Furthermore, the system and the pulmonary circulation process maintain their pressure, respectively. It has a lymphatic system that works separately. In this system, the lymphatic system is working separately.
Here, the blood is responsible for transporting gases oxygen and carbon dioxide , cells that defend the body and chemical substances hormones, salts and nutrients ; regulating the electrolyte and fluid balance, acid and base balance, and body temperature; and protecting the body from infection and from loss of blood by means of clotting. Meanwhile, the lymph system is responsible for cleansing the cellular environment; offering a pathway for absorbing fats and fat-soluble vitamins into the blood stream; returning tissue fluids and proteins to the blood; and defending the body against illnesses.
It is more complex than the open circulatory system. As already implied, humans, vertebrates and larger, more active animals have a closed circulatory system. Compared to the open circulatory system, the closed circulatory system is quite more complex that includes two major processes—the above-mentioned pulmonary and systemic circulation.
While pulmonary circulation transports deoxygenated blood through the lungs to get oxygen, systemic circulation distributes this oxygenated blood throughout your body. And to direct this blood to every organ and tissue, it uses a network of arteries and veins. As opposed to bathing all tissues and organs with blood as what happens in the open circulatory system, the closed circulatory system works with the blood remaining in the vessels and transported to all extremities of the body at high pressures and rapid rate.
As you can see, the open circulatory system is simpler, where the heart pumps blood into open cavities, with blood vessels carrying the blood at a low pressure throughout the body, and then bathes all organs and tissues with blood.
Also, it does not use major veins and arteries to increase blood pressure and efficiently direct distribution. Organisms with an open circulatory system, such as spiders, insects, mollusks and prawns, typically have lots of blood, yet they have low blood pressure. There are several important advantages for organisms that have a closed circulatory system rather than an open system. The pressure in the closed system also makes it possible for the organisms to move blood more quickly throughout the body and supply oxygen to tissues more rapidly.
In the open circulation, the blood is not enclosed in the blood vessels and is pumped into a cavity called hemocoel. On the contrary, in the closed circulation, the blood is pumped through the vessels separate from the interstitial fluid of the body.
Hint: A closed type of circulatory system is the one in which the blood flows inside the vessels and reaches the cells via the capillaries. Moreover, species of phylum Pisces have a closed circulatory system. Pulmonary circulation moves blood between the heart and the lungs. It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart. Blocked arteries, also known as Atherosclerosis, is the build-up of fibrous and fatty material inside the arteries and is the underlying condition that causes coronary heart disease and other circulatory diseases.
In animals with multiple layers of cells, especially land animals, this will not work, as their cells are too far from the external environment for simple osmosis and diffusion to function quickly enough in exchanging cellular wastes and needed material with the environment. In higher animals, there are two primary types of circulatory systems: open and closed. Arthropods and mollusks have an open circulatory system. In this type of system, there is neither a true heart nor capillaries as are found in humans.
Instead of a heart, there are blood vessels that act as pumps to force the blood along. Instead of capillaries, blood vessels join directly with open sinuses.
Other vessels receive blood forced from these sinuses and conduct it back to the pumping vessels. It helps to imagine a bucket with two hoses coming out of it, these hoses connected to a squeeze bulb.
As the bulb is squeezed, it forces the water along to the bucket. One hose will be shooting water into the bucket, the other is sucking water out of the bucket. Needless to say, this is a very inefficient system. Insects can get by with this type of system because they have numerous openings in their bodies spiracles that allow the "blood" to come into contact with air.
The closed circulatory system of some mollusks and all vertebrates and higher invertebrates is a much more efficient system. Here blood is pumped through a closed system of arteries , veins , and capillaries. Capillaries surround the organs , making sure that all cells have an equal opportunity for nourishment and removal of their waste products.
However, even closed circulatory systems differ as we move further up the evolutionary tree. One of the simplest types of closed circulatory systems is found in annelids such as the earthworm. Earthworms have two main blood vessels—a dorsal and a ventral vessel—which carry blood towards the head or the tail, respectively. Blood is moved along the dorsal vessel by waves of contraction in the wall of the vessel.
These contractible waves are called 'peristalsis. These connecting vessels function as rudimentary hearts and force the blood into the ventral vessel. Since the outer covering the epidermis of the earthworm is so thin and is constantly moist, there is ample opportunity for exchange of gasses, making this relatively inefficient system possible.
There are also special organs in the earthworm for the removal of nitrogenous wastes. Still, blood can flow backward and the system is only slightly more efficient than the open system of insects.
As we come to the vertebrates, we begin to find real efficiencies with the closed system. Fish possess one of the simplest types of true hearts.
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