An open circulatory system is able to pump blood into a body cavity, called a “hemocel.” The blood then diffuses back to the circulatory system between cells. Tissues are surrounded by blood from the heart as it fills up body cavities instead of using a routing system of arteries and veins.
List of Open Circulatory System Pros
1. Pressure changes do not create vulnerabilities.
Within an open circulatory system, pressure changes do not have the same negative impacts. That makes it possible for life to exist in high-pressure environments, such as at the bottom of the ocean.
2. It creates less urgency.
An open circulatory system processes oxygen and carbon dioxide through separate systems. This reduces the amount of urgency within the system to restore balance. When both systems are working as they should, balance is achieved at virtually all times.
3. Body temperature control is better.
Open circulatory systems can dispel heat more efficiently, which makes it possible to live in a high temperature environment. In colder temperatures, heat can be maintained if shelter can be found.
List of Open Circulatory System Cons
1. It is almost impossible to increase blood distribution.
Because the heart causes blood to fill into body cavities, the total capacity of the system is achieved with virtually every heartbeat. That makes it difficult to increase the velocity or distribution of the blood flow should changes be required.
2. It requires a low metabolic rate.
Most open circulatory systems create a low metabolic rate because there are limits to the diffusion process which cannot be change. This results in slower movements and adaptability to new environments.
3. It does not work for larger creatures.
An open circulatory system only benefits small creatures because the size limits the distance the blood must travel to each body cavity. For larger creatures, the diffusion process would be slow enough that cell starvation could occur because not enough oxygen could be processed in time.
These open circulatory system pros and cons offer key points to consider when evaluating its efficiency. Some systems see improvements with body muscles helping the diffusion process. Others rely on a heart. Either way, because oxygen intake is controlled by another system, there will always be natural limitations to this design.