Blood gases and respiration

See A Clinical Perspective Blood Gases and Respiration, Chapter 6. 

Blood Gases and Respiration Surface Tension Vapor Pressure of a Liquid Van der Waals Forces Flydrogen Bonding... 

Any volatile material, irrespective of its route of administration, has the potential for pulmonary excretion. Certainly, gases and other volatile substances that enter the body primarily through the respiratory tract can be expected to be excreted by this route. No specialized transport systems are involved in the loss of substances in expired air simple diffusion across cell membranes is predominant. The rate of loss of gases is not constant it depends on the rate of respiration and pulmonary blood flow. 

Arterial pH and concentrations of blood gases are kept at physiological levels by adjusting respiration and infusion of sodium bicarbonate. 

Silicone rubber, however, shows the highest permeability rates for these gases, and in fact, silicone mbber is used in blood oxygenators required for open heart surgery. It is also used in extended wear contact lenses since the transport of O2 and CO2 through the lens allows the cornea to respire. Thus, cloudiness and rainbows are not generally experienced, even after continuous wear for a mmifh. 

The absorption of gases is dependent on the solubility of the gas in the blood. For example, chloroform has high solubility and is nearly completely absorbed. Respiration rate is the limiting factor. However, ethylene has low solubility and only a small percentage is absorbed - blood flow limited absorption. It is of interest to note that as a generalization, there is a pattern of relative absorption rates that extends between the different routes of exposure. This order of absorption (by rate from fastest to slowest and in degree of absorption from most to least) is intravenous inhalation intramuscular intraperitoneal subcutaneous oral intradermal other dermal. It should be remembered that because of the arrangement of the body s circulatory system, compounds inhaled and absorbed initially enter the systemic circulation without any first-pass metabolism by the liver. 

Fine particles are those that are respirable. Traditionally this would have been particles less than 10 pm in diameter that can make their way into the respiratory system. These particles, often referred to as PM-10 (PM is short for particulate matter), are usually accompanied by even finer particles about 2.5 pm called PM-2.5. These finer particles can go deep into the lung and become deposited in the alveoli, the terminal sacs of the airways, where gases are exchanged with the blood. Once in the alveoli various biochemical processes seek to combat the invading particles which ultimately place the individual under increased stress and at risk from a range of health effects. 

---