Human Reproductive System Functions and Anatomy

Male Reproductive System Components

Sperm Production and Testicular Hormones

Spermatogonial: Embryonic cell producing sperm.

Testosterone: A hormone produced by the testis; its function is the development and maintenance of male sexual characteristics.

Hormones Synthesized by the Testis: Testosterone acts on the maturation of testicular germ cells.

Luteinizing Hormone (LH): Stimulates the secretion of testosterone by the Leydig cells.

Follicle-Stimulating Hormone (FSH): Stimulates the Sertoli cells.

Epididymis and Vas Deferens Function

Epididymal Function: Allows the passage of spermatozoa and facilitates their maturation.

Role of the Vas Deferens: Its function is to allow sperm to leave the epididymis and transport them to the ejaculatory duct.

Male Accessory Glands and Semen

Accessory Glands of the Male Genital System:

• Seminal Vesicles: Provide around 60% of seminal fluid.
• Prostate: Secretes a milky fluid contributing 30% of the total semen volume.
• Bulbourethral Glands (Cowper's Glands): Produce a mucous secretion contributing 5% of the total volume of semen.

Constitution of Semen:

• Sperm: The cellular component of the ejaculate, consisting of spermatozoa suspended in a liquid medium.
• Seminal Fluid: Produced by the accessory glands, composed of water, mineral salts, and readily available energy sources like glucose for metabolism.

Role of the Penis

Role of the Penis: Has a dual role as a genitourinary organ, involved in urination and sexual intercourse.

Female Reproductive System Basics

Ovary Function

Ovary Function: Formation of eggs (ova) or female gametes; production of female hormones estrogen and progesterone.

Role of Fallopian Tubes

Role of Fallopian Tubes: Connect the uterus with the ovaries; they are the site of fertilization.

Layers of the Uterus

Layers of the Uterus:

• Serous Layer (Perimetrium): The outer layer, part of the peritoneum, covering most of the uterus except the cervix.
• Myometrium: The thick middle layer, consisting of smooth muscle tissue.
• Endometrium: The innermost mucous layer, formed by 2 distinct layers:
  • Functional Endometrium: The most superficial layer, which is shed during menstruation.
  • Basal Endometrium: The deeper layer, responsible for regenerating the functional layer after menstruation.

Functions of the Uterus

General Functions of the Uterus: The main function is gestation, as it facilitates the implantation of a fertilized ovum and supports fetal development until birth.

The Hymen

Hymen: A thin membrane with a crescent-shaped opening located in the vagina, acting as a protector of the vagina in childhood and adolescence.

The Menstrual Cycle Explained

The Menstrual Cycle: A series of physiological changes that occur in the female reproductive system.

Phases of the Menstrual Cycle

• Proliferative Phase: (Starts after menstruation, ends with ovulation) The follicle matures (stimulated by FSH). The uterine lining thickens. Estrogen secretion increases, reaching maximum levels.
• Secretory Phase: (Starts after ovulation, ends with menstruation) The corpus luteum (formed in the ovary after ovulation, stimulated by LH) develops. The corpus luteum secretes estrogen and progesterone, causing further thickening and preparation of the endometrium. Estrogen and progesterone inhibit the release of LH and FSH. If the egg is not fertilized, the corpus luteum degenerates into a corpus albicans (white body), ceasing estrogen and progesterone secretion. This leads to vessel constriction and necrosis of the endometrium.
• Menstrual Phase: (Starts after the secretory phase if no fertilization) Accumulation of blood in the uterus. Detachment of the endometrial layer. Appearance of menstrual flow.