2. The Circulatory System
• This is the
circulatory system of
the human body.
• Arteries are shown
in red, veins in blue.
The heart is in the
middle of the chest.
3. The Blood
• Here are three types
of blood cells viewed
under a scanning
electron micrograph
microscope.
• You can see red
blood cells, white
blood cells and,
shown in blue,
platelets.
4. The Heart
• The heart is a muscle.
• It pumps blood around the body.
• Your heart is about the size and shape of
your fist.
5. The Heart
• Blood is the body's delivery and collection
service.
• It delivers food and oxygen to every part of
the body, and it collects waste products,
particularly carbon dioxide.
• Blood circulates, or goes round and round
your body, about 2000 times a day. It is
pumped by the heart through tubes called
blood vessels.
6. Inside the Heart
• When a heart is cut open, you can see a thick
wall down the middle, dividing it up into two
halves – a left and a right side.
• The heart is really two pumps working side by
side. Each pump has a top space, or atrium,
which receives blood from the veins. Below
each atrium is another space, a ventricle,
which pumps blood out of the heart and into
arteries.
7. The Structure of the Heart
1. valve
2. Right
atrium
3. valve
4. Right
ventricle
5. aorta
6. Left
atrium
7. valve
8. Left
ventricle
9. septum
