Circulatory System

• Capillaries are tiny blood vessels that connect arteries and veins, allowing for the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues.
• Blood flows from the right atrium into the right ventricle through the tricuspid valve.
• The surface area of capillaries is vast and allows for efficient exchange of materials between the blood and interstitial fluid.
• The heart has four chambers - two atria and two ventricles.
• The heart is located between the lungs, behind the sternum (breastbone), and to the left side.
• The heart is a muscular organ that pumps blood throughout the body.
• Veins are blood vessels that carry deoxygenated blood back to the heart.
• Systole is when the heart contracts and pumps blood out into the arteries.
• Blood pressure refers to the force exerted by blood against the walls of blood vessels as it flows through them.
• The circulatory system is responsible for transporting oxygen, nutrients, hormones, and other substances throughout the body while removing carbon dioxide and metabolic wastes.
• Oxygenated blood returns to the left atrium via the pulmonary vein.
• The circulatory system includes the heart, blood, and blood vessels; Responsible for carrying blood and dissolved substances to and from different places in the body.
• The right side of the heart deals with deoxygenated blood
• The left side of the heart deals with oxygenated blood
• Lungs -> Heart -> Body -> Heart -> Lungs
• The left side of the heart is more important because it pumps oxygenated blood to the rest of the body.
• Veins have valves which act to stop the blood from going in the wrong direction
• Body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push blood along the vessel
• Arteries carry blood away from the heart
• Elastic fibers allow the artery to stretch under pressure
• Capillaries exchange materials between the blood and the body
• The wall of a capillary is only one cell thick
• capillaries link arteries and veins
• Atria/Atriums are the two upper chambers of the heart; Also known as receiving chambers
• Ventricles are the lower chambers of the heart; also known as pumping chambers
• Valves prevent backflow of blood through the heart
• Coronary arteries are blood vessels that branch from the aorta and carry oxygen rich blood to the heart muscles; the hearts own blood supply
• Step one of heart function: The heartbeat begins when the heart muscles relax and blood flows into the atria
• Step two of heart function: The atria then contract and the valves open to allow blood into ventricles
• Step three of heart function: The valves close to stop blood flowing backwards; The ventricles contract forcing blood to leave the heart; at the same time, the atria are relaxing and once again filling with blood. Then repeats
• What's in blood?

  Red blood cells, white blood cells, platelets, waste, digested food, oxygen, carbon dioxide, plasma, hormones
• What are red blood cells?

  • A biconcave disc that is round and flat without a nucleus.
  • Contain hemoglobin, a molecule specially designed to hold oxygen and carry it to cells that need it; deliver carbon dioxide to the lungs;
• What are white blood cells?

  • Fight Disease
  • There are many types and all contain a big nucleus
  • The two main types are the lymphocytes and the macrophages
• What are macrophages?

  'Eat' and digest micro-organisms
• What are lymphocytes?

  • Fight disease by making antibodies to destroy invaders by dissolving them
  • Other lymphocytes make antitoxins to break down poisons
• What are platelets?

  • They clot blood
  • Bits of cell broken off of larger cells
  • Platelets produce tiny fibrinogen fibers to form a net. This net traps other blood cells to form a blood clot
• What is plasma?

  • A straw-colored liquid that carries the cells and the platelets which help blood clot.
  • Contains useful things like: Carbon dioxide, glucose, amino acids, proteins, minerals, vitamins, hormones, waste
• Arteries take blood away from the heart. The walls of an artery are made up of thick muscular walls and elastic fibers. Veins carry blood towards the heart and also have valves. The capillaries link arteries and veins, and have a one cell thick wall. Blood is made of up four main things, plasma, the liquid part; red blood cells: to carry oxygen; white blood cells: to protect the body from disease; and platelets to help blood clot.
• What is the heart separated by?

  Septum/muscle
• What is the most important chamber of the heart?

  The left ventricle. It is responsible for pumping oxygenated blood to tissues all over the body