Airways resistance: Lecture 6 Flashcards
To change the pressure and get flow we need to overcome what?
resistance
What is the Posielles law?
Flow = change in pressure/resistance
Airway resistance is influenced by what 2 factors?
- Physical Factors
- Neurological
What are examples of physical factors that influence airway resistance?
- transpulmonary pressure
- mucous accumulation
What are examples of neurological factors that influence airway resistance?
- Parasympathetic (Ach) constricts, which will decrease the radius
- Epinephrine dilates
- Histamine constricts
What are obstructive diseases of the airway?
- narrowing, affecting the flow of air
- constriction
True or False
Asthma can be seasonal or triggered by environmental factors
True
What is asthma?
inflammation in the airways leading to broncho-constriction
What are the triggers of asthma?
- exercise
- smoke
- pollutants
What are the 2 ways we treat asthma?
- Anti-inflammatory drugs
- leukotriene inhibitors
- inhaled cortical steroids - Bronchodilators
- Relax the airways
(i) Mimic epinephrine - relaxes the smooth muscles
(ii) inhibit acetylcholine
What is COPD?
Chronic obstructive pulmonary disease
What is the cause of COPD?
- smoking
- Secondhand smoke
- environments with poor air quality
What is the main difference between COPD and asthma?
- COPD has excess mucous production in the small airways
- The cause of asthma is mainly genetic
COPD is characterized by 2 things which are what?
- Emphysema
- Chronic bronchitis
If we give a person with trouble breathing a puffer and their breathing does not completely normalize what do you think they have?
COPD
Airway resistance is dependent on 3 factors which are?
- size of tube (fixed)
- interactions between gas molecules
- airway radius (MOST IMPORTANT)
True or False
A decreased radius means increased pressure
true
True or False
As transpulmonary pressure /recoil pressure increases, lung volume increases, and airway resistance decreases as we breathe in
True, as we breathe we increase the volume of the lung
If the smooth muscle in the walls of the bronchioles contract, what will happen to airway resistance?
- when smooth muscle contracts, it shortens making the diameter of the airway smaller
- increase the resistance to flow
When smooth muscles in the airways contract what kind of signal is this?
parasympathetic, where Ach was released overall resulting in a decreased radius
What would epinephrine or increased adrenal activity do to the airway’s resistance?
dilate the airways, via receptors on the smooth muscles resulting in less resistance and increased radius
What are the treatments for COPD?
- similar to asthma
- even with a puffer, the symptoms can only be partially reversible
Each disease with resistance to the airways causes 3 disturbances which are what?
- Increases work of breathing
- Compromises gas exchange
- Impaired oxygenation of blood
