Tag: biology

• The brain has three divisions, i.e., forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus. 
• The midbrain has decreased in size during vertebrate evolution and the forebrain has gradually acquired much of its function, while the hindbrain consists of medulla, cerebellum and the pons. 

Three layers of protective tissue that surround the brain and spinal cord are called meninges. These three layers are dura mater, arachnoid mater, and pia mater.

• Superior colliculi is a part of the midbrain. There are paired structures that are responsible for controlling eye movement. 
• There are one colliculi in each side of the brain which is responsible for creating a map of the visible area. 
• The fixation of the vision and the tracking of any object is controlled and regulated by this region of the brain. 

The membrane which covers the brain and the spinal cord is called as the meninges. There are three layers of the meninges. The outermost is the Dura mater, middle one is the arachnoid mater and the innermost is the pia mater. Dura mater is the tough membrane which is present in the outermost region. The three meninges provide protection to the brain from shock and injury. 

White matter is a component of the central nervous system, in the brain and spinal cord. The white matter is placed on the grey matter in the brain while it lies outer to the grey matter in the spinal chord. It consists mostly of glial cells and myelinated axons that transmit signals from one region of the cerebrum to another and between the cerebrum and lower brain centres.

A normal human brain weighs on average about 1.5 kg (3.3 lb) with a volume of around 1130 cubic centimetres ($cm^3$) in women and 1260 $cm^3$ in men.