The circulatory system carries blood الدم andيحملdissolved substances الذائبة to and from الموادdifferent places in the body.

The Heart has the job وظيفة of pumping ضخ these things around the body.

The Heart pumps blood and substances around

the

body in tubesانابيب called تسمىblood vessels الدموية . األوعية

The Heart and blood vessels الدموية makeاالوعيةupيكونوا the Circulatory System.

What is the circulatory system?

The heart is surrounded by بـ the محاطmyocardium التامور . غشاء

Functions of the circulatory system

The circulatory system has three functions:

1. Transporting substances around the body. These include oxygen, glucose, carbon dioxide, nutrients, water and waste products.

3. Protecting يحمي the body.

2. Controlling body temperature.

lungs

head & arms

liver

digestive system

kidneys

legs

pulmonary artery

aorta

pulmonary vein

main vein

Left Right

How does this system work?

Circulatory System

Lungs

Body cells

Our circulatory system is a double circulatory system.

This means it has two parts.

the right side of

the system

deals with

deoxygenated

blood.

the left side of

the system

deals with

oxygenated

blood.

The double circulatory system

oxygenated blood to the rest of the body through the arteries

deoxygenated blood back to the heart through the veins.

The pulmonary الرئويcirculation carries:deoxygenated blood from the

heart to the lungsالرئتين

oxygenated blood back from the lungs to the heart, ready to be pumped out to the body.

The systemic circulation carries:

lungs

body’scells

• The heart contracts about 72 times per minute

• Pumps about 70mL of blood with each contraction.

• The right and left sides of the heart are separated by a septum, or wall.

• The septum prevents the mixing of oxygen rich and oxygen poor blood.

septum

The Heart

The Heart

These are arteries. They carry blood away from the heart.

This is a vein. It brings blood from the body, except the lungs.

Coronary arteries,

التاجية the الشرايينhearts own

blood supplyThe heart has four chambers

2 atria

2 ventricles

now lets look inside the heart

The Heart

Left Ventricle

االيسر البطين

Left Atrium

االيسر االذين

Right Atrium

Right Ventricle

Vein from Lungs

Artery to Head and BodyArtery to Lungs

Vein from Head and Body

Here are some other important parts of the heart:

The semi-lunar valves

Bicuspid (mitral) valveTricuspid

valve

• The semi-lunar valves prevent expelled blood flowing back into the heart.

• Bicuspid (mitral) valve and Tricuspid valve prevent blood flowing back into the atria from the ventricles.

• The walls are made of cardiac muscle.

cardiac muscle

How does the Heart work?

blood from the body

blood from the lungs

The heart beat begins when the

heart muscles relax and blood

flows into the atria.

STEP ONE

The atria then contract and

the valves open to allow

blood

into the ventricles.

How does the Heart work?

STEP TWO

How does the Heart work?

The valves الصماماتclose to stop blood

flowing backwards.

The ventricles contract forcingتنقبض

the blood to leave the heart.

At the same time, the atriaالشرايين are

relaxing and once again filling with

blood.

The cycle then repeats itself.

STEP THREE