What does circulation transport throughout the body

This movement allows for gas and nutrient exchange. An open circulatory system does not use as much energy to operate and maintain as a closed system; however, there is a trade-off with the amount of blood that can be moved to metabolically-active organs and tissues that require high levels of oxygen. In fact, one reason that insects with wing spans of up to two feet wide 70 cm are not around today is probably because they were outmatched by the arrival of birds million years ago.

Birds, having a closed circulatory system, are thought to have moved more agilely, allowing them to obtain food faster and possibly to prey on the insects. The circulatory systems of animals differ in the number of heart chambers and the number of circuits through which the blood flows.

The circulatory system varies from simple systems in invertebrates to more complex systems in vertebrates. The simplest animals, such as the sponges Porifera and rotifers Rotifera , do not need a circulatory system because diffusion allows adequate exchange of water, nutrients, and waste, as well as dissolved gases figure a. Organisms that are more complex, but still have only two layers of cells in their body plan, such as jellies Cnidaria and comb jellies Ctenophora , also use diffusion through their epidermis and internally through the gastrovascular compartment.

Both their internal and external tissues are bathed in an aqueous environment and exchange fluids by diffusion on both sides figure b. Exchange of fluids is assisted by the pulsing of the jellyfish body. Animals without circulatory systems : Simple animals consisting of a single cell layer, such as the a sponge, or only a few cell layers, such as the b jellyfish, do not have a circulatory system. Instead, gases, nutrients, and wastes are exchanged by diffusion. For more complex organisms, diffusion is not efficient for cycling gases, nutrients, and waste effectively through the body; therefore, more complex circulatory systems evolved.

Closed circulatory systems are a characteristic of vertebrates; however, there are significant differences in the structure of the heart and the circulation of blood between the different vertebrate groups due to adaptation during evolution and associated differences in anatomy.

Fish have a single circuit for blood flow and a two-chambered heart that has only a single atrium and a single ventricle figure a. The atrium collects blood that has returned from the body, while the ventricle pumps the blood to the gills where gas exchange occurs and the blood is re-oxygenated; this is called gill circulation.

The blood then continues through the rest of the body before arriving back at the atrium; this is called systemic circulation. The result is a limit in the amount of oxygen that can reach some of the organs and tissues of the body, reducing the overall metabolic capacity of fish.

Examples of animal circulatory systems : a Fish have the simplest circulatory systems of the vertebrates: blood flows unidirectionally from the two-chambered heart through the gills and then to the rest of the body. The blood is pumped from a three-chambered heart with two atria and a single ventricle. The heart is three chambered, but the ventricles are partially separated so some mixing of oxygenated and deoxygenated blood occurs, except in crocodilians and birds.

In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart pulmonary circulation and the other throughout the rest of the body and its organs, including the brain systemic circulation.

Amphibians have a three-chambered heart that has two atria and one ventricle rather than the two-chambered heart of fish figure b. The two atria receive blood from the two different circuits the lungs and the systems. The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body. The mixing is mitigated by a ridge within the ventricle that diverts oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit where gas exchange occurs in the lungs and through the skin.

For this reason, amphibians are often described as having double circulation. Most reptiles also have a three-chambered heart similar to the amphibian heart that directs blood to the pulmonary and systemic circuits figure c.

The ventricle is divided more effectively by a partial septum, which results in less mixing of oxygenated and deoxygenated blood. Some reptiles alligators and crocodiles are the most primitive animals to exhibit a four-chambered heart. Content on this website is provided for information purposes only. Information about a therapy, service, product or treatment does not in any way endorse or support such therapy, service, product or treatment and is not intended to replace advice from your doctor or other registered health professional.

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Skip to main content. Blood and blood vessels. Home Blood and blood vessels. Circulatory system. Actions for this page Listen Print. Summary Read the full fact sheet. On this page. All cells in the body need to have oxygen and nutrients, and they need their wastes removed. These are the main roles of the circulatory system. The heart, blood and blood vessels work together to service the cells of the body.

Using the network of arteries, veins and capillaries, blood carries carbon dioxide to the lungs for exhalation and picks up oxygen. From the small intestine, the blood gathers food nutrients and delivers them to every cell.

Blood Blood consists of: Red blood cells — to carry oxygen White blood cells — that make up part of the immune system Platelets — needed for clotting Plasma — blood cells, nutrients and wastes float in this liquid.

The heart The heart pumps blood around the body. The heart lies at the center of the circulatory system and pumps blood through the rest of the network. This hollow muscle is made up of four chambers: The left and right atriums make up the two chambers at the top and the left and right ventricles form the two chambers at the bottom, according to the University of Michigan. The chambers are separated by one-way valves to ensure that blood flows in the correct direction.

The rest of the circulatory system is made up of two independent networks that work together: The pulmonary and systemic systems. The pulmonary system is responsible for providing fresh oxygen to the blood and removing carbon dioxide, according to the National Center for Biotechnology Information NCBI.

Oxygen-poor blood arrives from veins leading to the right atrium of the heart. The blood is then pumped through the right ventricle, then through the pulmonary artery, which splits off into two and divides into increasingly smaller arteries and capillaries before entering the lungs. The tiny capillaries form a network within the lungs that facilitate the exchange of carbon dioxide and oxygen. From the lungs, the oxygen-rich blood flows back toward the heart.

Next, the systemic system of arteries, veins and capillaries takes over. Arteries and veins are not the same, although they are both types of blood vessels. Arteries carry oxygen- and nutrient-rich blood from the heart to all parts of your body, according to the National Cancer Institute. Veins carry the oxygen- and nutrient-poor blood back to the heart.