respiratory system

describe the mechanics of breathing and the muscles during inspiration at rest? (active)

D - diaphragm contracts

E - external intercostal muscles contract

R - rib cage moves upwards and outwards

V - volume of the thoracic cavity increases

P - pressure inside the lungs decreases

A - air rushes into lungs from high pressure to low pressure

describe the mechanics of breathing and the muscles during expiration at rest? (passive)

D - diaphragm relaxes

E - external intercostal muscles relax

R - rib cage moves inwards and downwards

V - volume of thoracic cavity decreases

P - pressure of air inside lungs increases

A - air rushes out of lungs from high pressure to low pressure

describe the mechanics of breathing and the muscles during inspiration during exercise?

D - diaphragm contracts with more force

E - external intercostal muscles contract with more force

E - sternocleidomastoid and pectoralis minor contract

R - rib cage moves up and out more

V - volume of thoracic cavity increases more

P - pressure inside lungs decreases more

A - more air rushes into the lungs faster from high pressure to low pressure

describe the mechanics of breathing and the muscles during expiration during exercise?

D - diaphragm relaxes more

E - external intercostal muscles relax more

E - internal intercostal muscles and rectus abdominis contract

R - rib cage moves down and in more

V - volume of thoracic cavity decreases more

P - pressure inside lungs increases more

A - more air rushes out of lungs faster from a high pressure to low pressure.

describe the role of the inspiratory centre at rest?

• the RCC controls the inspiratory centre which stimulates the phrenic nerve and intercostal nerve

  • the phrenic nerve causes the diaphragm to contract and flatten

  • the intercostal nerve causes the external intercostals to contract

• this causes the ribs to move up and out so;

  • the volume of the thoracic cavity increases

  • air pressure inside the lungs decreases

  • and so air rushes into the lungs

• inspiratory muscles relax so;

  • ribs move in and down

  • volume inside thoracic cavity decreases

  • air pressure inside lungs increases

  • and so air rushes out of lungs

describe the role of the expiratory centre and rest and exercise?

• passive at rest but active during exercise

• during exercise it stimulates additional respiratory muscles to contract and cause forced expiration;

  • internal intercostals

  • rectus abdominis

describe chemical control during inspiration

• chemoreceptors detect an increase in CO2 and lactic acid and a decrease in O2 and PH.

• these receptors inform the RCC which controls the inspiratory centre

• the inspiratory centre;

  • D - increases stimulation of phrenic nerve so diaphragm contracts with more force

  • E - increases stimulation of intercostal nerve so external intercostals contract with more force

  • E - stimulates additional muscles to contract - sternocleidomastoid and pectoralis minor

  • R - ribs move up and out more

  • V - increases volume of thoracic cavity more

  • P - decreases pressure inside the lungs more

  • A - more air rushes into the lungs faster from high pressure to low pressure

describe neural control during inspiration.

• thermoreceptors detect an increased body temp

• proprioceptors detect an increased muscle activity

• these inform the RCC which controls the inspiratory centre

  • D - increased stimulation of the phrenic nerve causes the diaphragm to contact with more force

  • E - increased stimulation of the intercostal nerve causes the external intercostal muscles to contract with more force

  • E - stimulates additional muscles to contract - sternocleidomastoid and pectoralis minor

  • R - rib cage moves up and out more

  • V - increases volume of thoracic cavity more

  • P - decreases pressure inside lungs more

  • A - more air rushes into the into the lungs faster from high pressure to low pressure

describe neural control during expiration

• baroreceptors detect an increased stretch on lung walls

• informs the RCC which controls the expiratory centre

  • E - stimulates additional muscles to contract - internal intercostal muscles and rectus abdominis

  • R - ribs move in and down more

  • V - decreases volume of thoracic cavity more

  • P - increases pressure in lungs more than at rest

  • A - more air rushes out of the lungs - increasing the frequency of breathing

definition of breathing frequency?

the number of times you inspire or expire per minute

definition of tidal volume?

the amount of air inspired or expired per breath

define minute ventilation

the amount of air inspired or expired per minute

how do you work out minute ventilation?

minute ventilation = breathing frequency x tidal volume

affect of sub-max exercise of minute ventilation (VE)?

• anticipatory rise in minute ventilation due to adrenaline

• a rapid increase in VE at the start of exercise due to increased breathing rate and tidal volume

• a steady-state VE is reached as O2 supply = demand

• an initial rapid decrease in VE at the start of recovery as demand for O2 decreases

• a more gradual decrease in VE to resting values

affect of maximal exercise on minute ventilation (VE)?

• anticipatory rise in VE due to adrenaline

• a rapid increase in VE at the start of exercise due to an increased breathing rate and tidal volume

• a slower increase in VE, no steady-state reached, as the supply of O2 never meets the demand

• an initial rapid decrease in VE at the start of recovery as demand for O2 decreases

• a more gradual decrease in VE to it’s resting values

explain external gas exchange between alveoli and blood at rest.

G - O2

A - between alveoli and blood

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

P - PPO2 in alveoli high, PPO2 in blood low (blood has just returned from muscles)

D - creates an O2 diffusion gradient

D - O2 diffuses from alveoli into blood

G - CO2

A - between alveoli and blood

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

P - PPCO2 in blood high (blood returned from muscles where CO2 is produced), PPCO2 in alveoli low

D - creates a CO2 diffusion gradient

D - CO2 diffuses from blood into alveoli

explain internal gas exchange between blood and working muscles at rest

G - O2

A - between blood and working muscles

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

P - PPO2 in blood high, PPO2 in working muscles low

D - creates an O2 diffusion gradient

D - O2 diffuses from blood into working muscles

G - CO2

A - between blood and blood

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

P - PPCO2 in blood low PPCO2 in working muscles high

D - creates a CO2 diffusion gradient

D - CO2 diffuses from the working muscles to the blood

explain external gas exchange between blood and alveoli during exercise

G - O2

A - between alveoli and blood

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

EXAGGERATE

P - PPO2 in alveoli is higher, PPO2 in blood is lower

D - creates an O2 diffusion gradient

D - more O2 diffuses from the alveoli into the blood faster

G - CO2

A - between alveoli and blood

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

EXAGGERATE

P - PPCO2 in blood is higher PPCO2 in alveoli is lower

D - creates a CO2 diffusion gradient

D - more CO2 diffuses from the blood into the alveoli faster

explain internal gas exchange between blood and working muscles during exercise

G - O2

A - between the blood and working muscles

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

EXAGGERATE

P - PPO2 in working muscles lower, PPO2 in blood higher

D - creates an O2 diffusion gradient

D - more O2 diffuses from the blood into the working muscles faster

G - CO2

A - between the blood and working muscles

S - gases diffuse from an area of high partial pressure to an area of low partial pressure

EXAGGERATE

P - PPCO2 in blood is lower, PPCO2 in working muscles is higher

D - creates a CO2 diffusion gradient

D - more CO2 diffuses from the working muscles into the blood faster

describe the oxyhaemoglobin curve during exercise

DCR - dissociation curve shifts right, so there is more oxygen dissociated from haemoglobin and becomes available for diffusion into the muscle tissue due to…

T - increased temperature

A - increased acidity

C - steeper carbon dioxide gradient

O - steeper oxygen gradient