The respiratory system Flashcards
Oxygen is transported in what 2 ways:
1) Haemoglobin = oxygen binds with haemoglobin to from oxyhaemoglobin this accounts for (97%) of oxygen.
2) the other 3% is transported through blood plasma
Carbon Dioxide is transported in what 3 ways:
1) Carbonic Acid = 70% is dissolved in water and carried as carbonic acid
2) Carbaminohaemoglobin = 23% binds with haemoglobin
3) 7% is dissolved in the blood plasma
Define breathing rate (f)
the number of breaths taken per minute. resting is between 12-15 breaths
Define tidal volume (TV)
the amount of air inhaled on exhaled per breaths. resting TV is around 500ml
Define minute ventilation (VE)
the amount of air inhaled or exhaled per minute
Define vital capacity
Maximum amount of air exhaled following a maximum inhalation.
VE = TV x f (litres per min)
how does tidal volume change in response to exercise?
1) TV increases in proportion to exercise intensity
2) TV plateaus at sub-maximal intensity as demand is met.
how does breathing rate change in response to exercise?
1) Breathing rate increases in proportion to exercise intensity.
2) Breathing rate increases to about 40-50 breaths per min for untrained and 50-60 breaths per min for trained.
3) Breathing rate can plateau once demand is met in sub-maximal work.
how does minute ventilation change in response to exercise?
1) VE increases in line with exercise intensity
2) During sub-maximal work VE can plateau
3) Plateau represents oxygen demand and waste removal being met
4) During maximal intensity VE does not plateau as intensity continues to increase
5) TV will reach its capacity but breathing frequency will continue to increase
What happens to inspiration at rest ?
ACTIVE PROCESS
1) External intercostal muscles contract & internal intercostals relax which pulls the ribs up and out
2) Diaphragm contracts –> it flattens
EFFECTS:
Increased size of thoracic cavity , decrease in pressure, higher atmospheric pressure forces air into lungs
What happens to inspiration during exercise ?
ACTIVE PROCESS - more muscles recruited
1) sternocleidomastioid –> contracts to lift sternum
2) pectoralis minor –> contracts to lift ribs MORE
3) external intercostals contract with MORE force, internal intercostals relax –> ribs move up and out more
4) Diaphragm contracts with MORE force
EFFECTS:
volume of the thoracic cavity increases, pressure decreases more, larger conc. gradient meaning air enters lungs quicker
what happens to expiration at rest ?
PASSIVE PROCESS
1) external intercostals relax –> ribs move in and down
2) diaphragm relaxes
EFFECTS:
decrease of thoracic cavity, pressure increases, air is forced out of lungs
what happens to expiration during exercise ?
ACTIVE PROCESS - change from passive to active due to increase depth
1) external intercostals relax
2) internal intercostals contract –> ribs move in and down
3) diaphragm relaxes
4) rectus abdominus contracts –> pushes diaphragm up
EFFECTS:
muscles are recruited to reduce thoracic cavity more, increase pressure and conc. gradient
What controls breathing?
The respiratory control centre (RCC) which is located in the Medulla Oblongata. The RCC has 2 areas :
1) Inspiratory Centre – active at rest and stimulates muscles to contract when we breathe in
2) Expiratory Centre – active during exercise only
what are the main receptors in the Inspiration Centre?
Receives information and initiates recruitment of additional muscles to increase depth of inspiration
1) chemoreceptors
2) thermoreceptors
3) proprioceptors
