386 ANATOMY FOR NURSES [Chap. XIX 



(1) The respiratory centres for regulating the function of respi- 

 ration. 



(2) Accelerator centres for the heart. 



(3) Vasomotor centre to regulate size of arterioles in any part 

 of the body, thus controlling the amount of blood furnished to 

 that part. 



(4) Other centres, such as the vomiting centre, heat control- 

 ling centre, etc. 



The student will readily appreciate that, the medulla being the 

 seat of such important centres as those controlling respiration 

 and the heart's action, if the medulla be seriously injured, death 

 will result. 



Cerebellum. — The cerebellum, or " little brain," occupies the 

 lower and back of the skull cavity, overhanging the medulla 

 oblongata. It is of a flattened, oblong shape, and measures 

 from three and a half inches to four inches (87 to 100 mm.) trans- 

 versely, and from two to two and a half inches (50 to 03 mm.) 

 from before backward. It is divided in the middle line into two 

 lateral lobes, or hemispheres, and a median lobe, by a central 

 depression, each lobe being subdivided by fissures into smaller 

 portions. The surface of the cerebellum consists of gray matter 

 and is traversed by numerous curves, or furrows, which vary in 

 depth. The interior consists of white matter. 



Peduncles of cerehcUiim. — The cerebellum is connected with 

 the rest of the cerebro-spinal system by many white nerve- 

 fibres grouped in bundles called the peduncles. 



The peduncles are arranged in three pairs. The anterior 

 (superior) peduncles pass forward from the cerebellum to enter 

 into the cerebrum. The posterior (inferior) peduncles pass down 

 to the medulla, where they are known as the restiform bodies. 

 The middle pair pass into and make up the larger portion of 

 the pons Varolii, thus serving as a means of intercommunication 

 between the two halves of the cerebellum. Thus it is seen that 

 the cerebellum communicates most freely with the entire cerebro- 

 spinal system. 



Functions of the cerebellum. — The principal function of the 

 cerebellum seems to be the coordination of ordinary movements, 

 and the maintenance of equilibrium. The reason for this belief 

 is that disease or destruction of the cerebellum apparently exerts 



