alveolar dead space

Examples of alveolar dead space in the following topics:

• Pressure Changes During Pulmonary Ventilation

  • It is defined as $VA=(Tidal Volume-Dead Space Volume)* Respiratory Rate$
  • It is defined as $VD=DeadSpaceVolume*Respiratory Rate$.
  • This is most apparent in changes of the dead space volume.
  • Breathing through a snorkeling tube and having a pulmonary embolism both increase the amount of dead space volume (through anatomical versus alveolar dead space respectively), which will reduce alveolar ventilation.
  • Differentiate among the types of pulmonary ventilation: minute, alveolar, dead space

• Alveoli

  • Type I (Squamous Alveolar) cells: These form the structure of an alveolar wall.
  • The alveoli are the site of alveolar ventilation, and are not normally considered dead space.
  • However, alveoli that are injured and can no longer contribute to gas exchange become alveolar dead space.
  • Physiological dead space is the sum of normal anatomical dead space and alveolar dead space, and can be used to determine the rate of ventilation (gas exchange) in the lungs.
  • When any type of dead space increases, the rate of ventilation in the lungs will decrease.

• Trachea

  • The trachea is also considered a part of normal anatomical dead space (space in the airway that isn't involved in alveolar gas exchange) and its volume contributes to calculations of ventilation and physiological (total) dead space.
  • It is not considered alveolar dead space, a term that refers to alveoli that don't partake in gas exchange due to damage or lack of blood supply.

• Lungs

  • The pleural cavity is the fluid-filled space between the parietal and visceral pleura, and provides room for the lung to expand during inhalation.
  • Too low perfusion (and a higher ratio) indicates alveolar dead space, while too low ventilation (and a lower ratio) indicates a shunt, which is a lack of air supply relative to perfusion.

• Functional Anatomy of the Respiratory System

  • It is defined as tidal volume minus dead space (the space in the lungs where gas exchange does not occur) times the respiratory rate.
  • Dead Space Ventilation (VD): The amount of air per unit of time that doesn't reach the alveoli.
  • It is defined as volume of dead space times the respiratory rate.
  • Dead space is any space that isn't involved in alveolar gas exchange itself, and it typically refers to parts of the lungs that are conducting zones for air, such as the trachea and bronchioles.
  • If someone breathes through a snorkeling mask, the length of their conducting zones increases, which increases dead space and reduces on alveolar ventilation.

• Bronchi and Subdivisions

  • The bronchi and bronchioles are considered anatomical dead space, like the trachea and upper respiratory tract, because no gas exchange takes place within this zone.
  • Each terminal bronchiole then gives rise to several respiratory bronchioles, which go on to divide into two to 11 alveolar ducts.
  • There are five or six alveolar sacs associated with each alveolar duct.
  • Like the trachea, the bronchi and bronchioles are part of the conducting zone, so they moisten and warm air and contribute to the volume of anatomical dead space.

• Pulmonary Edema

  • Pulmonary edema is fluid accumulation in the air spaces and parenchyma of the lungs.
  • Pulmonary edema is fluid accumulation in the air spaces and parenchyma of the lungs and it leads to impaired gas exchange which may cause respiratory failure.
  • Chest X-ray will show fluid in the alveolar walls, Kerley B lines, increased vascular shadowing in a classical batwing peri-hilum pattern, upper lobe diversion (increased blood flow to the superior parts of the lung), and possibly pleural effusions as shown in Figures 1 and 2.
  • Interstitial and alveolar pulmonary edema with small pleural effusions on both sides.

• Mammary Glands

  • The myoepithelial cells can contract under the stimulation of oxytocin thereby excreting milk secreted from alveolar units into the lobule lumen toward the nipple where it collects in sinuses of the ducts.
  • In some species there is complete or partial involution of alveolar structures after weaning; however, in humans there is only partial involution and the level of involution in humans appears to be highly individual.
  • This big structure change leads loose fat tissue to fill up the empty space thereafter.

• Accessory Sex Glands

  • Lipofuscin granules from dead epithelial cells give the secretion its yellowish color.
  • The bulbourethral glands are compound tubulo-alveolar glands, each approximately the size of a pea.

• Dystocia and Cesarean Section

  • A cesarean section is a surgical procedure in which one or more incisions are made through a mother's abdomen (laparotomy) and uterus (hysterotomy) to deliver one or more babies; or, rarely, to remove a dead fetus.
  • The classical incision involves a midline longitudinal cut in the uterus, which allows a larger space to deliver the baby.