You are looking through a microscope at a slide of animal tissue and see a single layer of flat, closely packed cells that cover a surface. this specific tissue is most likely

just go with your heart buddy

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

answer; endoplasmic reticulum;