Respiratory Physiology II: Pulmonary Circulation (Exam IV) Flashcards
It takes a red blood cell about _______ to travel through pulmonary circulation at resting cardiac output; about _______ of this time is spent in pulmonary capillaries; when in reality gas exchange takes only about _______
4-5 seconds; 0.75 seconds; 0.25 seconds
List the order of blood flow from start to finish through the circulation:
- Vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary artery
- Pulmonary capillaries
- Pulmonary vein
- Left atrium
- Bicuspid valve
- Left ventricle
- Aortic valve
- Aorta
Compared to systemic circulation, pulmonary circulation has: (4)
- Lower pressure
- Lower resistance
- Higher compliance
- Lower volume
Pulmonary arteries & arteriole diameters are _____ than systemic arteries & arterioles
larger
Pulmonary arteries & arteriole walls are _____ & _____ resulting in ______
Thin; distensible; large compliance
Compared to systemic circulation in which only the veins have a high compliance, in pulmonary circulation what has the high compliance?
Arteries, capillaries & veins all have high compliance
What is unique about the pulmonary capillaries in pulmonary circulation?
There is a population of capillaries in the lungs that are closed at rest that can be recruited
Bronchial circulation is part of _____ circulation:
Systemic
Supplies oxygen & nutrients to the tracheobronchial tree down to the terminal bronchioles & also pulmonary blood vessels, visceral pleura, nerves & hilar lymph nodes:
Bronchial circulation
Pulmonary capillaries in the Zones of the lung experience force from the fluids inside _______ & outside the vessel _______
Inside vessel: Pa (hydrostatic pressure)
Outside vessel: PALV (alveolar air pressure)
The hydrostatic pressure of blood inside the capillaries:
(how do we abbreviate this)
Pa
The hydrostatic pressure of blood in the capillaries favors _____ and functions to ______
Filtration; keep the vessel open
Pa is greater in zone ______ of the lungs compared to zone ______ due to _____
Zone 3; Zone 1; gravity
The tissue pressure of the lungs is largely based on:
Alveolar air pressure (PALV)
The tissue pressure (largely based on alveolar air pressure- PALV) outside the capillary opposes _____ & favors _____
FIltration
Vessel collapse
Only the capillaries & smallest of the arterioles & venules (alveolar vessels) are altered by:
P-Alveolar
A pressure that can compress & close the vessel:
PALV
A pressure that can hold the vessel open because it is the pressure inside the vessel:
Pa (sometimes referred to as Pc)
Capillaries at the base of the lungs have a higher _____ meaning it will hold the vessel open more efficiently
Hydrostatic pressure
The pulmonary capillaries near the alveolar can become _______ during ______
Compressed; inspiration
What happens to the resistance of the vessel in the alveolus when there is more air in the alveolus and why?
The resistance in the alveolus goes up if the alveolus has more air in it, because there is more external pressure from the outside compressing that vessel
In zone 1: P-arterial (Pa) is ______ than P-Alveolar (PA)
This means that the capillaries are _____
Lower; compressed
If P-arterial (Pa) drops (hemorrhage) or P-Alveolar (PA) increases (positive pressure breathing), a greater portion of the lung is converted to:
Why?
Zone 1
Compared to zone 1, zone 2 has a higher ______ due to ____
P-arteriole (Pa)
Gravity
Because zone 2 has a higher P-arteriole (Pa) due to gravity, this means that P-arteriole is _____ than P-Alveolar (PA) during ______
Higher; systole
In zone 2 during diastole, what occurs with the P-arteriole (Pa) and P-Alveolar (PA)
During diastole, P-arteriole (Pa) will drop lower than P-alveolar (PA)
In zone 2, because of the pressure differences during systole & diastole, we call this the region of:
Intermittent blood flow
In zone 2, during systole (heart contraction) the vessels are _____ & during diastole (heart relaxation) the vessels are _____
Systole- open
Diastole- closed
Zone 3 has the highest ______ due to ______
P-arteriole (Pa); gravity
Zone 3 is considered the region of:
Continuous blood flow