Complete this paragraph by filling in the blanks using science vocabulary that you learned this year: All living things are made of cells. Each cell is made up of that combine to form . YOUR cells contain many different organelles, such as and . The cells of a plant are different, because they have organelles like and

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.