ABSTRACT
Cerebellum Occupies most of the posterior cranial fossa Attached to pons, medulla, and midbrain by peduncles at the sides of the fourth ventricle Superior surface against tentorium cerebelli Responsible for muscle synergy and coordination so that movements are performed smoothly Malfunction of the cerebellum leads to ataxia, tremor; nystagmus, and hypotonia
The medulla comprises the myelencephalon
Medullaa (medulla oblongata)
Pivotal role in integration of neural function Includes centres for autonomic reflex control of respiratory and cardiovascular function (the socalled ‘vital centres’) Swallowing and gag reflexes are other examples of medullary integrated reflex responses Chemoreceptor trigger zone located in the area postrema (lateral walls of fourth ventricle) The cranial nerves VIII to XII originate here
choroid plexus epithelium, which collectively are known as the blood-brain barrier (BBB). These cells are structurally and functionally unique (compared with systemic capillary endothelia) in that they lack fenestrations and endothelial clefts, while developing tight junctions (occlusive zones) between adjacent cells (Figure 22.13). There are also large astrocyte foot processes surrounding the basement membrane (see Figure 22.4). This ‘barrier’ is selectively permeable to some substances and impermeable to others.
