs (eventually)

Superficial veins of the upper limb Cephalic vein Basilic vein Median cubital vein

Superficial veins of the lower limb Great saphenous vein Small saphenous vein