Reproductive System Chapter 22

I. Introduction Male and female reproductive systems are a series of glands and tubes that:  Produce and nurture sex cells  Transport them to the site of fertilization

II. Organs of the Male Reproductive System The male sex organs are designed to transport sperm to the eggs. Primary sex organs (testes) produce sperm and hormones; accessory sex organs have a supportive function

Testes  Oval-shaped structures inside the scrotum  Produce sperm cells  Produce male hormones (androgens)  Carry sperm to the epididymis and vas deferens

A sperm cell has a head containing the haploid nucleus (23 chromosomes), a mid-piece containing mitochondria, and a tail that is flagellum. At the tip of the head is the acrosome, a bag of digestive enzymes that helps to erode tissues surrounding the female egg cell.

Male internal accessory organs  Includes the epididymis, vas deferens, ejaculatory ducts, seminal vesicles, prostate gland, and the bulbourethral glands.  Epididymis 2 tightly coiled tubes leading from each testis to the vas deferens

Vas Deferens  2 tubes leading from each epididymis up to the ejaculatory duct, where it unites and empties its contents into the urethra Seminal Vesicles  2 saclike structures attached to the vas deferens near the base of the urinary bladder  During emission, seminal vesicles secrete and alkaline fluid containing fructose to nourish the sperm and prostaglandins to cause muscular contractions in the female tract to help propel sperm to the eggs

Prostate Gland  A chestnut-shaped structure surrounding the urethra at the base of the urinary bladder  Secretes a thin, milky alkaline fluid that both enhances the mobility of the sperm cells and neutralizes the acidity of the female reproductive tract.

Bulbourethral Glands (cowpers gland)  Small pea-like structures inferior to the prostate that secretes mucus to lubricate the penis during sexual arousal Semen  A combination of sperm (~120 million/mL) and the secretions of the seminal vesicles, prostate gland, and the bulbourethral glands.  Sperm cells cannot fertilize an egg until they undergo capacitation within the female reproductive tract.

Male reproductive organs Consists of the scrotum, which houses the testes, and the penis Scrotum  A pouch of skin that houses the testes, and is posterior to the penis Penis  A cylindrical organ made up of an erectile tissue that is designed to convey both urine and semen to the outside

III. Organs of the Female Reproductive System Specilized to  Produce and maintain egg cells  Transport these cells to the site of fertilization  Provide a favorable environment for a developing fetus  Give birth  Produce female sex hormones

The primary sexual organs are the ovaries; the other parts of the system comprise the external and internal accessory organs. Ovaries  solid, oval-shaped structures located within the pelvic cavity

Female Internal Accessory Organs  Consists of a pair of Uterine Tubes, a Uterus, and a Vagina  Uterine Tubes Also called oviduct Lead to the uterus Cells lining the tubes bear cilia, which beat to draw in the egg cell into the uterine tube

 Uterus Upper 2/3, called the body, and has a dome shaped top Lower 1/3, is called the cervix, that extends into the vagina It is a highly muscular organ  Vagina A tube that extends from the uterus to the outside of the body

Female External Reproductive Organs (vulva)  Includes the labia majora, labia minora, clitoris, and vestibular glands  Labia Majora Encloses and protects the other external organs; corresponds to the scrotum of the male  Labia Minora Flattened folds between the labia majora that form a hood around the clitoris

 Clitoris A mass of erectile tissue at the anterior end of the vulva between the labia minora Corresponds to the penis in males  Vestibule Space enclosed by the labia minora that corresponds to male’s bulbourethral glands (cowper’s) – to provide lubrication during sexual arousal

IV. Hormonal Control of Female Reproductive Functions Menstrual Cycle  Monthly changes in the uterine lining that lead to menstrual flow as a the lining is shed  Begins around ages of and continues through middle-age (40-50).

 Women athletes experience disturbances in the menstrual cycle Diminished flow or complete stoppage of the cycle Related to the loss of adipose tissue (fat) and decline in estrogen

Major Hormones  Follicle-Stimulating Hormone (FSH) stimulates maturation of the follicle (immature egg)  Luteinizing Hormone (LH) – stimulates synthesis of estrogen  Estrogen – maintains secondary sex characteristics and causes the uterine lining to thicken  Progesterone – promotes changes in the uterus

The Process – 28 day cycle  Pituitary gland secretes FSH and LH  Follicle cell secretes estrogen, which causes the uterine lining to thicken  On day 14, the pituitary gland releases a surge of LH resulting in ovulation (release of an egg from a mature ovarian follicle

 Estrogen and Progesterone levels increase Uterine wall thickens Inhibits FSH and LH  If fertilization DOES NOT occur: Estrogen and Progesterone levels decline Uterine blood vessels constrict and disintegrate, causing menstrual flow

V. Birth Control Birth control refers to the voluntary regulation of the number of offspring produced, requiring the use of contraception.

Methods of Birth Control  Coitus Interruptus  Rhythm Method  Mechanical Barriers  Chemical Barriers  Combined Hormone Contraceptives  Injectable Contraceptives  Intrauterine devices  Surgical Methods

Surgical Methods of Birth Control 22-50

Sexually Transmitted Diseases silent infections most are bacterial and can be cured herpes, warts, and AIDS are viral and cannot be cured many cause infertility AIDS causes death symptoms of STDs include burning sensation during urination pain in lower abdomen fever or swollen glands discharge from vagina or penis pain, itch, or inflammation in genital or anal area sores, blisters, bumps or rashes itchy runny eyes 22-51

Clinical Application Prostate Enlargement benign prostatic hypertrophy occurs in most men over 50 BPH causes frequent urination risk factors include a fatty diet, having had a vasectomy, or exposure to certain environmental factors treatments include surgical removal, drugs, insertion of balloon into urethra, freezing of tumor, or insertion of stent between lobes of prostate to relieve pressure on urethra 22-52