Hindbrain Health Dictionary

The small section of brain stem – excluding the pons and medulla – linking the hindbrain to the forebrain. (See BRAIN.)... mesencephalon

n. the enlarged and highly developed mass of nervous tissue that forms the upper end of the *central nervous system (see illustration). The average adult human brain weighs about 1400 g (approximately 2% of total body weight) and is continuous below with the spinal cord. It is invested by three connective tissue membranes, the *meninges, and floats in *cerebrospinal fluid within the rigid casing formed by the bones of the skull. The brain is divided into the hindbrain (rhombencephalon), consisting of the *medulla oblongata, *pons, and *cerebellum; the *midbrain (mesencephalon); and the forebrain (prosencephalon), subdivided into the *cerebrum and the *diencephalon (including the *thalamus and *hypothalamus). The brain is usually considered to be the site of the working of the mind, but to what extent the concepts of ‘brain’ and ‘mind’ are interchangeable is a matter of debate and of concern to anyone facing brain surgery. Anatomical name: encephalon.... brain

n. the largest part of the hindbrain, bulging back behind the pons and the medulla oblongata and overhung by the occipital lobes of the cerebrum. Like the cerebrum, it has an outer grey cortex and a core of white matter. Three broad bands of nerve fibres – the inferior, middle, and superior cerebellar peduncles – connect it to the medulla, the pons, and the midbrain respectively. It has two hemispheres, one on each side of the central region (the vermis), and its surface is thrown into thin folds called folia (see illustration). Within lie four pairs of nuclei.

The cerebellum is essential for the maintenance of muscle tone, balance, and the synchronization of activity in groups of muscles under voluntary control, converting muscular contractions into smooth coordinated movement. It does not, however, initiate movement and plays no part in the perception of conscious sensations or in intelligence. —cerebellar adj.... cerebellum

n. part of the hindbrain, formed by the pons and the cerebellum and continuous below with the medulla oblongata. See brain.... metencephalon

(mesencephalon) n. the small portion of the *brainstem, excluding the pons and the medulla, that joins the hindbrain to the forebrain.... midbrain

n. the anterior lobe of the cerebellum. In evolutionary terms it is one of the earliest parts of the hindbrain to develop in mammals.... palaeocerebellum

n. see hindbrain.... rhombencephalon

n. 1. either of the two lower chambers of the *heart, which have thick muscular walls. The left ventricle, which is thicker than the right, receives blood from the pulmonary vein via the left atrium and pumps it into the aorta. The right ventricle pumps blood received from the venae cavae (via the right atrium) into the pulmonary artery. 2. one of the four fluid-filled cavities within the brain (see illustration). The paired first and second ventricles (lateral ventricles), one in each cerebral hemisphere, communicate with the third ventricle in the midline between them. This in turn leads through a narrow channel, the cerebral aqueduct, to the fourth ventricle in the hindbrain, which is continuous with the spinal canal in the centre of the spinal cord. *Cerebrospinal fluid circulates through all the cavities. —ventricular adj.... ventricle

n. the central portion of the *cerebellum, lying between its two lateral hemispheres and immediately behind the pons and the medulla oblongata of the hindbrain.... vermis