Respiratory system
- Created by: Mr Rushton
- Created on: 30-04-19 16:18
Respiratory system - response to exercise
Increased breathing rate - increased rate + depth breathing caused by O2 demand and CO2 increase. anticipatory rise = minor rise. steady state exercise = breathing rate plateaus. maximum intensity - breathing rate increases until it exhaustion.
Increased tidal volume - O2 depletion = increased tidal volume allowing more air to pass to lungs. strenuous exercise = O2 diffusion rate 3x higher. minute ventilation = BRxTV (upto 15 times higher during exercise)
Respiratory system - long term
Increased vital capacity - provides increased / more efficient O2 supply
Increased respiratory muscle strength - intercostal muscles + diaphragm increase strength, allows greater expansion, therefore more air volume breathed in.
Increase O2 + CO2 diffusion rate - greater capillarisation muscles + alveoli allows O2+CO2 to diffuse rapidly (steeper diffusion gradient), can train longer and harder if more O2 available.
Maximal breathing rate increases - enables more air to move in and out of the lungs allowing for more efficient gas exchange
Increased lung capacity - therefore allowing a greater quantity of air to move in and out.
Increased tidal volume - the amount of air breathed in and out per breath
Increased pulmonary ventilation (VĖ) - the amount of air breathed in and out in a minute
Greater capillarisation - enables more blood to flow in and out of the lungs to provide a greater surface area for haemoglobin to bind with the blood
Increased number of alveoli enables more gas exchange to occur
Lung Volume Key terms
Pulmonary Ventilation - total volume of gas / air inspired (breathed in) or expired (breathed out) per minute - Resting volume 6-9 L/min
Residual Volume - Amount of air left in the lungs after fully exhaling - volume = 1 / 1.5 L
Tidal Volume - Volume of air breathed in and out with each breath - volume 0.5L
Inspiratory reserve volume - after normal T.V. amount of extra air that can be inhaled - volume 3L
Vital capacity - volume forced out of lungs after max inhale - volume 4.8L
Total lung volume - lung capacity after maximal inhale - volume 6L
Mechanics of Breathing
Inspiration
- External intercostals contract and internal intercostals relax
- lift the ribs/thoracic cavity up and out
- diaphragm contracts / flattens
- increase the size / decrease the pressure of the thoracic cavity
Expiration
- External intercostals relax and internal intercostals contract
- pull the ribs/thoracic cavity down and in
- diaphragm relaxes / rises
- decrease the size / increase the pressure of the thoracic cavity
DURING EXERCISE - (use) greater force, further, more
Gaseous Exchange
O2 / CO2 /gas moves from high / pp / Partial pressure to low pp / Partial pressure
At Alveoli
- PPO2 (Partial Pressure of Oxygen) / concentration / levels of oxygen in the alveoli is high
- PPO2 (Partial Pressure of Oxygen) concentration / levels of oxygen in the blood is low
- This creates a steeper diffusion gradient / oxygen diffuses quicker
- oxygen moves from the alveoli into the blood
- There is a low ppCO2 in the alveoli
- There is a high ppCO2 in the blood
- Because CO2 produced as by-product of aerobic respiration.
- Causes diffusion gradient
- CO2 diffuses from blood into alveoli and is expired
- Steeper diffusion gradient created during a race so body’s gas exchange becomes more efficient
Altitude
Immediate effects - when training at altitude (above 3000 m)
- Possible altitude sickness, unable to train, limiting improvements to respiratory system
- reduced PPO2, less oxygen available for respiration, leads to hypoxia
- Decreased air pressure causes increase in breath frequency
- PPO2 in air is less, therefore oxygen supply to alveoli is less
- Reduced diffusion gradient of oxygen at alveoli, less oxygen diffuses into blood
- Less oxygen combines with haemoglobin, less oxygen transported in blood
- Reduced diffusion gradient of oxygen at muscle tissue
- Performance at altitude deteriorates, fatigue quicker
Long-term effects
- Increase in EPO levels
- Increased number red blood cells, greater capacity carry oxygen
- Increased concentration gradient oxygen at sea level
- Exercise longer without fatiguing
- Improved recovery times after exercise
Neural Factors
Increased CO2 produced by body from exercise
CO2 dissolved in blood detected by chemoreceptors
these send message to medulla oblongata / respiratory control centre / RCC
responds sending nervous signals to respiratory system to increase tidal volume / depth and breathing rate / frequency
Asthma
Negative
- Exercise induced asthma / asthma attack
- wheezing whilst breathing and coughing
- feeling of tightness in the chest
- inflamed bronchi narrowed airways
- reduction in the amount of air able to get into the lungs.
Positive
- air breathed swimming is warm and moist reducing chance of asthma attack
- exercise strengthens respiratory muscles
- increase in vital capacity reduces effects of asthma.
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