The penis is a male sex organ, and it reaches its entire size when a man reaches the age of puberty. The penis is extremely essential for sexual functioning and reproduction, and it is also responsible for providing a conduit for the urine to exit the human body.
The penis contains the following parts:
Also referred to as the head of the penis, its shape and color tend to be different amongst circumcised and uncircumcised men. For instance, uncircumcised men have a glans that is covered with mucosa, which is basically a pink moist tissue. And in circumcised men, a surgical operation is conducted to remove the foreskin in order to turn the mucosa atop the glans into dry skin.
2. Corpus cavernosum
These are basically two columns of tissues that travel on both sides of the penis. These tissues are filled with blood, and they are responsible for causing an erection.
3. Corpus spongiosum
This is a column of tissues that are like sponge, and they travel from the front of the penis and end at the penis head. The urethra runs through this part of the penis. When the penis is erect, the corpus spongiosum fills up with blood, and it also keeps the urethra open.
The urethra is responsible for emptying the urine out of the body, and it runs from within the corpus spongiosum.
The penis experiences an erection due to the changes that occur in the blood flowing through the penis. When a man feels sexually aroused, his brain nerves command the penis blood vessels to expand, and this increases the inflow of blood into the penis, while decreasing the out flow of blood from the penis. This process hardens the tissue in the corpus cavernosum, and the man gets an erection.