Related Experiment Video
Updated: Jan 31, 2026
07:09
Assessment of Pulmonary Capillary Blood Volume, Membrane Diffusing Capacity, and Intrapulmonary Arteriovenous Anastomoses During Exercise
Published on: February 20, 2017
13.7K
A perpetual switching system in pulmonary capillaries
Wiltz W Wagner1,2,3, Eric M Jaryszak2, Amanda J Peterson1
1Department of Anesthesiology, Indiana University School of Medicine , Indianapolis, Indiana.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|December 21, 2018
Summary
Pulmonary capillaries remain primed for emergencies without active regulation. Flow patterns in canine lung lobes were identical in fresh and fixed lungs, suggesting passive switching mechanisms.
Area of Science:
- Physiology
- Microcirculation
- Pulmonary Circulation
Background:
- Pulmonary capillaries form a large reserve, requiring rapid recruitment during stress.
- The pulmonary microcirculation's flow distribution is hypothesized to be actively or passively switched.
Purpose of the Study:
- To test whether pulmonary capillary switching is an active or passive process.
- To investigate the regulatory mechanisms behind capillary recruitment in the lungs.
Main Methods:
- Ex vivo canine lung lobes were perfused with blood.
- Capillary flow patterns were recorded using videomicroscopy before and after fixation.
- Flow data in fresh and fixed lungs were compared to assess active vs. passive switching.
Main Results:
- Capillary switching patterns remained unchanged after glutaraldehyde fixation.
- No significant differences were observed in flow distribution between fresh and fixed lung vasculature.
- Over 60,000 measurements confirmed consistent perfusion patterns.
Conclusions:
- Pulmonary capillaries can remain primed for emergencies without active regulation or feedback loops.
- Passive switching mechanisms, potentially explained by chaos theory and fractal mathematics, govern pulmonary capillary flow.
- This finding challenges previous assumptions of active control in the pulmonary microcirculation.
Related Concept Videos
01:22Switching of BJT
860
Switching behavior in Bipolar Junction Transistors (BJTs) is a fundamental aspect utilized in various electronic circuits, particularly for digital logic applications like switches and amplifiers. In a typical switching circuit, a BJT alternates between cut-off and saturation modes, corresponding to the "off" and "on" states, respectively, thus behaving like an ideal switch.
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are...
Cut-off Mode ("Off" State): In this state, both the emitter-base and collector-base junctions are...
860
01:20Capillary Beds
7.1K
Capillary beds are networks of tiny blood vessels that play a crucial role in the circulatory system. These beds are where the exchange of gases, nutrients, and waste products occurs between the blood and surrounding tissues. Each capillary bed consists of numerous capillaries, which are the smallest blood vessels in the body, typically only one cell-thick. This thinness allows for the efficient diffusion of substances.
Capillaries connect arterioles, small branches of arteries, to venules,...
Capillaries connect arterioles, small branches of arteries, to venules,...
7.1K
01:28Capillary Exchange
11.2K
The cardiovascular system's chief role is to disseminate gases, nutrients, waste, and other substances to the body's cells. Small molecules like gases, lipids, and lipid-soluble substances directly diffuse through capillary wall endothelial cell membranes. Glucose, amino acids, and ions, including sodium, potassium, calcium, and chloride, use transporters for facilitated diffusion via membrane-specific channels. Glucose, ions, and bigger molecules may also pass through intercellular...
11.2K
02:57Surface Tension, Capillary Action, and Viscosity
33.3K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
33.3K
01:20Capillaries and Their Types
7.7K
Capillaries, a crucial constituent of the circulatory system, are diminutive vessels with a diameter between 5–10 micrometers, accommodating perfusion to the tissues through the phenomenon known as microcirculation. Through their permeable walls, consisting of an endothelial layer ensconced by a basement membrane and sporadically dispersed smooth muscle fibers, the exchange of substances between the blood and the interstitial fluid becomes plausible. Variance in wall composition exists,...
7.7K
01:20Capillary Electrophoresis: Instrumentation
1.2K
Capillary electrophoresis instrumentation typically consists of several key components. A high-voltage power supply generates the electric field necessary for the separation by connecting to an anode (the positively charged electrode) and a cathode (the negatively charged electrode) located in buffer reservoirs at each end of the capillary tube. The system includes a sample vial, a fused silica capillary tube coated with polyimide for mechanical strength through which the sample components...
1.2K