Circulatory System (Grp 2)

Facts on our heart

• The  heart beats roughly 100,000 times, in a single day,pumping blood throughout your body.

• It is a hollow, muscular organ which is about the size of a fist. It pumps blood by contracting and relaxing its muscles. The heart beats because it is pumping blood. The right side of the heart takes in blood rich in oxygen to the rest of the body. While the left side takes in blood rich in carbon dioxide to the lungs. When the heart muscles contract, blood is squeezed out of the heart into the blood vessel. When the heart muscles relax, blood flows back into the heart through the blood vessel.

• The heart is located near the middle of our chest and is slightly tilted towards the left.

• It is a vital organ that keeps working continuously through our life without rest.
• Although our heart weighs less than half a kilogram, it can pump around five liters of blood every minute!

• The walls of the heart are made up of three layers.
• The 2 upper chambers are called the  right and left atria
• The right atrium is the larger of the two atria, having very thin walls.
• The right atrium,receives blood from the upper and lower body

• The left atrium receives blood from the lungs
• The left atrium is smaller than the right atrium, but has thicker walls.
• Used blood is drawn from the body by the right half of the heart, and then sent to the lungs to be re-oxygenated.

The heart is protected by our ribs and is made by a special kind of muscle

• Blood that has been reoxygenated by the lungs is drawn into the left side of the heart and then pumped into the blood stream.

Under normal conditions, an adult's heartbeat rate is around 70 times per minute.But it changes,depending on:

• Our age----Children normally have a higher heartbeat rate than adults
• Our activity level----Our muscles work harder when we are exercising as we need more energy which comes from food and oxygen.Thus, our body will need more food and oxygen during exercise.
• Our health conditions----Heart failure is only one of the many illnesses related to the heart. It does not really mean that the heart stops working, it just means that the heart is not working as efficiently as it should.

The many tubes in our body are called blood vessels.
They are similar to the plant's transport tubes found in the stem

There are 3 types of blood vessels in the body.They are the arteries,capillaries and the veins.

The function of the blood vessels are as follows:

1)Arteries: To bring blood rich in oxygen to the rest of the body.
2)Veins: To carry blood rich in carbon dioxide from the rest of the body back to the heart.
3)Capillaries: Connects arteries to the veins


More on capillaries:

1. They exist all over our body.b>
2. Food and oxygen leave the circulatory system through our capillaries and pass into our body.
3. Carbon dioxide also enters the body through the capillaries.

If you cut yourself by accident, relax! The bleeding comes just from the small capillaries. If a vein or artery is cut, the veins cannot transport blood rich in carbon dioxide back to the heart and the artery cannot transport blood rich in oxygen. This is more serious! If you cut yourself in the artery, you will not get any blood rich in oxygen...the gas that allows us to survive!

If have you cut a vein or artery, this is what you should do:

Apply pressure with a clean cloth on the wound to stop the bleeding. For any severe bleeding, and especially for an artery cut, go to the hospital -- it will likely need sutures. Do not treat the cuts at home. Seek medical attention as soon as possible. Even if you do not like seeing a doctor. If an injury like this does not have proper care, such an injury could result in death.

Note: Sutures is something like stitching up a deep wound/cut

Here's some videos of our most important organ, the heart!

And this is the most important: What happens during a heart attack?