circulatory system - 3 - the heart

• Biologie
• Middelbare school
• vwo
• Leerjaar 2

Circulatory system

par 3 - the heart

The heart 

- is a double pump

 - left side pumps oxygen rich

    blood (red) towards your

    body

- right side pumps oxygen

   poor blood (blue) towards

   your lungs 

left = right

Yes, in the picture the left side is blue - this indicates oxigen poor blood, but actually it is the right side of the heart

We always see the heart from the front, but we consider it our own heart.

When I raise my right hand, you will not say that it is my left hand...

The heart

- four chambers

- 2 atria

- 2 ventricles

Blood always enters the heart via an atrium

Bloodflow

Bloodflow in the heart is a 

one-way street.

It follows the direction of the arrows

How is it possible that blood only flows one way?
Because:

1. of the blood pressure
2. blood cells know how to flow
3. there are valves
4. how the heart contracts

Valves

Valves only open in one way,

just like a door, if you push from one side the door opens easily, but if you push from the other side you will push it even closer...

one way valve

As you can see, a valve only opens in one direction

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cardiac cycle

- atria contract, blood flows into 

   ventricles (atrial systole)

- ventricles contract, blood 

   flows into aorta and pulmonary 

   artery (ventrical systole)

- Heart relaxes, blood flows 

   into atria (diastole)

Homework

study par3,3 - the heart

do ex 10,11,12,15,16