Physiology Review Slides Lec. 22 Flashcards
How quickly can Lethal Pulmonary Edema can occur?
Within Minutes or Hours
Right Ventricle Pressure in mmHg
- Systole
- Diastole
- 25 mmHg
- 0-1 mmHg
How many Zones can the lungs be divided into?
3
Mean Pulmonary CAPILLARY Pressure
7mmHg
Pulmonary Artery Pressure in mmHg
- Systole
- Diastole
- 24-25mmHg
- 8-9mmHg
The 2 Circulations of the Lungs
- High Pressure, Low flow
2. Low Pressure, High flow
Mean Pulmonary ARTERIAL Pressure
15mmHg
Apices of the Lungs have what zone of blood flow?
Zone 2
Normal Atm O2 and CO2 Partial Pressure
O2
- 150mmHg
CO2
- 0mmHg
What is the cause of a Va/Q ratio to be 0?
OBSTRUCTION to the airways
- Mucus Plug
What does Va/Q = Infinity force the body to do?
- No blood flow
- Must make a PHYSIOLOGICAL shunt
When is Va/Q normal?
When BOTH factors are Normal for a given Alveolus
- Normal Breathing
- Normal blood flow
Why does the Alveolar Gas exchange remain unchanged when Va/Q = Infinity
Alveolar Gas composition remains UNCHANGED because there is No blood Contact
High pressure, low flow in the Lungs
- Found in the THORACIC AORTA as it goes to the Bronchial arteries
- Goes to the Trachea, Bronchial Tree, Adventitia, and CT
Most common causes of Pulmonary Edema?
- Left Sided heart failure
(Mitral Valve disease) - Damage to the Pulmonary blood Capillary MEMBRANES
(Infections or breathing noxious substances)
When is Gas exchange complete in the capillary during Normal Ventilation?
In the Initial THIRD of the Capillary
Lower areas of the Lungs have what time of Zone flow?
Zone 3
Cause for the Alveolar Gas exchange to be Va/Q = Infinity
Pulmonary Embolism
In the Standing position, what is the ratio of blood flow to the Top and Lower parts of the Lungs?
- Little Blood flow to the TOP of the Lungs
- 5x as much to the Bottom of lungs
T/F: All of the Bronchial arteries come off of the Thoracic Aorta
False
- No all but some
Low Pressure flow is measures to be what?
7 ml/mm Hg
What happens when the [O2] in Alveoli is 70% or BELOW Normal?
- Adjacent blood vessels Constrict
Unknown Vasoconstrictor
Alveolar Partial pressure when Va/Q = Infinity
PO2
- 149mmHg
PCO2
- 0mmHg
Zone 3 of the Lung
- Continuous Blood flow
Left Ventricle Pressure in mmHg
- Systole
- Diastole
- 120-125mmHg
- 0-5mmHg
Normal ALVEOLAR O2 and CO2 Partial Pressure
O2
- 100mmHg
CO2
- 40mmHg
T/F: Those Alveoli that are Poorly ventilated will get LESS blood flow while those with adequate ventilation gets more blood.
True
Zone 1 of the Lungs
- NO blood flow
- Local Alveolar Capillary Pressure NEVER rises higher than the Alveolar Air pressure
- NOT observed in Healthy individuals
Pulmonary Edema occurs when what?
- Occurs when Pulmonary capillary pressure is GREATER than 25mmHg
When Va/Q = 0
- Va = 0
- BUT there is still Perfusion
- Blood/Gas Composition remains UNCHANGED in the Capillary
Normal Va/Q value
- Ventilation flow rate = 4L/min
- Pulmonary Blood flow= 5L/min
- 4/5 = 0.8
Zone 2 of the lungs
- Intermittent blood flow
- ONLY during Systole
Low Pressure, High flow Lung Circualtion
- Fount in the Pulmonary Artery and Branches as they go to the Alveoli
- THINNER wall thickness (1/3) compared to the Aorta
- Larger Compliance
When Va/Q = Infinity
Q = 0 (not absolute zero)
- NO gas exchange BUT there is still Ventilation
What can convert the Apices from Zone 2 to Zone 3 flow?
Exercise
Normal CAPILLARY O2 and CO2 Partial Pressure
O2
- 40-100mmHg
CO2
- 40-45mmHg
Normal Alveolar Perfusion
PO2
- 104mmHg
PCO2
- 40mmHg
Va/Q Ratio
Ventilation-Perfusion Ratio
- = Alveolar Ventilation/blood flow
