COMPARING THE HUMAN CIRCULATORY
SYSTEM WITH THAT OF OTHER SPECIES

As there may be some unfamiliar terms in the following page, you are advised to look at the terminology table below to better understand the information.
Table 1: terms and definition
Terms
Definition
Hemocoel
The cavity of the body of an organism, often in invertebrates, including mollusks and arthropods (Hemocoel).
Taxon
“A taxonomic category or group, such as a phylum, order, family, genus, or species” (Taxon).
Aorta
The main artery that transports blood from the left ventricles of the heart to other parts of the body, except the lungs (Aorta).
Perforation
An opening made in something
Hemolymph
“The circulatory fluid of various invertebrate animals that is functionally comparable to the blood and lymph of vertebrates” (Hemolymph).
Thorax
“(In insects) the portion of the body between the head and the abdomen” (Thorax).
Dorsal
“Situated on or toward the upper side of the body, equivalent to the back, or posterior, in humans” (Dorsal).
Cavity
Or "Body Cavity" is any space that is filled with fluid in a multicellular organism

Types of Circulatory system

Closed circulatory system

Closed circulatory system is present in vertebrates and some invertebrates. In a close circulatory system, blood is pumped from the heart, to the blood vessels that are connected, creating high pressure which allows the blood to flow faster around the body. Also as a result, blood does not fill the cavity of the body of the organism but rather remain flowing inside the blood vessels (Sakurai).

Open circulatory systemOpen circulatory system is often present in mollusks and arthropods. In an open circulatory system, there are no arteries or veins; the hemolymph is pumped by the heart, into the hemocoel of the organism, allowing the organs and tissues to be “bathed” in hemolymph. The hemolymph flows at a lower rate for there is no pressure once it is released into the hemocoel and the organism must use its muscle to move the hemolymph in the cavity. In the final stage, the hemolymph diffuses back into the circulatory system through the cells (Circulatory system).
Diagram 1: Open and closed circulatory system
open_versus_closed_diagram.gif
Diagram of examples of the open and closed circulatory system (Open Versus Closed)




Single circulatory system
In a single circulatory system, the blood flows through the heart only once during each circuit of blood throughout the body. For example, in fish, the blood is carried from the heart, and it is then carried by the arteries to the gills where the blood is oxygenated. The blood is then carried to various parts of the body of the organism and then collected by the veins, but the blood is not as full of oxygen by the time that the blood enters the veins and back to the heart. This is less efficient than the double circulatory system as the gill capillaries slow down the blood flow, resulting in low pressure blood flow, reducing the amount of oxygen that reaches the cells (What is Meant).
Double circulatory system
The double circulatory system commonly found in mammals, amphibians, reptiles, and birds. In this circulatory system, the blood passes through the heart twice for each circuit of blood that is pumped around the body. Deoxygenated blood is carried from the heart to the lungs, and the oxygenated blood is returned to the heart. This is the pulmonary circulation. The second loop, the systemic circulation, carries the oxygenated blood from the heart to the muscles and organs of the body. The deoxygenated blood is then returned back to the heart (Heart & Circulatory).



Differences between Single & Double circulatory system:


Single Circulation
Double Circulation
Occurrence
Found in only fishes.
Found in amphibians, reptiles, birds and mammals.
Mode of circulation
Blood passes only once through the heart to supply once to the body
Blood passes twice through the heart to supply once to the body.
Nature of blood
Only venous blood passes through the heart
Mixed or oxygenated or venous blood passes through heart.
Efficiency
Less efficient as gill capillaries slow down the blood flow so the body receives blood at a low pressure which decreases the rate of oxygen supply to the cells.
More efficient as blood flows at higher pressure, especially in birds and mammals, which increases the rate of food and oxygen supply to the cell and also rapid removal of wastes from them


For further information on the double circulation, please watch the following video:


Video of explanation of double circulation (Systemic and Pulmonary)



Insect

Type of circulatory system:


  • Open circulatory system
  • Single circulatory system

Diagram of circulatory system:
Diagram 2: Insect circulatory system

insect_diagram.jpg
Diagram of insect circulatory system (Jaworski)
Key7 – Blood vessel of insect (like aorta)14 – chambers of blood vessel (acts as hearts)

General idea of process of circulatory system:

In the circulatory system of an insect, there is a single blood vessel that lies on the dorsal side of the insect, from the head to the abdomen. Since insects have open circulatory system, their hemolymph flows in the hemocoel and makes contact with the organs and tissue. In the abdomen, the vessel is divided into chambers. These chambers act as hearts as the muscle contraction of these vessels push the hemolymph towards the head, which is where the blood is release into the hemocoel. After released, as there are ostia (which are perforations) on the heart wall, the hemolymph can re-enter the circulation system, from the hemocoel for the cycle to start again (Hadley).

Video/animation of circulatory system:
For a general idea of how the insect circulatory system works, please watch the following animation:


From: http://entochem.tamu.edu/insect_structure-function/index.htmlClick for animationAnimation of the insect circulatory system (Keeley)


Worm
Type of circulatory system

  • Simple closed circulatory system
  • Single circulatory system

Diagram of circulatory system
Diagram 3: Worm circulatory system
earthworm_diagram.gif
Diagram of worm circulatory system (Diagram of earthworm)

General idea of process of circulatory system
In a worm circulatory system, there are three main features: the aortic arches (hearts), dorsal blood vessels, and ventral blood vessels. The aortic arches (there are 5 pairs in an earthworm_ acts as heart and pumps blood around the dorsal and central vessel. The ventral vessel, in responsible for transporting blood toward the end of the worm while the dorsal vessel is responsible for transporting blood toward the front end of the worm (Earthworms).

Fish
Type of Circulatory system

  • Closed circulatory system
  • Single circulatory system (oxygen deprived blood comes to the heart. From there, it is pumped to the gills and then enters the heart. Then, it is pumped into the lungs for oxygenation)

Diagram of circulatory systemDiagram 4: fish circulatory system
fish_diagram.jpg
Diagram of fish circulatory system (Diagram of fish)

General idea of process of circulatory system
The heart of a fish consists of four parts. The first is the sinus venosus, a thin-walled sac which collects blood from the fish's veins before it flows to the second part of the heart. The second part, the atrium, is a large muscular chamber which sends blood to the third part of the heart. The third part, the ventricle, is a thick-walled muscular chamber which pumps blood to the fourth part and then out of the heart. The fourth part, the bulbus arteriosus, is connected to the aorta, which is where the blood flows through for oxygenation (Fish). Even though the heart has 4 parts, it is considered 2-chambered (Bora).
Video/animation of circulatory system
View the key and then the following animation to get a better visual idea of the fish circulatory system

key_diagram.JPG

Vertebrate circulatorium key (Keller and Amagai)From:http://www.hhmi.org/biointeractive/circulatorium/frames.htmlClick on this link for animation
Fish circulatory system (Keller and Amagai)From:http://www.hhmi.org/biointeractive/circulatorium/frames.htmlClick on this link for animation


Amphibians

Type of circulatory system:


  • Closed circulatory system
  • Double circulatory system

Diagram of circulatory system
Diagram 5: amphibian circulatory system
amphibian_diagram.jpg
Diagram of amphibian circulatory system (Diagram of amphibian)General idea of process of circulatory system
Deoxygenated blood from the body enters the right atrium at the same time as the oxygenated blood from the lungs and skin enters the left atrium. Then, the deoxygenated blood in the right atrium enters the ventricle while the oxygenated blood from the left atrium enters the also enters ventricle. Even though the oxygenated blood and deoxygenated blood is not separated, the spongy, irregular interior surface of the ventricle, along with the coordinated contractions of the atria, keeps the oxygenated and deoxygenated blood from mixing too much, causing them to only mix slightly (Heart & Circulatory). The ventricle then pumps the deoxygenated blood to the lungs and the skin to pick up oxygen, while the oxygenated blood gets pumped to the body (Amphibian Circulation – The Frog).

Video/animation of circulatory system
View the key and then the following animation to get a better visual idea of the amphibians’ circulatory system

key_diagram.JPG

Vertebrate circulatorium key (Keller and Amagai)From:http://www.hhmi.org/biointeractive/circulatorium/frames.htmlClick on this link for animation
Amphibian circulatory system (Keller and Amagai)From:http://www.hhmi.org/biointeractive/circulatorium/frames.htmlClick on this link for animation


Human

Type of circulatory system:
  • Close circulatory system
  • Double loop circulatory system

Diagram of circulatory system:
Diagram 6: Human circulatory system
Human_diagram.jpg
Diagram of the human circulatory system (Human Circulatory system)

General idea of process of circulatory system:
In the human circulatory system, the heart is made up of 4 chambers: the right atrium, left atrium, right ventricle, and left ventricle. The left atrium collects the oxygen-rich blood that is returning from the lungs and forces it into the left ventricle, through the mitral valve. The Left ventricle, being the strongest part of the heart, pushes the oxygen-rich blood into the aorta (which transport the blood to other parts of the body), through the aortic valve. The right atrium then collects the oxygen-poor blood, returning from the body and forces it into the right ventricle, through the tricuspid valve. Finally, the right ventricle forces the oxygen-poor blood into the lungs, through the pulmonary valve for the cycle to start again (Anatomy of the Human).

Video/animation of circulatory system:
For additional information and a visual explanation of the human circulatory system, please watch following video:
Animation on how the human circulation system works (Circulatory system)


The 5 organisms have been organized based on their complexity (from least complex to most complex). The following is an inference on how the complexity affects the lifestyle/ability/metabolism of the organism
When a system is more complex, meaning that it is a double circulation or a closed system, more energy (oxygen and food) is distributed to the cells around the body, which allows the organism to be larger. In a closed system, the blood is pumped around at a higher pressure, which means that more blood is transported in a shorter amount of time. This result in more food and oxygen reaching the cells, and the organism can be more active. As a result, an organism with a more complex circulatory has a more active lifestyle. On the contrary, in an open system, the blood pressure is higher than that in a closed system, which means that less oxygen and food molecules are transported to the cells, resulting in less energy for the organism. Organisms with open circulatory systems are less active, and as a result, they will have a less active lifestyle
If an organism with an open circuit was large, it would not be able to survive because the blood takes a long time to be pumped around the whole body, as the blood pressure is very low in an open circuit, compare to a closed circuit. As a result, not enough oxygen and food would be reaching all the parts of their body. Organisms with a closed circuit are able to be large because the blood pressure is very high and as a result, blood can be efficiently pumped around the body. Humans, for example, are able to be quite large compared to organisms such as insects and worms because of how complex their circulatory system is. Human have a closed circuit and they have a double circulatory system, so their blood flows at a very fast rate.
Organisms with lower blood pressure (less complex circulation system), have slower metabolism because food and oxygen are not as efficiently distributed around the cells for metabolism to occur quickly. In contrast, organisms with higher blood pressure (more complex circulation system), have faster metabolism as oxygen and food are delivered around the body efficiently, allowing chemical reactions to occur rapidly.
Works Cited

“Amphibian Circulation – The Frog.” N.d. Microsoft PowerPoint file. <http://chesterfield.k12.va.us/Schools/Monacan_HS/science/colemanbio/powerpoints/vertebrateunits/07unit/Amphibian%20Circulation%20-%20The%20Frog.ppt>.

“Anatomy of the Human Heart with Flash Illustration .” Texas Heart Institute. N.p., n.d. Web. 25 May 2011. <http://www.texasheartinstitute.org/hic/anatomy/anatomy.cfm>.

“Aorta.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Aorta>.

Bora, Chandramita. “Circulatory System of a Fish.” Buzzle.com. N.p., n.d. Web. 25 May 2011. <http://www.buzzle.com/articles/circulatory-system-of-a-fish.html>.

"Body Cavity ." Wikipedia. N.p., n.d. Web. 30 May 2011. <http://en.wikipedia.org/wiki/Body_cavity>.

“Circulatory System.” Clinton Community College. N.p., n.d. Web. 25 May 2011. <http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20102/bio%20102%20lectures/circulatory%20system/circulat.htm>.

Circulatory system . You Tube. N.p., n.d. Web. 25 May 2011. <http://www.youtube.com/watch?v=D3ZDJgFDdk0&feature=player_detailpage>.

Diagram of amphibian circulatory system . N.d. Estrella Mountain Community College. Web. 25 May 2011. <http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookcircSYS.html>.

Diagram of earthworm circulatory system. N.d. University of Pennsylvania . N.p., n.d. Web. 25 May 2011. <http://www.sas.upenn.edu/~rlenet/Earthworms.html>.

Diagram of fish circulatory system . N.d. Estrella Mountain Community College. Web. 25 May 2011. <http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookcircSYS.html>.

"Differences between Single Circulation and Double Circulation." Human Circulatory System. Web. 01 June 2011. <http://www.circulatory-system.com/differences-between-single-circulation-and-double-circulation/>.

“Dorsal.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Dorsal>.

“Earthworms.” University of Pennsylvania . N.p., n.d. Web. 25 May 2011. <http://www.sas.upenn.edu/~rlenet/Earthworms.html>.

“Fish.” Wikipedia. N.p., n.d. Web. 25 May 2011. <http://en.wikipedia.org/wiki/Fish#Circulation>.

Hadley, Debbie. “The Insect Circulatory System.” About.com. N.p., n.d. Web. 25 May 2011. <http://insects.about.com/od/morphology/ss/internalanatomy_4.htm>.

“Heart & Circulatory System.” Mr Reilly’s Amphibiant Tutorial. N.p., n.d. Web. 25 May 2011. <http://mset.rst2.edu/portfolios/r/reilly_t2/end_project/frogtutor/circulatory_system.htm>.

“Hemocoel.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Hemocoel>.

“Hemolymph.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Hemolymph>.

Human Circulatory system. N.d. Blogspot. Web. 25 May 2011. <http://xii00epu.blogspot.com/2011/05/human-circulatory-system-diagram-for.html>.

Jaworski, Piotr. Insect circulatory system. N.d. About.com. N.p., n.d. Web. 25 May 2011. <http://insects.about.com/od/morphology/ss/internalanatomy_4.htm>.

Keeley, Larry. Vertabrate Circulatorium. Entomology. N.p., n.d. Web. 25 May 2011. <http://entochem.tamu.edu/insect_structure-function/index.html>.

Keller, Eric, and Satoshi Amagai. Vertabrate Circulatorium. Howard Hughes Medical Institute. N.p., n.d. Web. 25 May 2011. <http://www.hhmi.org/biointeractive/circulatorium/frames.html>.

Open versus Closed Circulatory Systems. N.d. Cornell University. Web. 25 May 2011. <http://www.biog1105-1106.org/demos/105/unit7/vascularsys.html>.

Sakurai, Akira. “Closed and Open Circulatory System.” Georgia State University. N.p., n.d. Web. 25 May 2011. <http://www2.gsu.edu/~bioasx/closeopen.html>.

Systemic and Pulmonary Circulation . You Tube. N.p., n.d. Web. 25 May 2011. <http://www.youtube.com/watch?v=0jznS5psypI>.

“Taxon.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Taxon>.

“Thorax.” Dictionary.com. N.p., n.d. Web. 25 May 2011. <http://dictionary.reference.com/browse/Thorax>.

“What Is Meant By Single And Double Circulation?” Blurt it. N.p., n.d. Web. 25 May 2011. <http://www.blurtit.com/q138819.html>.