Cardiovascular system

•  1. THE CIRCULATORY SYSTEM CARRIES BLOOD FROM THE HEART TO THE TISSUES OF THE BODY AND RETURNS THE BLOOD TO THE HEART.

   2. ALLOWS FOR NUTRIENT, WASTE, AND GAS EXCHANGE WITH THE TISSUES.

   

  3. TRANSPORTS OTHER SUBSTANCES (HORMONES, ENZYMES, ETC.) THROUGHOUT THE BODY. 

  4. REGULATES BLOOD PRESSURE AND BLOOD FLOW TO THE TISSUES.
• Blood is a fluid/ liquid ( Plasma)

   *Plasma is made up of 91% of water and 9% of other substances
• 3 Main Substances 

  • Erythrocytes/ Red Blood Cells- transport of oxygen and carbon dioxide
• • Leukocytes/ White Blood CellsImmune defense
• • Thrombocytes/ Platelets-  blood clothing ( minimizing blood lost in an injury)
• Heart- is an involuntary muscle that works somewhat independently from the Nervous system
• Heart chambers

      Your heart is divided into four chambers. You have two chambers on the top (atrium, plural atria) and two on the bottom (ventricles), one on each side of the heart.
• • Right atrium: Two large veins deliver oxygen-poor blood to your right atrium. The superior vena cava carries blood from your upper body. The inferior vena cava brings blood from the lower body. Then the right atrium pumps the blood to your right ventricle.
• • Right ventricle: The lower right chamber pumps the oxygen-poor blood to your lungs through the pulmonary artery. The lungs reload blood with oxygen.
• • Left atrium: After the lungs fill blood with oxygen, the pulmonary veins carry the blood to the left atrium. This upper chamber pumps the blood to your left ventricle.
• • Left ventricle: The left ventricle is slightly larger than the right. It pumps oxygen-rich blood to the rest of your body
• 3 layers of Tissue

  Endocardium (inner most layer)-thin, smooth membrane that lines the inside of the chambers of the heart 
• Myocardium (Middle Layer) - Heart muscle
• Pericardium (outer layer) -tough, double-layered fiber sack which covers the heart
• Heart valves

         Your heart valves are like doors between your heart chambers. They open and close to allow blood to flow through.
• The atrioventricular (AV) valves open between your upper and lower heart chambers. They include:

  • Tricuspid valve: Door between your right atrium and right ventricle.
• • Mitral valve: Door between your left atrium and left ventricle.
• • Semilunar (SL) valves open when blood flows out of your ventricles. They include:
• • Aortic valve: Opens when blood flows out of your left ventricle to your aorta (artery that carries oxygen-rich blood to your body).
• • Pulmonary valve: Opens when blood flows from your right ventricle to your pulmonary arteries (the only arteries that carry oxygen-poor blood to your lungs
• Your heart receives nutrients through a network of coronary arteries. These arteries run along your heart’s surface. They serve the heart itself.
• • Left coronary artery: Divides into two branches (the circumflex artery and the left anterior descending artery).
• • Circumflex artery: Supplies blood to the left atrium and the side and back of the left ventricle.
• • Right coronary artery (RCA): Supplies blood to the right atrium, right ventricle, bottom portion of the left ventricle and back of the septum
• • Left anterior descending artery (LAD): Supplies blood to the front and bottom of the left ventricle and the front of the septum.
• Electrical conduction system

        Your heart’s conduction system is like the electrical wiring of a house. It controls the rhythm and pace of your heartbeat. It includes:

  • Sinoatrial (SA) node: Sends the signals that make your heart beat.
  • Atrioventricular (AV) node: Carries electrical signals from your heart’s upper chambers to its lower ones.
• Your heart also has a network of electrical bundles and fibers. This network includes:

  • Left bundle branch: Sends electric impulses to your left ventricle.
  •  Right bundle branch: Sends electric impulses to your right ventricle.
  • Bundle of His: Sends impulses from your AV node to the Purkinje fibers.
  • Purkinje fibers: Make your heart ventricles contract and pump out blood
• Blood vessels

  Your heart pumps blood through three types of blood vessels:

  • Arteries carry oxygen-rich blood from your heart to your body’s tissues. The exception is your pulmonary arteries, which go to your lungs.
• • Veins carry oxygen-poor blood back to your heart.
• • Capillaries are small blood vessels where your body exchanges oxygen-rich and oxygen-poor blood.