Circulatory System

by Casey Whitworth

What is the circulatory system?

The circulatory system is the organ system that pumps out blood and carries blood to the areas in the body where it is needed. It is made up of three parts- the heart, the blood/blood vessels, and the lymph nodes. The heart pumps the blood, the blood vessels are a series of networks that carry the blood, and the blood is what contains the blood cells, which are the cells that contain necessary substances for our body. The lymph nodes are like filters that remove germs from the body that can harm us. The five main functions of the circulatory system are to provide the cells with food and oxygen, to carry carbon dioxide and waste away from the cells, to regulate the body temperature, to protect the body from diseases, and to transport hormones.

What are the blood/blood vessels?

The blood is a liquid made of plasma, consisting of mostly water, proteins, minerals, etc. Its also made of three elements- red blood cells, white blood cells, and platelets. The red blood cells carry oxygen and carbon dioxide throughout the body. The white blood cells carry substances that protect the body from diseases. The platelets release substances that allow the blood to clot and prevent blood loss from injured vessels. The blood vessels are a system of connected tubes throughout the body that carry the blood. The three main functions of the blood/blood vessels are to carry oxygen and carbon dioxide throughout the body, to protect the body from diseases, and to allow the blood to clot.

Types of Tissue/Cells in Blood and Blood Vessels

Tunica intima- the inner lining of the blood vessels
Tunica media- the central layer of the blood vessels
Red blood cells- carry oxygen and carbon dioxide throughout body
White blood cells- protect body from diseases

Fun Fact- Did you know that the heart can still beat when it's taken out of the body?

Functions of Blood/Blood Vessels

  1. Carry oxygen and carbon dioxide throughout the body.
  2. Protect the body from diseases.
  3. Release substances to allow blood to clot.

4 Diseases Associated with the Circulatory System

  1. Coronary Artery Disease (CAD)- When your coronary arteries become diseased or damaged. Plaque or inflammation usually cause this.
  2. Hemophilia- When your blood does not clot normally.
  3. Hypertension- When your blood pressure is so high that it can cause damage to the arteries.
  4. Arteriosclerosis- When your blood vessels become thick and stiff, restricting blood flow to your organs and tissue.


Hemophilia is a disease in which your blood is unable to clot normally, or at all. Some symptoms are-
  • unexplained or excessive bleeding from cuts or injuries
  • many large or deep bruises
  • pain, swelling, or tightness in your joints
  • nosebleeds without a known cause
  • in infants, unexplained irritability
  • painful, prolonged headache
  • neck aches
  • double vision
  • repeated vomiting
  • extreme fatigue
And more. Some treatments are vaccinations, physical therapy, and reduced to no contact physical activity.

You could not live without the circulatory system. Without it, your body would not be able to fight off diseases or maintain a stable internal environment.

Medical Advances for the Circulatory System

  • extended CPR practices and methods save lives
  • doctors can now convert non-beating heart cells into beating heart cells
  • biopsied (removed for examination) heart cells improved heart function and reduced scars
  • disconnecting your kidney can reduce high blood pressure
  • having too many sugary drinks can cause damage to your body

Interactions with Other Organ Systems

  1. The largest artery in the body, the aorta, branches out into smaller arteries. These smaller arteries deliver blood to the digestive organs.
  2. The muscles in veins can contract and help push the blood throughout the body.
  3. Special circuits deliver blood to your kidney, your liver, your brain, and to the heart itself.

More pictures: