Respiratory System

• Functions of the Respiratory System 


  Getting air in and out of the lungs

  Gaseous exchange between the blood and lungs

  Transport gases

  Enable cellular respiration
• Pathway of Air 


  Nose

  Larynx

  Trachea

  Bronchi

  Bronchioles

  Alveoli
• Diffusion


  The movement of gas molecules from an area of high concentration to low concentration
• Gaseous Exchange 


  The movement of oxygen from the air into the blood

  Returns carbon dioxide into the air
• Mechanics of Breathing (IN)

  Intercostals and Pectorals contract which moves the ribcage up and out

  Diaphragm contracts and flattens
• Mechanics of Breathing (OUT)

  Intercostals and Pectorals relax and fall back into shape

  Diaphragm relaxes and pushes upwards
• Inspirational Reserve Volume 


  The volume of air forcibly expired after one breath

  Average = 3 litres

  Decrease during exercise
• Expiratory Reserve Volume 


  The volume of air that can be forcibly expired in one breath

  Average = 1.3 litres

  Small decrease during exercise
• Residual Volume 


  The volume of air that remains in the lungs after forced maximum expiration

  Average = 1.2 litres

  No change during exercise
• Minute Ventilation 


  Volume of air breathed in or out per minute

  Average = 6 litres

  Big increase during exercise

  Minute Ventilation = Tidal Volume + Breathing Rate
• Tidal Volume 


  Volume of air breathed in or out per breath

  Average = 0.5 litres

  Increase during exercise
• Spirometer


  Measures the amount of air you can breathe out in one second and the total volume of air you can exhale in one forced breath.
• Total Lung Capacity 


  Calculated by adding vital capacity to the residual lung volume

  Vital Capacity + Residual Volume
• Gaseous Exchange at the Alveoli

  Partial pressure of oxygen at the alveoli is higher in the blood

  Oxygen in the blood has been removed by the working muscles
• Gaseous Exchange into the Muscle

  Oxygenated blood arrives at the muscle with a PO2 of 100mmHg compared to 5mmHg in muscles

  Meaning a difference of 95mmHg causes quick diffusion
• Gaseous Exchange out of the Muscle

  Muscles have 46mmHg of Co2 compared to 40mmHg in the blood

  Blood diffuses out of the blood with a difference of 6mmHg
• Respiratory Control


  Neural Control

  Chemical Control

  Hormonal Control
• Control of Ventilation 


  Nervous system increases and decreases rate and depth of breathing

  The SNS prepares body for exercise by increasing the breathing rate

  The PNS returns body to rest by lowering breathing rate
• The Respiratory Centre 


  Located at the medulla oblongata

  Controls depth and rate of breathing
• Parasympathetic Nervous System 


  Reduces breathing rate and return the breath to pre-exercise levels
• Sympathetic Nervous System 


  Increases breathing rate and prepares the body for the demands of exercise
• Inspiratory Centre

  Baroreceptors - Detect decrease in blood pressure

  Chemoreceptors - Detect an increase in blood acidity

  Proprioceptor - Detect an increase in muscle movement
• Expiratory Centre 


  Stretch Receptors - Prevent over inflation of the lungs by sending impulses
• Impact of a Sedentary Lifestyle 


  A lifestyle with little or irregular physical activity

  Causes strain and damage to the respiratory system
• The Effects of Smoking

  Causes irritation of the trachea and the bronchi

  Reduces lung function and narrows the path for gasses

  Damages cell lining

  Damages cilia and causes a buildup of mucus
• COPD 


  Chronic Obstructive Pulmonary Disease

  A poor efficiency in gas exchange and lack of oxygen around the body