CIRCULATORY SYSTEM

• Circulatory System


  Network of blood carrying tubes responsible for the distribution of oxygen and nutrients to the cells, as well as the collection of metabolic wastes and carbon dioxide from the cells
• Circulatory system


  • Joined forces of a delivery service crew and a waste management team whose goal is to restore your body
  • Respiratory and circulatory systems are so interconnected that some respiratory organs are considered part of the circulatory network
• Main circulatory parts

  • Blood
  • Blood vessels
  • Heart
• Blood


  Thick red fluid that circulates throughout the body
• Human blood functions like a courier service that delivers the nutrients and oxygen to the cells of the body and carries the carbon dioxide to the lungs during exhalation
• Average adult blood volume

  4.5 - 5.5 liters, making up about 8 to 10 percent of the total body mass
• Blood composition

  Plasma, blood cells, and platelets
• Components of blood

  • Plasma
  • Erythrocytes or Red Blood Cells
  • Leukocytes or White Blood Cells
  • Thrombocytes or Platelets
• Plasma


  Liquid portion of the blood that carries the blood cells and platelets, and enables blood to flow in the vessels
• Erythrocytes or Red Blood Cells


  Blood cells that carry and transport oxygen to different organs
• Red blood cells


  • Biconcave shape with thick edges and depressed middle surfaces for flexibility and maximum surface area
  • Lack nucleus and mitochondrion to accommodate hemoglobin and avoid consuming oxygen
  • Red color from hemoglobin, a protein that contains iron and carries oxygen
• Leukocytes or White Blood Cells


  Bigger in size but lesser in number than red blood cells, contain nuclei and mitochondria but not enough space for hemoglobin, increase immunity and protect the body from pathogens, infections, and other foreign substances
• Thrombocytes or Platelets


  Small disc-shaped fragments of large bone marrow cells called megakaryocytes, function is to form a blood clot when a blood vessel is damaged
• Blood vessels


  Interconnected tunnels or passages that blood flows through, attached to different organs
• Major blood vessels


  • Artery
  • Vein
  • Capillary
• Arteries


  Largest and thickest blood vessels that carry oxygen and nutrient-rich blood away from the heart and deliver them to the rest of the body, branch out into smaller arterioles that transport blood flow into the capillaries
• Pulmonary arteries


  Transport deoxygenated blood into the lungs
• Systemic arteries


  Deliver oxygenated blood to the rest of the body
• Capillaries


  Thinnest vessels that bridge the arteries and the veins, where the exchange of oxygen, carbon dioxide, nutrients, and waste products occur
• The network of capillaries varies depending on the metabolic activity of every organ in the body
• Veins


  Carry the blood from different parts of the body to the heart, have thinner walls than arteries
• Pulmonary veins


  Deliver oxygenated blood from the lungs back to the heart
• Systemic veins


  Carry oxygen-poor blood back to the heart
• Heart


  Main organ of the circulatory system, located behind the sternum, made of cardiac muscle with several tubes that open into different chambers, contracts or pulses constantly to pump blood into the arteries
• Heart


  • Size of a closed fist, shape similar to a tilted mango, size can vary depending on age and health of a person
• Chambers of the heart

  • Right atrium
  • Left atrium
  • Right ventricle
  • Left ventricle
• Blood flow through the heart

  1. Deoxygenated blood from the body enters the right atrium

  2. Right atrium contracts and opens the tricuspid valve, pumping blood into the right ventricle

  3. Right ventricle contracts and releases pressure to push open the pulmonary valve, pumping blood into the pulmonary artery

  4. Oxygenated blood from the lungs enters the left atrium

  5. Left atrium contracts and opens the mitral valve, releasing blood into the left ventricle

  6. Left ventricle contracts and opens the aortic valve, pumping oxygenated blood into the aorta
• Pulse


  Rhythmic bulging of the arteries that can be felt at the wrist, neck, and temple, reflects the beating of the heart
• Pulse rate can be measured by counting the number of pulses per minute