The circulatory system comprises the heart and network of blood vessels. It circulates blood throughout the body to supply oxygen, distribute heat, transport nutrients, and collect waste. The heart lies in the chest cavity between the lungs. It is a muscular, double pump divided into left and right sides. Factors like exercise, fever, stress, alcohol, and bleeding can increase heart rate. Average heart rates are 60-80 beats per minute for adults, 80-100 for children, and 100-120 for infants. The main types of blood vessels are arteries, which carry oxygenated blood away from the heart; capillaries, which exchange fluids and gases; and veins, which return deoxygenated blood

1. LESSON 3
The Circulatory System
人体血液循环系统

2. The circulatory system:
Comprises of the heart and the network blood
vessels.
Main Functions:
1. Supply oxygen to all parts of the body.
2. Distribute heat
3. Distribute（分配） the absorbed nutrients.
4. Collect and carry waste materials to the organs
concerned with their discharge（排遗物）

3. Position and structure of the heart
Position:
1. lies in the chest cavity between two lungs.
Structure :
1. muscular organ, acts as double pump.
2. Divided into left and right side
(right : upper collecting , left : lowers pumping)

5. The Factor which increase the heartbeat
1. Exercise
2. Fever
3. Emotional Stress
4. The consumption of alcohol
5. Severe bleeding
The Average heartbeat
Adult 60~80/min
children 80~100/min
Infant 100~120/min

6. The structure and function of blood vessels and
Blood
Arteries（动脉）*有氧
• Strongest blood vessels
• Carry blood away from heart.
Capillaries（微血管）
• Very small blood vessels
• Exchange of fluids and gases to and from tissues of
body.
Veins（静脉）*无氧
• Very small vessels.
• Returning blood to right chamber of heart.

7. Artery 动脉 Capillaries 微血
管
Veins 静脉
血管的大小 小 最小 大
血管的厚度 厚 最薄 薄
血液 充氧血 充氧和缺氧血 缺氧血
血流的流速 快 最慢 慢
血压 高 低 中
功能 将有氧血输
送至全身
交换体内物质 将缺氧血带
回心脏

8. Blood
• Red , white blood cell and platelets.
• Blood carry nutrient from digestive organs and
carry waste products to excretory排出organs.
Red Blood Cell carry oxygen
White Blood Cell remove germs and dead cells
Platelets help blood clot

9. Carotid
Radial
FemoralBrachial
The pulse
Carotid 颈动脉
Brachial 上臂脉
Radial 手腕
Femoral 大腿内侧

10. Practical
• 量自己的脉搏