Respiratory Flashcards
Mechanics of breathing for inspiration at rest
Diaphragm actively contracts and flattens and External intercostal muscles actively contract
Which moves the ribcage and sternum upwards and outwards
Thoracic Cavity Volume increases
Lung air pressure decreases below atmospheric air (outside)
Air rushes into lungs
Mechanics of breathing for expiration at rest
Diaphragm passively relaxes and is pushed upwards and external intercostal muscles passively relax
Which moves ribcage and sternum downwards and inwards
Thoracic cavity volume decreases
Lung air pressure increases above atmospheric air (outside)
Air pushed out of lungs
Mechanics of breathing for inspiration at exercise
Diaphragm actively contracts harder than at rest and flattens with more force and External intercostals actively contract harder than at rest. Sternocleidomastoid contracts, scalenes contract and pectoralis minor actively contract
Which moves the ribcage and sternum upwards and outwards more than at rest
Thoracic Cavity Volume increases more than at rest
Lower air pressure in lungs than at rest
More air rushes into lungs than at rest
Mechanics of breathing for expiration at exercise
Diaphragm relaxes and is pushed upwards with more force and External intercostal muscles actively relax. Internal intercostals actively contract, Rectus abdominis/ obliques actively contract
Which moves ribcage and sternum downwards and inwards more than at rest
Thoracic cavity volume decreases more than at rest
Higher air pressure in lungs than at rest
More air pushed out of lungs than at rest
What is the respiratory control centre
The RCC receives information from sensory nerves to change the rate at which the respiratory muscles contract. It is located in the medulla oblongata.
There are two centres within the RCC
- The inspiratory centre (IC)
- The expiratory centre (EC)
When are the inspiratory and expiratory centre are actioned?
The IC stimulates inspiratory muscles to contract at rest and during exercise
The EC is inactive at rest, but will stimulate additional expiratory muscles to contract during exercise to force air out when expiring.
How are the muscles stimulated at rest and what does this cause
Nerve impulses are generated and stimulate the inspiratory muscles causing them to contract via the…
Intercostal nerve which stimulates the external intercostal muscles
The phrenic nerve which stimulates the diaphragm
This causes the thoracic cavity volume to increase which lowers the lung air pressure which means air will be inspired.
After approximately 2 seconds – stimulation will stop and the inspiratory muscles will relax passively
How are the muscles stimulated during exercise
There is a rising demand for O2 and CO2 removal therefore, breathing rate and depth of breathing must be increased.
Sensory nerves relay the information to the RCC where a response will be initiated by the IC and the EC
What are the 4 sensory nerves and what do they detect
Chemoreceptors detect an increase in CO2/ acidity/ lactic acid or detect a decrease in O2/ pH
Proprioceptors detect an increase in motor activity or movement
Baroreceptors detect and increase in pressure and stretch of lung walls
Thermoreceptors detect an increase in blood temperature
Inspiratory centre
Information is sent to the RCC (located in the medulla oblongata)
This stimulates the IC (inspiratory centre)
Increased stimulation or force of contraction of diaphragm via phrenic nerve
Increased stimulation or force of contraction of external intercostals via the intercostal nerve
Recruitment of stimulation of additional inspiratory muscles e.g. SCM or scalenes or pectoralis minor
Causes rest of mechanics of breathing
Expiratory centre
Expiratory centre is stimulated by baroreceptors
Expiration becomes active
Recruitment of expiratory muscles e.g. internal intercostals/ obliques / rectus abdominis
This causes rest of mchanics of breathing
What are the 2 sites of gaseous exchange
Internal site - Between the muscles and the capillaries (bloodstream)
External site - Between the alveoli and the capillaries (bloodstream)
External site - ppO2
The ppO2 in the alveoli is high and the ppO2 in the capillary blood is low. Oxygen diffuses down the diffusion gradient from the alveoli into the capillary blood
What is the order of neural control
Chemoreceptors, proprioceptors and thermoreceptors inform the IC
To increase stimulation of diaphragm via the phrenic nerve and the external intercostals via the intercostals nerve to contract with more force than at rest
The IC recruits additional inspiratory muscles e.g. scalenes and SCD to contract
Allowing the thoracic cavity to have a greater increase in volume than at rest. This increases the depth of inspiration
External site - ppCO2
The ppCO2 in the capillary blood is high and the ppCO2 in the alveoli is low. The CO2 diffuses down the concentration gradient from capillary blood into the alveoli
Internal site - ppO2
The ppO2 in the capillary bed is high and the ppO2 in the muscle cell is low. The O2 diffuses down the concentration gradient from capillary bed into the muscles
Internal site - ppCO2
The ppCO2 of the capillary bed is low and the ppCO2 of the muscle cells is high. CO2 diffuses down the concentration gradient from the muscles to the capillary
Changes at the External site during exercise
Steeper gradient due to faster diffusion
PPO2 in alveoli = higher
PP02 in capillary blood = lower
PPCO2 in capillary blood = higher
PPCO2 in alveoli = lower
Changes at the Internal site during exercise
PPO2 in capillary blood = higher
PPO2 in muscle cells = lower
PPCO2 in muscle cells = higher
PPCO2 in capillary bed = lower
What is the oxygen dissociation curve
Oxygen dissociation curve shows the relationship between dissociation of oxygen within respiratory tissues.
Dissociation is the release of oxygen from haemoglobin for gaseous exchange
Also takes into account the pp02 against how saturated the haemoglobin is.
General overview of shifting dissociation curve
The oxygen dissociation curve can be shifted right or left by a variety of factors. A right shift indicated decreased oxygen affinity of haemoglobin allowing more oxygen to be available to the tissues. A left shift indicates increased oxygen affinity of haemoglobin allowing less oxygen to be available to the tissues.
What are the factors affecting the oxygen dissociation curve
pH
CO2
Temperature
Organic Phosphates
O2
How does pH affect oxygen dissociation curve
Decrease in pH shifts the curve to the right while an increase in pH shifts the curve to the left.
This occurs because a higher hydrogen ion concentration causes alteration in amino acid residues that stabilises deoxyhaemoglobin in the T state that has a lower affinity for oxygen. Rightward shift referred to as Bohr effect
How does CO2 affect oxygen dissociation curve
Decrease in CO2 shifts curve to left whilst an increase in CO2 shifts curve to the right.
Accumulation of CO2 causes carbamino compounds to be generated which bind to oxygen and form carbaminohaemoglobin which stabilises deoxyhaemoglobin in the T state
Accumulation of CO2 causes increase H+ ions concentrations and decrease in pH will shift curve right
How does temperature affect oxygen dissociation curve
Increased temperature shifts the curve to the right whilst a decrease in temperature shifts curve to left. Increasing the temperature denatures the bond between oxygen and haemoglobin increasing the amount of oxygen and haemoglobin decreasing the concentration of oxyhaemoglobin.
Temp doesn’t have a dramatic effect but is noticeable in cases of hyper and hypothermia
How does organic phosphates affect oxygen dissociation curve
An increase in 2,3-DPG shifts curve to the right wholst decrease leads to left shift. 2,3-DPG binds to haemoglobin an rearranges into the T state decreasing its affinity for oxygen
How does O2 affect oxygen dissociation curve
Increase oxygen = right shift
Decrease oxygen = left shift
Define breathing rate and what are the trained and untrained values at rest
The number of inspirations or expirations taken in 1 minute
Trained - 11-12 breaths per minute
Untrained - 12 - 15 breaths per minute
Define tidal volume and what are the trained and untrained values at rest
Volume of air inspired or expired per breath
Trained - 500ml
Untrained - 500ml
Define minute ventilation and what are the trained and untrained values at rest
Volume of air inspired or expired per minute
Trained - 5.5-6L/min
Untrained - 6-7.5L/min
What is a respiratory adaptation to aerobic exercise
Adaptation – stronger respiratory muscles
Impact - this will lead to a higher TV during exercise
Breathing rate and tidal volume in response to increasing exercise intensity
Breathing rate: Increases in proportion to exercise intensity up to
max 50-60 breaths/min
Tidal volume: Increases in proportion to exercise intensity up to
max 3 litres
Breathing rate during sustained sub maximal exercise
Breathing rate (f) – during sub-maximal, steady state exercise, breathing rate can plateau due to the supply of oxygen meeting the demand from the working muscles
Tidal volume during sustained sub maximal exercise
Tidal volume (TV) – reaches a plateau during sub-maximal intensity because increased breathing rate towards maximal intensities does not allows enough time and requires too much muscular effort for maximal inspirations or expirations
Minute ventilation graph during sub maximal exercise
1.An initial anticipatory rise in VE due to the release of the hormone adrenaline.
2.A rapid increase in VE at the start of exercise due to increased breathing rate and tidal volume to meet the demand for oxygen, increase oxygen delivery and waste removal in line with exercise intensity
3.A plateau in VE where oxygen demands are met due to the steady state exercise
4.An initially rapid decrease as the demand for oxygen has been significantly reduced
5.A more gradual decrease in VE as VE returns to resting levels – recovery is entered (active cool down should be followed)
Minute ventilation graph during maximal exercise
- Still have an anticipatory rise
- Still have a sharp rise due to sudden demand
- The graph will not plateau – instead it will have a steady increase to try and meet the demand
- There will still be a rapid decline in minute ventilation (demand for o2 significantly reduced)
- Longer and lower decline as the body enters recovery and tries to repay the oxygen debt
Breathing rate trained and untrained maximal values
Trained - 50-60 breaths per minute
Untrained - 40-50 breaths per minute
Tidal volume trained and untrained maximal values
Trained - 3-3.5L
Untrained - 2.5-3L
Minute ventilation trained and untrained maximal values
Trained - 160-210L/min
Untrained - 100-150L/min
How can asthma impact an endurance performer
Less oxygen is supplied to the working muscles
Reduced intensity and duration of performance
Early onset of fatigue
Tidal volume is reduced
Reduced efficiency of gaseous exchange (internal/external) – which means increased levels of lactic acid
Recovery takes longer
Structural changes to the respiratory system from regular involvement in endurance activities
Increased size and efficiency of alveoli and increased surface area
for diffusion
Increased capillary density and increased diffusion & greater
saturation of Hb with O2
Mechanical changes to the respiratory system from regular involvement in endurance activities
Increased strength of respiratory muscles e.g. diaphragm/ scalenes/ SCM causing increased TV
Increased efficiency of the respiratory muscles so less oxygen required for the respiratory muscles/ less chance of fatigue
Effects from regular involvement in endurance activities of F, TV and VE how will these change at different intensities
Increased breathing rate during maximal exercise/ sub-maximal exercise
Increased minute ventilation at maximal intensities
Increased TV during sub-maximal/maximal intensities
Increased VO2 Max
Can use the aerobic system at higher intensities/ for longer periods of time/ with a delayed onset of fatigue
Reduced effort at sub-maximal work loads
How does asthma affect airways and name some triggers
Asthma causes the airways to constrict and causes inflammation and more mucus is secreted
Exercise, Allergens e.g. dust/ pollen, The cold weather, Smoke, Stress
Methods available to control asthma
Inhalers
Warm-up
IMT (inspiratory muscle training)
Diet
Overall impact of training on the respiratory system
Regular training can;
Increase the strength of respiratory muscles (decreases respiratory effort and alleviates the symptoms of asthma)
Decreases resting and sub-maximal frequency of breathing (reducing the onset of fatigue and making everyday tasks easier)
Maintain full use of lung tissue and elasticity (decreasing the risk of infection associated with COPD)
Increase the surface area of alveoli and pulmonary capillaries (maximising the efficiency of gaseous exchange and the health of respiratory membranes)
