explain the evaluation of circulation system from lower organisms to higher organisms with suitable examples
Answers
Explanation:
Open Circulatory System
The open circulatory system is the simpler of the two systems. This system is common among arthropods. The heart pumps blood - or as it is commonly known for open circulatory systems, hemolymph - into an open cavity called a hemocoel. The hemolymph mixes with interstitial fluid and sloshes around the hemocoel, bathing the internal organs and delivering nutrients and in some cases, gases such as oxygen. In some animals, the heart is simply an aorta or other blood vessel, and the hemolymph is pulsed throughout the body by muscle contractions.
There are no arteries or major veins to pump the hemolymph, so blood pressure is very low. Organisms with an open circulatory system typically have a relatively high volume of hemolymph and low blood pressure. Examples of animals with open circulatory systems include insects, spiders, prawns and most mollusks.
Closed Circulatory System
Larger and more active animals, including all vertebrates, have a closed circulatory system. This more complex system consists primarily of blood, the heart and a network of blood vessels. The main functions of the circulatory system are gas exchange, hormone and nutrient distribution, and waste elimination.
The two major processes of the system are pulmonary circulation and systemic circulation. In the former process, deoxygenated blood is passed through the lungs for gas exchange, in order to receive oxygen from inhaled air. Next, systemic circulation distributes the newly oxygenated blood throughout the body. The blood picks up carbon dioxide, a metabolism waste product, from cells, and brings it back to the lungs again.
In a closed circulatory system, blood is directed through arteries to veins and to smaller blood vessels throughout the body. As opposed to bathing all tissues and organs with blood, the blood remains in vessels and is transported at high pressures to and from all extremities of the body at a rapid rate.
Answer:
Explanation:
Open circulatory systems
In an open circulatory system, blood vessels transport all fluids into a cavity. When the animal moves, the blood inside the cavity moves freely around the body in all directions. The blood bathes the organs directly, thus supplying oxygen and removing waste from the organs. Blood flows at a very slow speed due to the absence of smooth muscles, which, as you learnt previously, are responsible for contraction of blood vessels. Most invertebrates (crabs, insects, snails etc.) have an open circulatory system. Figure 7.1 shows a schematic of an open circulatory system delivering blood directly to tissues.
Closed circulatory systems
Closed circulatory systems are different to open circulatory systems because blood never leaves the blood vessels. Instead, it is transferred from one blood vessel to another continuously without entering a cavity. Blood is transported in a single direction, delivering oxygen and nutrients to cells and removing waste products. Closed circulatory systems can be further divided into single circulatory systems and double circulatory systems.