Cardio-respiratory

• pathway of air

  nose/mouth --> trachea --> bronchus --> bronchioles --> alveoli --> capillaries
• respiratory system

  brings oxygen into the body so it can be used to produce energy and enable activity, then gets rid of carbon dioxide (a waste product) which is produced in the muscles during exercise
• inhalation

  diaphragm contracts: and moves downwards - intercostal muscles contract, raising the ribs and pushing out the sternum - lungs increase in size and pressure inside the lungs is reduced - air pressure outside the body is now higher inside the body, air travels from areas of high concentration to areas of low concentration, so air is pulled into the lungs
• exhalation

  diaphragm relaxes: it moves back into a dome shape - intercostal muscles relax, lowering the ribs and dropping the sternum, making the chest cavity smaller - lungs reduce in size and air pressure inside the lungs is increased - air pressure outside the body is now lower than the air pressure inside the body, air travels from areas of high concentration to areas of low concentration, so air leaves the lungs
• site of gaseous exchange

  alveoli
• gaseous exchange

  oxygen passes through the alveoli and into the red blood cells in the capillaries - in the capillaries, the oxygen combines with haemoglobin (a protein in blood cells) to form oxyhaemoglobin and then carried around the body - at the same time, haemoglobin carries carbon dioxide from the body to the capillaries - the carbon dioxide in the capillaries passes through the alveoli and is breathed out
• oxygen and carbon dioxide concentration in the alveoli

  high oxygen concentration, low carbon dioxide concentration
• oxygen and carbon dioxide concentration in the capillaries

  low oxygen concentration, high carbon dioxide concentration
• spirometer

  a piece of equipment that measures the air capacity of the human lungs
• tidal volume

  the normal amount of air inhaled or exhaled per breath
• expiratory reserve volume

  the amount of air that can be forced out after tidal volume.
• inspiratory reserve volume

  the amount of air that can be forced in after tidal volume.
• residual volume

  the amount of air that remains in the lungs after maximal expiration
• vital capacity

  the largest volume of air that can be forcibly expired after the deepest possible inspiration
• components of the cardiovascular system

  blood, heart, blood vessels
• Arteries

  • Carry blood away from the heart
  • Pulse as blood moves through them
  • Have thick muscular walls
  • Blood pressure is high
  • Carry oxygenated blood
  • Proportionately small internal diameter
  • Can vasodilate and vasoconstrict
• Pulmonary artery

  Carries deoxygenated blood to the lungs to become oxygenated
• Veins

  • Carry deoxygenated blood
  • Carry blood back to the heart
  • Have valves which open due to the pressure of the blood and close to prevent backflow
  • Blood pressure is at its lowest
  • Large internal diameter
• Pulmonary vein

  Carries oxygenated blood from the lungs back to the heart
• Capillaries

  • Run across the alveoli
  • Gases can diffuse though the walls
  • Blood becomes oxygenated
  • Carbon dioxide diffuses into the air in the lungs
  • Very thin walls (one cell thick)
  • Microscopic
• Heart beat

  One contraction and one relaxion of the heart
• Average resting heartrate of an adult is 72 bpm
• Why heartrate increases during exercise

  The heart is working to supply more oxygen to the working muscles and therefore must work harder
• Pathway of blood

  Vena cava --> right atrium --> valve --> right ventricle --> pulmonary artery --> lungs --> pulmonary vein --> left atrium --> valve --> left ventricle --> aorta --> body
• Cardiac cycle

  One cycle of diastole and systole
• Diastole

  The chambers of the heart relax and fill with blood
• Systole

  The chambers of the heart contract and blood is ejected from the heart (emptied)
• Readings taken when measuring blood pressure

  • Systolic pressure
  • Diastolic pressure
• Systolic pressure

  The pressure that the blood is under when contracting and ejecting the blood from the heart
• Diastolic pressure

  The pressure that the blood is under when the heart relaxes and fills with blood
• High amount of blood to organs

  Rest
• High amount of blood to muscles

  Exercise
• Vasoconstriction

  The narrowing of the internal diameter of a blood vessel to decrease blood flow
• Vasodilation

  The widening of the internal diameter of a blood vessel to increase blood flow
• Cardiac output equation

  Cardiac output (Q) = stroke volume (SV) x heartrate (HR)
• Effect on cardiac output during exercise

  Increases
• Anticipatory rise

  Caused by adrenaline and the warm up
• Maximal exercise

  High intensity
• Sub-maximal exercise

  Moderate (less intense) exercise
• Heart rate

  The number of times the heart beats per minute - measured in beats per minute (bpm)