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.
The basic function of muscle is to generate force. Secondarily, muscles can provide some shape and form to the organism. Anatomically and functionally, muscle can be divided into two types, smooth and striated.Striated or striped muscle can be further divided into skeletal muscle and cardiac (heart) muscle.he basic function of muscle is to generate force. Secondarily, muscles can provide some shape and form to the organism. Anatomically and functionally, muscle can be divided into two types, smooth and striated.