Chapter 22 Study Guide

o   What is the most important function of the respiratory system?

• supply tissues with O2

• dispose of CO2

• functions in olfaction and speech

o   Define the four processes of respiration including pulmonary ventilation, external respiration, transport, and internal respiration.

Respiratory system:

• pulmonary ventilation

• external respiration

  circulatory system:

• gas transport

• internal respiration

o   What are five major functions of the nose?

1. provides an airway for respiration

2. moistens and warms entering the air

3. filters and cleans inspired air

4. serves as a resonating chamber for speech

5. houses olfactory receptors

o   What are two functions of the paranasal sinuses?

• Lighten the weight of the skull

• Improve voice resonance

o   What are the names of the four paranasal sinuses?

• Frontal sinus

• Maxillary sinus

• Ethmoid sinus

• Sphenoid sinus

o   Name the three regions of the pharynx from superior to inferior.

• nasopharynx

• oropharynx

• laryngopharynx

o   Which type of epithelium lines the nasopharynx? How does this relate to the function of the nasopharynx?

The nasopharynx is lined with pseudostratified ciliated columnar epithelium, which helps trap and move particles out of the airway, playing a crucial role in respiratory health.

o   Why is it important for the lining of the oropharynx to transition to stratified squamous epithelium?

This transition is important because the oropharynx is involved in both respiratory and digestive functions, and the stratified squamous epithelium provides greater protection against abrasion from food and liquids.

o   Which type of epithelium lines the laryngopharynx? How does this relate to the function of the laryngopharynx?

The laryngopharynx is lined with stratified squamous epithelium as well, which is essential for protecting the airway from mechanical stress and potential damage during swallowing, ensuring a safe passage for both air and food.

o   Which respiratory structures make up the conducting zone of the airway?

The conducting zone of the airway includes the nasal cavity, pharynx, larynx, trachea, bronchi, and bronchioles, all of which are responsible for filtering, warming, and humidifying the air before it reaches the lungs.

o   Which respiratory structures make up the respiratory zone of the airway?

The respiratory zone of the airway comprises the respiratory bronchioles, alveolar ducts, and alveoli, where gas exchange occurs between the air and blood.

o   Does gas exchange happen in structures of the conducting zone of the airway or the respiratory zone?

Gas exchange occurs exclusively in the structures of the respiratory zone, as these are specialized for facilitating the exchange of oxygen and carbon dioxide.

o   What are the three main functions of the larynx?

• provides patient airway

• routes air and food into proper channels

• voice production (houses vocal cords- true & false)

o   Of which type of cartilage are the thyroid cartilage and cricoid cartilage made?

Both the thyroid cartilage and cricoid cartilage are made of hyaline cartilage, which provides support while allowing flexibility.

o   Of which type of cartilage is the epiglottis made?

made of elastic cartilage

o   What is the function of the glottis?

The glottis is responsible for producing sound during phonation and controlling airflow during breathing.

o   What is the function of the epiglottis?

• The epiglottis acts as a flap that covers the glottis during swallowing, preventing food and liquids from entering the trachea and directing them into the esophagus.

o   To what bone does the larynx attach?

attaches to the hyoid bone

o   What is the function of the vocal folds (true vocal cords)?

true- vibrate to produce sounds

o   What is the function of the vestibular folds (false vocal cords)?

false- help close glottis during swallowing

o   Name the four layers of the trachea.

• Mucosa: the innermost layer, lined with ciliated epithelium to trap particles

• Submucosa: contains connective tissue, blood vessels, and glands

• Cartilage: C-shaped rings that provide structural support

• Adventitia: the outermost layer that anchors the trachea to surrounding tissues.

o   What role does hyaline cartilage play in the structure and function of the trachea?

C shaped rings of hyaline cartilage keep trachea open

o   Why is it useful for the esophagus that the cartilage rings around the trachea leave a gap at the posterior side of the trachea?

This gap allows the esophagus to expand during swallowing, accommodating the passage of food without obstruction.

o   What is the carina?

carina- point where trachea branches into right and left main (primary) bronchi

o   Name the three divisions of the bronchi that connect the carina to the bronchioles.

• Main (primary) bronchi

• Lobar (secondary) bronchi

• Segmental (tertiary) bronchi

o   What is the diameter at which a bronchus is considered a bronchiole?

A bronchus is considered a bronchiole when its diameter is less than 1 millimeter.

o   What is the diameter at which a bronchiole is considered a terminal bronchiole?

A bronchiole is considered a terminal bronchiole when its diameter is less than 0.5 millimeters.

o   Of what two layers is the thin respiratory membrane composed?

The thin respiratory membrane is composed of the alveolar epithelium and the endothelial cells of the capillaries.

o   Name the main cell type in the epithelial layer of the respiratory membrane.

The main cell type in the epithelial layer of the respiratory membrane is the type I alveolar cell, which facilitates gas exchange.

o   Why is it important that the respiratory membrane be incredibly thin?

The thinness of the respiratory membrane is crucial because it allows for efficient diffusion of oxygen and carbon dioxide between the alveoli and the blood, ensuring that gas exchange occurs rapidly and effectively.

o   What are the main gasses being exchanged at the respiratory membrane?

The primary gases exchanged at the respiratory membrane are oxygen (O2), which is taken up by the blood, and carbon dioxide (CO2), which is expelled from the blood into the alveoli for exhalation.

o   Name the secretion of type II alveolar cells that prevents the alveoli from collapsing during exhalation.

The secretion of type II alveolar cells that prevents the alveoli from collapsing during exhalation is known as surfactant.

o   Be able to place in order the airway structures from the nasal passages to the alveoli.

1. Nasal passages

2. Pharynx

3. Larynx

4. Trachea

5. Bronchi

6. Bronchioles

7. Alveolar ducts

8. Alveoli

o   The base of the lung rests on the diaphragm.

o   The apex of the lung is located deep to the clavicle.

o   What is the name of the space provided for the heart by the smaller size of the left lung?

• Cardiac notch: A concave space that accommodates the shape of the heart.

o   What is the name for the structure (curvature) at which the bronchi and blood vessels enter the lung?

Hilum: The region on the medial side of the lung where the bronchi, blood vessels, and nerves enter and exit.

o   Of what type of membrane are the pleura an example?

Pleura: Serous membrane that lines the thoracic cavity and covers the lungs, consisting of two layers—the visceral pleura that adheres to the lung surface and the parietal pleura that lines the chest wall.

o   Which layer of the pleura covers the thoracic wall? Which layer covers the external surface of the lungs?

Parietal pleura- covers the thoracic wall

Visceral pleura- covers the external surface of the lungs.

o   What are two functions of the pleura related to lung function?

• Reduces friction during breathing by providing a lubricated surface between the lungs and thoracic wall.

• Helps to create a pressure gradient that aids in lung inflation.

o   The relationship between pressures in which three locations determines the flow of air into and out of the lungs? (Figure 22.14)

• The atmospheric pressure, which is the pressure outside the body;

• The intrapulmonary pressure, which is the pressure within the alveoli of the lungs;

• The intrapleural pressure, which is the pressure within the pleural cavity.

o   The period during which air exits the lungs is called expiration.

o   The period during which air enters the lungs is called inspiration.

o   Why is atmospheric pressure important when thinking about ventilation?

Atmospheric pressure is crucial for ventilation as it provides the necessary force for air to flow into and out of the lungs, facilitating the exchange of gases.

o   Define intrapulmonary pressure.

• pressure in alveoli

• fluctuates with breathing

o   Define intrapleural pressure and describe how it is important for ventilation.

• pressure in pleural cavity

• fluctuates with breathing

• always negative compared to Patm and Ppul.

o   Which pressure is always negative in healthy individuals?

• Intrapleural pressure: This pressure remains negative to prevent lung collapse and facilitate inflation during inhalation.

o   What happens if the transpulmonary pressure equals zero? What is this condition called and what might cause it?

If the transpulmonary pressure equals zero, it results in lung collapse, a condition known as pneumothorax, which can be caused by trauma, disease, or a rupture of the pleural space.

o   What does it mean for air to “flow down its pressure gradient?”

This phrase refers to the natural movement of air from areas of higher pressure to areas of lower pressure, allowing for the exchange of gases in the respiratory system.

o   Relative to atmospheric pressure, during which phase of ventilation is intrapleural pressure highest? In which phase is it lowest? (Figure 22.17)

• Intrapleural pressure is highest during the expiration phase, as the lungs recoil and push air out, increasing pressure in the pleural space.

• Conversely, intrapleural pressure is lowest during the inspiration phase when the diaphragm contracts and the thoracic cavity expands, creating a negative pressure that facilitates air inflow.

o   Relative to atmospheric pressure, during which phase of ventilation is intrapulmonary pressure highest? In which phase is it lowest? (Figure 22.17)

Intrapulmonary pressure is highest during the expiration phase, as the air is pushed out of the lungs, resulting in increased pressure within the airways. Conversely, intrapulmonary pressure is lowest during the inspiration phase when air is drawn into the lungs, leading to a decrease in pressure relative to atmospheric pressure.

o   Is ventilation an active or passive process?

Ventilation is considered an active process during inspiration, as it requires energy expenditure to contract the diaphragm and intercostal muscles. Conversely, expiration is typically a passive process driven by the elastic recoil of the lungs.

o   Which muscle must contract to create a normal quiet inspiration?

The diaphragm must contract to create a normal quiet inspiration, allowing for an increase in thoracic cavity volume and facilitating the inflow of air into the lungs.

o   Which muscles must contract to create a forced inspiration?

The external intercostal muscles, along with the diaphragm, must contract to create a forced inspiration, further expanding the thoracic cavity and allowing for a greater volume of air to enter the lungs.

o   What happens to intrapulmonary and intrapleural pressures when the diaphragm contracts? What happens when the diaphragm relaxes?

When the diaphragm contracts, intrapulmonary pressure decreases below atmospheric pressure, facilitating air inflow, while intrapleural pressure becomes more negative, aiding lung expansion. Conversely, when the diaphragm relaxes, intrapulmonary pressure increases as the thoracic cavity volume decreases, leading to air being expelled from the lungs, while intrapleural pressure returns to its baseline level.

o   Is normal quiet expiration active or passive?

Normal quiet expiration is considered a passive process, as it relies on the elastic recoil of the lungs and the relaxation of the diaphragm and intercostal muscles, allowing air to flow out without the need for active muscular contraction.

o   Which muscles must contract to create a forced expiration?

To create a forced expiration, the abdominal muscles (such as the rectus abdominis and obliques) and the internal intercostal muscles must contract, actively decreasing the volume of the thoracic cavity and pushing air out of the lungs.

o   What are the five steps of inspiration? What are the five steps of expiration? (Figure 22.16)

1. Inspiration Steps:

   • Diaphragm contracts and moves downward, increasing the thoracic cavity volume.

   • External intercostal muscles contract, elevating the ribs.

   • Thoracic cavity expands, reducing pressure inside the lungs.

   • Air flows into the lungs due to the pressure gradient.

   • Lungs fill with air until intrapulmonary pressure equals atmospheric pressure.

2. Expiration Steps:

   • Diaphragm relaxes and moves upward, decreasing the thoracic cavity volume.

   • Internal intercostal muscles contract, pulling the ribs downward.

   • Thoracic cavity decreases, increasing pressure inside the lungs.

   • Air is pushed out of the lungs due to the pressure gradient.

   • Expiration continues until intrapulmonary pressure equals atmospheric pressure.

o   Name three physical factors that influence pulmonary ventilation.

• Lung compliance: The ease with which the lungs can expand during inhalation.

• Airway resistance: The degree of obstruction in the airways that can impede airflow.

• Surface tension: The force exerted by the fluid lining the alveoli that can affect lung inflation.

o   What is the relationship between airway resistance and air flow during ventilation?

ventilation will fall as airway resistance increases

o   What is the relationship between lung compliance and air flow during ventilation?

ventilation will fall as lung compliance falls

o   What is the relationship between alveolar surface tension and air flow during ventilation?

ventilation will fall as alveolar surface tension increases

o   Why is surfactant important for lung function? What would happen to alveoli in the absence of surfactant?

surfactant reduces alveolar surface tension and prevents collapse upon expiration

o   What is the major cause of infant respiratory distress syndrome (IRDS) in premature babies born before 28 weeks of development?

The major cause of infant respiratory distress syndrome (IRDS) in premature babies born before 28 weeks of development is the insufficient production of surfactant, which leads to increased surface tension in the alveoli, causing them to collapse and resulting in difficulty breathing.

o   What is the typical treatment for IRDS?

The typical treatment for IRDS includes the administration of exogenous surfactant to improve lung function and reduce surface tension, along with supportive care such as oxygen therapy and mechanical ventilation if necessary.

o   Name the volume of air inhaled or exhaled under resting conditions.

The volume of air inhaled or exhaled under resting conditions is referred to as the tidal volume.

o   Name the volume of air inhaled or exhaled with forced ventilation.

The volume of air inhaled or exhaled with forced ventilation is known as the vital capacity.

o   Name the volume of air that can be forcefully inhaled beyond a normal tidal volume inspiration.

The volume of air that can be forcefully inhaled beyond a normal tidal volume inspiration is called the inspiratory reserve volume.

o   Name the volume of air that can be forcefully exhaled beyond a normal tidal volume expiration.

The volume of air that can be forcefully exhaled beyond a normal tidal volume expiration is known as the expiratory reserve volume.

o   Name the amount of air that can be forcefully inspired.

The amount of air that can be forcefully inspired is referred to as the inspiratory capacity.

o   Name the amount of air that can be forcefully expired.

The amount of air that can be forcefully expired is known as the expiratory reserve volume.

o   Name the lung volume that remains after a forced exhalation.

The lung volume that remains after a forced exhalation is called the residual volume.

o   Name the maximum amount of air that can be contained in the lungs.

The maximum amount of air that can be contained in the lungs is referred to as the total lung capacity.

o   How is Dalton’s law related to the composition of the atmosphere?

Dalton's law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas, which helps us understand how different gases contribute to the overall atmospheric pressure.

o   What is a partial pressure? What units do we normally use to measure partial pressure of a gas?

Partial pressure is defined as the pressure that a single gas in a mixture would exert if it occupied the entire volume by itself. Typically, we measure partial pressure in units of millimeters of mercury (mmHg) or atmospheres (atm).

o   Is the partial pressure of oxygen higher in the atmosphere or in the alveoli?

The partial pressure of oxygen is higher in the atmosphere, where it is approximately 21% of the total atmospheric pressure, compared to the alveoli, where it is lower due to the mixing of gases during respiration.

o   Is the partial pressure of oxygen higher in the alveoli or in the pulmonary capillary blood?

The partial pressure of oxygen is higher in the pulmonary capillary blood, as oxygen diffuses from the alveoli into the blood, increasing its concentration in the capillaries.

o   Is the partial pressure of carbon dioxide higher in the atmosphere or in the alveoli?

The partial pressure of carbon dioxide is higher in the alveoli due to the accumulation of CO2 from the blood during respiration, making it essential for gas exchange.

o   Is the partial pressure of carbon dioxide higher in the alveoli or in the pulmonary capillary blood?

The partial pressure of carbon dioxide is higher in the pulmonary capillary blood, as CO2 is transported from the tissues to the lungs, where it will be expelled during exhalation.

o   Which are three major gases found in the atmosphere? What is the typical percentage of each gas at sea level? What is the typical partial pressure of each gas at sea level?

• Nitrogen (N2): 78.08% - Partial pressure: 593 mmHg

• Oxygen (O2): 20.95% - Partial pressure: 159 mmHg

• Argon (Ar): 0.93% - Partial pressure: 0.7 mmHg

o   Where does external respiration occur? Where does internal respiration occur?

• External respiration occurs in the lungs, where oxygen is exchanged for carbon dioxide between the alveoli and the blood.

• Internal respiration occurs at the cellular level, where oxygen is utilized by tissues to produce energy while carbon dioxide is released as a byproduct.

o   Which three factors influence external respiration?

The three factors that influence external respiration are:

• Partial pressure gradients of oxygen and carbon dioxide between the alveoli and the blood.

• Surface area available for gas exchange, which can be affected by the health of the lungs.

• The thickness of the respiratory membrane, as a thinner membrane facilitates more efficient gas exchange.

o   On what three factors does the amount of a gas that will dissolve in a liquid depend?

1. The partial pressure of the gas in contact with the liquid.

2. The solubility of the gas in the liquid.

3. The temperature of the liquid, as higher temperatures can decrease gas solubility.

o   What are two ways in which oxygen is transported through the blood? Which one is, by far, the most important?

• Dissolved in plasma: A small amount of oxygen is transported dissolved directly in the plasma.

• Bound to hemoglobin: The majority of oxygen is carried by hemoglobin in red blood cells, making this the most important method of oxygen transport.

o   Define hypoxia. What is a visible sign of hypoxia in pale-skinned people? Name a few common causes.

Hypoxia is a condition in which there is a deficiency of oxygen in the tissues. A visible sign of hypoxia in pale-skinned individuals is cyanosis, which is a bluish discoloration of the skin, particularly around the lips and fingertips. Common causes of hypoxia include high altitudes, respiratory diseases, and carbon monoxide poisoning.

o   What is the relationship between the arterial partial pressure of oxygen and the binding of oxygen to hemoglobin?

The relationship between the arterial partial pressure of oxygen (PaO2) and the binding of oxygen to hemoglobin is described by the oxygen-hemoglobin dissociation curve, which shows that as PaO2 increases, the affinity of hemoglobin for oxygen also increases, allowing more oxygen to bind. Conversely, at lower PaO2 levels, hemoglobin releases oxygen more readily to the tissues.

o   What is the relationship between pH and oxygen binding to hemoglobin?

The relationship between pH and oxygen binding to hemoglobin is explained by the Bohr effect, which states that a decrease in pH (increased acidity) reduces hemoglobin's affinity for oxygen, promoting oxygen release to the tissues. Conversely, an increase in pH (decreased acidity) enhances hemoglobin's affinity for oxygen, facilitating oxygen binding.

o   What is the relationship between carbon dioxide partial pressure and oxygen binding to hemoglobin?

The relationship between carbon dioxide partial pressure and oxygen binding to hemoglobin is also described by the Bohr effect, where an increase in carbon dioxide (CO2) levels leads to a decrease in pH, thereby reducing hemoglobin's affinity for oxygen. This results in enhanced oxygen release in tissues where CO2 concentration is high, ensuring that oxygen delivery is matched to metabolic demand.

o   What is the name of the effect that describes the relationship between pH, P_CO2, and hemoglobin binding to oxygen?

The effect that describes the relationship between pH, PCO2, and hemoglobin binding to oxygen is known as the Bohr effect.

o   What is the relationship between temperature and oxygen binding to hemoglobin?

An increase in temperature reduces hemoglobin's affinity for oxygen, promoting oxygen release in active tissues that generate heat, further facilitating oxygen delivery during metabolic activity.

o   What is the relationship between BPG and oxygen binding to hemoglobin?

An increase in 2,3-bisphosphoglycerate (BPG) levels decreases hemoglobin's affinity for oxygen, enhancing oxygen release in tissues where it is most needed, particularly during states of high metabolic demand.

o   Name three ways carbon dioxide is transported through the blood. Which is the most typical?

• Dissolved in plasma (approximately 7% of CO2 is transported this way)

• Bound to hemoglobin as carbaminohemoglobin (about 23% of CO2)

• Converted to bicarbonate ions (HCO3-) in red blood cells, which is the most typical method (about 70% of CO2 is transported this way).

o   What is the relationship between the partial pressure of oxygen and the amount of carbon dioxide that hemoglobin can carry? What is the name of this effect?

The relationship is known as the Haldane effect, which states that an increase in the partial pressure of oxygen (pO2) leads to a decrease in the affinity of hemoglobin for carbon dioxide (CO2), thereby enhancing CO2 release in the lungs.

o   Where are the respiratory centers located?

The respiratory centers are primarily located in the brainstem, specifically in the medulla oblongata and the pons, which regulate the rate and depth of breathing.

o   What is a normal breathing rate during eupnea?

A normal breathing rate during eupnea is typically between 12 to 20 breaths per minute for adults, reflecting a state of restful and efficient breathing.

o   Which two peripheral nerves innervate respiratory muscles?

The two peripheral nerves that innervate respiratory muscles are the phrenic nerve, which controls the diaphragm, and the intercostal nerves, which stimulate the intercostal muscles.

o   Describe the relationships between blood pH, oxygen partial pressure, carbon dioxide partial pressure, and breathing rate. (Figures 22.27 and 22.28)

The relationship between blood pH, oxygen partial pressure (pO2), carbon dioxide partial pressure (pCO2), and breathing rate is complex and interdependent. Generally, as pCO2 levels rise, blood pH decreases (becomes more acidic), leading to an increase in breathing rate to expel excess CO2 and restore pH balance. Conversely, a decrease in pO2 can also stimulate an increase in breathing rate to enhance oxygen intake. Therefore, the body continuously adjusts breathing patterns based on these parameters to maintain homeostasis.

o   Under normal circumstances, which factor has the biggest impact on breathing?

• Carbon dioxide partial pressure (pCO2) is typically the most significant factor influencing breathing rate, as the body is more sensitive to changes in CO2 levels than to variations in oxygen levels.

o   Under what circumstance does the partial pressure of oxygen have the biggest impact on breathing?

The partial pressure of oxygen (pO2) has the biggest impact on breathing during situations of hypoxia, where oxygen levels in the blood are significantly low. This can occur at high altitudes, in cases of respiratory diseases, or during strenuous exercise, prompting the body to increase the breathing rate to enhance oxygen uptake.

o   What factors can stimulate peripheral chemoreceptors?

Peripheral chemoreceptors can be stimulated by several factors, including low pO2 levels, increased pCO2 levels, and elevated hydrogen ion concentration (acidosis), all of which signal the body to adjust respiratory rates accordingly.

o   What factors can stimulate central chemoreceptors?

Central chemoreceptors are primarily stimulated by changes in the pH of cerebrospinal fluid, which is influenced by elevated pCO2 levels. This increase in pCO2 leads to a decrease in pH (acidosis), prompting the central chemoreceptors to signal for an increase in respiratory rate to expel more carbon dioxide and restore normal pH levels.

o   Define apnea.

Apnea is defined as a temporary cessation of breathing, which can occur during sleep or as a result of various medical conditions, potentially leading to decreased oxygen levels in the body.

o   Define hyperventilation. How does hyperventilation differ from hyperpnea?

Hyperventilation is characterized by an increased rate and depth of breathing that exceeds the body's metabolic needs, often resulting in a decrease in carbon dioxide levels (hypocapnia). In contrast, hyperpnea refers to an increased breathing rate that is proportional to the body's metabolic demands, such as during exercise, without causing a significant change in carbon dioxide levels.

o   Why can hyperventilation be dangerous? What is a simple method to reduce the symptoms of hyperventilation?

Hyperventilation can be dangerous because it may lead to symptoms such as dizziness, tingling in the extremities, and even loss of consciousness due to significantly reduced carbon dioxide levels in the blood. A simple method to reduce the symptoms of hyperventilation is to practice controlled breathing techniques, such as inhaling slowly through the nose and exhaling gently through pursed lips, which helps to restore normal breathing patterns and balance carbon dioxide levels.

o   What are four common features of COPD?

• Chronic cough: Often accompanied by sputum production, this persistent cough is a hallmark of COPD.

• Shortness of breath: Patients typically experience difficulty breathing, especially during physical activities.

• Wheezing: A whistling or squeaky sound during breathing, indicating narrowed airways.

• Frequent respiratory infections: Individuals with COPD are more susceptible to lung infections due to compromised lung function.

o   What are two major risk factors for COPD?

• Smoking: The leading cause of COPD, with both current and former smokers at increased risk.

• Exposure to environmental pollutants: Long-term exposure to harmful substances such as dust, chemicals, and fumes can contribute to the development of COPD.

o   How is asthma different from COPD?

Asthma is primarily characterized by reversible airway obstruction, often triggered by allergens or irritants, whereas COPD is marked by persistent airflow limitation that is not fully reversible.

o   What is the single largest risk factor for lung cancer?

The single largest risk factor for lung cancer is smoking, which accounts for approximately 85% of all cases.

o   What is the 5-year survival rate for lung cancer?

The 5-year survival rate for lung cancer varies significantly depending on the stage at which it is diagnosed, but overall, it is approximately 19% for all stages combined.