the circulatory system

Organs of the Circulatory System

The Circulatory System carries blood and dissolved substances to and from different places in the body.

Heart

Blood Vessels (Arteries, Veins, Capillaries)

Blood travels throughout the body using a network of blood vessels. There are 3 specific types of blood vessels: arteries, veins, and capillaries.

• pumps blood through the network of arteries and veins

• The arteries and veins are responsible for carrying the blood to and from the heart and the rest of the body

• CARDIAC = HEART

• CARDIOVASCULAR SYSTEM

• The heart is the main organ of the circulatory system

Blood vessels that carry oxygenated blood from the heart to other parts of the body.

The largest artery in the human body is the aorta.

Arteries contain elastic fibers that allow it to stretch under increased pressure.

Arteries contain muscles that contract to push blood along.

Veins carry blood back to the heart

Veins have valves that force blood to travel in only 1 direction.

Veins run parallel to arteries in the body.

When muscles contract to move the body, they also help the blood flow through veins (as they surround the vein).

Capillaries are the smallest and most numerous of the blood vessels.

Oxygen, nutrients, and waste are transferred through the capillaries into/from the tissues. This exchange can ONLY occur through a capillary.

• Red blood cells (RBC)

• White blood cells ( WBC)

• Plasma

• Platelet

• Plasma- About 55% of our blood. It is the liquid part of blood. It is mostly water.

• Red blood cells- They are red because of the hemoglobin.

• White blood cells- larger than red blood cells, and they have a nucleus. WBC help to defend against bacteria and viruses that get into the body.

• Platelets - little fragments of cells. If a blood vessel gets damaged, the platelets help the blood to clot and seal the wound.