CIRCULATORY SYSTEM

• The circulatory system is transporting blood throughout the body
• Transporting oxygenated blood from the heart to lungs are via arteries
• Deoxygenated blood is returned to its origin though veins
• Functions: Delivers oxygen and nutrients to all cells of the body, transport Co2 and other wastes away from the cells, help in coagulation, regulates body temperature, assist fighting diseases
• Two main components: Cardiovascular and Lymphatic system
• Cardiovascular system: heart, blood, blood vessels
• Lymphatic system: WBC and immune system. Lymph, lymph nodes, and vessels
• Heart - hollow muscular organ that has 4 chambers and is surrounded by a thin, fluid-filled sac called pericardium. The size of the heart is same size of person's clenched fist.
• Epicardium is thin, water membrane on the outer layer of heart. It consist the heart and is attached to the pericardium.
• Pericardium - membrane that encloses the heart and routs of the major heart vessels. It protects the heart and prevent friction during heart contraction
• Parietal pericardium - layer of pericardium that consist of dense connective tissue that protects the heart and maintain its position within the thoracic.
• Visceral pericardium - layer of pericardium that envelopes the heart and forms epicardium
• Epicardium- most superficial layer of the heart
• The layer of pericardium forms the pericardial sac and normally contains clear, straw-colored fluid called pericardial fluid. The color may vary due to tumor present in area.
• Pericardial cavity- space between parietal and visceral
• Myocardium - thick layer of cardiac muscle in the middle layer of heart. It pumps blood into the arteries by conracting
• Endocardium - thin layer of epithelial cells in the inner layer of the heart. It lines the valve and interiors chamber
• Right atrium - upper right chamber. It received deoxygenated blood from the body
• Right ventricle - lower right chamber. It receives the blood from the right atrium and pumps it into the pulmonary artery
• Left atrium - upper left chamber. Receives oxygenated blood from the lungs and pumps it into the left ventricle
• Left ventricle - lower left chamber. It receives blood from the left atrium and pumps it into the aorta
• Right AV (atrioventricular valve) - tricuspid valve located between the right atrium and right ventricle. It closes as the right ventricle contracts preventing the blood from flowing back to right atrium
• Left AV (atrioventricular valve) - bicuspid or mitral valve located between the left atrium and left ventricle. It closes as the left ventricle contracts preventing the blood from flowing back to the left atrium
• Septa : plural of septum
• Interatrial septum - partition that separated the right atrium to left atrium
• Interventricular septum - separates the right ventricle from the left ventricle
• Coronary circulation - composed of left and right coronary arteries and veins. It receives the blood supply thru left and right coronary arteries, and coronary veins return the oxygen-depleted blood from the heart muscle back to the heart. It also supplies the blood and also provides drainage the tissue.
• Cardiac cycle - systole or contractions and diastole or relaxation which lasts about 0.8 seconds
• Electrical Conduction system - sends electric impulses throughout the myocardium which is initiated by the sinoatrial (SA) and node (pacemaker)
• ECG/Electrocardiogram - provides the graphical representation of the cardia cycle's activity
• Origin of the heart sounds - "lubb" first sound produced as the ventricles contract or the AV valves close. "Dubb" second sound produced when the semilunar valve close and the ventricles relax.
• Heart rate and cardiac output - the average heart rate is 72 bpm, and the cardiac output refers to the volume of blood pumped per minute
• Pulse - rhythmic throbbing resulting from the altering expansion and contracting of the artery
• Blood pressure - force exerted by the blood on the walls of the vessels measured by the sphygmomanometer