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Anatomy of the Cardiovascular System. Cardiovascular System. Also circulatory system Consists of: the heart , arteries , veins , capil laries. Heart. Four chamber muscular organ Comparable to the size of a closed fist Located in the mediastinum. Heart. Coverings of the Heart. - PowerPoint PPT Presentation
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Cardiovascular System
• Also circulatory system• Consists of: the heart, arteries, veins,
capillaries
Heart
• Four chamber muscular organ• Comparable to the size of a closed
fist• Located in the mediastinum
Coverings of the Heart• Pericardium – loose fitting sac
surrounding the heart– Fibrous pericardium – tough, loose-
fitting, inelastic– Serous pericardium
• Parietal layer: lines the inside of the fibrous pericardium
• Visceral layer: adheres to outside of the heart
– Pericardial space: between parietal and visceral layer• Filled with 10-15mL of pericardial fluid• Decreases friction
Walls of the Heart• Epicardium – outer layer
– Epicardium = serous pericardium
• Myocardium – thick, contractile layer composed of cardiac muscle cells
• Endocaridium – interior of cardiac wall
Chambers of the Heart
• Atria – two superior chambers– “Receiving chambers”– Blood from veins enters atria
• Ventricles – two inferior chambers– “pumping chambers”– Separated by interventricular septum
Valves of the Heart
• Permit blood flow in one direction during circulation
• Atrioventricular valves (AV valves)– Also cuspid valves– Between atria and ventricles
• Semilunar (SL valves)– Between ventricles and vessles
Blood Supply to the Heart• After traveling through the capillaries
of the heart, blood empties into the R atrium via the coronary sinus
Conduction System of the Heart
• Four structures composed of modified cardiac muscle
• Sinoatrial Node (SA Node)– Pacemaker of the heart– 100s of cells in the R atrium near the
opening of the superior vena cava
• Atrioventricular Node (AV Node)– Left lower border of R atrium
Conduction System of the Heart
• Atrioventricular Bundle– Also Bundle of His– Bundle of specialized cardiac muscle
fibers originating in the AV node– Branches into R and L branches
eventually becoming Purkinje fibers– Extend into the walls of the ventricles
and papillary muscles
Types of Blood Vessels
• Artery – carries oxygenated blood away from the heart– Arteriole: small artery– Precapillary sphincters: regulate the
blood flow into capillaries
Types of Blood Vessels
• Vein – carries unoxygenated blood towards the heart– Great ability to stretch (capacitance)– Function as reservoirs: blood pools in
the valves then is pushed forward from the pumping pressure
– Venules: small vein
Types of Blood Vessels
• Capillaries – arterial system switches to venous system– “primary exchange vessels”– Transport materials to and from the cells– Speed of blood flow decreases to
increase contact time
Structure of Blood Vessels
• Tunica adventitia - outermost layer– Fibrous connective tissue– Holds vessels open; prevents tearing of
vessels walls during body movements– Larger in veins than arteries
• Tunica media – middle layer– Smooth muscle and elastic CT– Helps vessels constrict and dilate– Larger in arteries
Structure of Blood Vessels• Tunica intima – innermost layer
– Composed of endothelium– Semilunar valves present in veins– One cell thick in capillaries
Circulatory Routes
• Systemic Circulation – blood flow from the L ventricle to the body & back to the R atrium
• Pulmonary Circulation – blood flow from the R ventricle to the lungs and back to the L atrium
Systemic Arteries
• Arch of aorta• Subclavian (L and
R)• Brachiocephalic• common carotid (L
and R)• Axillary (L and R)• Brachial (L and R)• Radial• Ulnar
• Abdominal aorta• Common iliac• External iliac• Femoral• Popliteal• Posterior tibial• Anterior tibial• Dorsal pedis
Systemic Veins
• Superior vena cava• Inferior vena cava• External jugular• Internal jugular• Brachiocephalic (L
and R)• Subclavian (L and
R)• Cephalic• axillary
• Basilic• Median basilic• Median cubital• Common iliac• External iliac• Femoral• Popliteal• Great saphenous• Small saphenous
Fetal Circulation
• Two umbilical arteries carry blood to the placenta
• The placenta allows for exchange of oxygen and nutrients from the mother. Maternal and fetal blood do NOT mix.
• Umbilical vein returns oxygenated blood and enters fetus via the umbilicus
• Foramen ovale – hole btwn the R and L atria– Allows for blood to bypass the R ventricle and
pulmonary circulation
Changes After Birth
• Umbilical vein become round ligament• Umbilical arteries become umbilical
ligaments• Foramen ovale closes after first few
breaths– Full closure may take up to 9 months
• Ductus arteriosus contracts as soon as respirations begin– Become fibrous cord
Pericardium Disorders• Pericarditis – inflammation of the heart
– Causes: trauma, viral or bacteria infection, tumor– Edema causes visceral and parietal layers to rub
together = chest pain– Pus or blood build up in pericardial space– S/S
• Pain with respirations or coughing, dyspnea, restlessness
– Complications: Pericardial Effusion, Cardiac Tamponade
– Treatment: • Antibiotics, pain meds, antiinflammatory meds,
pericardiocentesis (Cardiac Tamponade)
Heart Valve Disorders
• General Principles:– Congenital defect: decreased pumping
efficiency– Incompetent valve leak: allows backflow
into previous chamber– Stenosed valves: narrowed valve;
slowing blood from out of chamber
Heart Valve Disorders
• Mitral Valve Prolapse (MVP)– Flaps of mitral valve extend back into L
atrium causes leaking– Mostly genetic basis– 1 in 20 people– S/S: most asymptomatic; chest pain,
fatigue– Treatment: valvuloplasty
Heart Valve Disorders
• Aortic Regurgitation– Blood leaks back into L ventricle during
ejection into the aorta– Volume overload in L ventricle,
hypertrophy, dilation of L ventricle– Complications: myocaridal ischemia– Treatment: valvuloplasty
Myocardium Disorders
• Atherosclerosis – Type of arteriosclerosis– Lipids build up on the inside of vessel
walls calcify vessels hard & brittle– Risk factors: cigarette smoking, high
fat/cholesterol diet, hypertension
Myocardium Disorders• Myocardial Infarction
– “Heart Attack”– Coronary thrombosis: clot– Coronary embolism: mobilized clot– Occlude coronary artery heart tissue
deprived of oxygen cell death– S/S:
• Angina pectoris – severe chest pain resulting from inadequate oxygen to myocardium
– Treatment: Coronary Bypass Surgery• Veins are harvested from other areas of the
body and used to bypass obstructions
Myocardium Disorders• Congestive Heart Failure (CHF)
– “Left-sided Heart Failure”– Inability of the L ventricle to pump blood
efficiently– Causes: myocardial infarction– S/S: decreased pumping pressure in
systemic circulation; retained fluids• Can lead to congestion in pulmonary
circulation pulmonary edema right-sided heart failure
– Treatment: heart transplant
Myocardium Disorders
• Coronary Artery Disease (CAD)– Leading cause of death in US– General term to describe decreased
blood flow to myocardium & associated side effects
Disorders of the Arteries
• Arteriosclerosis– Arteries become occluded, weak and
hardened– Complications: ischemia, necrosis, gangrene– Risk factors: age, diabetes, high
fat/cholesterol diet, hypertension, smoking– Treatment: vasodilators, angioplasty, stent
placement, bypass surgery– Complications: aneurysm
Disorders of Veins
• Varicose Veins– Enlarged veins caused by pooling– Results in varicosities or varices (“spider
veins”)– Risk factors: standing for long periods
• Semilunar valves widen more pooling
– Treatment: compression stockings, surgical removal
Disorders of Veins• Phlebitis – vein inflammation
– Causes: irritation by IV catheter
• Thrombophlebitis– Deep vein thrombosis (DVT)– Phlebitis caused by a clot– S/S
• Pain, redness, swelling
– Complications• Pulmonary embolism
Venous Stasis Ulcers
• Result of chronic vein insufficiency
• Lack of oxygen to peripheral tissues
• Elevate leg & apply pressure
• Irregular edges• “Aching” pain