Fun facts: You have km of blood vessels You have 100 trillion cells that need transport Your heart is about the size of your fist and has a mass of about 300g Your heart beats about 70 times/minute Every minute 5L of blood cycles through the heart and lungs Your circulatory system is closed. Your blood is your immune system!!

Types of Circulatory Systems There are two types of circulatory systems, open and closed. Closed: –Consists of blood vessels and a pumping organ. –Blood is pumped through a closed system of arteries, veins, and capillaries. –Our circulatory system is closed.

Open: –Blood does not always move within blood vessels. –There is no true heart or capillaries. Instead there are blood vessels that act as pumps to force the blood along. –Less efficient because the movement of blood is less rapid and under less pressure. –Snails, insects and crustaceans have an open system.

Open circulatory system

Transport Systems Cells need food and oxygen and need to get rid of wastes and carbon dioxide. A transport system is the way to move material to and from the body cells. The transport system has two parts. –A circulating fluid (blood) –A pump (one or more hearts) In animals the transport system is the Circulatory System

Functions 1.Takes oxygen and nutrients to every cell. 2.Removes carbon dioxide and waste from every cell. 3.Carries hormones from endocrine glands to different parts of the body. 4.Maintains body temperature and fluid levels. 5.Prevents infection from invading organisms

How blood is transported Arteries: –Vessels that carry blood away from the heart –Tough but elastic. Able to withstand the pressure of blood pumped by the heart Veins: –Thinner walls as there is no more blood pressure –Have “one way” valves to keep blood moving towards heart. Capillaries: –Very narrow tubes between arteries and veins where diffusion occurs

Accessory Organs Lungs - organ where oxygen is taken up and CO 2 is released Kidneys - organ where wastes are removed from blood; critical in regulating fluids in the body Small intestine - digestion Large intestine - water absorption

The Heart The human heart is a two-sided, 4 chambered structure with muscular walls. The four chambers are: –Left ventricle –Right ventricle –Left atrium –Right atrium

The Heart: Parts

What do valves do? The valves are one directional They keep blood moving in the right direction.

Pulmonary veins aorta Superior vena cava Pulmonary artery Right atrium left atrium Right ventricle Left ventricle Tricuspid valve pulmonary valve bicuspid valve aortic valve