Biomaterial Database

Role of diffusion in gas exchange of the avian egg. 1982

H Rahn, and C Paganelli

The pore system of the avian eggshell provides a unique exchange surface for the transport of gases. The dimensions of the microscopic pores do not change with time, and gas transport through them is essentially limited to diffusion. According to Fick's law of diffusion, eggshell conductance of a given gas will vary directly with the diffusion coefficient of the gas. This principle is illustrated by monitoring changes in air space CO2 in metabolizing eggs subjected to changes in barometric pressure or to substitutions of He and SF6 for N2 in the ambient atmosphere.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D009584	Nitrogen	An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.
D002245	Carbon Dioxide	A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.	Carbonic Anhydride,Anhydride, Carbonic,Dioxide, Carbon
D004058	Diffusion	The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.	Diffusions
D004528	Egg Shell	A hard or leathery calciferous exterior covering of an egg.	Eggshell,Egg Shells,Eggshells,Shell, Egg,Shells, Egg
D006371	Helium	A noble gas with the atomic symbol He, atomic number 2, and atomic weight 4.003. It is a colorless, odorless, tasteless gas that is not combustible and does not support combustion. It was first detected in the sun and is now obtained from natural gas. Medically it is used as a diluent for other gases, being especially useful with oxygen in the treatment of certain cases of respiratory obstruction, and as a vehicle for general anesthetics.	Helium-4,Helium 4
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001274	Atmospheric Pressure	The pressure at any point in an atmosphere due solely to the weight of the atmospheric gases above the point concerned.	Atmospheric Pressures,Pressure, Atmospheric,Pressures, Atmospheric
D013459	Sulfur Hexafluoride	Sulfur hexafluoride. An inert gas used mainly as a test gas in respiratory physiology. Other uses include its injection in vitreoretinal surgery to restore the vitreous chamber and as a tracer in monitoring the dispersion and deposition of air pollutants.	Hexafluoride, Sulfur