Head
In anatomy, the head of an animal is the rostral part (from anatomical position) that usually comprises the brain, eyes, ears, nose and mouth (all of which aid in various sensory functions, such as sight, hearing, smell, and taste). Some very simple animals may not have a head, but many bilaterally symmetric forms do. Heads develop in animals by an evolutionary trend known as cephalization. In bilaterally symmetrical animals, nerve tissues concentrate at the anterior region, forming structures responsible for information processing. Through biological evolution, sense organs and feeding structures also concentrate into the anterior region, which collectively form the head.
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Famous quotes containing the word head:
“Standing on the bare ground,—my head bathed by the blithe air, and uplifted into infinite space,—all mean egotism vanishes. I become a transparent eye-ball; I am nothing; I see all; the currents of the Universal Being circulate through me; I am part and particle of God.”
—Ralph Waldo Emerson (1803–1882)
“No country is so peaceful as the one that leads into death. Life arches above one’s head like a bridgespan, and below it flows the water, carries the boat, takes it further.”
—Alfred Döblin (1878–1957)
“All men are partially buried in the grave of custom, and of some we see only the crown of the head above ground. Better are the physically dead, for they more lively rot. Even virtue is no longer such if it be stagnant. A man’s life should be constantly as fresh as this river. It should be the same channel, but a new water every instant.”
—Henry David Thoreau (1817–1862)