Human Reproductive Anatomy and Physiology

Human Reproductive Anatomy and Physiology

• Textbook: Introductory Maternity and Pediatric Nursing, Fourth edition, by Nancy T. Hatfield and Cynthia A. Kincheloe; Chapters 3 and 4
• Tutoring: Monday 1-2 PM
• Office hours: By appointment

Puberty

• Involves changes in the whole body and psyche, occurring between ages 10-14
• Secondary sex characteristics develop
• Reproductive system matures and becomes capable of reproduction
• Ends when mature sperm are formed in males, and regular menstrual cycles begin in females

The Female

• Estrogen is released by developing ovaries, causing secondary sex characteristics like breast development (first at 10-12 years).
• Growth spurt occurs (earlier than in males)
• Hips broaden, pubic and axillary hair appears
• Acne can occur, which are hormone-related.
• First menstrual period (menarche) occurs approximately 2-2.5 years after breast development (around 12-14 years of age).
• Estrogen levels are cyclical.
• Fat releases estrogen.

The Male

• Hormonal changes (testosterone) begin between ages 10 and 16.
• Secondary sex characteristics are caused by testosterone, including increased muscle mass and strength, promotion of long bone growth, and increased basal metabolic rate (BMR).
• Testosterone increases red blood cell (RBC) production.
• The voice deepens due to the enlargement of vocal cords.
• Body hair distribution is affected (axillary, pubic, facial, body).
• Penis and testes grow in size.
• Testosterone levels become constant.
• Nocturnal emissions ("wet dreams") may occur. These do not contain sperm.

Female Reproductive System - External Genitalia

• Collectively called the vulva
• Includes: mons pubis, labia majora, labia minora, fourchette, clitoris, vaginal vestibule, and perineum
• Mons pubis: Pad of fat tissue covered by coarse skin and pubic hair; protects symphysis pubis
• Labia majora: Two folds of fatty tissue; contain pubic hair and many small oil and sweat glands.
• Labia minora: Two thin, soft erectile folds; sensitive to stimulation. They secrete substances to lubricate and protect the vulva.
• Fourchette: Fold of tissue below the vagina where the labia majora meet; part of the obstetrical perineum.
• Clitoris: Hooded erectile body; Most sensitive part of the female genitalia; produces smegma (a cheese-like secretion).
• Perineum: Strong muscular area between the vaginal opening and anus. It is the site of an episiotomy.

Female Reproductive System - Internal Genitalia

• Includes: vagina, uterus, fallopian tubes, and ovaries.
• Vagina: Tubular structure of muscle and membrane that connects the vulva to the uterus. Provides a passageway for sperm, drains menstrual fluid and allows for childbirth. Has rugae (folds) allowing for stretching during intercourse.
• Uterus: Hollow muscular organ; site of implantation of a fertilized ovum. It develops into an embryo and then fetus. It has three layers: endometrium (hormone cyclic changes; sloughs off during menstruation), myometrium (muscular layer), and perimetrium (outer layer). Pear shaped, located between the urinary bladder and rectum, above the vagina. Supported by ligaments. Controlled by autonomic nerves (not conscious control). It has a fundus (rounded portion on top) and corpus (body).
• Fallopian tubes (oviducts): Passageway for sperm to meet the ovum (fertilization). Nourishing environment for the zygote and means of transporting to the uterus. Comprised of infundibulum, ampulla, and isthmus.
• Ovaries: Almond-shaped; held in place by ovarian and uterine ligaments.; Produce hormones (estrogen and progesterone), crucial for development of secondary sex characteristics and endometrial growth. Ovum maturation happens inside them, with oum release during ovulation.

Ovarian Cycle

• Follicular Phase: Follicle in the ovary matures under the influence of FSH; estrogen levels increase. LH causes ovulation.
• Ovulation: Release of ovum (mature egg)
• Luteal Phase: Follicle ruptures becoming corpus luteum, which secretes progesterone. If ovum isn't fertilized, corpus luteum degenerates, progesterone level drops, and menstruation begins.

Male Reproductive System - External Genitalia

• Includes: penis, scrotum
• Penis: Expels urine; deposits sperm into the vagina. Composed of three erectile tissues (corpus cavernosum and corpus spongiosum) that trap blood for erection. It has a sensitive head (glans penis) and foreskin (prepuce).
• Scrotum: Sac that encloses the testes and suspends them from the perineum. Helps regulate temperature for spermatogenesis (sperm production).

Male Reproductive System - Internal Genitalia

• Includes: testes, epididymis
• Testes: Manufacture spermatozoa (sperm cells), produce testosterone (promotes male sexual development). Located in the scrotum.
• Epididymis: Stores and carries sperm to the penis; stores sperm for 2 to 10 days

Spermatic Cord

• Contains the vas deferens, nerves, and arteries and veins.
• Mature sperm travel here next.
• Ejaculatory duct forms from seminal vesicle joining vas deferens to urethra.

Accessory Glands

• Includes: prostate gland, bulbourethral glands (Cowper's)
• Prostate Gland: Muscular organ that provides a thin alkaline fluid for semen. Helps in ejaculation.
• Bulbourethral Glands: Produce thick secretions that help clean the urethra.

Male Hormone Control

• Hypothalamus: Releases GnRH for control.
• Anterior Pituitary Gland: Produces FSH and LH.
• Interstitial cells (Leydig cells): Stimulated by LH to produce testosterone.
• Sertoli Cells: Support sperm maturation.

Semen and Sperm

• Semen: Mixture of sperm and fluid. Ejaculation typically contains 50–150 million sperm in 2-4ml. Sperm survive 72 hours in vagina and 3–5 days in uterus. Sperm head contains acrosome and nucleus (DNA). Midpiece contains mitochondria; tail/flagellum enables movement.

Menstrual Disorders

• Amenorrhea: Absence or irregular menstruation.
• Dysmenorrhea: Painful menstruation.
• Mittelschmerz: Middle pain associated with ovulation.
• Premenstrual Syndrome (PMS): Cycling emotional and physical symptoms before menstruation.
• Menopause: Cessation of menstruation (usually between 45–50 years). This is a normal body change, but symptoms can be diverse (insomnia, vaginal atrophy, etc).
• Fibroids: Muscular tumors in the uterus that often lead to bleeding problems like heavy bleeding or bleeding between periods.

Pelvic Floor

• Pelvic floor: Strong muscles that stabilize reproductive organs, supports urethra, vagina, and rectum.
• Kegel exercises can help strengthen this muscle group

NCLEX Style Questions

• Which gland provides sugar needed for sperm energy? -> Seminal vesicles.