Male Reproductive System

• The male and female reproductive systems facilitate sexual reproduction
• These systems produce gametes and sex hormones, enabling fertilization

Male Reproductive System

• The primary function is to produce and deliver sperm to the female reproductive tract
• Key organs include: testes, epididymis, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, and penis

Testes

• The testes (testicles) are the primary male reproductive organs
• They produce sperm and testosterone
• They reside within the scrotum, which maintains a cooler temperature optimal for sperm production
• Each testis contains seminiferous tubules, the site of spermatogenesis (sperm production)
• Interstitial cells (Leydig cells) located between the seminiferous tubules produce testosterone
• Sertoli cells within the seminiferous tubules support and nourish developing sperm cells
• Spermatogenesis involves meiosis, reducing the chromosome number from diploid (46) to haploid (23) in sperm cells
• The process takes approximately 64-72 days

Epididymis

• A coiled tube on the posterior surface of each testis
• It serves as a storage and maturation site for sperm
• Sperm spend approximately 2-3 weeks in the epididymis, developing the ability to swim and fertilize an egg

Vas Deferens

• The vas deferens (ductus deferens) is a muscular tube that transports sperm from the epididymis to the ejaculatory duct
• Ascends through the spermatic cord, containing blood vessels, nerves, and muscles
• It passes through the inguinal canal and into the pelvic cavity

Seminal Vesicles

• Located on the posterior surface of the bladder
• Produce a viscous, alkaline fluid containing fructose, prostaglandins, and other substances that nourish and protect sperm
• Contributes roughly 60-70% of semen volume

Prostate Gland

• A walnut-sized gland inferior to the bladder
• Secretes a milky, slightly acidic fluid with enzymes, zinc, and other substances that enhance sperm motility and viability
• Prostatic fluid makes up about 20-30% of semen volume

Bulbourethral Glands

• The bulbourethral glands (Cowper's glands) are small glands inferior to the prostate gland
• Secretes a clear, alkaline mucus that lubricates the urethra and neutralizes acidic urine residue before ejaculation

Semen

• A mixture of sperm and seminal fluids from the testes, seminal vesicles, prostate gland, and bulbourethral glands
• The average ejaculate volume is approximately 2-5 ml, containing 20-150 million sperm per ml
• The alkaline pH of semen assists in neutralizing the acidic environment of the female vagina, protecting sperm

Penis

• The male copulatory organ, delivering sperm to the female reproductive tract
• Consists of the root, body (shaft), and glans penis (head)
• The body contains three cylindrical masses of erectile tissue: two corpora cavernosa and one corpus spongiosum
• The corpus spongiosum surrounds the urethra and forms the glans penis
• During sexual arousal, erectile tissues fill with blood, causing an erection
• Erection is controlled by the parasympathetic nervous system
• Ejaculation is controlled by the sympathetic nervous system, involving the propulsion of semen from the urethra

Hormonal Control in Males

• Gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the anterior pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
• FSH stimulates Sertoli cells in the seminiferous tubules to support spermatogenesis
• LH stimulates Leydig cells in the testes to produce testosterone
• Testosterone promotes spermatogenesis, the development of secondary sexual characteristics, and libido
• Testosterone also has negative feedback effects on GnRH, FSH, and LH secretion, maintaining hormone balance

Female Reproductive System

• The primary function is to produce eggs, provide a site for fertilization, support fetal development, and facilitate childbirth
• Key organs include: ovaries, fallopian tubes, uterus, vagina, and mammary glands

Ovaries

• The primary female reproductive organs
• Responsible for producing eggs (ova) and female sex hormones (estrogen and progesterone)
• Located in the pelvic cavity, one on each side of the uterus
• Each ovary contains ovarian follicles, which consist of an oocyte (immature egg) surrounded by follicle cells
• Oogenesis (egg production) begins before birth, with primary oocytes arrested in prophase I of meiosis
• At puberty, hormonal changes stimulate some primary oocytes to continue meiosis
• Typically, one oocyte matures each month and is released during ovulation
• Ovulation involves the release of a secondary oocyte from a mature follicle
• After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone and estrogen
• Should fertilization not occur, the corpus luteum degenerates into the corpus albicans

Fallopian Tubes

• The fallopian tubes (uterine tubes or oviducts) transport the egg from the ovary to the uterus
• Fimbriae are finger-like projections that surround the ovary, helping to capture the released egg
• Fertilization typically occurs in the ampulla, the widest part of the fallopian tube
• The fertilized egg (zygote) is transported to the uterus for implantation

Uterus

• A hollow, muscular organ where a fertilized egg implants and develops
• Located in the pelvic cavity, between the bladder and the rectum
• Consists of three layers: the perimetrium (outer serous layer), the myometrium (middle muscular layer), and the endometrium (inner mucosal layer)
• The endometrium undergoes cyclical changes in response to hormones, preparing for implantation
• Endometrium layers: the stratum functionalis (shed during menstruation) and the stratum basalis (regenerates the functionalis layer)
• The cervix is the narrow lower portion of the uterus that connects to the vagina

Vagina

• A fibromuscular tube that extends from the cervix to the outside of the body
• Functions as the female copulatory organ, the birth canal, and the passageway for menstrual flow
• The vaginal wall contains rugae (folds) that allow it to stretch during childbirth
• The hymen is a thin membrane that partially covers the vaginal opening

Mammary Glands

• Modified sweat glands that produce milk to nourish a newborn infant
• Located in the breasts and consist of lobules containing alveoli, which secrete milk
• Milk is transported through ducts to the nipple
• Milk production is stimulated by the hormone prolactin, and milk ejection is stimulated by the hormone oxytocin

Hormonal Control in Females

• Gonadotropin-releasing hormone (GnRH) from the hypothalamus stimulates the anterior pituitary gland to release FSH and LH
• FSH stimulates the growth of ovarian follicles and estrogen production
• LH triggers ovulation and stimulates the formation of the corpus luteum
• Estrogen promotes the development of secondary sexual characteristics, regulates the menstrual cycle, and prepares the endometrium for implantation
• Progesterone, primarily secreted by the corpus luteum, helps maintain the endometrium during pregnancy
• If fertilization occurs, the developing embryo secretes human chorionic gonadotropin (hCG), which maintains the corpus luteum and prevents menstruation
• Estrogen and progesterone have negative feedback effects on GnRH, FSH, and LH secretion, maintaining hormone balance
• During menopause, the ovaries cease to function, resulting in decreased estrogen and progesterone levels and the cessation of menstruation.

Overview of the male reproductive system including the primary function of producing and delivering sperm. Includes key organs such as the testes, epididymis and vas deferens. Also describes the function of the scrotum and spermatogenesis.