The cardiovascular system delivers oxygen and nutrients to the whole body, defends against infections, transports hormones, and collects waste products that end up in the excretory system.

Parts Involved

• Heart – the extremely consistent pumping organ
• Blood (plasma, red blood cells, white blood cells, platelets)
• Vascular system (arteries, veins, capillaries)
• Bone marrow – produces blood cells
• Liver – produces plasma

Functions

• Pulmonary circulation pumps to lungs for the release of carbon dioxide and the intake of oxygen.
• Systemic circulation pumps oxygen-rich blood to the body.  Splanchnic or visceral circulation supplies the digestive organs as a branch directly off the aorta.  Before it returns to the heart,  blood supplied to the gastrointestinal tract goes to the liver (known as portal circulation) where nutrients are absorbed and toxins are neutralized.  There is also a small portal flow from the hypothalamus to the anterior pituitary gland.
• Fetal circulation obtains oxygen and nutrients from the placenta through the umbilical chord rather than the lungs and the mouth.

Fun Facts

If the vascular system of one person were laid end to end, it would circle the globe twice! The heart pumps about 3,600 gallons (13,640 liters) of blood per day. The heartbeat is the sound of the valves closing as they push blood through its chambers.