Mammalian Transport System - Part 3

Learning Objectives

• Learn about the structure and function of arteries, veins and capillaries. 
• Compare and contrast the structure of arteries and veins, and state how they are adapted for its function.
• Learn about the components of blood.
• Understanding blood pressure.

From very big vessels, blood flows at a very fast rate. When it goes to the smaller vessels, extremely slow.(capillary)

Capillary, Arteriole, venule -----> no muscles

Functional Comparison Between Arteries & Veins

Arteries

-Transport blood away from the heart

-Transports blood under higher pressure (than veins)

-Carry oxygenated blood (except in the case of the pulmonary artery)

Veins                                                             

-Transports blood towards the heart              

-Transports blood under lower pressure (than arteries)      

-Carry de-oxygenated blood (except in the case of the pulmonary vein) 

Structural Comparison Between Arteries & Veins

Arteries

-Have relatively more muscle/ elastic tissue; 

-Have relatively narrow lumens

-Do not have valves (except for the semi-luna valves of the pulmonary artery and theaorta)

Veins

-Have relatively less muscle/elastic tissue

-Have relatively wider lumens

-Have valve throughout the main veins of the body. These are to prevent blood flowing in the wrong direction, as this could (in theory) return waste materials to the tissues.