The skin is richly supplied with arteriovenous anastomoses in which blood flows directly between an artery and a vein, bypassing the capillary circulation. What is the primary significance of these structures?

Answer: Temperature control

Explanation:

Arterio-venous anastomoses (AVAs) are direct connections between small arteries and small veins. In humans they are numerous in the glabrous skin of the hands and feet.

They are very significant in body temperature control. These temperature control are under the dual control of the central nervous system and the local thermal influence. While the arteriovenous anastomoses control the skin temperature through volume changes in the superficial venous bed, the arterioles and capillaries operate by generalized dilatation which results both in increased temperature and in redness of the skin.