dead space

Examples of dead space in the following topics:

• Dead Space: V/Q Mismatch

  • There are two types of V/Q mismatch that produce dead space.
  • Dead space is characterized by regions of broken down or blocked lung tissue.
  • Dead space is created when no ventilation and/or perfusion takes place.
  • Anatomical dead space, or anatomical shunt, arises from an anatomical failure, while physiological dead space, or physiological shunt, arises from a functional impairment of the lung or arteries.
  • Compare and contrast anatomical and physiological dead space and their role in V/Q mismatch

• 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

• 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.
  • Feedback mechanisms increase the ventilation rate in such a case, but if dead space becomes too great, they won't be able to counteract the effect.

• Alveoli

  • The alveoli consist of an extremely thin epithelial layer and an extracellular matrix (a fluid space made of collagen and elastin that contains no cells); it is surrounded by many capillaries, the tiniest type of blood vessel.
  • 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.

• 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.
  • 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.

• The Book of the Dead

  • The New Kingdom saw the Book of the Dead develop and spread further.
  • There was no single Book of the Dead, and works tended to vary widely.
  • Books were often prefabricated in funerary workshops, with space left for when the name of the deceased would be written in later.
  • During the New Kingdom, the Book of the Dead was typically written in cursive hieroglyphs.
  • Describe what the Book of the Dead was and explain its use in Ancient Egypt

• The Structure of Cities

  • In the 1960s, urban planners moved away from grids and began planning suburban developments with dead ends and cul-de-sacs.
  • Urban structure can also refer to urban spatial structure; the arrangement of public and private space in cities and the degree of connectivity and accessibility.
  • In this context, urban structure is concerned with the arrangement of the CBD, industrial and residential areas, and open space.
  • Urban open spaces provide citizens with recreational, ecological, aesthetic value.
  • Open spaces offer aesthetic value for citizens who enjoy nature, cultural value by providing space for concerts or art shows, and functional value—for example, by helping to control runoff and prevent flooding.

• Stelae in the Greek High Classical Period

  • Stelae were inscribed with the name of the dead and often the names of the relatives.
  • Each stele is unique for its attempts to individualize and characterize the attributes and personality of the dead.
  • The Grave Stele of a Little Girl (450-440 BCE), which lacks a pediment and allows the deceased to assume most of the space, depicts a young child holding two doves, presumably her pets.

• 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.