The Human Brain — The Cerebrum

Image result for brain longitudinal fissure

When you picture the brain, what do you see? Most of the brain is the cerebrum, which controls higher functions like thinking and speaking. The cerebrum is split down the middle by the longitudinal fissure (the red line in the picture) into the left and right hemispheres. These two halves are able to communicate through a bridge of nerve fibers known as the corpus callosum.

Each half of the cerebrum is divided into four lobes: the frontal lobe, the temporal lobe, the parietal lobe and the occipital lobe. Therefore, the brain has eight lobes all together. Each lobe is associated with different functions.

The top layer of the brain's wrinkly surface is the cortex. The cortex not only covers the surface of the brain but also the space between the hemispheres. The part of the cortex that covers the cerebrum is known as the cerebral cortex. The cortex is gray matter, which consists of unmyelinated axons, dendrites, cell bodies and glial cells. However, the gray matter actually appears pink.

The brain resembles a wrinkled walnut, with its many folds and convolutions that increase surface area to allow room for more neurons. These wrinkles form what are known as gyri (singular gyrus) and sulci (singular sulcus). The gyri are the hills while the sulci are the valleys.

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Image Credit:
(1) Gray. “Human Brain Longitudinal Fissure.” Wikipedia, 25 Oct. 2009, en.m.wikipedia.org/wiki/File:Human_brain_longitudinal_fissure.png.

(2) Cancer Research UK. “Lobes of the Brain.” Wikimedia Commons, 30 July 2014, commons.wikimedia.org/wiki/File:Diagram_showing_the_lobes_of_the_brain_CRUK_308.svg.

(3) “Gyrus and Sulcus.” Wikimedia Commons, 24 May 2007, commons.wikimedia.org/wiki/File:Gyrus_sulcus.png.

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