The Circulatory System, Exams of Nursing

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The Circulatory

System

Interesting Facts

 (^) The heart beat is strong enough to squirt blood 30 feet  (^) The longer a boy’s ring finger is, the less likely they are to have a heart attack (according to one study)  (^) The human heart beats ~35 million times per year  (^) The heart pumps ~1,000,000 barrels of blood in a lifetime  Most heart attacks occur between 8- 9 a.m.  In fetus, Heart development starts at start of 4th^ week of pregnancy, why so early?  At the same week its beating starts, but that can be feel after 5 weeks

 The Circulatory System is responsible for transporting materials throughout the entire body.  It transports nutrients, water, and oxygen to your billions of body cells and carries away wastes such as carbon dioxide that body cells produce.  It is an amazing highway that travels through your entire body connecting all your body cells.

Component s  Heart  Blood  Vessels  Arteries  Veins  Capillaries Heart Blood

Veins^ Arteries

The Heart

 (^) Size of a fist; less than a pound  (^) In thorax; flanked by lungs; rests on diaphram  (^) Top: base  (^) Bottom: apex

Pericardium

 (^) Double-layered sac covering the heart  (^) Outer layer anchors heart in chest  (^) Inner layer (epicardium) attached to heart wall  (^) Lubricating fluid in pericardial space (between layers) reduces friction

l Tamponade

 (^) Bleeding into pericardial space after chest trauma  (^) Excess blood restricts expansion of heart during pumping  (^) Causes shock or death if not corrected

 The inside of the heart is divided into two sections so that the two types of blood ( oxygen-rich and oxygen- poor ) are kept apart Oxygen-poor blood Right side of the heart Oxygen-rich blood Left side of the heart

Heart Chambers

Four chambers:  (^2) atria: top of heart – receive blood from veins  (^2) ventricles: bottom of heart – pump blood through arteries

Heart Chambers

 (^) Septum: divides left from right heart  (^) Valves: keep blood flowing in one direction  (^) Four valves:  (^2) AV valves,  (^2) semilunar valves Heart sounds (Lupp- dupp) from valves closing

Semilunar Valves

 (^) Located in arteries leaving ventricles  (^) Pulmonic valve: at base of pulmonary artery  (^) Aortic valve: at base of aorta  (^) When ventricles contract, valves are forced open & let blood flow  (^) When ventricle relaxes, backflow of blood fills flaps of valve & forces them to shut

 Myocardium

 The muscle of the heart  Strong and thick  Composed of spontaneously contracting cardiac muscle fibers  Can conduct electricity like nerves.  It’s blood supply comes from the coronary arteries.

 Four chambers  Two Atria

◼ Upper chambers

◼ Left and right

◼ Separated by interatrial

septum

 Two Ventricles

◼ Lower chambers

◼ Left and right

◼ Separated by interventricular

septum

Right Ventricle

Right Atrium

Left Ventricle

Left Atrium

 The chambers of the heart have different functions: blood to the body blood from the body blood to the lungs blood from the lungs The Atria collect blood that enters the heart. The ventricles pump blood out of the heart.