Circulatory system

• Circulatory system: delivers oxygen to all cells in the human body
• two main components: Cardiovascular and lymphatic
• Cardiovascular system: helps in the circulation
• Lymphatic system: made up of the lymp, lymph nodes, and vessels
• Cardiovascular is composed of the heart, blood vessels, and blood
• 4 chambers of the heart: right atrium, right ventricle, left atrium, left ventricle
• Layers of the heart: epicardium, endocardium, myocardium
• Epicardium: the outer layer of the heart. thin, watery membrane

  Function : covers the heart and is attached to the pericardium
• Myocardium: the middle layer of the heart. thick layer of cardiac muscles

  Functions: pumps blood into the arteries by contracting
• Endocardium: inner layer of the heart. thin layer of epithelial cells

  Functions: lines valves and interior chambers
• right atrium: receives deoxygenated blood from the body.Upper right chamber
• right ventricle: receives blood from the right atrium and pumps it into the pulmonary artery. lower right chamber
• Left atrium: receives oxygenated blood from the lungs and pumps it into the left ventricle

  upper left chamber
• Left ventricle: receives blood from the left atrium and pumps it into the aorta. lower left chamber
• valves of the heart: right AV valve, left AV valve, right semilunar valve, left semilunar valve
• Right AV valve: tricuspid valve located between the right atrium and right ventricle
• Left AV valve: bicuspid or mitral valve located between the left atrium and the left ventricle
• Right semilunar valve: pulmonary or pulmonic valve located at the entrance of the pulmonary artery
• Left semilunar valve: aortic valve located at the entrance of the aorta
• Right av valve: closes as the right ventricle contracts preven blood flow from the right atrium
• Left av valve: closes as the left ventrivle contracts preventing blood flow back to the left atrium
• Right semilunar valve: closes when the right ventricle relaxes preventing blood flow back to the right ventricle
• Left semilunar valve: closes when the left ventricle relaxes preventing blood flow back to the left ventricle
• Interatrial septum: separates the right and left atria.
• Interventicular septum: separates the right and left ventricles.