Respiratory

Cards (28)

  • Breathing rate is the number of inspirations or expirations per minute. Calculated using a spirometer.
    Tidal volume is the volume of air inspired or expired per breath. Calculated using a spirometer.
    Minute ventilation is the volume of air inspired or expired per minute. Calculated using TV*F
  • Breathing frequency
    Rest:
    Untrained - 15br/min
    Trained - 12br/min
    Submaximal:
    Untrained - Can plateau due to supply of oxygen.
    Trained - Can plateau due to supply of oxygen.
    Maximal:
    Untrained - 40br/min
    Trained - 50 br/min
  • Tidal volume
    Rest:
    Untrained - 0.5L
    Trained - 0.5L
    Submaximal:
    Untrained - 3L
    Trained - 3L
    Maximal:
    Untrained - 2.5-3L
    Trained - 2.5-3L
  • Minute ventilation
    Rest:
    Untrained - 7.5L/min
    Trained - 6L/min
    Submaximal:
    Untrained - 70L/min
    Trained - 70L/min
    Maximal:
    Untrained - 100-140L/min
    Trained - 150-210L/min
  • The resting minute ventilation of an aerobic athlete is lower than an untrained athlete because gas exchange of a trained athlete at their alveoli is more efficient causing an increased oxyhaemoglobin saturation, oxygen might be transported more efficiently due to an increased number of red blood cells that are needed to meet the demands of oxygen more efficiently.
  • Breathing rate responds to exercise by increasing from 12br/min as exercise intensity increases, during submaximal exercise BR can plateau as oxygen supply equals oxygen demand.
  • Tidal volume responds to submaximal exercise by increasing as exercise intensity increases from 0.5L before it possibly plateaus, during maximal exercise TV is 3L but can decrease due to high breathing rate.
  • Minute ventilation response to submaximal exercise, when exercise starts an anticipatory rise raises VE due to excitement, during exercise there is a rapid rise to 70L/min then plateau as oxygen supply meets oxygen demand, during recovery there is a rapid decline then a much slower decrease to resting values.
    Minute ventilation response to maximal exercise, when exercise starts an anticipatory rise raises VE due to excitement/nerves, during exercise there is a rapid rise to 160L/min (lower in untrained), during recovery there is a rapid decline then a much slower decrease to resting values.
  • Mechanics of breathing for inspiration at rest
    1. Diaphragm and external intercostals contract
    2. Diaphragm flattens
    3. Ribs lift up and out
    4. Thoracic cavity volume increases
    5. Lung air pressure decreases
    6. Air sucked into lungs
  • Mechanics of breathing for inspiration during exercise
    1. Diaphragm and external intercostals contract more forcefully
    2. Additional muscles contract including scalenes/pectoralis minor/sternocleidomastoid
    3. Diaphragm flattens with more force
    4. Ribs lift up and out with more force
    5. Thoracic cavity volume increases more than at rest
    6. Lung air pressure decreases more
    7. More air sucked into lungs
  • Mechanics of breathing for expiration at rest
    1. Diaphragm and external intercostals relax
    2. Diaphragm domes
    3. Ribs move down and in
    4. Thoracic cavity volume decreases
    5. Lung air pressure increases
    6. Air pushed out
  • Mechanics of breathing for expiration during exercise
    1. Diaphragm and external intercostals relax
    2. Additional muscles contract including rectus abdominals/internal intercostals
    3. Diaphragm domes with more force
    4. Ribs move down and in more than at rest
    5. Thoracic cavity volume decreases more than at rest
    6. Lung air pressure increases more
    7. More air forced out faster
  • Inspiratory centre controls:
    Inspiration at rest - external intercostals are stimulated by the intercostal nerve and the diaphragm is stimulated by the phrenic nerve.
    Expiration at rest - stops the stimulation down the phrenic and intercostal nerves so the diaphragm and external intercostals relax.
    Inspiration during exercise - external intercostals are stimulated more by the intercostal nerve, the diaphragm is stimulated more by the phrenic nerve (the stronger impulses provide stronger contraction) and it stimulates additional muscles.
  • Expiratory centre controls:
    Inactive at rest and during exercise it controls expiration by stimulating internal intercostals and rectus abdominus to contract.
  • Neural control of inspiration at rest
    1. IC tells the intercostal nerve to stimulate the external intercostals causing them to contract pulling the rib cage up and out
    2. IC tells the phrenic nerve to stimulate the diaphragm which flattens
  • Neural control of expiration at rest
    1. EC is inactive
    2. After 2 seconds the IC stops the stimulation down the phrenic and intercostal nerve
    3. Expiration is passive due to natural recoil of diaphragm and external intercostals
  • Neural control of inspiration during exercise
    1. Chemoreceptors detect an increase in carbon dioxide and an increase in oxygen
    2. Proprioceptors detect increased movement
    3. Thermoreceptors detect an increased blood temperature
    4. This increases stimulation of the phrenic nerve to the diaphragm and the intercostal nerve to the external intercostals
    5. Additional inspiratory muscles are stimulated which increases force of contraction and depth of breathing
  • Neural control of expiration during exercise
    1. Baroreceptors detect an increase in lung inflation and stimulate the EC due to the need for active forced expiration
    2. Internal intercostals and recuts abdominus are stimulated to contract causing forced expiration during exercise
    3. Known as Hering-Breuer reflex which prevents the lungs from overinflating
  • Structures that aid gas exchange:
    Millions of alveoli give a vast surface area, increases amount of gas exchanged.
    Dense capillary network around alveoli, allows a greater uptake of oxygen.
    Alveoli and capillary walls are 1 cell thick, making a short path for diffusion.
    Moist lining, quick diffusion as gases can dissolve.
    Lung walls are elastic, a greater volume of air can be inspired.
    Pleural membranes, create friction free movement.
    Muscle tissue is thin, making a short path for diffusion.
  • Gas exchange

    Oxygen is transported in haemoglobin and plasma, carbon dioxide is transported in haemoglobin, plasma and carbonic acid
  • Internal respiration
    1. Exchange of oxygen and carbon dioxide between blood and muscle cells
    2. Gases move from high to low partial pressure
    3. At rest, high pp of oxygen in blood, low pp of oxygen in muscle cells, oxygen diffuses into muscles
    4. At rest, high pp of carbon dioxide in muscle cells, low pp of carbon dioxide in blood, carbon dioxide diffuses into bloodstream
    5. During exercise, high pp of oxygen in blood, lower pp of oxygen in muscle cells, oxygen diffuses into muscles down steeper gradient
    6. During exercise, higher pp of carbon dioxide in muscle cells, low pp of carbon dioxide in blood, carbon dioxide diffuses into bloodstream down steeper gradient
  • External respiration

    1. Exchange of oxygen and carbon dioxide between blood and lungs
    2. Gases move from high to low partial pressure
    3. At rest, high pp of oxygen in alveoli, low pp of oxygen in blood, oxygen diffuses into bloodstream
    4. At rest, high pp of carbon dioxide in blood, low pp of carbon dioxide in alveoli, carbon dioxide diffuses into alveoli
    5. During exercise, high pp of oxygen in alveoli, lower pp of oxygen in blood, more oxygen diffuses into bloodstream faster down steeper gradient
    6. During exercise, higher pp of carbon dioxide in blood, low pp of carbon dioxide in alveoli, more carbon dioxide diffuses into alveoli faster down steeper gradient
  • Changes in pressure gradient:
    During exercise working muscles have a greater demand for oxygen for respiration, when exercising the pp of oxygen in the muscles is lower than at rest as more has been used in aerobic respiration, pp of oxygen in the capillary blood is high creating a steeper diffusion gradient and causing more oxygen to diffuse from the blood into the muscles faster than at rest. Diffusion gradient increases if there is an increase in muscle acidity, temperature and production of carbon dioxide.
  • Haemoglobin (Hb)
    A protein able to carry 4 oxygen molecules
  • Dissociation of oxygen from haemoglobin
    1. Hb readily associates with oxygen when the partial pressure of oxygen is high in order to form fully saturated oxyhaemoglobin
    2. The more oxygen, the more it will attach
    3. The more carbon dioxide, the more Hb will give up oxygen
  • During exercise
    The oxyhaemoglobin dissociation curve shifts to the right, known as the Bohr shift
  • Partial pressure of oxygen decreases in the muscle

    More oxygen is released to respiring muscles causing more oxygen to dissociate
  • Muscle tissue increases in
    • Carbon dioxide
    • Temperature
    • Lactic acid
    • Carbonic acid