Lecture 9 - Control Of Ventilation In Exercise Flashcards
What happens to ventilation during exercise?
Increase in ventilation, increase in blood flow to the face, sweat, heart rate
What happens towards the end of vigorous exercise?
Generation of lactic acid
How many phases are there during exercise?
5 phases
What parts of the body are important in the mechanics of exercise?
The diagram and intercostal muscles
What happens during inhalation?
The rib cage lifts up and out
What type of processes is exhalation?
Passive but not necessarily during exercise which is where the internal intercostal muscles help.they contract and force the ribcage down expelling air faster
What muscles help keep the airways open
Quadratic lumborum - a paired muscle of the left and right posterior abdominal wall (backs muscles) - also accessory muscles help
What does it mean if someone is bent over after exercise?
It is the most comfortable position to keep the airways open as much as possible
What is the 1st phase of ventilation?
The increase in ventilation is abrupt and immediate
What is the 2nd stage of ventilation?
Ventilation increases further, trying to reach a steady state to match demand with supply
What types of exercise to you reach a form of steady state?
Light and moderate exercise
What is phase 3 of ventilation during exercise?
The steady state, where you maintain the exercise you are doing
What controls the rate and depth of ventilation?
Apnostic centre
What controls and coordinates ventilation?
The pneumotaxic centre
What centre can override the other?
The aponstic centre can override the pneumotaxic centre
What specific type of exercise is it important than the Apnostic centre doesn’t override the pneumotaxic centre?
In swimming - you wouldn’t want to have an abrupt start of ventilation when your face is under water - need to be able to control or coordinate when ventilation is appropriate
What do the apnostic and pneumotaxic centre work under?
The dorsal group - they act through the diaphragm and intercostal muscles
What causes an abrupt increase in ventilation?
Active limbs - you get a central command response when you start moving arms and limbs - which is matched to exercise and increases ventilation
What would happen if you didn’t have an abrupt start?
Sprinter would probably pass it mid way through the 100metres due to lack of oxygen - this can be trained
What is an important experiment that was carried out for frequency and load?
Duffin 2014, legs were connected by bamboo canes and duck tape. Two participants sat on a chair on a treadmill. Treadmill switched on and limbs were moving but they weren’t actually moving - was used to measure the ventilation rate
What 2 things were tested on the treadmill?
The speed and gradient of the treadmill
Increasing the speed =
A bigger increase in ventilation
Increase the gradient =
Increased the load
What does the speed of active limbs give?
Gives more of a response and increases ventilation to a greater and quicker rate
Slow drive for ventilation =
Limbs are as active in frequency but putting a lot of load on
What potential mechanism causes an increase in further ventilation?
Trying to match the demand by sensing the demand by central chemoreceptors
What is most of the input through?
Active limbs, producing byproducts of respiration - generating lactic acid at Low levels which changes the blood pH
What picks up a change in pH?
Peripheral chemoreceptors - start to change the partial pressure of CO2 which increases ventilation
What do active limbs work through?
The dorsal group
What is the final phase?
Small fine tuning of supply to meet demand - involves central command but with peripheral chemoreceptors
What is the cause of abrupt reduction?
Central command is taken away, slower level of reduction back to resting levels
Describe maximal exertion
Massive increase in ventilation rates, don’t get a steady state because you are trying to match demand, towards the end of maximal exertion you start to see a reduction in CO2
What causes a change in blood pH - controls of ventilation?
Increase in lactic acid, hydrogen ion
What types of respiration can be seen in maximal exertion?
Aerobic and anaerobic towards the end of exercise which is when lactic acid is produced and pH will decrease
What is the anaerobic threshold?
At AT, where you start to rapidly produce lactic acid, from here ventilation increases further which is why more CO2 is expired
What is the limiting factor of exercise?
The capacity to both carry and utilise the oxygen before you start to response anaerobically which is the cause of lactic acid
What can be used to synthetically increase red blood cels?
Synthetic substances - increases mitochondria and there is more capacity to carry oxygen and use it
How is recovery helped?
By the hypothalamus, panting can help with ventilation, increase in body temperature
