You are cold, very cold! your body responds by: ~shivering - muscles contract and relax repeatedly, generating heat by friction and from metabolic reactions. ~glands secrete adrenaline and thyroxine, which increases the metabolic rate in different tissues. ~muscles contract, raising skin hairs and trapping an insulating layer of still, warm air next to the skin. what are the primary body systems that are cooperating to maintain your internal body temperature in this situation? a) nervous, skeletal, muscular b) integumentary, muscular, nervous, endocrine c) integumentary, muscular, nervous, digestive d) muscular, skeletal, integument, excretory