Respiratory Quiz #3 Flashcards
Describe the Universal Gas Law.
The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation to the behaviour of many gases under many conditions, although it has several limitations. It was first stated by Émile Clapeyron in 1834 as a combination of Boyle’s law and Charles’s law.[1] The ideal gas law is often introduced in its common form:
PV=nRT
P=pressure V=volume n=# of moles of gas R=universal gas constant(8.3 joules/kelvin/mole) T=temperature
Define Avogadro’s Law and the relationship between gas molecule quantity and volume.
- one mole of an ideal gas occupies a volume of 22.4 L at 1 atmosphere and 0’C
- # of molecules in 1 mole = 6.02 x 10^23
- equal volumes of different gases at same temp and pressure contain the same # of molecules with nitrous oxide being the only exception.
SO IF THE AMOUNT OF GAS IN A CONTAINER(E.G., BALLOON) INCREASES, THE VOLUME ALSO INCREASES
THIS GIVES THE RELATIONSHIP BETWEEN VOLUME AND QUANTITY WHEN PRESSURE AND TEMP ARE HELD CONSTANT(PV-NRT)
Define Boyle’s law and the relationship between pressure to volume. Given an application of Boyles law.
“The volume of a given mass of gas is inversely proportional to the pressure, provided that the temperature remains constant”
- IF PRESSURE DOUBLES THE VOLUME WILL DECREASE BY 1/2
- IF THE PRESSURE IS HALVED, THE VOLUME WILL DOUBLE
application would be a pressurized cylinder is opened and slowly emptied so that temp does not change. The volume of gas released from the cylinder can be estimated from Boyles law.
Define Charle’s law and the relationship between temperature and volume
“The volume of a given mass of an ideal gas is proportional to the absolute temperature, provided that the pressure remains constant”
- AS TEMPERATURE INCREASES, VOLUME INCREASES AS LONG A PRESSURE REMAINS CONSTANT(i.e.,increased temp, increased volume with hot air balloon)
- V1/V2=T1/T2
Define Gay-Lussac’s number and the relationship between temperature and pressure.
“The pressure of a given mass of an ideal gas is proportional to the absolute temperature, provided that the volume remains constant”
- AS TEMPERATURE INCREASES, PRESSURE INCREASES(when cylinder is moved from loading dock pressure in the cylinder increases)
- P1/T1 = P2/T2
Identify the blood supply to the tracheobronchial tree down to the terminal bronchioles.
The aorta and the intercostal arteries supplies blood to the tracheobronchial tree down to the level of the terminal bronchioles.
Compare and contrast Bronchial blood flow and Pulmonary blood flow.
BRONCHIAL BLOOD FLOW:
-constitutes a very small portion(1-2%) of the left ventricular output
-provides the tracheobronchial tree with arterial blood
PULMONARY BLOOD FLOW:
-constitutes the entire output of the right ventricle
-supplies the lung with mixed venous blood draining the body to oxygenate
Describe the lungs as a reservoir for blood volume
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Describe the lungs as a reservoir for blood volume
- 450 ml(9%) of total blood volume is in the pulmonary circuit
- lungs act as a reservoir for excessive blood volume, especially in heart failure(20-30% increase—>CHF/Pulm Edema)
- increased intrathoracic pressure decreases pulmonary blood volume
- blood volume in each region depends on ventilation to each lung region
Compare Pulmonary Vascular Resistance to Systemic Vascular Resistance.
- mean systemic pressure is 100 mmHg
- mean pulmonary pressure is 15 mmHg
- SVR is 10 times PVR
The walls of the pulmonary vessels are very thin and compliant. They allow diversion of blood from one region to another, as with recruitment, dissension and HPV.
Compare the effects of after load on the right ventricle as compared to the left ventricle.
The RV is very sensitive to after load changes(fails with acute pulmonary hypertension). Thin walled, low compliance chamber unless chronic pulmonary hypertension.
Describe the effect of airway pressure on zero order capillaries.
Order “0” capillaries collapse or destined, depending on the pressure surrounding them.
Pulmonary capillaries form a dense network around the alveoli, much as a parking garage with scattered posts. Branching is asymmetrical.
Discuss the role of alveolar collapse in pulmonary vascular resistance.
Alveolar expansion or collapse plays a major role in pulmonary vascular resistance.
Identify the number of “1” order pulmonary capillaries and their volume.
300,000,000 pulmonary capillaries and 151 ml volume
Define recruitment and distention as they relate to perfusion.
- Recruitment refers to perfusion of previously closed capillaries when a critical opening pressure or blood volume is achieved.
- Distension refers to widening of individual capillaries.
Compare and contrast alveolar and extra-alveolar effects on capillary size.
- PVR is increased when lung volume is low
- alveolar vessels expand up to FRC then constrict but remain more patent
- Extra-alveolar vessels are pulled open as the lung expands
Describe the effect of increased blood flow on pulmonary vascular resistance.
PVR becomes even less when pressure and flow increase due to distention and recruitment
Describe the effects of increasing lung volume(above FRC) on pulmonary vascular resistance.
- PVR may drop even further as the pressure within it rises due to recruitment and distention*
- PVR is increased when lung volume is low
List 5 factors that increase pulmonary vascular resistance.
- atelectasis
- hypoxia
- hypercapnia
- acidemia
- catecholamines
- histamine
- serotonin
- prostaglandins
- lung inflation or deflation from FRC changes
- increased perivascular pressure
List 5 factors that decrease pulmonary vascular resistance
- isoproterenol
- milrinone
- flolan/epoprosterenol
- acetylcholine
- bradykinin
- prostoglandins
- theophylline
- nitric oxide
- increased CO
- increased pulm blood volume
