Pulmonary Circulation Flashcards
2 Circulations
Pulmonary circulation: xchange of gases in blood
Bronchial Circulation: oxygen to bronchial tree/pleura
Bronchopulmonary Segment
Smallest functionally independent area of blood - tertiary bronchus supplied by one branch of pulmonary a. and can be removed w/out compromising blood/air to other parts of lung
Pulmonary Arteries
Arise from pulmonary trunk and travel w/ bronchi/bronchioles and generally same size as them and terminate as capillaries in alveolar walls
Notable Features About Pulmonary Arteries/Arterioles (3)
Have less muscle, elastin, and ability to contract
Type I and II Alveolar Cells
I: Squamos alveolar
II: Surfactant-producing
Type of Capillary in Alveoli
Type I, continuous
Notable Feature of Pulmonary Veins
Lack valves
Bronchial Vein Drainage
Azygos and hemiazygos, but some drain into pulmonary veins causing RIGHT-LEFT SHUNT: mixing of oxygenated and deoxy blood
Blood Pressures b/w the 2 Artery Systems
Bronchial is normal, like 120/80
Pulmonary is way lower, like 25/10
Difference b/w SVR and PVR
Like 20 and 2, so 10x difference
Starling’s Law of Inhalation
RONAK SUCKS FAT DICKS
Transmural Pressure
Pressure across vascular wall
3 Zones by Upright Pressure Relationships (and what mainly guides/determines these)
Gravity determines blood flow a lot
Zone 1: Palv > Pa > Pv, so closed and blood doesn’t flow up here
Zone 2: Pa > Palv > Pv, so vessel collapses higher in Z2 but blood flow increases as you go further down
Zone 3: Pa > Pv > Palv so works perfectly
3 Influencers of Resistance
Lung Volumes
Hypoxia
Exercise
Lung Volume Influence of Resistance
Breath at level of least resistance - too little lung V get crowding of alveolar vessels, too large and you get too much tension
Hypoxia Influence of Resistance
Vessels constrict to direct blood flow to area with more O2 (even though that might not exist), so increase resistance, so you have to increase pressure to get the same flow
Exercise Effect on Resistance (2 mechs)
Reduces R by recruiting unused capillaries and increasing distension
Hemoptysis
Spitting blood, usually caused or associated w/ cystic fibrosis resulting in bronchiectasis (dilated bronchus)
