freewheel. 1  a device in the transmission of a motor vehicle that automatically disengages the drive shaft whenever it begins to turn more rapidly than the engine. 2  a form of rear bicycle wheel that has a device freeing it from the driving mechanism, as when the pedals are stopped in coasting.
Ampullae are an important part of the water vascular system of starfish, which is the responsible for the animal's locomotion. The only function of the ampullae is to store the water that enters the vascular system and send it to the minuscule tube feet, located in the ventral side of the starfish's arms.he contraction of the muscles also causes the water stored in the ampullae to move to the tube feet, which are the locomotion organs of the starfish. Nerve cells connected to the ampullae and other parts of the vascular water system control the relaxation and contraction of the ampullae's muscle fibers.
The main function of the thalamus is to process information to and from the spinal cord and the cerebellum. The medulla oblongata helps regulate breathing, heart and blood vessel function, digestion, sneezing, and swallowing. This part of the brain is a center for respiration and circulation.Sensory and motor neurons (nerve cells) from the forebrain and midbrain travel through the medulla.edulla oblongata. The medulla oblongata is located in the brain stem, anterior to (in front of) the cerebellum. This is a cone-shaped, neuronal (nerve cell) mass in the hindbrain, which controls a number of autonomic (involuntary) functions.