Pulmonary System Flashcards
Define term minute ventilation and describe the changes you would expect to see in minute ventilation during exercise
Is the total volume of air breathed in or out per minute. During exercise minute ventilation would increase as the O2 demand increase as working muscles require more inorder to effectively function
Explain 3 ways that smoking as a lifestyle choice can have a negative impact on the respiratory system
- Cigarette smoke damages the cells lining the trachea, bronchi and bronchioles, which have cilia that help to push mucus out the lungs, damage=excess build up of mucus which blocks airways (smokers cough)
- Damage alveoli as breaks down walls and join together forming larger air spaces than usual = reduced efficiency or gas exchange and increases risk of COPD
- Affects o2 transport as carbon monoxide combines with hb in rbc more readily than o2 reducing o2 carrying capacity of blood increasing breathlessness during exercise
Vital capacity
The air breathed in and out in one breath and includes tidal vol, irv, erv combined
Total lung capacity
The max vol of gas in lungs after max inhalation
Tidal vol
The volume of air inhaled or exhaled in one breath
Inspiratory reserve vol
The max amount of additional air inhaled after tidal vol
Expiratory reserve vol
The amount of air exhaled after tidal vol
Residual vol
The vol of air left in the lungs after maximal expiration
What changes would the lung volumes undergo during exercise
- tidal vol — increase as breathing becomes active rather than passive due to increased demand of o2
- erv + irv — decrease as breathing rate increases so lungs don’t get chance to fully fill up or empty
- residual vol — stays the same
What is minute ventilation
Vol of air breathed in or out per minute (l/m3)
Equation for minute vol
Tidal vol x respiratory rate
What changes occur in minute ventilation during different types of exercise
- Higher during heavy exercise than light as more demanding so breathing increases to meet the extra o2 demand
- low intensity exercise = will steady out after increase due to o2 demands being met
Benefits of increased minute ventilation for endurance
- increased o2 to working muscles and co2 removed —> decreased lactic acid production—> less muscle inhibition + fatigue —> run faster for longer, recovery quicker as don’t have to remove lactic acid
- increased aerobic resp rather than anaerobic—> use fat instead of carbs so can use carbs for anaerobic and can push harder and faster, decreased lactic acid production —> movement more coordinated
Partial pressure
The pressure exerted by an individual gas when it exists within a mixture of gases
Conc./diffusion gradient
Explains how gas flow from an area of high conc. to and area of low conc. - the steeper the the gradient the faster diffusion
Gas exchange at alveoli
Partial pressure of o2 is higher in alveoli than in capillary blood vessels (as o2 has been removed by working muscles) so o2 will diffuse from alveoli into the blood (reverse for co2)
Gas exchange in muscles
Partial pressure of o2 in the tissues is lower than the partial pressure in the blood so o2 will diffuse from blood to tissues (movement in reverse foe co2)
Mechanics of inhalation during exercise
Pectorals, sternocleidomastoid and intercostals contract pulling ribcage up and out (diaphragm contracts - flattens). Increasing the size of thoracic cavity, decreasing pressure inside lungs causing air to rush in
How is co2 transported in the blood
Binds to haemoglobin (carbiminohaemoglobin) or dissolved in the blood in plasma
Describe how processes of inspiration and expiration differ at rest and during exercise
- at rest inspiration is an active process (requires contraction of muscles), whereas expiration is a passive process (intercostals relax)
- during exercise pectorals and stern. contract to force ribcage up and out further
- during exercise expiration becomes active and abdominals contract
Structural feature of respiratory system
- Large surface area - increase rate of diffusion
- Thin cell walls - short diffusion path
- High capillary density - increased opportunity for diffusion
- Narrow lumen of capillary - flatten haemoglobin so increase s.a + allows for slower rate of blood flow so more time for gas exchange
Explain changes that would occur at both the alveoli and working muscles during a period of exercise
Increased use of o2 in the muscle cell so less in the blood that returns to the alveoli. Increase in partial pressure of co2 in working muscles so diff gradient increases increasing rate of diff of co2 into blood going back to lungs so more co2 is breathed out. Decrease of partial pressure of o2 in blood so rapid diffusion of o2 into blood occurs to saturate hb
Explain how rage and depth of respiration is controlled during exercise
During exercise the chemoreceptors detect an increase in co2 in the blood, Baroreceptors detect an increase in pressure, Proprioreceptors detect an increase in muscle movement and inform the inspiratory control centre. This informs the respiratory control centre that stimulates the phrenic nerve causing additional muscles to contract (scalenes, pectorals, stern) + diaphragm + external intercostals causing a pressure change in lungs so more air is drawn in. Stretch receptors detect full inflation of lungs and inform expiratory control centre which stimulates, via respiratory control centre, intercostal nerve causing all inspiratory muscles to relax + internal intercostals + abs to contract so air is exhaled
