Locomotion of Cells By far the most important type of movement that occurs in the body is
that of the muscle cells in skeletal, cardiac, and smooth muscle, which constitute almost 50 percentof
the entire body mass. The specialized functions of these cells are discussed in Chapters 6 through 9.
Two other types of movement—ameboid locomotion and ciliary movement—occur in other cells.
Ameboid Movement Ameboid movement is movement of an entire cell in relation to its
surroundings, such as movement of white blood cells through tissues. It receives its name from the fact
that amebae move in this manner and have provided an excellent tool for studying the
phenomenon.Typically, ameboid locomotion begins with protrusion of a pseudopodium from one end
of the cell. The pseudopodium projects far out, away from the cell body, and partially secures itself in
a new tissue area. Then the remainder of the cell is pulled toward the pseudopodium. Figure 2-16
demonstrates this process, showing an elongated cell, the right-hand end of which is a protruding
pseudopodium. The membrane of this end of the cell is continually moving forward, and the
membrane at the left-hand end of the cell is continually following along as the cell moves.
Mechanism of Ameboid Locomotion.
Figure 2-16 shows the general principle of ameboid motion.
