Final answer:
Peristalsis is the wave-like muscle contractions in smooth muscle that moves substances through hollow organs, such as the gastrointestinal tract.
Step-by-step explanation:
The smooth muscle contraction that occurs in wave-like motions to move contents along the length of tubular organs is called peristalsis. This process is crucial for the movement of food through the gastrointestinal tract and urine through the urinary tract. Smooth muscle tissue, which is involved in peristalsis, is characterized by its spindle-shaped cells with a single nucleus and lack of visible striations.
It is found in the walls of hollow organs such as the intestines, stomach, and urinary bladder, as well as around passages like the respiratory tract and blood vessels. The coordinated contractions and relaxations of smooth muscle create a squeezing effect that propels contents through the body's tubular systems.
The peristalsis triggered by smooth muscle contractions is essential for the functioning of the digestive, urinary, and reproductive systems, as well as the airways and arteries. These movements are involuntary and are regulated by the autonomic nervous system. Smooth muscle has the ability for the stress-relaxation response, which allows hollow organs to maintain an appropriate tone and prevent premature emptying or flabbiness.