1 Chemically, ATP is an adenine nucleotide bound to three phosphates. 2  There is a lot of energy stored in the bond between the second and third phosphate groups that can be used to fuel chemical reactions. 3  When a cell needs energy, it breaks this bond to form adenosine diphosphate (ADP) and a free phosphate molecule.
calf muscle pump. calf muscle pump. an action of the calf (soleus) muscles in which the muscles contract and squeeze the popliteal and tibial veins, forcing the blood in those veins to move upward toward the heart. Also called soleus pump.
I. FUNCTION AND TYPES OF MUSCLE. Locomotion: One of the most obvious functions of muscle tissue is locomotion. When muscles contract, the fibers pull or relax bones to which they are attached, thus causing locomotion. Muscle contraction is also the primary means of moving lymph in the lymphatic vessel.. FUNCTION AND TYPES OF MUSCLE. Locomotion: One of the most obvious functions of muscle tissue is locomotion. When muscles contract, the fibers pull or relax bones to which they are attached, thus causing locomotion. Muscle contraction is also the primary means of moving lymph in the lymphatic vessel.