Respiratory System Extras Flashcards
What are the two main functions of the respiratory system?
Pulmonary Ventilation (inspiration and expiration) and Gaseous Exchange (internal and external respiration)
Describe the pathway of air into the lungs
nasal cavity > pharynx > larynx > trachea > bronchi > bronchioles > alveoli
Describe the alveoli
one cell thick and lined with fluid
2 ways oxygen can be transported
Haemoglobin (97%) and blood plasma (3%)
3 ways carbon dioxide can be transported
Water (as carbonic acid - 70%), haemoglobin (23%) and blood plasma (7%)
What is f and what is it measured in?
Breathing rate (breaths per minute)
What is the resting rate of f?
12-15 breaths per minute
What is TV and what is it measured in?
Tidal Volume (ml)
What is an average resting TV?
500ml
What is VE and what is it measured in?
Minute Ventilation (l/min)
What is an average resting VE?
7.5l/min or 7500ml/min
Equation for VE
f x TV = VE
Mechanics of inspiration at rest
- External intercostals contract to lift the rib cage up and out
- Diaphragm contracts and flattens
- Thoracic cavity volume increases
- Pressure decreases
- Air rushes into the lungs
Mechanics of inspiration during exercise
- additional muscles recruited for more force (sternocleidomastoid and pectoralis minor)
- rib cage moves up and out more
- thoracic cavity volume increases more
- pressure decreases more
- more air rushes into the lungs
Mechanics of expiration at rest
- this is a passive process
- External intercostals relax to lower the rib cage down and in
- Diaphragm relaxes and domes
- Thoracic cavity volume decreases
- Pressure increases
- Air rushes out of the lungs
Mechanics of expiration during exercise
- this is an active process
- additional muscles recruited for more force (internal intercostals and rectus abdominis)
- rib cage moves down and in more
- thoracic cavity volume decreases more
- pressure increases more
- more air rushes out of the lungs
RCC
Respiratory Control Centre
IC
Inspiratory centre
EC
Expiratory centre
What is the role of the IC?
stimulates inspiratory muscles to contract at rest and during exercise
What is the role of the EC?
inactive at rest but stimulates additional expiratory muscles to contract during exercise
Where does the intercostal nerve go?
External intercostals
Where does the phrenic nerve go?
Diaphragm
What is the role of chemoreceptors and where are they located?
located in the aorta and carotid arteries - they detect an increase in blood acidity levels, increase in CO2 concentration and decrease in O2 concentration
What is the role of thermoreceptors?
detect increased blood temperature
What is the role of proprioceptors?
detect motor activity in the muscles and joints
What is the role of baroreceptors and where are they located?
located in the lung tissue and bronchioles - they detect lung inflation
How is the IC stimulated?
Chemoreceptors, thermoreceptors and proprioceptors inform the IC about exercise levels so the additional muscles can be recruited and contract with more force
How is the EC stimulated?
Baroreceptors inform the EC about excessive stretch on the lung walls so the additional expiratory muscles can be recruited and contract with more force
What is Gaseous Exchange?
movement of gases across a membrane
What is the impact of exercise on gaseous exchange?
There will be a steeper diffusion gradient which will increase the rate of diffusion
What is external respiration?
exchange of gases between the lungs (alveoli) and the blood
What happens to O2 during external respiration?
it moves from a high pp in the alveoli into the low pp in the blood down the diffusion gradient
oxygen + haemoglobin
oxyhaemoglobin
What happens to CO2 during external respiration?
it moves from a high pp in the blood to the low pp in the alveoli down the diffusion gradient
carbon dioxide + haemoglobin
carbaminohaemoglobin
What is internal respiration?
exchange of gases between the blood and the muscles
What happens to O2 during internal respiration?
it moves from the high pp in the blood to the lower pp in the muscles down the diffusion gradient
What happens to CO2 during internal respiration?
it moves from the high pp in the muscles to the lower pp in the blood down the diffusion gradient
What happens to O2 and CO2 during external respiration during exercise?
they diffuse quicker because the diffusion gradient steepens due to the change in partial pressure
What happens to O2 and CO2 during internal respiration during exercise?
they diffuse quicker because the diffusion gradient steepens due to the change in partial pressure
What happens to the oxyhaemoglobin dissociation curve during exercise?
it shifts to the right
What makes the oxyhaemoglobin dissociation curve shift to the right?
- decrease in partial pressure of oxygen
- increased temperature, blood acidity levels and CO2 levels (Bohr shift)
What happens to the oxyhaemoglobin dissociation curve during recovery?
it shifts to the left
What makes the oxyhaemoglobin dissociation curve shift to the left?
- increased partial pressure of oxygen
- decreased temperature, blood acidity levels and CO2 levels
What happens to breathing rate (f) during exercise?
it increases linearly with exercise intensity levels until it plateaus at around 50-60 breaths per minute
What happens to breathing rate (f) during sub-maximal exercise?
it can plateau because the oxygen supply has met the demand
What happens to tidal volume (TV) during exercise?
it increases linearly with exercise intensity until it plateaus at around 3 litres
What happens to tidal volume (TV) during sub-maximal exercise?
it plateaus because increased breathing rate does not allow enough time to increase tidal volume
What happens to minute ventilation (VE) during exercise?
it increases linearly with exercise intensity
What happens to minute ventilation (VE) during sub-maximal exercise?
- initial anticipatory rise
- rapid increase at the start
- plateaus throughout sustained activity as supply has met demand
- rapid then more gradual decrease
What happens to minute ventilation (VE) during maximal exercise?
- initial anticipatory rise
- rapid increase at the start
- VE continues to increase due to growing demand for oxygen
- rapid then more gradual decrease
