Understanding the human penis

The structure and function of penis made incredibly simple

Introduction

Penis is the external male sex organ used to copulate and ejaculate semen and to convey urine outside the body. The penis is the counterpart of the clitoris in the female.  In Latin, the word "penis" originally meant "a tail." The Latin "penis" is related to the verb pendere meaning "to hang down." 

The penis is a wonder of nature, a pleasure receptor so perfect it has no doubt inspired many of the myths of man due to its seeming intelligent design. It is, at times, remarkably sensitive and protuberant, and at others durable and discreet.

Structure of penis

a) Glans: The head of the penis is normally shiny and supple. It is the highly innervated and sensitive homologue to the female clitoris. The glans is really an internal organ except during sexual arousal, when it emerges from the prepuce. The surface of the glans is not skin, but mucous membrane, like the inside of the lips. In circumcised men, the mucous membrane becomes keratinized; which is to say dried, thickened, and insensitive - in a word, calloused.

The ridge where the glans blends with the shaft of the penis is called the corona. Even in circumcised men, the corona is very sensitive, if not ticklish, during arousal.

b) Frenulum: The frenulum is a very elastic connective tissue joining the ventral (under) side of the glans to the skin tube. During arousal the frenulum is so sensitive that persistent light flicking of only this area is sufficient to bring most men to orgasm. After arousal subsides, the frenulum pulls the prepuce skin back into place over the glans, protecting the glans from the drying effects of air and whatever the penis might come into contact with (clothing, bedding).

c) Inner Skin: Just below the corona is a region known is the inner skin or pink skin. Like the glans, this area only sees daylight during arousal, and is protected by the skin tube at other times. In the circumcised penis, more than half of the pink skin is typically removed.

The pink skin has sebaceous glands which exude natural emollients. These fight bacteria and keep the skin soft and sensitive. When combined with dead skin cells, the emollients make up a natural compound known as smegma. Smegma can be rinsed away with clear water (not soap - avoid dissolving the protective emollients) if desired. It has a musky aroma, not dis-similar to that associated with female genitalia. If any type of cleanser is to be used it should be a non-soap liquid like Cetaphil.

d) Skin Tube: The main shaft of the penis is covered by a folded tube of skin. This area is less sensitive than the pink skin. In a circumcised man, the base of the shaft area includes hair-bearing skin that would have otherwise been on the scrotum or pubic mound. Hairiness migrates up the shaft due to a lifetime of tension from erections. Intact men have no coarse hairs on the penis shaft.

e) Prepuce: The prepuce is the portion of inner and outer skin that covers the glans. Also known as the foreskin, this (along with most of the frenulum typically) is what is removed in circumcision. The leading edge of the prepuce where it folds back contains specialized nerve receptors, sometimes called J-cells that respond to being straightened.

f) Erectile Tissue: Within the shaft of the penis are three chambers of erectile tissue that engorge with blood during arousal. These are rooted deep within the body, so that the true length of the penis is a few inches more than what is seen externally.

g) Urethra: The urethra is the duct that carries urine and semen from the body. It runs just under the frenulum, and this area (about an inch down from the glans) is (in not everyone's opinion) the male homologue to the G-Spot. Just as in the female G-spot, the urinary ductwork is present, and just as in the female it responds to a deep kneading stimulation, but only at a moment of very thorough arousal.

Function of penis

The functions of penis can be divided into two main types:

• Penis acts as a source or passageway to expel the unwanted wastes out of the body in the form of urine.
• Penis acts as the key reproductive organ or genital in males and hence is responsible for procreation.
• Other secondary functions of penis include an important factor in achieving sexual and psychological satisfaction, pleasure and social well being.

Speaking of its function (or physiology), your penis is made up of 3 main areas, 2 large chambers on the top (The technical term for this is the Corpora Cavernosa) and 1 smaller chamber on the bottom (the Corpus Spongiosum). 

When you gain an erection your penis fills with blood, filling these three chambers. The Corpus Spongiosum is the chamber used mainly when you urinate and ejaculate. The Corpora Cavernosa however, is the main blood holding chamber of the penis. This is where 90% of all blood is retained each and every time you gain an erection. 

Understanding erection of the penis

The penis does not contain any bones or muscle but is made up of soft, spongy tissue that is full of blood vessels and lots of nerves. When a man is sexually excited, these vessels fill with blood. This causes the penis to enlarge and stiffen, which is called an erection. When semen comes out of the penis it is called ejaculation.

Erection is achieved by filling the two Corpora Cavernosa chambers with blood. Unlike some other mammals, humans have to rely instead on engorgement with blood to reach erection.  When the erection is triggered by sexual stimulation, the arteries that bring blood to the penis dilate in order to increase blood flow. The sponge-like Corpora Cavernosa fills up with blood, which makes the penis stiff. The stiffer tissues constrict the veins that carry blood away from the penis in order to maintain the erection.

The three states of penis

Based on its existing state or condition, a penis, at a time, can have one of the following three states:

Flaccid penis: A flaccid penis is one that is unstimulated or not aroused, and would be seen when the man is in the normal position.

Flaccid stretched penis: A flaccid stretched penis is when the flaccid penis is pulled to its maximal distance.

Erect penis: An erect penis is one that is maximally stimulated, either through visual, tactile or pharmaceutical manipulation.

How to measure the length of your penis?

Here is the simplest and easiest way to measure your penis at home. After obtaining an erection, angle your penis down until it is parallel to the floor. Set your ruler or measurement tape against your pubic bone just above the base of the penis, and measure to the tip. This will be the average length of your penis in erect state.