The Reproductive System: An Overview

The reproductive system includes organs, ducts, glands, hormones and specialised cells. These structures have roles in sexual function, hormone production and reproduction. They also interact closely with the brain, bones, muscles, circulation and other body systems.

The reproductive system has several functions The reproductive system does more than enable pregnancy. It produces reproductive cells, releases hormones, supports sexual function and transports reproductive cells and fluids. The specialised reproductive cells are called gametes. Sperm are the smaller gametes. The cell released from an ovary is commonly called an egg, although its more precise name before fertilisation is an oocyte. The ovaries and testes are called gonads. Gonads produce reproductive cells and important reproductive hormones. Not every person has the same reproductive anatomy. Some people are born with variations in genes, hormones or reproductive structures. Surgery, medical treatment, injury and life stage can also change reproductive anatomy or function. The ovarian reproductive system The ovaries produce oocytes and hormones including oestrogen and progesterone. They lie in the pelvis, close to the uterus. The uterine tubes sit near the ovaries and connect with the uterus. They help move an oocyte towards the uterus. Fertilisation usually occurs within a uterine tube rather than inside the uterus. The uterus is a muscular organ where an embryo can implant and a pregnancy can develop. Its inner lining, called the endometrium, changes during the menstrual cycle. The cervix is the lower part of the uterus. It opens into the vagina and produces mucus that changes during the menstrual cycle. The vagina is a muscular passage between the cervix and the outside of the body. The external structures, including the labia and clitoris, are collectively called the vulva. A dedicated lesson on the female reproductive system covers this anatomy in more detail. The testicular reproductive system The testes produce sperm and hormones including testosterone. They usually sit within the scrotum outside the main body cavity. Sperm form inside small coiled structures within the testes. They then move into the epididymis, where they continue to mature. During ejaculation, sperm travel through the vas deferens. Fluids from the seminal vesicles, prostate and other glands mix with sperm to form semen. Semen travels through the urethra and leaves through the penis. The urethra also carries urine, but urine and semen normally pass through it at different times. A dedicated lesson on the male reproductive system covers this anatomy in more detail. The brain helps control both systems Reproductive hormones are coordinated through a feedback system involving the hypothalamus, pituitary gland and gonads. The hypothalamus releases gonadotrophin releasing hormone, usually shortened to GnRH. GnRH signals the pituitary gland to release follicle stimulating hormone and luteinising hormone. Follicle stimulating hormone is usually shortened to FSH. Luteinising hormone is shortened to LH. FSH and LH act on the ovaries or testes. The gonads then produce reproductive cells and hormones. These hormones feed information back to the brain and pituitary gland. This feedback system helps adjust hormone production rather than keeping hormone levels permanently fixed. Reproductive hormones act throughout the body Oestrogen, progesterone and testosterone are often described as female or male hormones. That language is incomplete because all three can be present in every sex, although typical levels and patterns differ. These hormones affect reproductive tissues, but their effects are wider. They can influence bones, muscles, skin, body hair, sexual desire and parts of brain function. A reproductive hormone problem can therefore produce symptoms outside the reproductive organs. However, symptoms such as tiredness, mood change or reduced sexual desire have many possible causes. Sexual function and fertility are not the same Sexual desire, arousal, erection, lubrication, orgasm, ejaculation and fertility involve overlapping but different processes. A person can have normal sexual function and reduced fertility. Another person can be fertile but experience pain, reduced desire or difficulty with arousal. Fertility depends on several steps working together. These include reproductive cell production, hormone signals, open pathways, sexual or assisted reproduction, fertilisation and implantation. A dedicated lesson on the menstrual cycle, and another on fertilisation and implantation, cover these steps in detail. No single hormone level, body part or semen result describes every part of fertility. Reproductive health includes the whole life course Reproductive health includes puberty, menstruation, sexual function, contraception, fertility, pregnancy, menopause, infections, screening and reproductive choices. It also includes consent, bodily autonomy, relationships and access to suitable healthcare. These wider subjects require their own lessons. This overview provides the anatomical and physiological map needed to understand them. Why anatomy matters during assessment A clinician uses the location, timing and pattern of a symptom to consider which reproductive structures may be involved. An examination, blood test or scan may provide further information. No one test can assess the entire reproductive system. Sudden severe testicular pain requires emergency assessment because blood flow to a testis may be threatened. Possible pregnancy with heavy bleeding, severe abdominal pain, shoulder pain, dizziness or fainting also requires immediate medical help.

The reproductive system is a connected network of organs, cells, glands and hormones. It supports sexual function and reproduction while interacting with many other body systems.