Investigating arteries and veins
Suspend a ring of artery from a hook on a clamp stand.
Use a metre rule to record the length of the ring once the mass carrier has been attached to the free end of the ring. 3.
Attach a 10 g mass and record the length of the ring after the mass is added. 4.
Remove the mass and record the length of the ring.
Repeat steps 2 and 3 using 20, 30, 40 and 50 g masses. Record the length with and without the masses each time.
When comparing the arteries and veins, the results show that the percentage change gradually increases as the amount of weights increases. The vein with mass started off with a small percentage increase of 4%, and then rose to 9%, which was maintained. The artery with mass varied from 10-29%. The artery walls contain collagen and elastic tissues which allow it to stretch and recoil, where as the veins do not have as much connective tissue containing collagen fibres. This is not a problem as the arteries, being closer to the heart, have to withstand a much higher pressure than the veins do. When returning to the original length, the vein without mass increased by 4% then ultimately grew to 9% and the artery without mass varied from 0-10% then back to 0% again. The artery went back to 0% at the end because of its ability to recoil to its original size. This proves that the arteries have more collagen in the muscle walls which allows them to stretch and recoil. The elastic fibres allow the arteries to dilate and constrict. The main properties of the artery are the connective tissue with collagen fibres which make up the outer coat, the smooth muscle and the elastic tissue. This elastic tissue gives the blood vessels their much needed flexibility. Furthermore the artery walls contain a fibre named collagen. Collagen works well with elastic fibres to provide the arteries with firmness and strength. It has a special network structure which gives the protein its unique characteristics....
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