The Reproductive and Urinary Systems Overview

What are the primary sex organs in males and females?

The primary sex organs are the testes in males and the ovaries in females.

What is the function of the primary sex organs?

They produce gametes (sex cells) and secrete various sex hormones that regulate reproduction and development.

What are the accessory reproductive structures?

They include various ducts, glands, and external genitalia that support the primary sex organs.

What is the scrotum and its function?

The scrotum is a sac of skin hanging outside the abdominopelvic cavity that houses the paired testes.

Why are the testes located in the scrotum?

The testes are held away from the body to maintain a temperature about three degrees lower than the body's normal 37 degrees Celsius, which is optimal for sperm production.

What are the two muscles associated with the scrotum?

The Dartos Muscle (smooth muscle that wrinkles the scrotum) and the Cremaster Muscle (skeletal muscle that elevates the testes).

What are the tunics surrounding each testicle?

The Tunica Vaginalis (outer covering, double layered, derived from the peritoneum) and the Tunica Albuginea (fibrous capsule that surrounds the testes).

What are testicular lobules and their function?

Testicular lobules are generally about 250-300 per testicle and contain seminiferous tubules that serve as sperm factories.

What are myoid cells and their role?

Myoid cells surround the seminiferous tubules and contract to aid in squeezing sperm and testicular fluids through the tubules.

What is the pathway of sperm from the seminiferous tubules?

Sperm leave the seminiferous tubules, converge to form the Tubulus Rectus, enter the Rete Testis, and then exit through the Efferent ductules into the Epididymis.

What are Leydig cells and their function?

Leydig cells line the seminiferous tubules and produce androgens, primarily testosterone.

What do sustentacular cells do?

Sustentacular cells supply nutrients to developing sperm and produce the hormone inhibin.

What is the spermatic cord?

The spermatic cord is a connective tissue sheath that encloses and protects the blood vessels and nerves that run to the testes.

What is the primary function of the penis?

The penis delivers sperm to the female reproductive tract.

What is the glans penis?

The glans penis is the enlarged tip of the penis, covered by a cuff of tissue known as the prepuce or foreskin.

What are the internal structures of the penis?

The internal structures include the corpus spongiosum (central erectile portion surrounding the urethra) and the corpora cavernosa (paired erectile regions).

What is the male duct system?

The male duct system, known as the accessory ducts, includes the Epididymis, Vas Deferens, Ejaculatory Duct, and Urethra.

What is the function of the epididymis?

The epididymis absorbs nutrients passed to sperm stored in its lumen and is where sperm are ejaculated from.

What is the vas deferens?

The vas deferens is a tube from the epididymis to the abdomen, approximately 18 inches long, serving as a passageway for sperm.

What happens during a vasectomy?

The vas deferens is cut to prevent sperm from being transmitted.

What is the function of the ejaculatory duct?

The ejaculatory duct is a one-inch long tube that ejects sperm and seminal fluid into the prostatic urethra.

What is the urethra's role in the male reproductive system?

The urethra is the terminal duct that transmits both sperm and urine.

What are the three sections of the urethra?

1) Prostatic Urethra - passes through the prostate gland. 2) Membranous Urethra - a 2-inch tube that passes through the urogenital diaphragm. 3) Penile Urethra - a 6-inch tube that passes through the spongiosum of the penis.

What is the function of the accessory glands in the male reproductive system?

They produce seminal fluids.

Where are the seminal vesicles located and what do they secrete?

Located on the lower part of the posterior surface of the urinary bladder, they secrete alkaline, viscous fluid containing fructose that activates the whip-like action of sperm flagella.

What is the role of the prostate gland in semen production?

The prostate gland secretes a slightly acidic fluid that gives semen its milky appearance.

What do the bulbourethral (Cowper's) glands secrete and when?

They secrete mucus prior to ejaculation to neutralize the acidity of the female reproductive system.

What is semen composed of?

Semen is composed of sperm plus seminal fluids.

What is the pH range of semen?

The pH of semen ranges from 7.2 to 7.6.

What is the average volume of semen released during ejaculation?

The average ejaculation is about 2.5 to 5 ml.

How many sperm are typically released per ejaculation?

Males release about 200 million sperm per ejaculation.

What is seminalplasmin and its function?

Seminalplasmin is an antibiotic that inhibits bacterial growth.

What percentage of the total semen weight do sperm account for?

Sperm account for only about 5% of the total semen weight.

What is the vulva?

The vulva is the external genitalia of the female reproductive system.

What is the mons pubis?

The mons pubis is a skin-covered pad of adipose tissue over the pubic symphysis, containing coarse pubic hair.

What are the labia majora and their function?

The labia majora are paired folds of skin that form the outer border of the vulva and are homologous to the scrotum, containing numerous oil and sweat glands.

What is the function of the labia minora?

The labia minora are longitudinal folds of skin that unite to enclose the clitoris.

What is the clitoris and its role in the female reproductive system?

The clitoris is a cylindrical structure composed of erectile tissue and nerves; it enlarges during sexual excitement and is homologous to the male penis.

What structures are contained within the vestibule?

The vestibule contains the External Urethral Orifice, Vaginal Orifice, Paraurethral Glands, and Bartholin's Glands.

What is the function of the paraurethral glands?

The paraurethral glands secrete mucus and are homologous to the prostate gland.

What do Bartholin's glands secrete?

Bartholin's glands secrete a lubricating fluid during excitement and are homologous to the bulbourethral gland.

What are the primary functions of the ovaries?

The ovaries are responsible for egg production (oogenesis), ovulation (discharge of eggs), and secretion of the female hormones estrogen and progesterone.

What are the support ligaments associated with the ovaries?

1) Mesovarian ligament - attaches to the broad ligament. 2) Ovarian ligament - attaches to the uterus. 3) Suspensory ligament - attaches to the pelvic wall.

What is the germinal epithelium?

The germinal epithelium is the outer covering of the ovaries.

What are ovarian follicles?

Ovarian follicles are structures containing oocytes in various stages of development.

What is a Graffian Follicle?

A large, fluid-filled follicle that contains an immature ovum and secretes estrogen.

What is the function of the Corpus Luteum?

It is an empty follicle after ovulation that secretes progesterone.

What is a Corpus Albicans?

A degenerated corpus luteum containing white fibrous tissue.

What is the Stroma in the context of the ovaries?

The area between the follicles.

Where is the uterus located?

In the pelvic cavity between the urinary bladder and the rectum.

What are the three divisions of the uterus?

Fundus (dome-shaped portion), Body (central region), and Cervix (lower portion that protrudes into the vagina).

What is the Perimetrium?

The outer layer of the uterine wall, composed of epithelial tissue.

What is the Myometrium?

The middle muscular layer of the uterine wall that contracts during childbirth.

What is the Endometrium?

The inner layer of the uterine wall where the embryo implants during pregnancy.

What are the two parts of the Endometrium?

Stratum basalis (typically remains intact) and Stratum functionalis (shed during menstruation).

What are the functions of the uterus?

Menstruation (shedding of the functionalis), Pregnancy (houses embryo), and Labor (aids in childbirth).

What is the Broad Ligament?

A ligament that attaches to either side of the pelvic cavity.

What does the Uterosacral Ligament connect?

It connects the uterus to the sacrum.

What is the Cardinal Ligament?

A ligament that attaches the cervix and vagina to the pelvic wall.

What is the Round Ligament?

A ligament located between the layers of the broad ligament.

What are the Fallopian Tubes?

Paired structures that attach to the uterus and extend toward the ovaries, with a funnel-like section known as the infundibulum.

What is the function of the fimbriae?

They sweep over the ovaries to pull the egg into the fallopian tube.

Where does fertilization usually occur?

In the fallopian tubes.

What is the Vagina?

A passage that opens to the outside of the body via the vaginal orifice.

What are the functions of the vagina?

Serves as part of the birth canal, receives the penis during copulation, and is a passageway for menstrual flow.

What is the Hymen?

A fold of connective tissue that partially closes the external opening of the vagina.

What are Rugae?

Transverse folds of the vaginal mucosa.

What are Mammary Glands?

Glands located under the pectoralis major muscle, composed of adipose tissue, lobes, lobules, ducts, and alveoli.

What is Spermatogenesis?

The process of sperm formation that occurs in the seminiferous tubules, regulated by Follicle Stimulating Hormone (FSH).

What are the stages of Spermatogenesis?

Spermatogonium (diploid), Primary Spermatocyte, Secondary Spermatocyte, Spermatids (haploid), and Spermatozoa.

What is the purpose of Erection in the male reproductive system?

It enables penetration into the vagina.

What is the role of nitric oxide (NO) in the process of erection?

Nitric oxide promotes vasodilation of the arteries and vasoconstriction of the veins of the penis, allowing more blood to enter than leave, resulting in an erection.

What are the steps involved in the process of erection?

1. Impulses from the parasympathetic division promote release of nitric oxide. 2. Blood fills the spongy tissue of the cavernosa and spongiosa, causing rigidity. 3. Emission occurs as semen moves into the prostatic urethra. 4. Ejaculation propels semen to the exterior.

What is oogenesis and when does it begin?

Oogenesis is the process of egg formation that occurs in the ovaries and begins at puberty.

Which hormone regulates oogenesis?

Follicle Stimulating Hormone (FSH) regulates oogenesis.

What are the stages of oogenesis?

1. Primordial follicles (diploid). 2. Primary Oocyte (in prophase I of meiosis). 3. Secondary Oocyte and First Polar Body (after FSH and LH stimulation). 4. Ootid and Secondary Polar Bodies (if fertilized).

What happens to the primary oocyte at puberty?

At puberty, FSH and LH cause meiosis I to resume, resulting in a secondary oocyte and a first polar body.

What occurs during ovulation?

During ovulation, the secondary oocyte is released and will only continue into meiosis II if fertilized.

What are the products of fertilization in oogenesis?

If fertilized, the secondary oocyte produces an ootid (larger cell) and secondary polar bodies (smaller cells), with polar bodies disintegrating.

What hormones are associated with the menstrual cycle?

1. Gonadotropin Releasing Hormone (GnRH). 2. Follicle Stimulating Hormone (FSH). 3. Lutenizing Hormone (LH). 4. Estrogen. 5. Progesterone.

What is the function of Gonadotropin Releasing Hormone (GnRH)?

GnRH influences the anterior pituitary gland to produce FSH and LH.

What are the functions of Follicle Stimulating Hormone (FSH)?

FSH stimulates the growth of the ovum within the follicle and the release of estrogen by the growing follicle.

What are the functions of Lutenizing Hormone (LH)?

LH induces ovulation, stimulates the ruptured follicle to become the corpus luteum, and stimulates the corpus luteum to produce progesterone.

What role does estrogen play in the menstrual cycle?

Estrogen stimulates the growth of the endometrium, development of secondary sex characteristics, and inhibits the release of GnRH and FSH.

What is the function of progesterone during the menstrual cycle?

Progesterone stimulates further growth of the endometrium during pregnancy and inhibits the production of GnRH and Prolactin.

What are the phases of the menstrual cycle?

1. Menstrual Phase (days 1-4/5). 2. Preovulatory or Follicular Phase (days 6-13). 3. Postovulatory or Luteal Phase (days 15-28).

What occurs during the Menstrual Phase?

The functionalis layer of the endometrium is shed, including blood, mucus, and epithelial tissue.

What happens during the Preovulatory or Follicular Phase?

High levels of FSH cause the secondary follicle to develop into a mature follicle, and estrogen rebuilds the endometrium.

What triggers ovulation in the menstrual cycle?

Estrogen acts as a feedback mechanism to inhibit FSH and LH production, leading to ovulation around day 14.

What occurs during the Postovulatory Phase or Luteal Phase?

After ovulation, estrogen levels drop slightly, and LH stimulates the ruptured follicle to become the corpus luteum.

What hormones does the corpus luteum secrete to prepare the endometrium for implantation?

Progesterone and estrogen.

What happens to FSH and LH secretion near the end of the luteal phase?

FSH secretion gradually increases while LH secretion decreases.

What is the dominant hormone during the luteal phase?

Progesterone.

What occurs if fertilization does not happen?

The corpus luteum degenerates into the corpus albicans, leading to decreased estrogen and progesterone, breakdown of the endometrium, and the start of menstrual flow.

How do birth control pills prevent new follicle development?

They keep estrogen and progesterone levels high, inhibiting FSH output.

What maintains the corpus luteum if fertilization occurs?

The hormone Human Chorionic Gonadotrophic Hormone (hCG) produced by the placenta.

What role does the placenta play after its formation during pregnancy?

It produces estrogen to support pregnancy and progesterone for breast development and lactation.

What is prostatitis?

Chronic inflammation of the prostate.

What is the most common type of cancer in men?

Prostate cancer.

What is testicular cancer and who is most commonly affected?

Cancer of the testicles, most common in young males.