Otterbein/CRNA A&p Midterm Review - Respiratory

Hypoxia is a PaO2

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.

This flow loop indicates an obstruction.

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."

Not efficient, only 3 mL of O2 per liter of blood

Related to Starling's law
Net result is force pushing fluids out, which is drained by lymphatics.
20 mL/hr under normal conditions

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.

Hydrogen ion concentration or pCO2.

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.

These receptors are responsible for all of the increase in ventilation d/t arterial hypoxemia

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.

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.

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".

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.

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.

Remember to subtract 47 mmHg of water vapor pressure when dealing with gases inside the body.

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.

Related to Boyle's law - as pressure drops, volume increases.

Decreased w/fibrosis, obesity, edema, ARDS, external forces.

RQ = respiratory quotient, normally 0.8

not-available-via-ai

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.

The other two are inversely proportional to the rate of diffusion.

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.

Also known as chloride shift

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.

Body needs 15-20 mL of O2 per 100 mL of blood
O2 is either dissolved or transported by Hgb

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.

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.

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.

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.

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.

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

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.

Max amount is usually 20.4 mL of O2 per 100 mL blood.