1. Circulatory system

2. Why is the circulatory system important
Transfer
Nutrients
Oxygen
Waste
Cells with immune function
*Brain cells die within just a few minutes if their oxygen supply is interrupted

3. Path of blood Arteries – carries blood away from heart
Arterioles – small vessels that lead to capillaries (away from heart)
Capillaries – microscopic vessels with thin porous walls (these pass within a few cells of every cell in the body)
Venules – small vessels that capillaries lead to (back to the heart)
Veins – carries blood to the heart

5. Mammalian Circulation
Blood begins its flow with the right ventricle pumping blood to the lungs
In the lungs, the blood loads O2 and unloads CO2

6. Superior vena cava Capillaries of head and forelimbs 7 Pulmonary
Fig. 42-6
Superior
vena cava
Capillaries of
head and
forelimbs 7
Pulmonary
artery
Pulmonary
artery
Capillaries
of right lung
Aorta 9
Capillaries
of left lung 3 2 3 4 11
Pulmonary
vein
Pulmonary
vein 5 1
Right atrium 10
Left atrium
Figure 42.6 The mammalian cardiovascular system: an overview
Right ventricle
Left ventricle
Inferior
vena cava
Aorta
Capillaries of
abdominal organs
and hind limbs 8

7. Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped through the aorta to the body tissues by the left ventricle

8. Superior vena cava Capillaries of head and forelimbs 7 Pulmonary
Fig. 42-6
Superior
vena cava
Capillaries of
head and
forelimbs 7
Pulmonary
artery
Pulmonary
artery
Capillaries
of right lung
Aorta 9
Capillaries
of left lung 3 2 3 4 11
Pulmonary
vein
Pulmonary
vein 5 1
Right atrium 10
Left atrium
Figure 42.6 The mammalian cardiovascular system: an overview
Right ventricle
Left ventricle
Inferior
vena cava
Aorta
Capillaries of
abdominal organs
and hind limbs 8

9. Animation: Path of Blood Flow in Mammals
Blood returns to the heart through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs)
The superior vena cava and inferior vena cava flow into the right atrium
Superior vena cava
Animation
Animation: Path of Blood Flow in Mammals
Inferior vena cava

10. 7 9 6 2 3 3 4 11 5 1 10 8

11. 8 7 9 7 10 6 2 9 5 3 3 5 1 4 11 12 5 6 1 4 3 10
Right ventricle
Pulmonary artery
Lungs
Left atrium
Left ventricle
Aorta
Cappilaries of the head and arms
Capillaries of the hind limbs
Surperior vena cava
Inferior vena cava
Right atrium 8 2

12. Circulation and Evolution