The second law of thermodynamics says that the entropy of the universe (or any isolated system therein) is increasing; i.e., the energy of the universe is becoming more uniformly distributed. It is often noted that the second law indicates that nature tends to go from order to disorder, from complexity to simplicity.
Small-bore catheters and Heimlich valves have been successfully used in. the treatment of pneumothoraces in several studies.4,5 The thoracic vent. (see Figure 1) is a minimally invasive device for the treatment of. pneumothorax. It consists of a polyurethane catheter connected to a. plastic chamber containing a one-way valve.
The ventricle pumps blood out to the gills for oxygen and then on to the body delivering it. The blood returns to the heart filling the atrium. There is a single loop in the circulatory system, such that the capillary branching in the gills reduces the pressure. Once reduced, the pressure cannot be recovered.