Name: exhalation and lung pressure changes
Uploaded: 2024-09-12T13:22:46.000Z
Duration: 1 min 17 s
Channel: JoVE

K12 Standards

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

9-12

Human Anatomy and Physiology

Absorption And Excretion

Respiratory System

Pulmonary Cycle: Exhalation

La exhalación, el proceso de expulsar aire, durante la respiración tranquila en personas sanas depende de la elasticidad de los pulmones en lugar de la contracción muscular.
El retroceso de las fibras elásticas estiradas durante la inhalación causa principalmente el retroceso de los pulmones.
Además, el tirón interno de la tensión superficial creada por la capa de líquido intrapleural entre las pleuras viscerales y parietales contribuye a este retroceso pulmonar.
A medida que los músculos involucrados en la inhalación detienen su actividad, el diafragma y los intercostales externos se relajan, lo que hace que el diafragma ascienda y las costillas desciendan.
Estos movimientos reducen las dimensiones de la cavidad torácica, reduciendo así el volumen pulmonar.
Durante la exhalación, la presión intrapulmonar aumenta a 1 mm Hg por encima de la presión atmosférica. Y cuando la presión intrapulmonar es mayor que la presión atmosférica, el gas fluye fuera de los pulmones.
En contraste con esta exhalación tranquila, la exhalación forzada incluye la contracción de los músculos abdominales e intercostales. Obliga al diafragma a ascender desde su posición normal para expulsar el aire con fuerza.

ventilación pulmonar: exhalación

En términos de la respiración humana, el acto de expulsar aire, conocido como exhalación (o espiración), funciona según el principio de gradientes de presión. Durante la espiración, la presión dentro de los pulmones supera la de la atmósfera circundante. En condiciones normales, la respiración tranquila implica una exhalación pasiva y está libre de contracciones musculares. Esto se debe a que el proceso de exhalación está impulsado por la retracción elástica natural de los pulmones y la pared torácica, que tienen una tendencia inherente a volver a sus posiciones originales después de la expansión.

A medida que los músculos involucrados en la inspiración cesan su actividad, el diafragma y los intercostales externos se relajan. Esto hace que el diafragma desciende y las costillas descienden. Estos movimientos reducen las dimensiones de la cavidad torácica, lo que reduce el volumen pulmonar y aumenta la presión alveolar a aproximadamente 762 mm Hg. Esta diferencia de presión fuerza el flujo de aire desde los pulmones (presión más alta) hacia la atmósfera (presión más baja). La exhalación sólo requiere un esfuerzo activo durante un esfuerzo físico intenso, como hacer ejercicio o tocar un instrumento de viento. En esos momentos, los músculos que participan en la exhalación (los abdominales y los intercostales internos) se activan, lo que provoca presión en la zona abdominal y el tórax. La contracción de los músculos abdominales comprime los órganos abdominales, empujando el diafragma hacia arriba, mientras que los intercostales internos empujan las costillas hacia abajo a través de su extensión inferior y posterior entre las costillas adyacentes. Aunque la presión dentro de la pleura siempre permanece más baja que dentro de los alvéolos, puede superar momentáneamente la presión atmosférica durante una exhalación forzada, como la tos.

Algunas afecciones clínicas relacionadas con la ventilación pulmonar

<ol>
	<li>Síndrome de dificultad respiratoria neonatal
	El síndrome de dificultad respiratoria neonatal, o enfermedad de la membrana hialina, afecta principalmente a los bebés prematuros. Esta afección se produce debido a la producción insuficiente de surfactante en los pulmones, una sustancia que ayuda a mantener abiertos los alvéolos. Sin la cantidad adecuada de surfactante, los alvéolos colapsen durante la exhalación, lo que dificulta la respiración del bebé.

	Los síntomas del síndrome de dificultad respiratoria incluyen respiración rápida y superficial, ensanchamiento de las fosas nasales, gruñidos y un tinte azulado en la piel (cianosis). El tratamiento suele implicar proporcionar oxígeno suplementario y administrar una terapia de reemplazo de surfactante para mejorar la función pulmonar. La mayoría de los bebés se recuperan del síndrome de dificultad respiratoria en unos pocos días o semanas con la intervención médica adecuada.
	</li>
	<li>Atelectasia
	La atelectasia es el colapso parcial de una porción del pulmón. Esta afección puede ocurrir por varias razones, como vías respiratorias bloqueadas, heridas de arma blanca o de bala en el pecho, apertura quirúrgica del pecho o tejido pulmonar debilitado. Las causas comunes incluyen tapones mucosos, tumores, objetos extraños y complicaciones posquirúrgicas.

	Los síntomas de la atelectasia dependen de la extensión del colapso pulmonar y pueden incluir dolor en el pecho, dificultad para respirar, aumento de la frecuencia cardíaca y tos. Las opciones de tratamiento varían desde ejercicios de respiración profunda y técnicas para toser hasta broncodilatadores o cirugía en casos graves.
	</li>
	<li>Bronquitis
	La bronquitis es una inflamación de los bronquios. La afección puede ser aguda o crónica, siendo las infecciones virales la causa más común de bronquitis aguda. La bronquitis crónica, por otro lado, a menudo se asocia con la exposición prolongada a irritantes como el humo del tabaco y la contaminación del aire.
	</li>
</ol>

Los síntomas de la bronquitis pueden incluir tos persistente, producción de moco, malestar en el pecho y sibilancia. El tratamiento generalmente implica descanso, mantenerse hidratado, oxígeno, broncodilatadores y abordar la causa subyacente. Si hay una infección bacteriana, se pueden recetar antibióticos.

Ventilación pulmonar: exhalación

La exhalación, el proceso de expulsar aire, durante la respiración tranquila en personas sanas depende de la elasticidad de los pulmones en lugar de ...

Education

Educación

JoVE Core

Anatomy and Physiology

Anatomía y Fisiología

Unit 1

Unidad 1

The Respiratory System

El sistema respiratorio

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

exhalation and lung pressure changes

Exhalation is the process of expelling air from the lungs. It depends on pressure differences between the lungs and the atmosphere. During normal quiet breathing, exhalation is passive and does not require muscle contraction. The elastic recoil of the lungs and chest wall helps both structures return to their resting positions after inhalation.

When the muscles used for inhalation stop working, the diaphragm and external intercostal muscles relax. The diaphragm moves upward, and the ribs move downward. These changes make the thoracic cavity smaller and reduce lung volume. As a result, alveolar pressure rises to about 762 mm Hg, and air flows out of the lungs into the lower-pressure atmosphere.

Active exhalation happens during exercise or when playing a wind instrument. In these cases, the abdominal muscles and internal intercostals contract. Abdominal muscle contraction compresses the abdominal organs and pushes the diaphragm upward. The internal intercostals pull the ribs downward because of their inferior and posterior position between adjacent ribs.

The pressure in the pleural space remains lower than the pressure inside the alveoli, but it can briefly rise above atmospheric pressure during forceful exhalation, such as coughing. The same pressure changes that help air leave the lungs can also relate to lung problems. Neonatal respiratory distress syndrome, atelectasis, and bronchitis are all conditions connected to pulmonary ventilation.

Neonatal respiratory distress syndrome, also called hyaline membrane disease, mainly affects premature infants. It happens when the lungs do not produce enough surfactant, a substance that helps keep alveoli open. Without enough surfactant, alveoli can collapse during exhalation, which makes breathing difficult. Common signs include rapid shallow breathing, nostril flaring, grunting, and cyanosis, or a bluish skin color. Treatment often includes supplemental oxygen and surfactant replacement therapy, and many infants recover within days to weeks.

Atelectasis is a partial collapse of part of a lung. It can result from blocked airways, stab or gunshot wounds, surgical opening of the chest, or weakened lung tissue. Common causes include mucus plugs, tumors, foreign objects, and post-surgical complications. Symptoms may include chest pain, shortness of breath, a faster heart rate, and coughing. Treatment can include deep breathing exercises, coughing techniques, bronchodilators, or surgery in severe cases.

Bronchitis is inflammation of the bronchial tubes. Acute bronchitis is most often caused by viral infections. Chronic bronchitis is often linked to long-term exposure to irritants such as tobacco smoke and air pollution. Symptoms can include a persistent cough, mucus production, chest discomfort, and wheezing. Treatment usually includes rest, hydration, oxygen, bronchodilators, and care for the underlying cause. If a bacterial infection is present, antibiotics may be used.

Exhalation and Lung Pressure Changes

overview of respiratory system

How Breathing Moves Air and Gases

The respiratory system moves air in and out of the body and exchanges oxygen and carbon dioxide with the environment. This gas exchange is part of respiration, which is essential for life. The system supplies the blood with oxygen so it can carry that oxygen to the rest of the body. Breathing starts when air enters through the nose or mouth. The nose and nasal cavity form the main external opening and the first part of the airway. Air then passes through the pharynx, or throat, which is shared...

nose and nasal cavity

How the Nose Filters and Senses Air

The nose filters, warms, moistens, and senses the air that enters the body. It also helps shape speech as sound vibrations pass through its large air spaces. The nose has an external part that is visible on the face and an internal part called the nasal cavity. The external nose is built from bone and hyaline cartilage, which gives it flexibility. It is covered by skin and muscle and lined with a mucous membrane. The frontal bone, nasal bones, and maxillary bone support this structure. The...

pharynx

Pharynx Pathways for Air and Food

The pharynx is a muscular tube lined with mucous membrane that connects the nasal cavities to the throat. It is divided into three parts: the nasopharynx, oropharynx, and laryngopharynx. Each part has a different role in moving air and food through the upper throat. The nasopharynx sits behind the nasal cavity and serves only as an air passage. Its upper region contains the pharyngeal tonsils, also called adenoids. These are clusters of lymphoid reticular tissue, similar to a lymph node, and...

larynx

Voice Box Anatomy and Function

The larynx is the voice box in the neck. It carries air into the lungs and helps produce voice. Its structure is complex because it must support both breathing and sound production. The larynx contains cartilage, muscles, and the vocal cords, also called vocal folds. It includes three large unpaired cartilages: the thyroid, cricoid, and epiglottis. It also includes three paired cartilages: the arytenoids, corniculates, and cuneiforms. Ligaments and membranes hold these parts together. The...

trachea

Trachea: Layers, Rings, and Airflow

The trachea is the windpipe, and it is a key airway in the human respiratory system. It carries air between the larynx and the bronchi so oxygen can reach the lungs. About half of the trachea lies in the neck, and it sits in front of the esophagus. In an average adult, the trachea is about 10 to 12 cm long. It extends from the larynx at the level of the sixth cervical vertebra to the level of the fifth thoracic vertebra. Its wall is supported by C-shaped cartilaginous rings. The back side is...

the bronchial tree

Bronchial Branching and Airflow Control

The bronchial tree carries air from the trachea into the lungs and helps control breathing. The trachea, or windpipe, connects the larynx to the bronchi. At the carina, the trachea splits into two primary bronchi. The right primary bronchus is wider, shorter, and more vertical than the left. Because of that shape, foreign objects and infections are more likely to enter the right lung. The carina is a cartilaginous ridge at the split in the airway. It helps keep the airway open. It also has...

alveoli and alveolar ducts

How Alveoli Enable Gas Exchange

The respiratory zone of the human body is where gas exchange happens. It begins when the terminal bronchioles branch into respiratory bronchioles, the smallest bronchiole type. These then lead into alveolar ducts and finally into clusters of alveoli. Alveoli are tiny air sacs that look like bunches of grapes. They connect to alveolar ducts, and a group of alveoli forms an alveolar sac. A single alveolus is about 200 μm wide, and its elastic shape lets it expand during inhalation. Nearby...

gross anatomy of the lungs

Lung Lobes, Airways, and Blood Flow

The lungs are paired organs that connect to the trachea through the left and right bronchi. Their base rests against the diaphragm, the dome-shaped muscle below the lungs. The lungs are covered by the pleurae and sit next to the mediastinum, the central space in the chest. The right lung is shorter and wider than the left lung, and it has a larger volume. The left lung has a cardiac notch, which is an indentation for the heart. The top of each lung is the apex, and the lower part is the base.

pleura of the lungs

Pleura Layers and Lung Protection

The pleura are membranes that protect the lungs inside the chest cavity. They are a type of serous membrane and wrap around each lung. The pleura have two layers: the visceral pleura and the parietal pleura. The visceral pleura covers the surface of the lung. The parietal pleura is the outer layer. It lines the thoracic wall, the mediastinum, and the diaphragm. The hilum is the point where the visceral and parietal layers connect. The space between these layers is called the pleural cavity. <br...

pressure relationships in thoracic cavity

pressure-relationships-in-thoracic-cavity

How Pressure Drives Breathing in the Lungs

Breathing depends on pressure changes in the lungs, chest, and airways. Pulmonary ventilation is the movement of air into and out of the lungs. It is driven by atmospheric pressure, intra-alveolar pressure inside the alveoli, and intrapleural pressure in the pleural cavity. Inhalation and exhalation rely on pressure differences between the atmosphere and the lungs. Gas pressure comes from the movement of confined molecules. Boyle’s law explains that pressure and volume are inversely...

pulmonary ventilation: inhalation

Pulmonary Ventilation and Breathing Pressures

Pulmonary ventilation depends on breathing movements and the pressure changes that move air into and out of the lungs. It supports the exchange of oxygen and carbon dioxide by letting the body take in oxygen and remove waste carbon dioxide. Boyle's law is important here because changes in volume and pressure affect how air moves in the respiratory system. Several respiratory volumes help describe how much air the lungs move. Tidal volume is the air inspired or expired during normal, quiet...

pulmonary cycle: exhalation

Exhalation is the process of expelling air from the lungs. It depends on pressure differences between the lungs and the atmosphere. During normal quiet breathing, exhalation is passive and does not require muscle contraction. The elastic recoil of the lungs and chest wall helps both structures return to their resting positions after inhalation. When the muscles used for inhalation stop working, the diaphragm and external intercostal muscles relax. The diaphragm moves upward, and the ribs move...

factors affecting pulmonary ventilation

What Changes Breathing Ease in the Lungs

Breathing ease in the lungs depends on alveolar surface tension, lung compliance, and airway resistance. These factors affect how hard it is to move air during pulmonary ventilation, along with the pressure difference between the outside environment and the lungs. Alveolar surface tension comes from the fluid lining the inside of the alveoli. Water molecules in this fluid attract each other more strongly than they attract the air, so the liquid tends to pull the alveoli inward. That force must...

respiratory volumes and capacities

Lung Volume Measurements in Breathing

Lung volume measurements show how air moves in and out of the respiratory system during breathing. They help explain how the body takes in oxygen and removes carbon dioxide. Respiratory volumes and capacities also give useful information about lung function. Tidal volume is the air breathed in and out during normal, quiet breathing. Inspiratory reserve volume is the extra air that can be forcefully inhaled beyond tidal volume. Expiratory reserve volume is the extra air that can be forcefully...

physical principles governing gas exchange

physical-principles-governing-gas-exchange

Gas Laws in Lung Gas Exchange

Gas laws explain how oxygen and carbon dioxide move during respiration. External respiration is the exchange of gases in the lungs. Oxygen diffuses into the blood, and carbon dioxide diffuses out. Internal respiration happens in body tissues, where the gases move in the opposite directions. Two gas laws guide this process: Dalton's law of partial pressures and Henry's law. Dalton's law says the total pressure of a gas mixture equals the sum of the pressures of each gas acting alone. The...

external and internal respiration

Gas Exchange in Lungs and Tissues

Gas exchange in the lungs and body tissues moves oxygen into the blood and removes carbon dioxide. External respiration happens in the lungs, where inhaled oxygen enters the alveoli, the tiny air sacs that provide a large surface area for diffusion. Oxygen moves across the thin alveolar membrane into the pulmonary capillaries because its partial pressure is higher in the alveoli than in the blood. At the same time, carbon dioxide moves in the opposite direction and is later breathed out during...

oxygen transport in the blood

How Hemoglobin Loads and Releases Oxygen

Hemoglobin is the main molecule that carries oxygen in blood. It is found in red blood cells and has four polypeptide chains, each attached to an iron-containing heme group. This structure lets one hemoglobin molecule bind up to four oxygen molecules quickly and reversibly. When hemoglobin is fully loaded with oxygen, it is called oxyhemoglobin. When it has released oxygen, it is called reduced hemoglobin, or deoxyhemoglobin. As hemoglobin binds oxygen, its shape changes, which helps it pick...

carbon dioxide transport in the blood

How Blood Carries Carbon Dioxide

Carbon dioxide is carried in the blood from body tissues to the lungs. Cells make about 200 mL of CO2 each minute, and the lungs remove about the same amount. The blood moves this waste gas in three main forms. A small amount, about 7-10%, stays dissolved in the plasma. Just over 20% binds to hemoglobin and forms carbaminohemoglobin. In this case, CO2 attaches to the amino acids of globin, not to the heme part of hemoglobin. The rest, about 70%, is carried as bicarbonate ions, or HCO3-. CO2...

hypoxia

Hypoxia: Types and Carbon Monoxide Poisoning

Hypoxia is a medical condition in which body tissues do not get enough oxygen. It can cause a bluish color in the skin and mucosae, especially in fair-skinned people. This sign is often seen when hemoglobin (Hb) saturation drops below 75%. Hypoxia can happen for several different reasons. Anemic hypoxia occurs when there are too few red blood cells (RBCs) or when RBCs have abnormal or too little Hb. Ischemic hypoxia comes from poor blood circulation or blocked blood flow, so blood becomes...

neural control of respiration

Brainstem Centers That Control Breathing

Breathing is controlled by nerve centers in the brainstem. These respiratory centers send nerve signals to the muscles that move the lungs. The main centers are in the medulla oblongata and the pons.

chemical factors affecting respiration centers

chemical-factors-affecting-respiration-centers

How Blood Gases Control Breathing Rate

Blood gases and blood pH help control breathing rate and depth. Changes in carbon dioxide, oxygen, and hydrogen ion levels in arterial blood are detected by chemoreceptors, which are special sensors in the body. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla. Peripheral chemoreceptors are located in the aortic arch and carotid arteries. Together, these sensors help the respiratory system respond to chemical changes in the blood. Carbon dioxide...

other factors affecting respiration centers

other-factors-affecting-respiration-centers

Respiratory Reflexes That Change Breathing

Breathing is controlled by the brainstem, but it can also be changed by the nervous system and by body signals. The cerebral motor cortex can override the medullary respiratory centers and send signals directly to the breathing muscles. This makes voluntary actions like holding your breath or taking deeper breaths possible. That control is limited. When carbon dioxide, or CO2, builds up in the blood to a critical level, the brainstem respiratory centers start breathing again. This is why a...

hyperpnea and hyperventilation

Breathing Changes in Exercise and Anxiety

Breathing changes in exercise and anxiety can look similar, but they do not have the same cause. Hyperventilation is a higher-than-normal rate and depth of breathing. It often happens during anxiety attacks and can push out more carbon dioxide than the body needs to remove. When too much carbon dioxide is lost, the blood develops hypocapnia, which means an unusually low level of carbon dioxide. Hypocapnia can narrow cerebral blood vessels and reduce blood flow to the brain. This may cause...

chronic obstructive pulmonary disease

COPD Signs, Causes, and Lung Damage

COPD is a lung condition that causes ongoing breathing problems. It leads to shortness of breath, cough, and sputum production because the airways become blocked and airflow is reduced. Smoking is the main risk factor for COPD, and more than 80% of patients have a history of it. People with COPD often develop worsening dyspnea, or labored breathing. They may also cough often and get repeated lung infections. Many patients with COPD can develop respiratory failure. This happens when...

other pulmonary disorders

Asthma, TB, Lung Cancer, and Sleep Apnea

Asthma, lung cancer, tuberculosis, and sleep apnea are major pulmonary disorders. They affect breathing in different ways. Some are chronic, some are infectious, and some can become life-threatening if not found and treated early. Asthma is marked by chronic airway inflammation and hypersensitivity. It can cause airway obstruction from bronchial spasms, mucosal edema, increased mucus secretion, or epithelial damage. Triggers vary and can include allergens or emotional upset. Treatment often...

key terms and concepts

Learn how exhalation works through pressure changes, when breathing becomes active, and how conditions like RDS, atelectasis, and bronchitis affect ventilation.

Exhalation and Lung Pressure Changes | JoVE K12

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From Molecules to Organisms: Structures and Processes

9-12.HA.1.9.b

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SC.912.L.14.44

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Digestive System

Exhalation and Lung Pressure Changes

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