What are the 2 main areas in respiratory centre ?
The inspiratory system - responsible for inspiration and expiration
The expiratory centre - stimulates the expiratory muscles during exercise
During exercise what happens to the blood as respiratory centre responds to changes in blood chemistry?
- increase in CO2 and blood acidity
- detected by chemoreceptors in the aortic arch and carotid artery
- nerve impulse sent to respiratory centre
- increase impulses sent down the phrenic nerve
- to the respiratory muscles to contract faster
- increased rate of contraction of diaphragm, intercostal muscles, scalene and sternocleidomastoid
- increase in breathing rate
What do stretch receptors do?
- during exercise lungs stretched
- stretch receptors prevent over inflation of the lugs by sending impulses to the expiratory centre and then down the intercostal nerve to the expiratory muscles so that expiration occurs
What happens in the immediate stages of exercise?
The existing oxygen supplies in the blood and muscles are depleted faster than the resting rate of retrieval currently occurring in the lungs
What happens as a result of oxygen supply depleting faster?
Results in slight hypoxia - A lack of oxygen which occurs when the blood and muscle are depleted faster. Hypoxia is detected by the chemoreceptors and the adrenal gland
What is adrenaline role in the hormone control mechanism?
Adrenaline is secreted within the sympathetic nervous system causing transmissions to be sent faster with greater action potential - providing a jump start to our body and increase pulmonary ventilation in an attempt to counteract the slightly hypoxia state created
Benefits of physical activity
- muscle hyper trophy
- heightened metabolism
- improved cardio- respiratory capabilities
Negatives of physical activity
- inactivity - risk of coronary hear diseases and strokes
- obesity and diabetes on rise in sedentary adults
- 1 billion in NHS costs
What can happen if there is an imbalance between work life and home life and what can it lead to?
- leads to unhealthy stress responses, we react to stimuli that put pressure on changing our natural state of balance - homeostasis
Why do stress responses occur?
- psychologically and physiologically due to the release of hormones adrenaline and cortisol. These can elevate breathing rate placing unnecessary stress on respiratory mechanisms and control
What can prolonged increase in blood pressure lead to?
It can contribute to difficulty in gaseous exchange
What are some of the physiological effects of smoking?
- CO binds to haemoglobin rather than oxygen which reduces oxygen carrying capacity of the blood. This increases breathlessness during exercise.
- nicotine constricts bronchioles
- damage to the cells lining the airways from cigarette smoke leading to build up of excess mucus in lungs.
- reduction in number of alveoli
What can the physiological effects of smoking lead to
A reduction in the efficiency of gaseous exchange in the lungs and reduced oxygen transport to the muscles
What happens to o2 if there is cholesterol build up in coronary blood vessels?
Blood pressure remains high - opportunity for O2 diffusion in cardiac muscle to reduce. Heart cannot work as hard for long supplying less o2 blood to body
How does high blood pressure impact o2 transport?
Sustained high BO can cause prolonged stress to be placed on smaller blood vessels and heart. Damage could reduce diffusion capabilities. Faster blood has less time for diffusion to occur
Partial pressure
The pressure exerted by an individual gas when it exists within a mixture of gasses
What is breathing frequency?
The number of breaths per minute. Average resting value 12bpm. Vary for every individual, the fitter, the lower.
What is tidal volume?
The volume of air breathed in or out per breath. ARV - 500ml
Higher tidal volume - larger amount of CO2 to be expelled from lungs per breath
What is Minute ventilation
The volume of air inspired or expired per minute. ARV- 6.0 I/min
Direct result in the relationship between HR and stroke volume. Large minute ventilation aids O2 transport
What are the changes in lung volume during physical activity?
Breathing frequency - at rest 12-20, exercise - 20-40, increased
Tidal volume - At rest 500, exercise - 1000 - 2000, increased
MV - 6-10 at rest, 40-80 exercise, increased
Residual volume
Volume of air that remains in the lungs after expiration
Whats the different between Expiratory reserve volume and inspiratory reserve volume ?
Volume of air that can be forcibly expired after a normal breath is expiratory whereas inspiratory reserve volume is the volume of air that can be forcibly inspired after a normal breath
Explain the changes in reporstory columns during exercise
TV increases to get more O2 in, expire more CO2, and endure more effective gaseous exchange
IRV decreases to allow more lung space for TV
ERV decreases to allow more lung space for TV
RV remains same as prevents lungs collapsing
Lifestyle choice effect - tar in alveoli
Creates a larger diffusion distance over which the haemoglobin attraction and diffusion gradient of CO2 is less effective
