exhalation

Examples of exhalation in the following topics:

• Expiration

  • Expiration, also called exhalation, is the flow of the respiratory current out of the organism.
  • The purpose of exhalation is to remove metabolic waste, primarily carbon dioxide from the body from gas exchange.
  • The pathway for exhalation is the movement of air out of the conducting zone, to the external environment during breathing.
  • There are two groups of muscles that are involved in forced exhalation.
  • It is generally defined by holding air in the lungs and releasing it at a fixed rate, which enables control over when and how much air to exhale.

• Factors Affecting Pulmonary Ventilation: Compliance of the Lungs

  • Measurements of lung volumes differ at the same pressure between inhalation and exhalation, meaning that lung compliance differs between inhalation and exhalation.
  • Exhalation of air also becomes much more difficult because the loss of elastic recoil reduces the passive ability of the lungs to deflate during exhalation.
  • Those with emphysema have considerable difficulty with exhaling breaths and tend to take fast shallow breaths and tend to sit in a hunched-over position in order to make exhalation easier.

• Functional Anatomy of the Respiratory System

  • Active or forced exhalation is achieved by the abdominal and the internal intercostal muscles.
  • During this process, air is forced or exhaled out.
  • During forced exhalation, as when blowing out a candle, the expiratory muscles, including the abdominal muscles and internal intercostal muscles, generate abdominal and thoracic pressure that force air out of the lungs.
  • Forced exhalation is often used as an indicator to measure airway health, as people with obstructive lung diseases (such as emphysema, asthma, and bronchitis) will not be able to actively exhale as much as a healthy person because of obstruction in the conducting zones from inhlation, or from a loss of elastic recoil of the lungs.

• Heart Murmurs

  • Interventions such as inhalation and exhalation may lead to changes in murmur sounds.
  • With exhalation, the opposite haemodynamic changes occur.
  • This means that left-sided murmurs generally increase in intensity with exhalation.
  • Abrupt standing or squatting may cause changes in murmur sounds, as does the valsalva maneuver, a forceful attempted exhalation against a closed airway, usually done by closing one's mouth and pinching one's nose while pressing out as if blowing up a balloon.

• Lung Capacity and Volume

  • It is usually measured as the amount of air that is exhaled after the inhalation of interest, which is measured with a device called a spirometer.
  • Vital Capacity (VC) is the maximum amount of air that a person can exhale after inhaling as much air as possible.
  • FEV1: The volume of air exhaled in one second of forced expiration.

• Breathing Patterns

  • During normal breathing, the volume of air cycled through inhalation and exhalation is called tidal volume (VT), and is the amount of air exchanged in a single breath.
  • The normal respiratory rate refers to the cyclical inhalation and exhalation of tidal volume (VT).

• Blood Flow in the Lungs

  • The air, along with the diffused carbon dioxide, is then exhaled.

• Factors Affecting Pulmonary Ventilation: Surface Tension of Alveolar Fluid

  • As the alveoli fill with air during inhalation they expand, and as air leaves the lung with exhalation, the alvoli return to their non-inflated size.
  • Because the alveoli of the lungs are highly elastic, they do not resist surface tension on their own, which allows the force of that surface tension to deflate the alveoli as air is forced out during exhalation by the contraction of the pleural cavity.
  • The force of surface tension in the lungs is so great that without something to reduce the surface tension, the airways would collapse after exhalation, making re-inflation during inhalation much more difficult and less effective.

• RBC Physiology

  • The respiratory system regulates blood pH by changing the rate at which carbon dioxide is exhaled from the body, which involves the RBC's molecular activity.
  • As carbon dioxide is converted from its dissolved acid form and exhaled through the lungs, blood pH becomes less acidic.

• Alveoli

  • They then spring back during exhalation in order to expel the carbon-dioxide-rich air.
  • Without surfactant, the surface tension would cause the lungs to collapse during exhalation, making normal breathing impossible.