The reproductive system produces specialized cells known as gametes to conceive offspring. The gonads are the primary reproductive organs that produce ...

The paired testes are the male gonads. Each testis, weighing 10 to 15 grams, measures about 5 cm long, 3 cm wide, and 2.5 cm thick. The tunica albuginea, ...

The tunica albuginea of each testis extends inward to form fibrous partitions, or septa testis, dividing it into internal compartments called lobules. ...

Spermatogenesis begins at puberty and continues late into life, producing sperm in the seminiferous tubules. It has three main stages — mitosis, ...

The epididymis, vas deferens, ejaculatory duct, and urethra form the accessory ducts responsible for sperm maturation and transportation. The epididymis ...

The penis, part of the external male genitalia, is involved in both sexual reproduction and urination. Its cylindrical shape has three primary regions ...

Inside the seminiferous tubule of the testis, fluid from the Sertoli cells pushes the non-motile sperm through a series of straight tubules into the rete ...

The paired seminal and bulbourethral glands and the single prostate gland comprise the accessory male reproductive glands. The 5-centimeter-long seminal ...

Males release 2-5 ml of semen, a mixture of mature sperm and accessory gland fluids. The 60 μm long mature sperm cells consist of the head, neck, ...

In response to the sexual stimuli, the parasympathetic neurons stimulate the local release of nitric oxide, or NO, dilating the arterioles in the penis. ...

Gonadotropin-releasing hormone from the hypothalamus stimulates the pituitary gland to release follicle-stimulating hormone, FSH and luteinizing hormone, ...

The external female genitalia are structures located outside the vagina. They include the mons pubis, labia, clitoris, and vestibule structures and are ...

The vagina is a fibromuscular tube, about 3 to 4 inches long, located between the urinary bladder and the rectum. The vaginal mucosa is made of areolar ...

The ovaries are paired glands fastened on either side of the uterus with the broad, suspensory, and ovarian ligaments. Each ovary features a hilum, where ...

The ovarian cycle mainly consists of the follicular and the luteal phases. In the follicular phase, a primordial follicle is transformed into a primary ...

Oogenesis involves the formation of egg cells, or female gametes, in the ovaries. In fetal development, diploid oogonia in the ovaries divides mitotically ...

Folliculogenesis is the maturation of ovarian follicles in the ovarian cortex, essential sites for oogenesis. During fetal development,  a single ...

The ovarian cycle, a monthly event in reproductive-age women, is regulated by the hypothalamic-pituitary-gonadal axis to ensure a mature oocyte is ...

The uterine or fallopian tubes are 10 to 13-cm long passageways on either side of the uterus. Each tube is divided into the infundibulum, ampulla, and ...

The uterus, or the womb, provides a nourishing environment for the implantation and development of a fertilized egg. It is a hollow, pear-shaped organ in ...

The uterus wall has three histological layers — the perimetrium, myometrium, and endometrium. The outermost perimetrium is a thin serous membrane ...

The menstrual cycle is a sequence of monthly changes in the endometrium. The menstrual cycle may last between 21 and 38 days and is typically divided into ...

The menstrual cycle starts with the menstrual phase, with its first day considered Day 1 of the cycle. This phase usually lasts for 1 to 5 days and is ...

The proliferative phase is the second phase of the uterine menstrual cycle. It begins after menstruation and lasts approximately 6 to 13 days in a typical ...

The secretory phase of the menstrual cycle starts after ovulation and spans from day 14 to day 28 in a typical 28-day cycle. During this period, triggered ...

Testicular cancer, arising from spermatogenic cells, is the most common cancer in males between the ages of 20 and 35. A common symptom is the presence of ...

Premenstrual syndrome, or PMS, is a cyclical condition marked by emotional and physical distress during the postovulatory phase of the female reproductive ...

The gonadotrophin-releasing hormone, GnRH, and the gonadotrophins regulate endometrial changes during the menstrual cycle. Starting at puberty, GnRH ...

Female breasts are hemispheric projections attached anteriorly to the pectoralis major and serratus anterior muscles by a dense, irregular connective ...

The human embryo is bipotential, allowing the formation of either male or female reproductive organs. During the fifth week of embryonic development, the ...

Puberty typically begins around ages 8 to 13 in females and 9 to 14 in males, signaling the onset of reproductive maturity. Puberty begins with bursts of ...

In vitro fertilization, or IVF, is a process where eggs are fertilized with sperm in a lab and then implanted in the uterus. The process begins with ...

Women's reproductive ability peaks in their 20s, after which ovarian function gradually declines, marked by a reduced response to gonadotropin ...

Birth control can be achieved by three primary methods — surgical, hormonal control, and barrier methods. Vasectomy is a surgical procedure for male ...

Male infertility impacts millions of couples globally. An endocrine imbalance due to hypogonadism, Klinefelter syndrome, or pituitary disorders can lead ...

Female infertility is the inability to conceive after at least a year of regular unprotected intercourse, with a global prevalence of around 10%. Most ...

There are several sexually transmitted infections or STIs contracted through unsafe sexual interaction. Chlamydia trachomatis, an intracellular pathogenic ...