anatomical dead space

(noun)

The space in the respiratory tract that isn't involved in alveolar ventilation and is part of the normal conducting zone of the respiratory system.

Related Terms

Examples of anatomical dead space in the following topics:

  • 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.
    • There are 10 segments in the right lung and 8 to 9 segments in the left lung due to anatomical differences.
    • The alveolus is the smallest anatomical unit of the lung, and the site of gas exchange between the lung and the bloodstream.
    • 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.

  • 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.

  • Alveoli

    • An alveolus is an anatomical structure that has the form of a hollow cavity.
    • 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.

  • 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

  • Directional Terms

    • Positional terms give precise descriptions of anatomical relationships and allow for consistency when referencing anatomical positions.
    • They allow a description of anatomical position by comparing location relative to other structures or within the rest of the body.
    • Standard anatomical terms for direction include:
    • Anterior refers to the side of the structure facing up in the standard anatomical position while posterior refers to the bottom side.
    • Identify the anatomical terms that define the human body in 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.

  • General Organization of the Somatosensory System

    • The somatosensory system is composed of the neurons that make sensing touch, temperature, and position in space possible.
    • At this location there is a map of sensory space referred to as a sensory homunculus. 
    • A cortical homunculus is the brain's physical representation of the human body; it is a neurological map of the anatomical divisions of the body.
    • It shows how the anatomical portions of the body, such as the tongue, elbow, and hip, are mapped out on the homonculus.
    • Describe how the somatosensory system is composed of neurons that make sensing touch, temperature, and position in space possible

  • Ulna and Radius (The Forearm)

    • The space between the two bones is spanned by the interosseous membrane.
    • Anatomically, the ulna is located medially to the radius, placing it near the little finger.
    • Anatomically, the radius is located laterally to the ulna placing it near the thumb.

  • Body Cavities

    • Vertebrates have fluid-filled spaces called body cavities that contain the organs.
    • By the broadest definition, a body cavity is any fluid-filled space in a multicellular organism.
    • The cranial cavity is the anterior portion of the dorsal cavity consisting of the space inside the skull.
    • These include the spinal cord, the meninges of the spinal cord, and the fluid-filled spaces between them.
    • The ventral cavity, the interior space in the front of the body, contains many different organ systems.

  • Fluid Compartments

    • While fluid compartments may share some characteristics with the divisions defined by the anatomical compartments of the body, these terms are not one in the same.
    • The interstitial fluid is found in the interstitial spaces, also known as the tissue spaces.
    • The majority of the intersitial space functions as an ECM, a fluid space consisting of cell-excreted molecules, lies between the basement membranes of interstitial spaces.
    • Transcellular fluid is the portion of total body water contained within epithelial lined spaces.
    • Spatial relationship between the blood vessels, basement membranes, and interstitial space between structures.