मराठी

External Genitalia: Penis

Topics

Estimated time: 13 minutes

CISCE: Class 12

Introduction

The human male reproductive system consists of both internal and external genitalia. The penis is the primary external genital organ of the male reproductive system. It is a cylindrical, muscular organ located outside the body in the pelvic region. It serves a dual physiological function, acts as the terminal passage for urine during excretion, and functions as the copulatory organ that deposits sperms into the female reproductive tract during sexual intercourse.

Its structure is uniquely adapted for both these functions through the presence of specialised erectile tissues and a rich nerve supply.

CISCE: Class 12

Structure of the Penis

A-B. Penis: A. in longitudinal section; B. in transverse section

CISCE: Class 12

Erectile Tissues

The internal structure of the penis is dominated by three columns of erectile tissue, each containing blood sinuses (spaces that can fill with blood):

Corpus Cavernosum (×2): Two paired columns of erectile tissue running along the length of the penis. These are the primary tissues responsible for engorgement and rigidity during erection.
Corpus Spongiosum (×1): A single column of erectile tissue. It surrounds the urethra and prevents its compression during erection. It also forms the glans penis at the distal end.

Together, these three columns make the penis capable of erection when stimulated.

CISCE: Class 12

Mechanism of Erection

Erection is a physiological response to sexual stimulation. The process occurs as follows:

Sexual stimulation triggers increased blood flow into the erectile tissues
Blood fills the sinuses (blood spaces) within the corpora cavernosa and corpus spongiosum
The engorgement of blood causes the penis to become rigid, enlarged, and erect
This erect state is essential for the insertion of the penis into the female vagina during intercourse

CISCE: Class 12

Glans Penis and Prepuce

1. Glans Penis

The glans penis is the bulbous, conical tip at the distal (outer) end of the penis.

It is the most sensitive part of the penis
It contains a rich supply of sensory nerve endings, making it highly responsive to touch and stimulation
It houses the external urethral orifice – the opening through which both urine and semen exit the body

2. Prepuce (Foreskin)

The glans penis is covered by a loose fold of skin called the prepuce, commonly known as the foreskin.

It acts as a protective covering for the glans
It is retractable, meaning it can be pulled back to expose the glans
Its surgical removal is called circumcision

CISCE: Class 12

Key Points: External genitalia: Penis

Penis is the external male genital organ that conducts urine and semen and transfers sperm to the female reproductive tract.
It contains erectile tissues (two corpora cavernosa and one corpus spongiosum) with blood sinuses.
Erection occurs when blood fills these sinuses during sexual stimulation, making the penis rigid.
The glans penis, covered by the prepuce (foreskin), is highly sensitive and rich in nerve endings.