Cardiovascular System Outline Structures n Heart n Beats

Cardiovascular System Outline

Structures n Heart n Beats 72 times a minute n 100, 000 times a day n 3 Trillion times in a lifetime! n Circulates about 5 -7 liters of blood n Blood Vessels n Arteries n Veins

Functions Transport nutrients and oxygen n Transport waste to kidneys n Distribute hormones and antibodies n Help control body temperature and maintain homeostasis n

Heart n n n 2 Sided double pump Is about the size of your fist Lies in the thoracic cavity between the lungs

Heart Tissue n Endocardium: smooth membranous lining inside the heart n Myocardium: thickest layer, muscle tissue that is contractile.

Heart Tissue Cont’d n Epicardium: outermost layer in the pericardium n Pericardium: covers the outside of the heart

Parts of the Heart Divided into right and left sides n 2 chambers in each side, for a total of 4 chambers n Atrium: top, where blood enters n Ventricles: bottom, where blood leaves n Left and right sides separated by a partition called a septum n

Parts of the Heart Left Atrium Right Atrium Left Ventricle Right Ventricle Septum

Heart Circulation Pulmonary: Flow of blood between the heart and lungs n Systemic: Flow of blood between the heart and the cells of the body n Coronary: Flow of blood within the heart n

Blood Flow n Vessels n Arteries carry blood away from the heart Largest = Aorta n Heart muscle contractions pump blood through arteries Veins carry blood towards the heart Largest = Superior/Inferior Vena Cava Valves prevent blood from returning to heart skeletal muscle contractions move blood through veins n

Blood Flow Cont’d n Valves n n control blood flow Valve between left atrium and ventricle = bicuspid Valve between right atrium and ventricle = tricuspid Pulmonary and aortic valves stop the back flow of blood into the heart

Cardiac Conduction System n n Electrical Impulses produce a wave that can be recorded on the ECG Consists of n n n Sinoatrial (SA) node Atrioventriclular (AV) node Bundle of His (AV Bundle) Bundle Branches Purkinje Fibers (network)

SA NODE Located in the upper right part of the atrium n Is a natural pacemaker n Fires at a rate of 60 to 100 times per minute n The heartbeat starts in the SA node n

AV NODE Located in the floor of the right atrium n Delays or slows the electrical impulse n Fires at a rate of 40 to 60 time per minute n Can take over if the SA node is not working n

Bundle of His Located next to the AV node n Transfers the electrical impulse from the atria to the ventricles n

Bundle Branches Located along the left and right side of the interventricular septum n Act as pathways or a fork in the road n Impulses in the bundle branch perform the important work of making the heart muscle contract n

Purkinje Network Provide an electrical pathway for each of the cardiac cells n Activate the left and right ventricles simultaneously causing the ventricles to contract n