Circulatory System Study Guide


Every tissue, organ, and muscle in our body plays a role in keeping us alive, barring a few exceptions. But how do they stay active? What gives all of these essential entities the energy required to function? That job falls onto our circulatory system. It not only transports nutrients and oxygen to all parts of our body, but it also whisks away poisonous by-products, regulates body temperature, and closes open wounds so that we don’t die from a simple paper cut. So, what does the circulatory system do? Let’s learn about it!

What is the Circulatory System?

All cells in the body need oxygen and other nutrients to function correctly. Consequently, need their wastes removed as well. The circulatory system fulfills both these tasks. Each cog of the system: heart, blood vessels, and blood work together to provide resources and remove waste from each cell in our body.

The only artery which carries deoxygenated blood:

  • Usually, arteries carry pure/oxygenated blood, and veins are responsible for impure/deoxygenated blood; however, the pulmonary arteries and veins don’t fit this mold.
  • The pulmonary artery carries impure blood from the heart to the lungs, extracting carbon dioxide and injecting oxygen.
  • The pulmonary vein then carries the oxygenated blood back to the heart.
  • As a rule of thumb, arteries carry blood away from the heart, and veins carry blood towards the heart.

Functions of the Circulatory System

The circulatory system’s primary purpose is to move blood. The blood circulation in our body works to keep our organs, muscles, and tissues healthy and keep us alive. The most critical functions of the circulatory system are:

  • The transport of oxygen through the body
  • Providing cells with nutrients and getting rid of waste
  • Clotting of open wounds
  • Regulation of body temperature

Parts of the Circulatory System

The circulatory system is made up of:

  • Heart: Pumps blood all over the body. It gets deoxygenated blood, sends it through the lungs, and then pumps it to the rest of the body.

  • Arteries: Mainly carry blood away from the heart

  • Veins: Mainly return blood to the heart

  • Capillaries: Facilitate the exchange of oxygen and nutrients into cells.


The human circulatory system consists of several circulations:

– Pulmonary Circulation: The blood flow between the heart and lungs (also called the heart circulatory system

– Systemic Circulation: The blood flow to and from every tissue in the body

– Coronary Circulation: Circulates blood flow to the heart

The lymphatic system works in tandem with the circulatory system and moves lymph through blood vessels. It also helps deliver nutrients and receive waste products. It is made up of:

  • Lymph
  • Lymph nodes
  • Lymphatic vessels
  • Collecting ducts

Lymphatic systemSource

Double Circulation of Blood in Humans

  • In the human circulatory system, blood is passed through the heart twice in one cycle.
  • The right pump sends deoxygenated blood through the pulmonary artery to the lungs, letting it expel carbon dioxide and become oxygenated.
  • The pulmonary vein takes the fresh blood back to the heart, after which the left pump sends it along to the rest of the body.

blood circulation in the heartSource

Humans have double circulation because it makes sure that our muscles and tissues get the optimum conditions for them to function. The differentiation of oxygenated and deoxygenated blood improves the efficiency of our circulatory system by giving tissues and muscles pure blood instead of a mixture with impure blood. Apart from this, it also helps better maintain body temperature.


  • The heart, blood, blood vessels, and lymphatic system work together to keep us alive and healthy.
  • They build and maintain our body by providing nutrients and oxygen to hard-working organs and muscles.
  • We should play our part in helping them work well by preventing fat build-up in our vessels.
  • Regular exercise and a healthy diet are an essential part of keeping ourselves cardiac disease-free; stretching, massages, and drinking plenty of water will help keep our circulation tip-top too.


1. What are the 3 systems within the circulatory systems?

The Circulatory System consists of three systems that work together:

  • Cardiovascular: Heart
  • Pulmonary: Lungs
  • Systemic: Arteries, veins, and capillaries

2. What is the circulatory system and its function?

The system responsible for ensuring tissues gets the oxygen and nutrients they require and disposing of the waste created is called the circulatory system. It is made up of the heart, blood vessels, and blood and is essential to keep the blood flowing.

3. What are the three circulatory systems?

There are three kinds of circulation:

  • Systemic circulation.
  • Coronary circulation.
  • Pulmonary circulation.

4. What is the circulatory system explained?

One of the body’s most essential systems, the circulatory system, is responsible for replenishing tissues, organs, and muscles with oxygen and nutrients they may need. It also whisks away waste from them by pumping blood throughout the body.

5. What is Circulatory System in short answer?

The heart, blood, and blood vessels together make up the Circulatory System, responsible for moving blood all over the body.

6. What are the 4 main functions of the cardiovascular system?

  • It helps maintain all organ systems.
  • Carries blood, nutrients, oxygen, carbon dioxide, and hormones around the body.
  • It protects cells from pathogens.
  • It acts as an interface for cell-cell interactions. Substances in the blood help repair damaged tissue.

7. How do you improve circulation?

Exercise, massages, drinking water, managing stress, stretching.

8. What is the function of the circulatory system in the animal body?

  • Pumping blood throughout the body
  • Providing oxygen to tissues, muscles, and organs
  • Extracting and transporting waste away from them
  • Regulating body temperature
  • Clotting wounds, when needed

9. What are the 5 main parts of the cardiovascular system?

  1. Heart
  2. Veins
  3. Arteries
  4. Capillaries
  5. Lymph

10. What is the role of the circulatory system in energy production?

Arteries carry oxygen and nutrient-rich blood to different parts of the body. The nutrients encapsulated in the blood are very energy-rich: glucose and fatty acids. The cells use these to produce energy.

11. How does blood circulate in the body?

The human body has a double circulation system. The deoxygenated blood is sent to the heart, which sends it to the lungs to get oxygenated. The pulmonary vein brings this rich blood back to the heart and is forwarded to different body parts.

We hope you enjoyed studying this lesson and learned something cool about the Circulatory System! Join our Discord community to get any questions you may have answered and to engage with other students just like you! Don’t forget to download our App to experience our fun, VR classrooms – we promise, it makes studying much more fun!😎

Continue your learning journey

Read about Lymphatic SystemRead about Central nervous system: Read about Respiratory System organs: Read about Heart Read about Blood vessels and blood


  1. Double Circulatory System. Accessed 23 Nov, 2021.
  2. 9 Ways to Improve Your Blood Circulation. Accessed 23 Nov, 2021.
  3. Circulatory System. Accessed 23 Nov, 2021.
  4. Lymphatic System. Accessed 24 Nov, 2021.
  5. Heart and Circulatory System.,waste%20products%2C%20like%20carbon%20dioxide. Accessed 24 Nov, 2021.

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