The open and closed circulatory system are two different ways that living things transport blood through their bodies. Most large vertebrates, including humans, have a closed circulatory system. The open circulatory system is found in most invertebrates such as crustaceans, spiders, and insects.
It is one of several ways that exist to classify the circulatory system. The main classifications are:
- Single or double circulation; it depends on the number of times the blood passes through the heart.
- Complete or incomplete circulation; whether or not oxygenated blood is mixed with non-oxygenated blood.
- Closed or open circulation; whether or not the blood is contained in blood vessels.
The circulatory system is made up of the cardiovascular system and the lymphatic system. The cardiovascular system is made up of the heart, blood vessels, and blood.
The lymphatic system is made up of the lymphatic vessels and organs (the spleen and thymus), the bone marrow, the lymph nodes, the lymphatic tissues, and the lymph or lymphatic fluid.
In this system the blood travels through the blood vessels and does not leave them, making a complete route that leaves the heart and reaches the heart.
In addition to vertebrates, some higher invertebrates such as annelids (worms, caterpillars, earthworms and leeches) and cephalopods (squid, octopus, cuttlefish and seahorses) also have this type of system.
Blood circulates through arteries, veins and capillaries such as highways and streets that carry nutrients and oxygen and returns with the waste materials that the body produces after all its many interactions.
Blood flow travels in two different circuits; the first one is performed on the right side of the heart and is the one that carries deoxygenated blood to the lungs. It is the so-called pulmonary circulation.
The other circuit is carried out by the left side of the heart and it is the one that carries the already oxygenated blood through the lungs, towards all the body's organs and returns it back to the heart. It is the so-called systemic circulation.
Blood is pumped by the powerful muscle of the heart and is kept circulating through veins and arteries thanks to the high pressure caused by the pumping. In this way, it reaches every hidden place in the body.
The human heart is a very complex organ that has 4 chambers (two atria and two ventricles) into which blood constantly enters and leaves.
Being a closed system, the blood does not make direct contact with the organs, that is, the blood at no time leaves the "channels" that contain it.
Open circulatory system
It is also known as the lagoon circulatory system. In this system the blood is not necessarily always within the blood vessels; it leaves the heart and goes directly to the organs and then returns by other routes or mechanisms.
To make it easier to understand, think of this system acting in organisms much smaller and less complex than mammals or any other larger vertebrates.
In this type of organisms, in addition to slow circulation, respiration, metabolism, digestion and locomotion are also slow.
Animals that have this type of system include crustaceans, spiders, and insects, as well as snails and clams. These animals can have one or more hearts, but in many cases there is not even a heart as such.
Blood vessels are not such, since the blood "bathes" the organs through open sinuses, and not even the blood of these organisms can be called blood, since it is combined with interstitial fluids. This fluid is called "hemolymph" that provides nutrients and oxygen to organs and cells.
In the case of crustaceans, for example, the circulatory system is similar to that of arthropods; the number and complexity of the capillaries depends directly on the size of the animal and the arteries can function as pressure reservoirs to irrigate the blood.
In these animals the heart is usually elongated and tubular, but in some cases it does not exist, nor can there be proper arteries.
Sometimes there is a heart without arteries, especially in smaller crustaceans. If the animals are larger, there may be an accessory pump.
Most insects have a dorsal aorta as the only blood vessel that runs through most of their body.
The heart has small holes called ostioles through which the hemolymph enters and leaves when it contracts in a peristaltic way to push it towards the rest of the body.
In some cases, there may be lateral arteries that form from the dorsal vessel. In any case, the blood vessel (s) end abruptly and with almost no ramifications, sending blood directly.
In insects, the circulatory system carries more nutrients than oxygen; the latter arrives in greater quantity through the respiratory system of the animal.
References
- Hill, Wyse and Anderson (2004). Animal Physiology. Editorial Médica Panamericana. P. 758.
- Crustaceans. Recovered from cccurstaceos.blogspot.com.ar.
- Animal circulatory system. Recovered from monogramas.com.
- Circulatory system of animals. Types of systems, examples. Recovered from paradis-sphynx.com.
- Closed and open circulatory system. Martinez Circulatory System. Recovered from sites.google.com.
- Open or closed circulatory system. Recovered from lasaludi.info.