Structure and functions of the cardio-respiratory system

Nota:

• Transport - transports oxygen from the lungs to the working muscles during excercise to allow them to work aerobically.

1. Transport - transports oxygen from the lungs to the working muscles during excercise = work aerobically. Carbon dioxide is transported from the muscles to the lungs where through diffusion is exhaled = stops build up of lactic acid = athlete perfom to highest potential.
2. Temperature regulation - in the heat, blood vessels close to the skin's surface enlarge (vasodilation) = more heat to be lost from the blood = the athlete can cool down. Vasoconstriction occurs in the cold to stop athlete from losing heat.
3. Blood clotting - if an athlete gets cut then platelets travel to the edges of the open wound, forming a platelet plug = allows athlete to continue exercising = perform to highest potential.

1. The right-hand side pumps deoxygenated blood around the body.
2. The left-hand side pumps oxygenated blood around the body.
3. Valves
   1. The tricuspid valve is located between the right atrium and right ventricle and opens due to a build up of pressure in the right atrium
   2. The bicuspid valve is located between the left atrium and left ventricle and opens due to a build up of pressure in the left atrium.
   3. The semilunar valves prevent the back flow of blood into the heart.
4. Blood vessels
   1. Aorta
      1. Largest artery in the body.
      2. Carries oxygenated blood from the left ventricle to the body
   2. Vena cava
      1. Largest vein in the body.
      2. Carries deoxygenated blood from the body back to the heart.
   3. Pulmonary artery
      1. Carries deoxygenated blood away from the right ventricle in the heart to the lungs
   4. Pulmonary vein
      1. Carries oxygenated blood from the lungs back to the left atrium in the heart.
5. Structure of the heart
   1. The atria (plural of atrium) is where the blood collects when it enters the heart.
   2. The ventricles pump the blood out of the heart to the lungs or the other parts of the body.
   3. The septum separates the left and right hand sides of the heart.

1. Maximum heart rate = 220-age
2. Any changes to heart rate, stroke volume or cardiac output are determined by the duration and intensity of exercise.
   1. Heart rate increases during exercise = more blood pumped to muscles = more oxygen to muscles = aerobic exercise = athlete performs better.
      1. More waste products can be removed = slower muscles fatigue.
   2. Stroke volume increases during exercise = more blood is pumped out of the heart each time it contracts.
   3. Cardiac output at rest is roughly 5 litres per minute - during exercise it can increase to roughly 30 titles per minute as both the heart rate and stroke volume increases.
3. Cardiac output = stroke volume X heart rate
   1. Heart rate = beats per minute (bpm)
   2. Stroke volume = volume of blood pumped out of the heart with every beat.
   3. Cardiac output = amount of blood pumped from the heart per minute

1. Arteries carry oxygenated blood away from the heart (apart for the pulmonary artery which carries deoxygenated blood to the lungs)
2. Thick elastic wall
   1. Withstand very high pressure from blood flowing out of the heart
3. Small lumen

1. Veins carry deoxygenated blood back to the heart from the body (apart from the pulmonary vein which carries oxygenated blood back to the heart from the lungs)
2. Thin wall
3. Large lumen
4. Valves

1. Single cell wall
   1. Semi-permeable membrane to allow for gaseous exchange.
2. Capillaries allow for diffusion of gases and nutrients into the blood from the body cells

1. Transports oxygen and nutrients to the muscles during exercise.
2. Red blood cells - transport oxygen.
   1. Contain haemoglobin
3. White blood cells - fight infection.
4. Platelets - clot to prevent blood loss.
5. Plasma - the liquid part of blood.

1. Passage of air into the lungs: Air enters the body and is warmed as it travels through the mouth and nose. It then enters the trachea. The trachea divides into two bronchi. One bronchus enters each lung. Each bronchus branches out into smaller tubes called bronchioles. Air travels through these bronchioles. At the end of the bronchioles, the air enters one of the many millions of alveoli where gaseous exchange takes place.
   1. Diffusion is the movement of gas from an area of high concentration to an area of low concentration.
      1. Carbon dioxide moves from the capillary to the alveoli and oxygen moves from the alveoli to the capillary.
         1. Removes carbon dioxide from muscles and stops lactic acid building up so aids performance.
2. Inspiration (breathing in)
   1. The diaphragm contracts and moves downwards = increases size of chest = decreases air pressure in the lungs
   2. 21% oxygen,78% nitrogen, 0.4% carbon dioxide.
3. Expiration (breathing out)
   1. The diaphragm relaxes and moves back into a dome shape = decreases size of chest = increases air pressure in the lungs
   2. 16% oxygen, 78% nitrogen, 4% carbon dioxide.

1. Tidal volume is the amount of air breathed in with each normal breath.
2. Vital capacity is the volume of air breathed in and out during a maximal inspiration and expiration.
3. Residual volume is the amount of air left in the lungs after a maximal out breath.
4. When you exercise you breath deeper first and then more frequently.