1. CHAPTER 1
:
TRANSPORT
1.2 The Concept of
Circulatory System

2. LEARNING OUTCOME
• Describe the structure
of human blood
vessels

3. STRUCTURE OF HUMAN BLOOD VESSELS
• Tubes that transport blood from one part to
another in the human body

5. 3 types of human blood vessels

6. • Transport blood to
the heart.
•Connect arterioles to
venules
•Transport blood away from the
heart

7. A R T E R IE
S
• Carry blood away from
the heart
• Branch into smaller
vessels  arterioles 
capillaries
• To transport blood
quickly & at high
pressure to the tissues.
• Arteries walls consist of
epithelial tissue, smooth

8. CAPILLARIES
• The sites for the exchange
of nutrients, respiratory
gases & waste products.
• Thin-walled blood vessels
which allow rapid gaseous
exchange to occur, only one-
cell thick.
• Capillaries  venules  veins

9. VEINS
• Transport blood back to the
heart
• Consist of epithelial tissue
surrounded by smooth
muscle (thinner than
arteries) & connective tissue
• Blood flows under low
pressure
• Have large lumens & valves
that maintain the one-way
flow of blood

10. Differences between arteries,
capillaries & veins
A r t e r ie s C a p il l a r ie s V e in s
Transport blood away Connect arterioles to Transport blood to the
from the heart venules heart
Transport oxygenated Act as the sites for Transport deoxygenated
blood (except the exchange of substances blood (except the
pulmonary artery) with the cells pulmonary vein)
Thick muscular wall Thinnest wall, one cell in Thinner wall
thickness
No valves except semi- No valves Valves present to prevent
lunar valves at the base of back flow of blood
the aorta & pulmonary
artery
Blood flows in pulse No pulses; pressure lower No pulses; blood flows
under high pressure than arteries but higher under lower pressure than
than veins arteries