Cm rs

Chapter_015.rtf

15-4

Audio Chapter Summaries

Patton: Structure & Function of the Body, 17th Edition

Chapter 15: Respiratory System

Audio Chapter Summaries

Welcome to the audio review of Chapter 15: Respiratory System.

First, we’ll review the organization of the respiratory system.

A 3-dimensional visual of the respiratory system would be similar to an inverted tree if it were hollow; branches would be the bronchi, and leaves of the tree would be comparable to alveoli, with the microscopic sacs enclosed by networks of capillaries.

The passive transport process of diffusion is responsible for the exchange of gases that occurs during respiration.

The respiratory tract is divided into upper and lower portions.

The upper respiratory tract includes the nose, pharynx, and larynx.

The lower respiratory tract contains the trachea, bronchial tree, alveoli, and lungs.

The respiratory mucosa is a specialized membrane that lines the air distribution tubes in the respiratory tree. Three types of epithelium are present in the respiratory mucosa:

Ciliated pseudostratified epithelium lines most of the tract and produces mucus.

Stratified squamous epithelium lines the nostrils, vocal folds, and pharynx; it serves a protective function.

Simple squamous epithelium lines the alveoli and facilitates gas exchange.

The respiratory mucosa serves several functions:

More than 125 mL of mucus is produced each day. It forms a “mucous blanket” over much of the respiratory mucosa.

Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen.

The respiratory mucosa also supports what could be called the ciliary escalator; cilia on mucosal cells beat in only one direction, moving mucus upward to the pharynx for removal.

Now we’ll review some specifics about the upper respiratory tract.

A nasal septum separates the interior of the nose into two cavities, called nares or nostrils.

Frontal, maxillary, sphenoidal, and ethmoidal sinuses of the skull drain into the nose.

Three shelflike structures in the nasal cavity called conchae or turbinates warms and moistens inhaled air. The nose also houses the sense organs of smell.

The pharynx or throat is about 12.5 cm (or 5 inches) long. It is divided into the nasopharynx, oropharynx, and the laryngopharynx.

The two nasal cavities, mouth, esophagus, larynx, and auditory tubes all have openings into the pharynx.

Pharyngeal tonsils and the openings of auditory tubes open into the nasopharynx. The tonsils are found in the oropharynx.

The pharynx functions as a passageway for food and liquids, as well as a passageway for air.

Nine pieces of cartilage form the framework of the last structure of the upper respiratory tract, the larynx.

The thyroid cartilage (also called the Adam’s apple) is the largest.

Note that the epiglottis partially covers the opening into the larynx.

Vocal cords stretch across the interior of the larynx.

Thus, one of the larynx’s functions is voice production. The other is air distribution; like the pharynx, it serves as a passageway for air to move to and from the lungs.

Next is a review of information about the lower respiratory tract.

The trachea is a tube about 11 cm (or 4.5 in) long and 2.5 cm (or 1 in) in diameter.

It extends from the larynx into the thoracic cavity.

C-shaped rings of cartilage hold the trachea open, but allow for swallowing.

The trachea functions as a passageway for air to move to and from the lungs.

Blockage of the trachea occludes the airway and, if complete, causes death in minutes.

In fact, tracheal obstruction causes more than 74000 deaths annually in the United States.

The bronchial tree is the next structure in the lower respiratory tract.

The trachea branches into right and left bronchi.

Each bronchus branches into smaller and smaller tubes, eventually leading to bronchioles.

Bronchioles end in clusters of microscopic alveolar sacs, the walls of which are made up of alveoli.

The function of the bronchial tree is air distribution; it serves as a passageway for air to move to and from alveoli.

The function of alveoli is the exchange of gases between air and blood.

The respiratory membrane is the thin wall that separates pulmonary blood from alveolar air, allowing diffusion of gases.

Surfactant is a substance released into alveoli to reduce surface tension and thus prevent collapse of the alveoli.

The lungs are large enough to fill the chest cavity, except for the middle space (the mediastinum) occupied by the heart, large blood vessels, thymus, and esophagus.

The apex of the lung is the narrow upper part, situated under the collarbone.

The base is the broad lower part of each lung; it rests on the diaphragm.

The pleura is the moist, smooth, slippery membrane that lines the chest cavity (the parietal pleura) and covers the outer surface of the lungs (the visceral pleura); The pleura reduces friction between the lungs and chest wall during breathing.

The function of lungs is respiration.

Next, we’ll review respiration and pulmonary ventilation.

Respiration involves several processes and mechanisms.

External respiration is pulmonary ventilation (or breathing) and pulmonary gas exchange.

These gases are transported by the blood and serve a function in the regulation of set point levels of blood gases.

Internal respiration is the gas exchange between the blood and systemic tissues. The term cellular respiration refers to the use of oxygen by cells in the process of metabolism.

To understand pulmonary ventilation, first you need to know the basic principles of the mechanics of breathing.

Pulmonary ventilation includes two phases called inspiration (movement of air into lungs) and expiration (movement of air out of lungs).

Changes in the size and shape of the thorax cause changes in air pressure within that cavity and in the lungs.

Pressure differences (or gradients) cause air to move into and out of the lungs.

Inspiration is the active process whereby air moves into the lungs.

Inspiratory muscles include the diaphragm and external intercostals.

The diaphragm flattens when stimulated by the phrenic nerve during inspiration, which increases the top-to-bottom length of the thorax.

The external intercostal muscles contract and elevate the ribs, which increases the size of the thorax from the front to the back and from side to side.

Increase in the size of the chest cavity reduces pressure within it; air then enters the lungs by moving down its pressure gradient.

Quiet expiration is ordinarily a passive process.

During expiration, the thorax returns to its resting size and shape.

Elastic recoil of lung tissues aids in expiration.

Expiratory muscles used in forceful expiration are the internal intercostals and abdominal muscles.

Contraction of the internal intercostals depresses the rib cage and decreases the size of the thorax from the front to back.

Contraction of abdominal muscles elevates the diaphragm, thus decreasing the size of the thoracic cavity from the top to bottom.

Reduction in the size of the thoracic cavity increases its pressure and air leaves the lungs.

Pulmonary volumes are volumes of air exchanged in breathing; they can be measured with a spirometer.

Tidal volume is the amount normally breathed in or out with each breath.

Vital capacity is the greatest amount of air that one can breathe out in one expiration.

Expiratory reserve volume is the amount of air that can be forcibly exhaled after expiring the tidal volume.

Inspiratory reserve volume is the amount of air that can be forcibly inhaled after a normal inspiration.

Residual volume is the air that remains in the lungs after the most forceful expiration.

Regulation of respiration permits the body to adjust to varying demands for oxygen supply and carbon dioxide removal by maintaining set point concentrations of blood gases.

Several mechanisms control respiration: the brainstem, cerebral cortex, and respiratory reflexes.

The most important central regulatory centers in both the medulla and pons in the brainstem are called respiratory control centers.

Under resting conditions, the medullary rhythmicity area produces a normal rate and depth of respirations. A normal rate is considered to be 12 to 18 breaths/min.

As conditions in the body vary, centers in the pons called the pontine respiratory group, can alter the activity of the medullary rhythmicity area, thus adjusting breathing rhythm.

Brainstem centers are influenced by information from other parts of the brain and from sensory receptors located in other body regions.

Control of respiratory activity by the cerebral cortex is voluntary but limited.

Respiratory reflexes include chemoreflexes and pulmonary stretch reflexes.

In chemoreflexes, chemoreceptors respond to changes in carbon dioxide, oxygen, and blood acid levels; these receptors are located in carotid and aortic bodies.

Pulmonary stretch reflexes respond to the stretch receptors in lungs, thus protecting respiratory organs from overinflation.

Be sure you understand the following terms for breathing patterns:

Eupnea is normal breathing.

Hyperventilation means rapid and deep respirations.

Hypoventilation indicates slow and shallow respirations.

Dyspnea is labored or difficult respirations.

Apnea is stopped respiration, absence of breathing.

Respiratory arrest is the failure to resume breathing after a period of apnea.

Cheyne-Stokes respiration are cycles of alternating apnea and hyperventilation associated with critical conditions.

Gas exchange and transport is the final section to review in Chapter 15.

Pulmonary gas exchange is the exchange of gases in the lungs. The following steps take place in pulmonary gas exchange.

Carbaminohemoglobin breaks down into carbon dioxide and hemoglobin.

Carbon dioxide moves out of lung capillary blood into alveolar air and out of the body into expired air.

Oxygen moves from alveoli into the lung capillaries.

Hemoglobin combines with oxygen, producing oxyhemoglobin.

Systemic gas exchange is the exchange of gases in tissues. The following steps take place in systemic gas exchange.

Oxyhemoglobin breaks down into oxygen and hemoglobin.

Oxygen moves out of tissue capillary blood into tissue cells.

Carbon dioxide moves from tissue cells into tissue capillary blood.

Hemoglobin combines with carbon dioxide, forming carbaminohemoglobin.

Blood transportation of gases includes transport of oxygen and carbon dioxide.

Only small amounts of oxygen gas can be dissolved in blood. Most oxygen combines with hemoglobin to form oxyhemoglobin to be carried in the blood.

Dissolved carbon dioxide is about 10% of the total carbon dioxide transported in the blood.

Carbaminohemoglobin is about 20%.

About 70% of the total carbon dioxide transported in the blood is carried in the form of bicarbonate ions.

This concludes the audio review of chapter 15.

Chapter_015.rtf

15-4

Audio Chapter Summaries

Patton: Structure & Function of the Body, 17th Edition

Chapter 15: Respiratory System

Audio Chapter Summaries

Welcome to the audio review of Chapter 15: Respiratory System.

First, we’ll review the organization of the respiratory system.

A 3-dimensional visual of the respiratory system would be similar to an inverted tree if it were hollow; branches would be the bronchi, and leaves of the tree would be comparable to alveoli, with the microscopic sacs enclosed by networks of capillaries.

The passive transport process of diffusion is responsible for the exchange of gases that occurs during respiration.

The respiratory tract is divided into upper and lower portions.

The upper respiratory tract includes the nose, pharynx, and larynx.

The lower respiratory tract contains the trachea, bronchial tree, alveoli, and lungs.

The respiratory mucosa is a specialized membrane that lines the air distribution tubes in the respiratory tree. Three types of epithelium are present in the respiratory mucosa:

Ciliated pseudostratified epithelium lines most of the tract and produces mucus.

Stratified squamous epithelium lines the nostrils, vocal folds, and pharynx; it serves a protective function.

Simple squamous epithelium lines the alveoli and facilitates gas exchange.

The respiratory mucosa serves several functions:

More than 125 mL of mucus is produced each day. It forms a “mucous blanket” over much of the respiratory mucosa.

Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen.

The respiratory mucosa also supports what could be called the ciliary escalator; cilia on mucosal cells beat in only one direction, moving mucus upward to the pharynx for removal.

Now we’ll review some specifics about the upper respiratory tract.

A nasal septum separates the interior of the nose into two cavities, called nares or nostrils.

Frontal, maxillary, sphenoidal, and ethmoidal sinuses of the skull drain into the nose.

Three shelflike structures in the nasal cavity called conchae or turbinates warms and moistens inhaled air. The nose also houses the sense organs of smell.

The pharynx or throat is about 12.5 cm (or 5 inches) long. It is divided into the nasopharynx, oropharynx, and the laryngopharynx.

The two nasal cavities, mouth, esophagus, larynx, and auditory tubes all have openings into the pharynx.

Pharyngeal tonsils and the openings of auditory tubes open into the nasopharynx. The tonsils are found in the oropharynx.

The pharynx functions as a passageway for food and liquids, as well as a passageway for air.

Nine pieces of cartilage form the framework of the last structure of the upper respiratory tract, the larynx.

The thyroid cartilage (also called the Adam’s apple) is the largest.

Note that the epiglottis partially covers the opening into the larynx.

Vocal cords stretch across the interior of the larynx.

Thus, one of the larynx’s functions is voice production. The other is air distribution; like the pharynx, it serves as a passageway for air to move to and from the lungs.

Next is a review of information about the lower respiratory tract.

The trachea is a tube about 11 cm (or 4.5 in) long and 2.5 cm (or 1 in) in diameter.

It extends from the larynx into the thoracic cavity.

C-shaped rings of cartilage hold the trachea open, but allow for swallowing.

The trachea functions as a passageway for air to move to and from the lungs.

Blockage of the trachea occludes the airway and, if complete, causes death in minutes.

In fact, tracheal obstruction causes more than 74000 deaths annually in the United States.

The bronchial tree is the next structure in the lower respiratory tract.

The trachea branches into right and left bronchi.

Each bronchus branches into smaller and smaller tubes, eventually leading to bronchioles.

Bronchioles end in clusters of microscopic alveolar sacs, the walls of which are made up of alveoli.

The function of the bronchial tree is air distribution; it serves as a passageway for air to move to and from alveoli.

The function of alveoli is the exchange of gases between air and blood.

The respiratory membrane is the thin wall that separates pulmonary blood from alveolar air, allowing diffusion of gases.

Surfactant is a substance released into alveoli to reduce surface tension and thus prevent collapse of the alveoli.

The lungs are large enough to fill the chest cavity, except for the middle space (the mediastinum) occupied by the heart, large blood vessels, thymus, and esophagus.

The apex of the lung is the narrow upper part, situated under the collarbone.

The base is the broad lower part of each lung; it rests on the diaphragm.

The pleura is the moist, smooth, slippery membrane that lines the chest cavity (the parietal pleura) and covers the outer surface of the lungs (the visceral pleura); The pleura reduces friction between the lungs and chest wall during breathing.

The function of lungs is respiration.

Next, we’ll review respiration and pulmonary ventilation.

Respiration involves several processes and mechanisms.

External respiration is pulmonary ventilation (or breathing) and pulmonary gas exchange.

These gases are transported by the blood and serve a function in the regulation of set point levels of blood gases.

Internal respiration is the gas exchange between the blood and systemic tissues. The term cellular respiration refers to the use of oxygen by cells in the process of metabolism.

To understand pulmonary ventilation, first you need to know the basic principles of the mechanics of breathing.

Pulmonary ventilation includes two phases called inspiration (movement of air into lungs) and expiration (movement of air out of lungs).

Changes in the size and shape of the thorax cause changes in air pressure within that cavity and in the lungs.

Pressure differences (or gradients) cause air to move into and out of the lungs.

Inspiration is the active process whereby air moves into the lungs.

Inspiratory muscles include the diaphragm and external intercostals.

The diaphragm flattens when stimulated by the phrenic nerve during inspiration, which increases the top-to-bottom length of the thorax.

The external intercostal muscles contract and elevate the ribs, which increases the size of the thorax from the front to the back and from side to side.

Increase in the size of the chest cavity reduces pressure within it; air then enters the lungs by moving down its pressure gradient.

Quiet expiration is ordinarily a passive process.

During expiration, the thorax returns to its resting size and shape.

Elastic recoil of lung tissues aids in expiration.

Expiratory muscles used in forceful expiration are the internal intercostals and abdominal muscles.

Contraction of the internal intercostals depresses the rib cage and decreases the size of the thorax from the front to back.

Contraction of abdominal muscles elevates the diaphragm, thus decreasing the size of the thoracic cavity from the top to bottom.

Reduction in the size of the thoracic cavity increases its pressure and air leaves the lungs.

Pulmonary volumes are volumes of air exchanged in breathing; they can be measured with a spirometer.

Tidal volume is the amount normally breathed in or out with each breath.

Vital capacity is the greatest amount of air that one can breathe out in one expiration.

Expiratory reserve volume is the amount of air that can be forcibly exhaled after expiring the tidal volume.

Inspiratory reserve volume is the amount of air that can be forcibly inhaled after a normal inspiration.

Residual volume is the air that remains in the lungs after the most forceful expiration.

Regulation of respiration permits the body to adjust to varying demands for oxygen supply and carbon dioxide removal by maintaining set point concentrations of blood gases.

Several mechanisms control respiration: the brainstem, cerebral cortex, and respiratory reflexes.

The most important central regulatory centers in both the medulla and pons in the brainstem are called respiratory control centers.

Under resting conditions, the medullary rhythmicity area produces a normal rate and depth of respirations. A normal rate is considered to be 12 to 18 breaths/min.

As conditions in the body vary, centers in the pons called the pontine respiratory group, can alter the activity of the medullary rhythmicity area, thus adjusting breathing rhythm.

Brainstem centers are influenced by information from other parts of the brain and from sensory receptors located in other body regions.

Control of respiratory activity by the cerebral cortex is voluntary but limited.

Respiratory reflexes include chemoreflexes and pulmonary stretch reflexes.

In chemoreflexes, chemoreceptors respond to changes in carbon dioxide, oxygen, and blood acid levels; these receptors are located in carotid and aortic bodies.

Pulmonary stretch reflexes respond to the stretch receptors in lungs, thus protecting respiratory organs from overinflation.

Be sure you understand the following terms for breathing patterns:

Eupnea is normal breathing.

Hyperventilation means rapid and deep respirations.

Hypoventilation indicates slow and shallow respirations.

Dyspnea is labored or difficult respirations.

Apnea is stopped respiration, absence of breathing.

Respiratory arrest is the failure to resume breathing after a period of apnea.

Cheyne-Stokes respiration are cycles of alternating apnea and hyperventilation associated with critical conditions.

Gas exchange and transport is the final section to review in Chapter 15.

Pulmonary gas exchange is the exchange of gases in the lungs. The following steps take place in pulmonary gas exchange.

Carbaminohemoglobin breaks down into carbon dioxide and hemoglobin.

Carbon dioxide moves out of lung capillary blood into alveolar air and out of the body into expired air.

Oxygen moves from alveoli into the lung capillaries.

Hemoglobin combines with oxygen, producing oxyhemoglobin.

Systemic gas exchange is the exchange of gases in tissues. The following steps take place in systemic gas exchange.

Oxyhemoglobin breaks down into oxygen and hemoglobin.

Oxygen moves out of tissue capillary blood into tissue cells.

Carbon dioxide moves from tissue cells into tissue capillary blood.

Hemoglobin combines with carbon dioxide, forming carbaminohemoglobin.

Blood transportation of gases includes transport of oxygen and carbon dioxide.

Only small amounts of oxygen gas can be dissolved in blood. Most oxygen combines with hemoglobin to form oxyhemoglobin to be carried in the blood.

Dissolved carbon dioxide is about 10% of the total carbon dioxide transported in the blood.

Carbaminohemoglobin is about 20%.

About 70% of the total carbon dioxide transported in the blood is carried in the form of bicarbonate ions.

This concludes the audio review of chapter 15.

Chapter_015.rtf

Chapter_015.rtf

Chapter_015.rtf