Cardiorespiratory - AOS 2

• Functions of the Cardiovascular System

  • Circulation of blood around all parts of the body
  • Transportation of oxygen, water and nutrients to the cells
  • Transportation of waste (e.g. carbon dioxide) away from the cells
  • Immunity (helps fight diseases through white blood cells)
  • Thermoregulation (maintenance of body temperature)
• Heart


  • A pump designed to circulate blood throughout the cardiovascular system
  • A muscle that has its own blood supply and needs oxygen and fuel to function
• Atrium


  • Upper chambers that receive blood from the veins and pump it into the lower chambers
• Ventricle


  • The lower chambers that receive blood from the atria and that pump blood to the lungs (RV) and to the body
• Heart function


  1. Continual contraction and relaxation of the atria and ventricles

  2. Heart contraction (systole) - forces blood out of the heart, via the ventricles and the arteries

  3. Heart relaxation (diastole) - the blood fills up with blood from the veins

  4. While the atria contract, the ventricles relax and vice versa
• Cardiac Cycle


  1. Heart filling up with blood

  2. Pumping blood to the rest of the body via the atrial system

  3. 4 stages: Atrial diastole, Ventricular diastole, Atrial Systole, Ventricular systole
• Heart Valves


  • 1 way valves that ensure blood flows in the right direction through the heart
  • Open when the atria contracts, close when the ventricles contract to prevent backflow
• Types of Blood Vessels


  • Arteries
  • Veins
  • Capillaries
• Arteries


  • Carry blood away from the heart
  • Large blood vessels with thick, strong, elastic walls
• Veins


  • Carry blood back towards the heart
  • Thinner walls with less smooth structure
• Capillaries


  • Sites of gaseous exchange, link the arteries to the veins
  • Microscopic, thin walled vessels
• Arteries carry oxygenated blood (except for pulmonary artery)
• Veins carry deoxygenated blood (except pulmonary vein)
• Capillaries carry both oxygenated and deoxygenated blood
• Arteries have valves, veins and capillaries do not
• Acute responses


  Those which happen immediately as a result of exercise or physical activity
• Commencement of Exercise


  1. Body makes physical changes to accommodate requirements of the activity

  2. Increased demand for oxygen and energy substances

  3. Cardiovascular, respiratory, and muscular systems respond

  4. These are called acute responses

  5. Level of response is dependent on the intensity, duration, and type of exercise being undertaken
• Cardiac


  Refers to the heart
• Vascular


  Refers to the blood and blood vessels
• Cardiac


  • Answers should be about HR, SV, Cardiac output
• Vascular


  • Answers should be about blood volume, blood flow, venous returns etc.
• Increased Heart Rate


  • Number of contractions of the heart within a minute
  • Measured in beats per minute (bpm)
  • Each beat pumps oxygenated blood around the body. When the beats per minute increases, there are more contractions leading to more oxygenated blood being delivered/transported to the muscles
  • Sometimes you may experience an increase in heart rate before you exercise because your body is preparing itself. This is called anticipatory rise
• Increased Stroke Volume


  • Stroke volume is a measure of the amount of blood ejected from the left ventricle of the heart in 1 contraction
  • Measured in ml per beat
  • An increase in stroke volume means that more blood is being delivered/transported during each contraction, resulting in more blood reaching the muscles
• Increased Cardiac Output (Q)


  • Total amount of blood ejected from the left ventricle each minute
  • Calculated by multiplying heart rate and stroke volume
  • Q = HR X SV
  • Measured in Liters per minute
  • The higher the cardiac output, the more blood being delivered to the muscles to be used for aerobic energy production
• Increased av02 Difference


  • av02 Difference is the measure of the difference of oxygen concentration in the arterial blood and venous return
  • Measured in ml of oxygen per 100ml of blood
  • The more oxygen in the blood that is delivered to the muscle allows for more energy production
  • For example, if the blood delivers 20ml of oxygen per 100ml of blood to the muscle via the arteries and 5ml is delivered back to the heart via the veins, the av02 difference is 15ml
• Increased Venous Return


  • The amount of blood that is returned to the heart via the veins to the right atrium
  • Measured in Liters per minute
  • Delivers blood back to the heart so that it can be re-oxygenated and the waste products can be removed
  • Shunting is used to return the blood back to the heart
• Increased Blood Pressure

  • The pressure exerted by the blood against the walls of the arteries when the heart contracts and relaxes
  • Measured in mmHg (millimeters of mercury)
  • Split into 2 phases → Systolic and Diastolic

  1. Systolic - is the pressure on the artery walls during the contraction phase.

  2. Diastolic - is the pressure on the artery wall during the relaxation phase
• Redistribution of Blood Flow


  • Redirection of blood flow away from the major organs and towards working muscles
  • Measured in % (percentage)
  • The more blood redirected to working muscles, the more energy can be produced
  • Can be achieved through the mechanisms of vasodilation and vasoconstriction
  • Vasodilation - involves the blood vessels expanding to let more blood into the working muscles
  • Vasoconstriction - involves the blood vessels constricting to allow less blood to be pumped into the vital organs
• Blood


  The fluid circulated by the heart around the body
• Blood Composition


  • 45% blood cells
  • 55% plasma
• Blood cells


  • 99% red blood cells
  • 1% white blood cells and platelets
• Plasma composition


  • 90% water
  • 7% proteins
  • 3% other
• Red Blood Cells


  • Carry oxygen to body tissue and muscles
  • Carry carbon dioxide away from the cells and muscles
  • Contains Hemoglobin → gives blood its color and is produced in bone marrow
  • Life span of approximately 4 months
• White Blood Cells


  • Fight infection, can pass through capillary walls into the body cells to fight a disease
  • Comes in a variety of shapes and sizes, larger than red blood cells
  • Produced in bone marrow, lymph tissue, and spleen
  • Approximate lifespan is a few days
• Platelets


  • Help form blood clots to stop bleeding
  • Produced in bone marrow, smaller than red blood cells
• Plasma


  • Carries nutrients (proteins, salts and glucose)
  • Clear yellowish fluid - 90% water
  • Transports waste products and assists with their removal from body
• The respiratory system allows for the body to breathe, bringing oxygen into the body and removing carbon dioxide
• Respiratory Functions


  1. Brings air from the atmosphere into the lungs

  2. Transfers oxygen into the blood

  3. Removes carbon dioxide from the blood

  4. Expels heat and water vapor in air breathed out

  5. Allows the vocal cords to create speech as air is breathed out
• Respiratory system


  Made of the mouth, nose, airways, and lungs
• Most of the respiratory system is encased and protected by the ribs, sternum, and vertebrae