1.
The diaphragm is innervated by the phrenic nerve originating from which 3 cervical nerves?
Explanation
The diaphragm is innervated by the phrenic nerve, which originates from the C3, C4, and C5 cervical nerves. These nerves provide the motor function to the diaphragm, allowing it to contract and facilitate breathing. Damage or injury to any of these cervical nerves can result in diaphragm dysfunction and impaired breathing. Therefore, it is important to understand the innervation of the diaphragm for proper diagnosis and treatment of respiratory conditions.
2.
Boat-rocking, or paradoxical movement, occurs when:
Correct Answer(s)
A. Patient is medically paralyzed.
B. When the airway is obstructed.
Explanation
Boat-rocking, or paradoxical movement, can occur when a patient is medically paralyzed or when the airway is obstructed. In the case of medical paralysis, the patient may experience involuntary movements that seem contradictory to their paralyzed state. This can be caused by the effects of certain medications or medical conditions. On the other hand, when the airway is obstructed, such as in cases of choking or severe asthma, the patient may exhibit paradoxical movement as they struggle to breathe, causing their chest and abdomen to move in opposite directions.
3.
Interscalene blocks always affect the _____ nerve, causing a hemidiaphragm.
Correct Answer(s)
phrenic
Explanation
Interscalene blocks are a type of regional anesthesia technique commonly used for shoulder surgery. They involve injecting local anesthetic near the brachial plexus, a network of nerves that innervate the shoulder and arm. The phrenic nerve, which originates from the cervical spine and supplies the diaphragm, is often affected by interscalene blocks. This can result in the temporary paralysis of half of the diaphragm, leading to a condition called hemidiaphragm.
4.
During inspiration, the intrapleural space becomes more negative, making intrapulmonary pressure more negative - this can be up to -90 cmH2O.
Correct Answer
A. True
Explanation
Related to Boyle's law - as pressure drops, volume increases.
5.
Normal ______ is passive recoil without contraction, the lungs and chest wall are elastic which cause the intrapulmonary pressure to return to near zero at end expiration.
Correct Answer
exhalation
Explanation
During exhalation, the process of passive recoil occurs without any contraction. The lungs and chest wall are elastic, meaning they can stretch and then return to their original shape. This elasticity causes the intrapulmonary pressure, which is the pressure inside the lungs, to decrease and return to near zero at the end of expiration. This allows for the expulsion of air from the lungs and completes the process of exhalation.
6.
Which two laws of physics contribute to resistance in the lungs?LL
Correct Answer(s)
A. Law of Laplace
B. Poisuelle's law
Explanation
The Law of Laplace and Poisuelle's law contribute to resistance in the lungs. The Law of Laplace states that the pressure inside a spherical structure, like an alveolus in the lungs, is directly proportional to the surface tension and inversely proportional to the radius of the structure. This means that smaller alveoli have higher pressure, leading to increased resistance. Poisuelle's law states that the flow rate of a fluid through a tube is directly proportional to the pressure difference between the ends of the tube and the fourth power of the radius, and inversely proportional to the viscosity of the fluid. In the lungs, this means that smaller airways have higher resistance to airflow.
7.
Lung compliance is increased with emphysema.
Correct Answer
A. True
Explanation
Decreased w/fibrosis, obesity, edema, ARDS, external forces.
8.
Normal lung compliance is ___ mL/cmH2O
Correct Answer
200
Explanation
Normal lung compliance is a measure of the lung's ability to stretch and expand. It is defined as the change in lung volume per unit change in pressure. A higher compliance indicates that the lungs are more elastic and can expand easily, while a lower compliance suggests stiffness or decreased ability to expand. The answer, 200 mL/cmH2O, indicates that the normal lung compliance is 200 milliliters per centimeter of water pressure change.
9.
Which of the following is not true about the dorsal respiratory group?
Correct Answer
C. Controls expiration with forceful breathing
Explanation
The dorsal respiratory group is responsible for the basic rhythm of ventilation and sends impulses to the diaphragm and external intercostal muscles, which contradicts the statement that it controls expiration with forceful breathing. Therefore, the statement that controls expiration with forceful breathing is not true about the dorsal respiratory group.
10.
The _____ respiratory group deals mostly with expiration.
Correct Answer
Ventral
Explanation
The ventral respiratory group is responsible for controlling expiration. It is located in the ventral part of the medulla oblongata in the brainstem. This group of neurons sends signals to the muscles involved in breathing, specifically the muscles that contract during expiration. Therefore, the correct answer is "ventral."
11.
Central chemoreceptors are located in the _____ surface of the medulla.
Correct Answer
ventral
Explanation
The central chemoreceptors are located in the ventral surface of the medulla. This means that they are positioned on the underside of the medulla, towards the front of the brainstem. The ventral surface is important for detecting changes in the levels of carbon dioxide and pH in the cerebrospinal fluid. These chemoreceptors play a crucial role in regulating breathing by sensing these changes and sending signals to the respiratory centers in the brainstem to adjust the rate and depth of breathing as needed.
12.
Central chemoreceptors respond to changes in pO2.
Correct Answer
B. False
Explanation
Hydrogen ion concentration or pCO2.
13.
Changes in pCO2 are the most important stimulus to ventilation because CO2 is soluble and readily crosses the blood brain barrier, where H+ and HCO3- are polar and do not cross.
Correct Answer
A. True
Explanation
Changes in pCO2 are the most important stimulus to ventilation because CO2 is soluble and readily crosses the blood brain barrier, while H+ and HCO3- are polar and cannot cross. This means that an increase in pCO2 levels will result in an increase in the concentration of CO2 in the brain, leading to an increase in the production of H+ ions. This increase in H+ ions stimulates the central chemoreceptors in the brainstem, which in turn increases ventilation to remove excess CO2 from the body. Therefore, changes in pCO2 play a crucial role in regulating ventilation.
14.
Carotid bodies and aortic bodies are the location of _______ chemoreceptors.
Correct Answer
Peripheral
Explanation
Carotid bodies and aortic bodies are the location of peripheral chemoreceptors. These chemoreceptors are responsible for detecting changes in the levels of oxygen, carbon dioxide, and pH in the blood. They are located in the carotid arteries and aorta, which are major blood vessels in the body. When these chemoreceptors detect low oxygen levels or high carbon dioxide levels, they send signals to the brain to increase respiration and maintain the body's homeostasis. Therefore, the correct answer is peripheral.
15.
Peripheral chemoreceptors respond to decreases in ARTERIAL pO2 and pH and somewhat to increases in pCO2.
Correct Answer
A. True
Explanation
These receptors are responsible for all of the increase in ventilation d/t arterial hypoxemia
16.
The rate of diffusion is directly proportional to:
Correct Answer(s)
A. Surface area
B. Partial pressure difference of gas
C. Solubility of gas
Explanation
The other two are inversely proportional to the rate of diffusion.
17.
_% of cardiac output goes to lung parynchema, not participating in gas exchange.
Correct Answer(s)
2
18.
What is the partial pressure of inspired O2 in room air at sea level? Round to the nearest whole number.
Correct Answer(s)
150
Explanation
Remember to subtract 47 mmHg of water vapor pressure when dealing with gases inside the body.
19.
PiO2 - (PACO2/RQ) is the equation for ______ PO2. This is determined by the balance of O2 removal and replenishment.
Correct Answer(s)
Alveolar
Explanation
RQ = respiratory quotient, normally 0.8
20.
Your patient's A-a gradient and CO2 gradient is greater than normal, this implies a ____ mismatch.
Correct Answer(s)
V/Q
Explanation
Normal PaCO2-PACO2 gradient is 2-10 mmHg.
If either gradient is normal it is either hypoventilation or altitude.
If either gradient is greater than normal is it a V/Q mismatch.
21.
What is the equation for total O2 delivered?
Correct Answer(s)
(1.39XHgbXsat/100) + (0.003xPO2)
Explanation
Max amount is usually 20.4 mL of O2 per 100 mL blood.
22.
The body requires 120-200 mL/min of O2.
Correct Answer
A. True
Explanation
Body needs 15-20 mL of O2 per 100 mL of blood
O2 is either dissolved or transported by Hgb
23.
Henry's law applies to _________ oxygen. It states that each 1 mmHg of PO2 dissolves into 0.003 mL O2/100 mL of blood.
Correct Answer
dissolved
Explanation
Not efficient, only 3 mL of O2 per liter of blood
24.
1 gram of Hgb contains ____ mL of O2.
Correct Answer
1.39
Explanation
When PO2 is high, all Hgb sites are bound - this will show 100% oxygen saturation but this doesn't necessarily indicate the amount of O2 in the blood that can be delivered to tissues.
25.
All of the following cause O2 dissociation curve to shift to the right (O2 affinity for hgb is reduced) EXCEPT:
Correct Answer
C. Increase in CO levels
Explanation
Right shift:
Less O2 carried by Hgb, more unloading to tissue.
Increase PCO2 and 2-3 DPG which is an end product of red cell metabolism assoc w/chronic hypoxia.
Maternal hgb - offloads o2 to fetus
Opioid use causing acidosis
Left shift:
O2 affinity for Hgb is increased
Decrease temp, increase pH, decrease PCO2, decrease 2-3 DPG
Increase CO levels - prevents O2 from unloading to tissue, worsening CO poisoning. CO 200-400x more affinity for Hgb than O2.
Fetal hgb.
Methemoglobin
26.
According to Henry's Law, CO2 is 20x more soluble than O2, meaning the equation to determine how much CO2 is dissolved in blood is ____ mL x PaCO2.
Correct Answer
0.067
Explanation
According to Henry's Law, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas. In this case, since CO2 is 20 times more soluble than O2, the equation to determine the amount of CO2 dissolved in blood is given by multiplying the mL value by the partial pressure of CO2 (PaCO2). Therefore, the correct answer is 0.067.
27.
The Hamburger shift occurs when H+ ion levels increase in a cell, HCO3 diffuses out, and ____ ions move into the cell to maintain electrical neutrality.
Correct Answer
chloride
Explanation
Also known as chloride shift
28.
What does this flow loop indicate?
Correct Answer
A. Obstruction
Explanation
This flow loop indicates an obstruction.
29.
What does this flow loop indicate?
Correct Answer
C. Restrictive
Explanation
This flow loop indicates a restrictive pattern. A restrictive pattern refers to a decrease in lung volume due to stiffness or scarring of the lung tissue. It is characterized by a reduced ability to expand the lungs and a decreased flow of air. This can be caused by conditions such as pulmonary fibrosis or chest wall deformities.
30.
Endothelin-1 and thromboxane A2 are examples of potent ________.
Correct Answer
vasoconstrictors
Explanation
Endothelin-1 and thromboxane A2 are both known for their ability to constrict blood vessels, leading to an increase in blood pressure. They are considered potent vasoconstrictors because they cause the narrowing of blood vessels, reducing blood flow and increasing vascular resistance. This can have various physiological effects, such as regulating blood pressure and blood flow distribution.
31.
Measurement of pulmonary blood flow using Fick's Principle:Q = VO2/CaO2-CvO2Where Q = flow, the volume of blood passing through the lungs each minuteVO2 = O2 consumption per minuteCvO2 is the concentration of O2 entering the lungsCaO2 is the concentration of O2 _______ the lungs.
Correct Answer
leaving
Explanation
The concentration of O2 leaving the lungs is represented by CaO2 in the equation. This is because Fick's principle is used to measure the pulmonary blood flow, which is the volume of blood passing through the lungs each minute. In this equation, the difference between the concentration of O2 entering the lungs (CvO2) and the concentration of O2 leaving the lungs (CaO2) is divided by the O2 consumption per minute (VO2) to calculate the flow. Therefore, the correct answer is "leaving".
32.
Regarding pulmonary blood flow, select all that apply
Correct Answer(s)
A. Mean PA pressure is 15 mmHg
B. Pulmonary artery walls are thin with little smooth muscle
D. Alveolar vessels can be compressed by increased alveolar pressure d/t high ventilator settings.
Explanation
Pulmonary blood flow accepts 100% of cardiac output
Pulmonary vascular resistance - Ohm's law (input pressure - output pressure/blood flow) normally small, decreases with exercise, increases w/alveolar hypoxia and at high and low lung volumes.
33.
Which gas has the faster reaction rate with Hgb?
Correct Answer
A. O2
Explanation
Oxygen (O2) has a faster reaction rate with hemoglobin (Hgb) compared to carbon dioxide (CO2). This is because oxygen binds to the iron in hemoglobin to form oxyhemoglobin, which is crucial for oxygen transport in the blood. On the other hand, carbon dioxide primarily forms bicarbonate ions in the blood, which helps regulate pH levels but does not directly bind to hemoglobin. Therefore, O2 has a higher affinity for hemoglobin and reacts more rapidly with it than CO2.