Making Healthy, Informed Choices about Sex

Welcome to BIG DECISIONS! In this lesson, we'll explore human reproductive anatomy and how it functions. Understanding your body and how reproduction works is a fundamental part of making informed decisions about your health and relationships.

This knowledge isn't just for a biology test—it helps you take ownership of your health, communicate effectively with healthcare providers, and make responsible choices as you grow older.

Remember: Knowledge is power! Understanding reproductive anatomy is a normal, important part of your health education.

Anatomy and Reproduction: How It Works

Reproductive anatomy might seem complicated, but breaking it down makes it much easier to understand. In this lesson, we'll examine both male and female reproductive systems.

We'll look at both external parts (what you can see) and internal structures (what's inside the body). Each part has specific functions related to reproduction, pleasure, and/or waste elimination.

Understanding these systems helps clarify how pregnancy happens, how STIs can spread, and how various birth control methods work—all essential information for making healthy decisions.

Male Reproductive Anatomy: External Parts

Let's start exploring male reproductive anatomy. The external parts are what you can see from the outside.

The penis is the primary external reproductive organ in males. It serves multiple functions: urination, sexual intercourse, and delivering sperm. The end of the penis (called the glans) is particularly sensitive to touch.

Some males are circumcised, which means the foreskin covering the glans has been surgically removed, usually during infancy. Others are uncircumcised, with the foreskin intact. Both are completely normal variations.

Fun fact: The penis contains no bones (unlike in some animals) and consists mainly of spongy tissue that fills with blood during arousal.

Male External Anatomy: The Penis

The shaft of the penis is the main body section. It's made of erectile tissue that fills with blood during arousal, allowing for sexual function. The shaft connects to the body at its base.

At the end of the shaft is the glans, or "head" of the penis. This area has many nerve endings, making it particularly sensitive to stimulation. The small opening at the tip of the glans is called the urethra, which allows both urine and semen to leave the body (though not at the same time).

Males are born with a foreskin that covers and protects the glans. In circumcised males, this skin has been removed, leaving the glans exposed.

Male External Anatomy: Additional Structures

The external male reproductive anatomy includes more than just the penis. The scrotum is a sac of skin that hangs behind the penis and contains the testicles.

The testicles (or testes) are housed in the scrotum rather than inside the body because sperm production requires a temperature slightly lower than normal body temperature. The scrotum naturally raises and lowers the testicles to maintain optimal temperature.

In uncircumcised males, the foreskin is a layer of skin that covers and protects the glans. During arousal, it naturally retracts to expose the glans.

Male Internal Reproductive Anatomy

Now let's look at what's happening inside. Male reproductive anatomy includes several internal structures that work together for reproduction and urination.

The testicles produce sperm (male reproductive cells) and testosterone (the primary male hormone). From there, sperm travel to the epididymis, a coiled tube where sperm mature and are stored until ejaculation.

When a male ejaculates, sperm move from the epididymis through the vas deferens, a long tube that connects to the urethra. The urethra is the channel that runs through the penis, allowing both urine and semen to exit the body.

Important: Urine and semen never come out at the same time—the body has a special valve system that prevents this from happening!

Male Reproductive System: Glands and Fluids

The male reproductive system includes important glands that contribute to semen production. Semen is more than just sperm—it's a mixture of fluids designed to transport and nourish sperm cells.

The seminal vesicles produce a sugar-rich fluid that provides energy for sperm. This fluid makes up about 70% of semen volume. The prostate gland adds another fluid that helps sperm move effectively and neutralizes the acidic environment of the vagina.

All these fluids combine with sperm to create semen, which is released during ejaculation. A typical ejaculation contains about 300 million sperm, though only one is needed for fertilization.

Female Reproductive Anatomy: External Parts

The external female reproductive structures are collectively called the vulva. The vulva includes several parts, each with important functions.

The labia majora (outer lips) and labia minora (inner lips) are folds of skin that protect the vaginal opening. The clitoris is a small, sensitive organ located where the labia minora meet, and it's primary purpose is sexual pleasure.

The vulva also has three openings: the urethra (where urine exits), the vaginal opening (connected to internal reproductive organs), and the anus (part of the digestive system). Each opening serves a completely different body system.

Health note: Understanding your anatomy helps you recognize what's normal for your body and identify when something might need medical attention.

Female External Anatomy: The Vulva

Looking more closely at the vulva, the labia majora are the outer folds of skin that contain fat and sweat glands. They protect the more sensitive parts of the vulva. The labia minora are thinner, inner folds that protect the vaginal and urethral openings.

The clitoris contains thousands of nerve endings, making it highly sensitive to touch. Though small, it's actually quite extensive internally and wraps around the vaginal opening.

Near the vaginal opening, some females have a hymen, which is a thin membrane that may partially cover the opening. Contrary to some myths, it doesn't completely seal the vagina (menstrual blood still flows out), and it can stretch or tear from many activities besides sex, including sports or tampon use.

Female Internal Reproductive Anatomy

The female internal reproductive system is designed for multiple functions: producing eggs, potential fertilization, pregnancy, and childbirth.

The vagina is a muscular canal that connects the external genitals to the cervix. It's where menstrual flow exits the body, where penetrative sex occurs, and serves as the birth canal during childbirth.

The cervix is the lower part of the uterus that extends into the vagina. It produces protective mucus, dilates during childbirth, and is where doctors take Pap smears to screen for cervical cancer.

The uterus (or womb) is a muscular, hollow organ where a fertilized egg implants and develops during pregnancy. When not pregnant, the uterine lining sheds monthly during menstruation.