Pulmonary Circulation Flashcards
How much blood is within the pulmonary circulation?
450mL
9% of total blood volume
70mL is in pulmonary capillaries
What results in the pulmonary circulation as a result of failure of left side of the heart?
blood volume increases as much as 100%
increase in blood pressure
What is a physiologic shunt?
This is the 2% of blood that has evaded the oxygenation process in the lungs.
How many zones are there in the lungs and what do they designate?
There are 3 lung zones. These zones are made because they receive different amounts of blood flow. The blood flow in bottom of lungs are 5x more than blood flow in upper lungs.
What type of blood flow is seen in zone 3?
continuous blood flow
What type of blood flow is seen in zone 2?
There is only blood flow during systole
What type of blood flow is seen in zone 1?
no blood flow, local alveolar capillary pressure never rises higher than alveolar air pressure
True or False.
Pulmonary veins are very distensible making them an important blood reservoir.
true
What are agents that can constrict pulmonary arterioles?
norepinephrine
epinephrine
angiotensin II
some prostaglandins
What are 3 agents that constrict pulmonary venules?
serotonin
histamine
E.coli endotoxin
What are 2 agents that dilate pulmonary arterioles?
isoproterenol
acetylcholine
What effect do sympathetic vasoconstrictors have on the circulation?
decreases pulmonary blood flow by as much as 30%, mobilizes blood from pulmonary reserve.
What effect does exercise have on blood flow through the lungs?
- increase number of open capillaries up to 3x
- distends all capillaries and increases flow rate up to 2x
- increase pulmonary arterial pressure
What are 4 causes of pleural effusion?
- blockage of lymphatic drainage from pleural cavity
- cardiac failure
- reduced plasma colloid osmotic pressure
- infection/inflammation
What is the most common cause of hypoxia?
bronchial obstruction
