Week 3 - Circulatory And Cardiovascular System

• Functions of the circulatory system

  • Transportation (nutrients, gases, water oxygen, waste products)
  • Thermoregulation
  • Protecting the body (immunity)
• Heart


  Situated behind the sternum and is made up of four chambers
• Heart chambers


  • Two upper chambers (atria - responsible for receiving blood into the heart)
  • Two lower chambers (ventria - responsible for pumping blood throughout the body, so its more muscular than the atria)
• Bicuspid valve and Tricuspid valve


  • Prevent blood flowing back into the atria from the ventricles
• Double circulatory system


  1. Pulmonary (Deoxygenated blood moves from the heart to the lungs. Oxygenate blood moves from the lungs to the heart)

  2. Systemic (Oxygenated blood moves from the heart to the rest of the body. Deoxygenated blood moves from the rest of the body to the heart)
• Arteries


  Move blood away from the heart
• Veins


  Move blood towards the heart
• The pulmonary vein is the only vein that carries oxygenated blood/ the pulmonary artery is the only artery that carries deoxygenated blood
• Types of blood vessels

  • Artery (carries blood away from the heart)
  • Capillary (carries blood to and from the body's cells)
  • Vein (carries blood back into the heart)
• Diffusion


  The passive process by which the body exchanges gases to and from the lungs or the body's cells
• Gas exchange


  1. Oxygenated blood moves from the arteries to arterioles and combine into the capillaries

  2. Deoxygenated blood in the capillaries moves into the venules which then combine at the vein
• Arteries


  • Have thick walls to withstand pressure
• Veins


  • Have thin walls and large lumens and valves to prevent backflow
• Capillaries


  • One cell thick for gas exchange
• Cardiac cycle


  1. Heart filling with blood then pumping this to the rest of the body, from the arterial system

  2. Takes just under one second to complete a heartbeat

  3. Four stages: Diastole (Relaxation), Systole (Contraction), atrial diastole, ventricular diastole, atrial systole, ventricular systole
• Blood pressure


  The pressure of blood on the walls of your arteries as your heart pumps blood around your body
• Dynamic exercise


  Systolic blood pressure increases, but diastolic pressures remain nearly identical
• Static exercise


  Increased both of the diastolic and systolic pressure
• Lifting vs running


  Lifting is more intensive / takes more hard work which increases the systolic pressure whilst running is less intensive / takes less hard work which means lower blood pressure
• Difference between participants


  Diastolic Pressure and the difference in systolic pressure
• Vasoconstriction


  Blood vessels getting smaller / thinner
• Vasodilation


  Vessel is getting larger
• The circulatory system is a closed circuit
• Blood vessels are able to dilate (widen) or constrict (narrow) to redirect flow of oxygenated blood to working muscles
• Whenever blood vessels dilate in one part, they must constrict elsewhere
• As exercise commences, the nervous system causes blood vessels to contract or constrict (vasoconstriction)
• Stroke volume


  Amount of blood pumped out of the left ventricle per beat
• Cardiac output


  Stroke volume x heart rate
• Regular exercises causes changes to the heart including: The heart gets larger, The muscular wall becomes thicker and stronger
• Regular exercise causes the heart to expand and become more muscular (higher stroke volume > higher pressure)
• Blood components


  • Red blood cells (RBCs) - Transport and bond oxygen and CO2
  • White blood cells (WBCs) - To destroy pathogens (basically the immune response)
  • Platelets - For plugging/clotting wounds
  • Plasma - Medium in which components our transported > Made of water, waste products, salts etc