Lesson 7: Airways Resistance and Lung Volumes Flashcards
what is resistance highly dependent on?
the diameter/radius of the tube
what happens to your alveoli and small bronchioles because of the negative intrapleural pressure when we inhale?
alveoli and small bronchioles get pulled open a little bit when we inhale because of the negative intrapleural pressure
what happens if there is too much mucous accumulation in the airways?
it can actually compromise your ability to move air in and out of the lung
what are the neurological factors that influences airway resistance?
- parasympathetic (acetylcholine) constricts (lowers radius)
- epinephrine (sympathetic) dilates
- histamine constricts (allergic reactions)
what type of muscle is bronchioles wrapped in?
smooth muscle
information from the ANS comes from?
the brain
what does it mean to say “the small airways are under pretty strict neural tone”
the smooth muscle in the bronchioles can contract or relax
when you are running from a bear, you have an adrenal rush. something that happens is your airways will open. why?
because your body is sensing a threat. so it is increasing the airways to allow for you to increase flow to run away from the bear
what neurologically leads to dilation of small airway?
epinephrine stimulating adrenal receptors on the small airways leads to dilation
what does an epi pen do?
opens up the airways to !!!temporarily!!! reduce the allergic reaction which was causing constriction
what does an anti-histamine do in terms of respiration?
helps to mitigate and open up the airways
when an airway constricts, resistance increases. does this represent smooth muscle contraction or relaxation?
contraction
what are the two types of diseases of the airway?
- obstructive diseases
- chronic obstructive pulmonary disease
what is “obstructive diseases”?
- the diameter of the airways may be a little bit lower and the resistance might be a little bit higher
if you have an increased airway resistance, to generate the same level of flow, you need to have?
a larger pressure generation
what type of respiratory disease is asthma?
obstructive
what is asthma?
- bronchoconstriction leading to airflow obstruction
- generally a disease of the small airways.
- can be seasonal
- can be based on triggers to certain environmental challenges, whether, exercise, smoke, pollutants
the bronchoconstriction in asthma is generally a secondary cause after?
neurological factors such as smooth muscle constriction
does individuals with asthma have inflammation of the airways?
yes
- can lead to bronchoconstriction
are individuals with asthma hyper or under responsive to triggers?
hyperresponsive to triggers
what type of triggers are individuals with asthma hyperresponsive to?
things like exercise, smoke, pollutants
why does the airways constrict during an asthma attack?
to try and move that stuff out. by constricting, it is trying to avoid air coming in
how is asthma trated?
1) with anti-inflammatory drugs
2) bronchodilators (reversing the bronchoconstriction)
what does bronchodilators do?
- relaxes the airways by:
a) mimic epinephrine (often beta-2 agonists)(inhalers)
b) inhibit acetylcholine (getting ride of inflammation)
why is bronchoconstriction happening in an asthma attack?
in asthma, they have bronchoconstriction because the smooth muscle is hyper reacting. (constricting more than it probably should)
what does a beta-2 agonist do?
Binds with a beta-2 receptor and relaxes the smooth muscle which then dilates the airways which will then decrease the airways resistance
in someone with asthma, what happens if you can treat the inflammation?
you can reduce the rate of them having an asthma attack and needing the bronchodilators
how do we typically treat asthma?
generally by targeting the smooth muscle and relaxing it
what does COPD stand for?
chronic obstructive pulmonary disease
what is COPD generally due to?
- tobacco smoking / second hand
- if you work in a factory with bad air quality
- breathing in toxins
- there is going to be damage, an inflammatory response, damage to the airways
can asthma be developed?
rarely. usually and genetic predisposition
what is COPD characterized by?
the development of both emphysema and bronchitis
what is emphysema?
a destruction and collapse of the small airways and also the interface with the pulmonary capillaries and the elastic tissue (recoil pressure) (losing the elasticity of the lung)
what is chronic bronchitis?
- chronic inflammation of airways
- excessive mucous production in smaller airways (more than asthma)
because of what is why individuals with COPD have CONSTANT bronchoconstriction/increased airway resistance?
excessive mucous production (physical factor so a puffer cannot fix this)
- also depends on severity of emphysema
what is the clinical treatment for individuals with COPD?
the same as asthma, but its only partially reversible
each diseases of the airway results in?
a) increased airway resistance
b) decreased air flow rate
what is the purpose of picking up our breathing?
maintain homeostasis
because of diseases in the airway, how may someone’s life be affected?
- increased work of breathing
- compromises gas exchange
- impaired oxygenation of blood
what is an example of a restrictive disease?
pulmonary fibrosis
what is a restrictive lung disease?
- normal airway resistance
- minimal airway narrowing
- reduced lung capacity (volume of air)
why does people with pulmonary fibrosis have a small lung capacity?
because their lungs are so stiff (low compliance), they can’t take as big of a breath in (small volume/capacity)
when we breath in, how does our diaphragm know to pull down and make space?
- the medulla sends a signal down the phrenic nerve to the diaphragm and it pulls down and opens the space
we could have a respiratory issue at what levels?
- the brain
- the nervous system
- muscle level
- so if there is something wrong in any of those, it can lead to restrictive respiratory physiology
what are examples of neuromuscular disorders?
- polio
- amyotrophic lateral sclerosis (ALS)
- muscular dystrophy (tears in the diaphragm)
in heart disease, why can you have a restrictive lung disease?
because you have a pressure fluid buildup in the heart, you get hypertrophy and the heart actually displaces the lungs. it pushes on the lungs and you cannot breathe as much you can get lung disease through heart disease
how do we measure the capacity/volume of the lung?
we look at the change in air volume that is displaced on inspiration and expiration
what device do we use to measure the capacity/volume of the lung?
a spirometer
what did the old spirometer that is 70-80 years old consist of?
an air-filled drum floating in a water-filled sealed chamber
- drums sitting in water and hoses attach to it. the hoses measure the inspired and expired breath and the air would go into the chamber and push the drum up or down. We would measure the change in the lung volumes
how can flow be determined by a spirometer?
only if we track time
- this is critical for measuring lung function
what helps to classify/characterize obstructive lung conditions?
flow
what is tidal volume (Vt)?
the volume of air entering or leaving the lungs during a single breath; average value under resting conditions
what is inspiratory reserve volume (IRV)?
the extra volume that can be maximally inspired over and above the typical resting tidal volume
what is inspiratory capacity (IC)?
the maximum volume that can be inspired, starting from the end of a normal, quiet expiration (IC = IRV + Vt)
what is expiratory reverse volume (ERV)?
the maximum volume that can be actively expired starting from the end of a typical resting tidal volume
your TLC (total lung capacity) is a direct index of?
the size of your lung
do we always have a residual volume (RV)?
yes, as long as our lung is not collapsed we will always have a little bit of air left
about how much of our total lung capacity is residual volume?
about a quarter
when we take a big breath in or a big breath out, what capacity/volume is that?
vital capacity
- difference of top or your breath to bottom of your breath
does our vital capacity and total lung capacity ever change?
they are pretty set. do not really change
- will go down as we age however
What are some chronic obstructive pulmonary diseases?
Emphysema and chronic bronchitis
