1. CIRCULATORY SYSTEM
7 SCIENCE

2. Review What things that humans need to survive?
Food – nutrients!
Water
Air – oxygen
Another name for the circulatory system is cardiovascular system
Includes:
Heart
Blood
Blood vessels (veins and arteries)

3. What is the purpose of the circulatory system?
Transports important substances to all parts of your body through your blood
Moves oxygen and nutrients to cells
Removes carbon dioxide and wastes from the cells

4. HEART Made of cardiac muscle 2 upper chambers called atria
Located between your lungs and protected by bones
2 upper chambers called atria
Right atrium
Left atrium
2 lower chambers called ventricles
Right ventricle
Left ventricle

5. BLOOD VESSELS Veins Arteries Capillaries Returns blood to heart
Valves keep blood moving towards the heart
Contains blood low in oxygen
Arteries
A = AWAY from the heart
Thick elastic walls
Capillaries
Connects veins and arteries
Only one cell thick!
E.g. in your eyes when you are tired

6. Circulation (movement) of Blood through the Heart
To watch an animation of the heart pumping:
Click here!
You can speed up/slow down the pumping of the heart here.

7. REVIEW: organs of the circulatory or cardiovascular system
Heart
Veins
Arteries
Capillaries
Blood

8. HEART
During a heartbeat, both atria contract then both ventricles contract
Valves separate the chambers
prevents blood from flowing between the atrias or ventricles

9. BLOOD CIRCULATION Blood continuously moves around your body 3 types:
Pulmonary: blood flows away from the heart TO THE LUNGS to get oxygen
Systemic: blood flows AWAY from the heart to rest of body
Veins
Arteries

10. BLOOD CIRCULATION
Coronary: blood that moves only in and around the heart
If this circulation stops or is blocked, oxygen cannot get to the heart
= heart attack

11. BLOOD PRESSURE
Heart pumps blood through your blood vessels and pressure builds on the inside
Like water flowing through a hose
Called blood pressure
As pressure increases and decreases, this creates your pulse
Highest in your arteries: WHY?
NORMAL: 65 – 80 beats/minute

12. CARDIOVASCULAR DISEASE
Heart disease is the #1 cause of death in Colombia
Stroke and heart attacks count for over 1/3 of adult deaths
Atherosclerosis
Fat deposits on inside of arteries block blood flow
Caused by: eating too much fat and foods high in cholesterol

13. CARDIOVASCULAR DISEASE
Hypertension
High blood pressure
Atherosclerosis can cause hypertension, i.e. blocked arteries can increase the pressure inside a blood vessel
Usually caused by: too much salt and fat
SOLUTIONS?
Good diet and exercise
Regular doctor appointments!