week 5 Flashcards
what does bronchial circulation supply
the lung parenchyma
where does bronchial circulation originate from 2
thoracic aorta
3rd ICS artery
drainage of bronchial circulation
1/3 will drain straight into pulmonary veins
2/3rds will drain into azygous and hemiazygous veins
when do the internal interocostals work
during expiration
when do the external intercostals contract
inspiration
what are the 2 key functions of lymph drainage in the lungs
allows removals of pathogens
allows removal of excess fluid
process of normal cough breathing (5 key steps)
- stimulation of sensory fibres
- AP transmission by vagal nerve fibres
- enters nucleus of solitary tract
- communicates with nucleus of the central pattern generator
- modulates ventral respiratory tract which controls the motor neurons responsible for inspiration and expiration
alveolar and pleural pressure during inspiration
both negative
alveolar and pleural pressure during expiration
alveolar = positive
pleural = less negative
what are the 2 key characteristics that control breathing
lung compliance
airway resistance
work of breathing
energy required to overcome the airway resistance and compliance
transmural pressure def and what it determines
pressure across the chest wall
controls collapse and distension
transpulmonary pressure def and what it determines
pressure difference between alveoli and the pleura
determines the level of lung expansion
what does greater compliance look like on a pressure volume loop
steeper slope and to left
what does lesscompliance look like on a pressure volume loop
flatter slope and to right
what are the three components which produce airflow resistance
airways = vessel diameter
chest wall
pulmonary = lung elasticity
what control 2 groups control bronchodilation/constriction
vagal = bronchoconstriction
sympathetic = bronchodilation
what area of the lung will always recieve blood
the base as arterial pressure is always greater than pulmonary pressure
how much blood will zone 2 of the lungs gain
will only gain blood during systole
how much blood will zone 1 of the lungs gain (apices)
lack of blood flow as alveolar pressure greater than arterial pressure
what substances cause increased pulmonary vascular resistance
endothelin - causes smooth muscle contraction
catecholamines - cause vasoconstriction
what substances cause a decrease in pulmonary vascular resistance
adenosine
nitric oxide
bohr effect
increased hydrogen and co2 will cause increased offloading of o2 in the tissues and increased o2 loading at the lungs
haldane effect
the greater the binding of oxygen to haemoglobin the greater the release of carbon dioxide
