Chapter 25 Circulatory System 3/ 14/ 2011 online

Two Circulatory Systems Blood-vascular System- major portion- transports blood Consists of heart, arteries, capillaries and veins Lymphatic System- minor portion – collects fluid from tissue spaces, filters through lymph system

Two Systems make up Circulatory System Both carry oxygen and nutrients to tissues in continuous, endless uni-direction Both transport waste products to organs of excretion- what are those 4 organs? Skin Lungs Liver kidneys

Heart has 2 circulation routes branching off it: Systemic (arterial circuit)- carries oxygenated blood to organs and tissues Pulmonary –carries blood to lungs for carbon dioxide exchange and re-oxygenation of blood

Pulmonary, systemic, and portal circulation red = oxygenated blue = deoxygenated purple -nutrient-rich

Systemic Circulation Pumps blood to organs

Pulmonary Circulation Takes returning blood to lungs to exchange carbon dioxide for oxygen Carries oxygenated blood from lungs to heart These are only veins in post-fetal human body carrying oxygenated (red) blood

Portal System Venous drainage from abdominal organs to liver- Filtered - Back to inferior vena cava Liver has 2 blood supplies!

Anatomy: Heart 4 chambers 2 atria 2 ventricles Myocardium - muscular wall of heart Endocardium -membrane lining interior of heart Pericardial sac- double-walled membrane enclosing heart exterior wall is fibrous thin inner wall- Epicardium - covers heart

Great Vessels of Heart Deoxygenated/Oxygenated Blood Flow Pulmonary artery- vessel carrying venous blood to lungs Aorta- carry oxygenated blood for systemic circulation Vena Cava Inferior and Superior - return of venous blood to heart Pulmonary Veins- carry oxygenated blood to left artrium

Anatomy: Heart Right side of heart- handles venous, or deoxygenated blood Left side of heart- handles arterial, or oxygenated blood

Atria act as receiving chambers Function of Chambers Atria act as receiving chambers Right atrium receives venous blood from superior and inferior vena cavae Left atrium receives oxygenated blood from right and left pulmonary veins

Ventricles act as distributers of blood Left ventricle pumps blood into aorta and systemic cirulation Right ventricle pumps blood into pulmonary circulation

Heart Valves Right atrioventricular (AV) valve or tricuspid valve controls opening between right atrium and right ventricle Left AV valve or mitral valve controls opening between left atrium and left ventricle

Coronary arteries supply blood to myocardium (muscular wall of heart) Left Coronary artery Right Coronary artery Coronary sinus

Myocardial infarction (MI) Commonly known as a heart attack interruption of blood supply to part of heart, causing some heart cells to die most commonly due to occlusion (blockage) of a coronary artery

CABG (Coronary Artery Bypass Graft) Surgery called revascularization to improve blood flow to heart in people with severe coronary artery disease (CAD) CAD - occurs when coronary arteries become blocked due to buildup (plaque) on inside of blood vessels. If severe enough:chest pain (angina), shortness of breath, possible heart attack and death Healthy artery or vein grafted, to blocked artery bypassing blocked portion -new passage routes oxygen-rich blood around blockage to heart muscle Replacing vessel will take over role previously performed by piece removed Up to 4 major blocked coronary arteries can be bypassed during 1 surgery.

Blood -Vascular System Radiological Studies

Angiography Exam of vascular structures using contrast medium Arteriography - exam of arteries Venography - exam of veins

Indications Claudication – Stenosis - Occlusion – Aneurysm – leg pain and cramping Stenosis - narrowing of vessel Occlusion – blockage of a vessel Aneurysm – weakened area of artery “ballooning” Suspected tumors Anatomic variances

Contrast dye is injected Automatic injector is most commonly used Manual injection is done rarely Injectors are programmed to coincide with imaging sequence Rapid film changers are rarely seen

Digital Equipment Digital subtraction -instantly “subtracts” overlying bony structures better visualization of contrast-filled vascular structures

Equipment

Catheterization Catheter - small, flexible tube inserted into vessel through which contrast is introduced Femoral artery most common introduction site Radial Brachial Axillary Jugular Subclavian

Possible Complications! Bleeding at puncture site Allergic reaction to contrast Nerve, vessel, or tissue damage Stroke Heart attack Death

Venography

Indications For Venography Deep vein thrombosis: Formation of blood clot inside blood vessel When blood vessel injured: body forms blood clot to prevent loss of blood If too much clotting & clot breaks free travels in bloodstream – blocks blood vessel - obstructs circulation (embolism) If goes to lungs - can rupture pulmonary artery, causing death

Other Indications for Venography Venous obstruction Recurrent varicose veins Swollen legs of unknown etiology Varicose ulcers Venous malformations

Main Veins of Upper Extremity Cephalic vein Basilic vein Subclavian vein Injection usually in median cubital

Injection usually in median cubital

Peripheral Venography Examines superficial and deep veins of extremities Less common today-replaced by advances in ultrasound

Lower-Limb Venogram AP of entire extremity Lateral of entire extremity

Central Venography Superior venacavogram performed by accessing axillary or subclavian vein Inferior venacavogram performed by accessing femoral vein and placing catheter in common iliac vein or inferior aspect of inferior vena cava