Lips are a visible part of the body at the mouth of many mammals, including humans.
Lips are movable, soft, and serve as the hole for food intake and articulation of speech and sound. Human lips are a physical, sensory organ and can be an erogenous zone when used in kissing and other intimate acts.
The lower and upper lips are referred to as the “Labium inferius oris” and “Labium superius oris,” respectively. The juncture where the lips meet the mouth area’s surrounding skin is called the vermilion border, and the reddish (pink or brownish) area within the borders is the vermilion zone.
The vermilion edge of the upper lip is called the cupid’s bow. The fleshy protuberance situated in the upper lip’s center is a tubercle known by various terms, including the “tuberculum labii superioris,” the procheilon (also spelled prochilon), and the “labial tubercle.” The perpendicular groove extending from the procheilon to the nasal septum is the philtrum.
With three to five cellular layers, the skin of the lip is very thin compared to typical face skin, which has up to 14-16 layers. The lip skin contains fewer melanocytes. Melanocytes cells are the cells that create melanin pigment, which gives skin its light color. Because of this, the blood vessels appear through the lip’s skin, which leads to their notable pinkish-red coloring. With darker skin color, this result is less prominent, as in this case, the skin of the lips holds more melanin and thus is darker. The lip’s skin forms the border between the mouth’s internal mucous membrane and the face’s exterior skin.
Lips are an essential part of facial features and the development of the exoskeleton. During the evolution of early primates, the lips developed to provide better food consumption support. According to my research, the early lips involved teeth protection as a primary objective. The law of evolution explicitly states that most of the exterior body evolution transpired to protect against bacterias and other microorganisms.
Lips serve a variety of purposes, and apart from the fundamental evolutionary function, primarily, that it helps us in consuming meals and protecting different parts of our mouth like teeth and tongue, for taking water, food, it has other functions — like grasping (there are people who (deprived of legs and hands) can write and even paint etc.), expressing (communicating thoughts) — language, a sole function that differentiates with other apes.
Lips may have developed first for food and later fastened themselves to speech, but they satisfy a strange kind of hunger in kissing. A kiss triggers cascades of chemicals and neural messages that transmit sexual excitement, tactile sensations, motivation, feelings of warmth, and even evident euphoria in the body.
I miss my husband and his lovely lips. We always wondered how lips may have evolved and why kissing is the best thing ever. This article is dedicated to him.