Respiration
1. A measurement of the absolute pressure of a gas 2. A value representing the absolute temperature 3. A measure of the total amount of the gas, usually measured in moles 4. A measurement of the volume that the gas occupies, usually measured in liters 5. A number representing the universal gas constant
1. P 2.T 3.n 4. V 5. R
As one moves up in altitude, the atmospheric pressure decreases. In Vail, CO (altitude 8022 ft or 2445 m), the atmospheric pressure is approximately 570 mmHg. What would the partial pressure of oxygen be in Vail?
120 mm Hg
If an alveolus with an initial volume of 3 ml of air with a total pressure of 810 mmHg decreases in volume to 1.7 ml, what would the new pressure be and in which direction would air flow? Assume you are at sea level.
1429 mmHg; air flow out of the alveolus to the environment
Fetal hemoglobin has an increased affinity to oxygen, which means that it is more saturated than maternal hemoglobin at any given partial pressure of oxygen.
45%
Using the numbers below, calculate the total pressure of the atmosphere. Partial pressure of O2: 148 mmHg Partial pressure of CO2: 0.26 mmHg Partial pressure of water vapor: 28 mmHg Partial pressure of N2 : 453 mmHg
629.26 mmHg
Using the oxygen dissociation curve, determine the percent saturation of hemoglobin at a partial pressure of 50 mmHg?
85%
What is the main driving force that directly causes air to flow in and out of the respiratory system? Hint: It is the same force that creates blood flow.
As the volume of the thoracic cavity changes, it creates a pressure gradient that allows air to flow.
Which of the following correctly describes the relationship between pressure and volume?
As volume increases, pressure decreases proportionally.
Why is hyperventilation a usual response when someone is exposed to a high altitude hypoxic situation?
Because it increases alveolar ventilation, which increases the partial pressure of O2 in the alveolus.
At the same pressure, about 25 times more CO2 will dissolve in plasma as O2. Why does this occur?
CO2 has a higher solubility than O2.
________ is the enzyme that converts CO2 into bicarbonate ions.
Carbonic anhydrase
What is the main difference between fetal and adult hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen.
Use the oxygen-dissociation curve below to answer the following question. How does affinity to hemoglobin in fetal blood compare to maternal blood and what does this mean regarding oxygen loading to hemoglobin?
Fetal hemoglobin has an increased affinity to oxygen, which means that it is more saturated than maternal hemoglobin at any given partial pressure of oxygen.
Which factor(s) from the ideal gas equation can be ignored in the human body?
Ideal gas constant Temperature Moles of gas
Match each of the following conditions with the type of shift it would create in the oxygen-hemoglobin dissociation curve.
Left shift: Decreased concentration of 2,3 DPG Increased pH Decreased partial pressure of CO2 Decreased temperature Right shift: Increased concentration of 2,3 DPG Decreased pH Increased partial pressure of CO2 Increased temperature
Choose the combination of factors that would lead to the greatest oxygen unloading from hemoglobin.
Low pH, high temperature, high PCO2, high 2,3-DPG
What is the significance of the shape of the oxygen-hemoglobin dissociation curve?
Only significant changes in the partial pressure of oxygen will result in significant changes to hemoglobin saturation.
The volume of air that remains in the lungs after a forced expiration is called the
Residual volume
If you were to compare the hematocrit between a person that lives at sea level and one that lives at high altitude, how would they compare?
The hematocrit in the person from high altitude would be higher than that of the person from sea level.
Which of the following best describes the affinity between oxygen and hemoglobin?
The higher the affinity, the more likely it is that oxygen bind to hemoglobin.
Why is Edna's forced expiratory volume lower than normal?
The inflammation in her lungs has caused her ability to expel air to become difficult because of increased resistance in the bronchioles.
Which of the following statements best describes the definition of Dalton's Law of partial pressures?
The total pressure of a mixture of gases is the sum of the pressures of the individual gases.
In its simplest form, which relationship between pressure and volume does the ideal gas law demonstrate?
They are inversely proportional.
Label the system
V1=7.5 V2=3 P1=2mmHg P3=5mmHg
What would a rightward shift in the oxygen-hemoglobin binding curve indicate?
a decrease in hemoglobin affinity for oxygen
Which of the following statements most accurately describes hypoxia?
a decrease in the amount of dissolved oxygen in plasma or air
Which of the following statements best defines the oxygen-hemoglobin dissociation curve?
a graphical representation of the relationship between hemoglobin's percent saturation and the partial pressure of oxygen
In which form is most carbon dioxide transported in the blood?
as bicarbonate ion
Histamine's primary role in the respiratory system is as a
bronchoconstrictor
About 23% of the carbon dioxide in blood is carried ________.
by hemoglobin, bound to amino groups
The most important chemical regulator of respiration is
carbon dioxide.
What are the two conditions that most people with COPD have?
chronic bronchitis and emphysema
The ease with which the lungs stretch in response to changes in pressure is termed
compliance
Which two factors have the greatest influence on the amount of work needed for breathing?
compliance and airway resistance
How does a rightward shift in the oxygen hemoglobin dissociation curve affect hemoglobin's affinity to oxygen?
decrease
The ability of a lung to recoil, or recover from stretch, is called
elastance
The ability for the lung to passively recoil and push air out is attributed to what type of tissue? What is this property called?
elastic tissue; elastance
The additional air that you can exhale after a normal exhale is the ________.
expiratory reserve volume
Surfactant
helps prevent the alveoli from collapsing.
What physiological factor is responsible for causing HAPE?
high pulmonary capillary hydrostatic pressure
Conditioning of air by the respiratory tract has three purposes: warming, filtering, and which other component?
humidifying
High carbon dioxide concentration in body fluids is called
hypercapnia.
Which term most accurately defines ventilation changes during exercise?
hypernea
Low alveolar PO2 can be caused by one of two mechanisms. One of them is that the inspired air has a low oxygen content. What is the other reason?
hypoventilation
When the respiratory diaphragm contracts, it flattens, lowering the floor of the thoracic cavity. At the same time, the intercostal muscles pull the ribs up and out. The active forces of the muscle groups cause a(n) __________ (increase/decrease) in thoracic volume. Given the relationship between pressure and volume, this would cause pressure within the lungs to __________ (increase/decrease).
increase; decrease
What happens to the resistance in the bronchioles of patients with chronic bronchitis and how does this affect air movement into and out of their lungs?
increases; decreases
Alveolar ventilation refers to the
movement of air into and out of the alveoli.
Pulmonary ventilation refers to the
movement of air into and out of the lungs.
Which chemical can stimulate ventilation by binding both peripheral and central chemoreceptors?
plasma CO2
Which disorder would usually result in a normal alveolar PO2 but a decreased arterial PO2?
pulmonary edema
Which of the following describes the shape of the oxygen-hemoglobin dissociation curve?
sigmoidal
The substance produced by the lungs to reduce surface tension is called
surfactant
An increase in PCO2 would cause
the bronchioles to dilate and the systemic arterioles to dilate.
Which of the following variables do you need to know in order to calculate the partial pressure of a gas?
the total pressure in the atmosphere the percentage of the gas the water vapor pressure
The volume of air moved in a single respiration is called the
tidal volume.
What is a function of the pleural fluid?
to hold the lungs to the thoracic wall
