Open vs Closed Circulatory System: Larger animals require a greater and more rapid supply of nutrients and oxygen to their tissues and also fast disposal of respiratory and nitrogenous wastes. So they have progressed blood as a specialized circulatory fluid and the circulatory system consists of heart, blood, and blood vessels for regulating and pumping blood to the tissues. The blood vascular system may be of two types. They are an open circulatory system and a closed circulatory system. Living Things have distinctive forms of circulatory systems.

Humans have a closed circulatory system, while many clams and other invertebrates have an open system. In a closed circulatory system, blood is encircled within blood vessels. In an open circulatory system, the blood vessels open into slots and not into capillaries, so that blood gets in direct contact with tissues. Whereas in a closed circulatory system, blood flows through capillaries attached by arteries and veins. In the open circulatory system, the rate of circulation is slow whereas it is rapid in the closed circulatory systems.

Circulatory System

The circulatory system, also recognized as the cardiovascular system, is a huge network of organs and blood vessels that acts both as a transmission and waste removal system for the body. Nutrients, oxygen, and hormones are transported to every cell and as these requirements are provided, waste products such as carbon dioxide are extracted, according to the nonprofit Nemours Children’s Health System.

Open vs Closed Circulatory Systems
Open vs Closed Circulatory Systems

Not only does the circulatory system keep our cells healthful, but it also keeps us alive. The heart regularly gets signals from the rest of the body that direct how hard it needs to pump to perfectly supply the body with what it needs, according to Nemours.

For example, when asleep, the body sends electrical indicators to the heart that tell it to slow down. When engaging in heavy exercise, the heart receives the information to pump harder to deliver extra oxygen to the muscles.


The heart exists at the center of the circulatory system and pumps blood through the rest of the network. This void 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 from the two chambers at the bottom.

The chambers are divided by one-way valves to ensure that blood flows in the correct direction. The rest of the circulatory system is made up of two separate networks that work together: The pulmonary and systemic systems. The pulmonary system is effective for providing fresh oxygen to the blood and disposing of carbon dioxide. Oxygen-poor blood reaches from veins leading to the right atrium of the heart.

The blood is then pumped through the right ventricle, then to the pulmonary artery, which divides into two and divides into progressively smaller arteries and capillaries before arriving the lungs. The tiny capillaries form a network within the lungs that help the transfer 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 different, although they are both types of blood vessels. Arteries carry oxygen- and nutrient-rich blood from the heart to all parts of your body. Veins carry the oxygen- and nutrient-poor blood back to the heart.

The capillaries are the shortest type of blood vessel and provide the overpass between the arteries and veins. Find out all about the blood, lungs, and blood vessels that make up the circulatory system. As the oxygen-rich blood reaches from the lungs, it enters the left atrium and then travels through to the left ventricle before being pumped throughout the body.

The blood gets pumped through the aorta artery (the hugest artery in the body) before coming in the shorter arteries that carry the blood to every part of the body. As the blood transfers, nutrients, and oxygen to each cell, carbon dioxide, and other waste products are picked up as the bloodstreams through the capillaries and into the veins. The shrinkage and relaxation of the heart the heartbeat is handled by the sinus node, which is a cluster of cells fixed at the top of the right atrium.

The sinus node sends electrical signals through the electrical conduction system of the heart that controls the muscle to contract or relax. The heartbeat is partitioned into two phases: the systole and diastole phases. In the first, the ventricles contract and force blood out into the pulmonary artery or the aorta.

At the same time, the valves disconnecting the atria and ventricles snap shut to prevent blood from flowing backward. In the diastole phase, the valves coupling to the atrium open, and the ventricles relax and fill with blood. The sinus node leads the pace of these two phases.

Adult humans have a total of about five to six quarts (a slightly less than five to six liters) of blood pumping through their bodies. On average, the heart beats about 100,000 times per day, depressing about 2,000 gallons (7,570 liters) of blood through a total of 60,000 miles (96,560 kilometers) of blood vessels. It only takes about 20 seconds for blood to migrate through the entire circulatory system.

Open Circulatory Systems

Gastrovascular voids work well for aquatic animals with two cell layers, but cannot support animals that have many layers of cells, especially those that don’t live in the water. For these more complicated animals, the digestive and circulatory systems became split and specialized to perform the more troublesome processes needed to support many cell layers and life out of water.

There are two main types of circulatory systems: open circulatory systems and closed circulatory systems. Open circulatory systems are systems where internal organs and body tissues are enveloped by circulatory fluid. This fluid is called hemolymph, and it’s pretty much like blood, except that it doesn’t contain oxygen transporting cells. Let’s take a closer look at an example of an open circulatory system.

Grasshopper Illustration In an open circulatory system, the hemolymph surrounds all private organs and fills elegant much all of the internal spaces between organs, muscles, and other body tissues. These hemolymph-filled spaces are labeled sinuses . Hemolymph moves around between organs and tissues as body developments of the animal changes the size and frame of the sinuses.

In extension, animals with open circulatory systems, like our grasshopper here, routinely have some sort of main vessel, like this one here, with simple tubular hearts that reduce and partially direct circulation of the hemolymph through the sinuses, like this.

Closed circulatory systems

Open circulatory systems solve the problem of how to send nutrients through organisms with more than two cell layers. But transport in open systems is most efficient over only short distances and occurs slowly.

So how do large animals displace nutrients long distances? The answer to this question can be found in most modern homes: internal plumbing! Think of it this way, before the boundless use of plumbing, human establishments were limited in size to areas within walking distance of a water source, whether it was a central well, a stream, or a river.

However, once humans initiated using plumbing to rapidly and efficiently direct water long distances, cities could grow larger and suburbs began showing around the cities. As long as there was plumbing to provide a source of freshwater, there was really no limit to how big a city or metropolitan area could be.

The same principles hold true for circulation in animals. A closed circulatory system is a circulatory system where blood resides within vessels. The purpose of these blood vessels is absolutely not much different from the function of water pipes in a city, which is to bring necessary property long distances and arrange it to many locations.

The difference or Open vs Closed Circulatory System

Vertebrates and some invertebrates have a closed circulatory system. The open circulatory system, on the other hand, is most commonly seen in invertebrates like cockroaches and crabs.

Open vs Closed Circulatory System

  1. In open circulatory system, the hemolymph directly bathes the organs and tissues while in the closed circulatory system the blood circulates within closed vessels.
  2. In open circulatory system, the blood and interstitial fluid cannot be distinguished while in the closed circulatory system blood and interstitial fluid are distinct.
  3. In open circulatory system present in mollusks and arthropods while the closed circulatory system present in annelids and vertebrates.
  4. In an open circulatory system, blood is pumped into the body cavity while in the closed circulatory system Blood is pumped through the vessels by the heart.
  5. In an open circulatory system, dorsal blood vessels present while in the closed circulatory system dorsal and ventral blood vessels present.
  6. In open circulatory system, The capillary system is absent while in the closed circulatory system capillary system found.
  7. In an open circulatory system, Blood is in direct contact with the tissues while in the closed circulatory system Blood is not in direct contact with the tissues.
  8. In an open circulatory system, Nutrients are exchanged directly between blood and tissues while in the closed circulatory system the nutrients are exchanged via tissue fluid.
  9. In open circulatory system, No transport of gases while in the closed circulatory system Gases are transported.
  10. In open circulatory system, The fluid flowing in this system is called hemolymph while in the closed circulatory system Fluid flowing in this system is called blood.
  11. In an open circulatory system, No respiratory pigments are present while in the closed circulatory system Respiratory pigments are present.
  12. In open circulatory system, The volume of blood cannot be controlled while in the closed circulatory system volume of blood can be controlled by contraction ad relaxation of blood vessels.
  13. In an open circulatory system, Blood flow is slow while in the closed circulatory system blood flow is rapid.
  14. In an open circulatory system, The open spaces are called sinuses and lacunae while in the closed circulatory system Closed spaces involve arteries and veins.
  15. In open circulatory system organisms with OCS: Snails, clams, cockroaches, and spiders while the closed circulatory system Organisms with CCS: Humans, squids, Cats, earthworms.


Do Humans Have Closed Or Open Circulatory System?
Humans Have Closed Circulatory Systems. This Means That Blood Is Always Enclosed In Vessels And The Heart While Circulating Throughout The Body. Traveling Through Arteries And Veins, Blood Carries Important Molecules Throughout The Body And Is Always Confined.
What Is The Main Difference Between An Open Circulatory System And A Closed One Quizlet?
Open Circulatory System – Fluid Is Pumped Through Open-ended Vessels & Flows Out Among The Cells; There Is No Distinction Between Blood & Interstitial Fluid. Closed Circulatory System – Blood Is Confined To Vessels, Which Keep It Distinct From The Interstitial Fluid.
Do Mammals Have An Open Or Closed Circulatory System?
The Vascular System Consists Of Arteries, Veins, And Capillaries. Vertebrates (Animals With Backbones Like Fish, Birds, Reptiles, Etc.), Including Most Mammals, Have Closed Cardiovascular Systems. The Two Main Circulation Pathways In Invertebrates Are The Single And Double Circulation Pathways.
What Are The 2 Types Of Circulatory System?
There Are Two Main Types Of Circulatory Systems: Open Circulatory Systems And Closed Circulatory Systems. Open Circulatory Systems Are Systems Where Internal Organs And Body Tissues Are Surrounded By Circulatory Fluid.
What Are The Disadvantages Of An Open Circulatory System?
As We See It, There Are More Disadvantages To Having An Open Circulatory System But Having An Open Circulatory System Suits Those Animals Well. There Is A Limited Capability For Such Animals To Increase Or Decrease Distribution And Velocity Of Blood Flow.
What Is The Main Benefit Of A Closed Circulatory System?
The Closed Circulatory System Has More Advantages Over The Open Circulatory System. The Blood Transfers Faster In The Closed System, Thus Oxygen, Nutritients, And Wastes Transport Fast Also.