What are examples of regenerated cellulose fibres and synthetic fibres?

Three questions about elastin fibres and collagen fibres in arteries?

• 1. what are they? 2. what is their function? 3. why are they in different quantities in the arteries? for example, elastin fibre is more in aortta than in medium sized artery but both have same quantities of collagen fibres, why? Please give your answer in simple language. i'm a student of a'levels. thanks. :)

• Answer:

  1. Collagen and elastin are proteins (proteins are polymers of amino acids). 2. They are structural proteins - they are strong and help to maintain the integrity of parts of the body (ie they hold things together and keep them in the same shape). Elastin has a greater amount of elasticity - this means it can be stretched out but will return to its original size when the stretching force is released. 3. Blood is squeezed from the heart under pressure into the arteries. Enough pressure is required to push the blood all the way through the circulation. To withstand this pressure, the arteries need to be strong but also flexible. Collagen serves this purpose. The pressure and flow waves of blood are transmitted with increased efficiency when the large arteries (eg aorta) have increased elasticity. So the elastin fibres in the aorta help to push the blood through the body, by passively storing and releasing the pumping power derived from the heart.