Untitled Flashcards Set

The combining form kinesi/o and the suffix -kinesis mean movement. Kinesiology (kih-nē-sē-ohl-ō-jē) is the study of movement.

Some muscles are arranged in pairs that work opposite or against each other. One muscle pair may produce movement in one direction, whereas another muscle pair produces movement in the opposite direction. Muscles that work against or opposite each other are called antagonistic (ahn-tā-gohn-ihs-tihck). Anti- means against; agon means struggle. Other muscles of the body are arranged to work with another muscle. Synergists (sihn-ər-jihsts) are muscles that contract at the same time as another muscle to help movement or support movement (synergists are also called agonistic (ā-gohn-ihs-tihck)). Syn- means together; erg means work. Antagonistic muscles work by producing contraction of one pair of muscles while the other pair relaxes. Contraction (kohn-trahck-shuhn) means tightening. Relaxation (rē-lahk-sā-shuhn) means lessening of tension. During contraction, the muscle becomes shorter and thicker. During relaxation, the muscle returns to its original shape. Muscles are signaled to contract or relax by nerve impulses. A neuromuscular (nū-rō-muhs-kū-lahr) junction is the point at which nerve endings come in contact with the muscle cells.

Tonus (tō-nuhs), or muscle tone, is balanced muscle tension. The combining form for tone, tension, or stretching is ton/o.