Human Reproductive System: Male and Female Anatomy and Physiology
Male Reproductive System
Components
The male reproductive system consists of the testicles, penis, reproductive tract, and accessory glands.
Testicles
The testicles produce sperm (male gametes) within seminiferous tubules. Cells in the tubule walls produce sperm, while interstitial cells produce androgens (male sex hormones). The testicles are located outside the abdomen in the scrotum.
Reproductive Tract
The reproductive tract comprises ducts that transport sperm.
- Epididymis: Formed by seminiferous tubules, the epididymis stores and matures sperm.
- Ductus Deferens: A continuation of the epididymis, the ductus deferens stores sperm until ejaculation.
- Urethra: Shared with the urinary system, the urethra carries sperm through the penis.
Accessory Glands
These glands contribute to semen production.
- Seminal Vesicles: Located behind the bladder, they secrete fluid into the ductus deferens.
- Prostate Gland: Located below the bladder, it secretes prostatic fluid.
- Cowper’s Glands: Located at the base of the penis, they secrete lubricating fluid.
Female Reproductive System
Components
The female reproductive system consists of the ovaries, fallopian tubes, uterus, vagina, and vulva.
Ovaries
The ovaries produce ova (female gametes) and hormones (estrogen and progesterone). Ova develop within ovarian follicles, with mature ova residing in Graafian follicles.
Reproductive Tract
- Fallopian Tubes: These tubes collect the released ovum, and fertilization typically occurs here. Cilia and secreted fluid facilitate ovum movement.
- Uterus: With a muscular wall (myometrium) and inner mucous lining (endometrium), the uterus hosts fetal development. The cervix connects the uterus to the vagina.
- Vagina: An elastic tube with lubricating glands, the vagina receives sperm during intercourse. The hymen is a membrane at the vaginal opening.
- Vulva: The external genitalia, including the labia majora and minora, and Bartholin’s glands, which secrete lubricating fluid.
Ovarian Cycle
The ovarian cycle involves ovum formation, maturation, and release.
Phases
- Follicular Phase: Follicle-stimulating hormone (FSH) from the pituitary gland promotes follicle development.
- Ovulation: Luteinizing hormone (LH) triggers ovum release.
- Secretory Phase: The corpus luteum forms at the ovulation site and secretes progesterone. If fertilization doesn’t occur, the corpus luteum degenerates, and a new cycle begins.
Uterine (Menstrual) Cycle
The menstrual cycle prepares the uterus for pregnancy.
Phases
- Menstrual Phase: Decreased hormone levels cause shedding of the uterine lining and bleeding.
- Proliferative Phase: Estrogen promotes uterine lining regeneration.
- Secretory Phase: Progesterone thickens the uterine lining for embryo implantation. If fertilization occurs, the corpus luteum continues progesterone secretion; otherwise, the lining sheds, initiating a new cycle.