Reproductive System rev 12-12

Name: Reproductive System rev 12-12
Uploaded: 2017-08-21T10:40:17+00:00
Duration: PTM18S56
Channel: Ricardo Sterne
Description: Reproductive System rev 12-12

Reproductive System rev 12-12
The term genitalia refers to male and female reproductive organs. Male Reproductive System Anatomy The scrotal sac contains 2 testes which produce sperm (the male reproductive cells). The process of sperm formation is called spermatogenesis. Reproductive-BIO 102 HANDOUT

Reproductive-BIO 102 HANDOUT
The testes are located outside of the body because sperm need lower temperatures to survive. Sperm production takes place in the seminiferous tubules of the testes In between the seminiferous tubules are interstitial cells which produce testosterone, the male hormone. Many seminiferous tubules join to become the epididymus which is located at the rear of the testes. Sperm are stored here and maturation also occurs. Reproductive-BIO 102 HANDOUT

Sperm enter the vas deferens or ductus deferens (the sperm duct) which passes through an opening in the wall of the body called the inguinal canal. The ability of newly formed sperm to swim develops in the epididymis and the vas deferens. Sperm continue their maturation here. A vasectomy ties off the vas deferens so sperm are no longer available for fertilization. Reproductive-BIO 102 HANDOUT

The vas deferens connects to the ejaculatory duct after it merges with the seminal vesicle duct. When the male ejaculates semen, rhythmic contractions of smooth muscle propel the sperm through the ejaculatory duct and then through the urethra. The penis is the male organ of sexual intercourse. It contains erectile tissue that fills with blood and causes the erection during sexual stimulation. Reproductive-BIO 102 HANDOUT

Glands which help sperm survive: Seminal vesicles produce seminal fluid which is a watery mixture containing fructose, which provides energy for the sperm, and prostaglandins which are thought to induce muscle contractions in the female reproductive system that help sperm travel more effectively. Prostate gland: surrounds the urethra and produces an alkaline fluid which is added to the seminal fluid. This raises the pH of the vagina to a more optimal pH for sperm survival. Typical size of prostate gland is about that of a kiwi fruit Cowper’s or bulbourethral glands secrete mucus into the urethra during sexual arousal. This provides lubrication for intercourse and washes away traces of acidic urine before the sperm arrive. Reproductive-BIO 102 HANDOUT

Meiosis: Purpose: produces sperm and eggs with half the number of chromosomes (23) of somatic cells. (Cells with ½ the chromosomes are called haploid cells.) Sperm formation and maturation takes about 9-10 weeks. Sertoli cells surround and nourish the growing sperm cells. Egg maturation and release takes about 14 days and occurs once per month Reproductive-BIO 102 HANDOUT

Cell division terminology: Gamete: sperm or egg produced by meiosis Diploid: describes the “normal” number of chromosomes in any cell Haploid: cell which contain 23 chromosomes (1/2 the “normal” amount) Reproductive-BIO 102 HANDOUT

Sperm consist of 3 major parts: a head, midpiece, and a tail. The head contains the nucleus and 1/2 of the chromosome number of the parent. Acrosome covers the head. This is a cap containing enzymes that help the sperm penetrate the egg The midpiece contains mitochondria and ATP. These produce the energy to power the tail. The tail propels the sperm. Reproductive-BIO 102 HANDOUT

Regulation of Male Reproductive Activity
Hormones: Testosterone: Source: Leydig cells in seminiferous tubules Function: controls growth and function of male reproductive tissues, stimulates aggression and sexual behavior, and secondary sexual characteristics Within testes, testosterone determines the rate of sperm formation GnRH: Gonadotropin-releasing hormone from the hypothalamus; stimulates the anterior pituitary gland to release LH and FSH LH: stimulates production of testosterone FSH: may enhance sperm formation by stimulating Sertoli cells Reproductive-BIO 102 HANDOUT

The Female Reproductive System
Anatomy: The external female genitalia or vulva: the Mons Pubis, a fatty, rounded tissue area, covers the pubic symphysis. It becomes covered with hair during puberty. The Labia Majora are 2 elongated, pigmented, hair covered, fat padded skin folds which surround and enclose the Labia Minora. Reproductive-BIO 102 HANDOUT

The Labia Minora are 2 smaller, highly vascular, hair free folds. The Clitoris is a small organ partly enclosed by the labia minora. It is composed of erectile tissue and is highly sensitive. The Urethral opening lies between the clitoris and the vaginal opening. Reproductive-BIO 102 HANDOUT

Internal female reproductive organs Ovaries are the primary reproductive organs. They lie near the ends of the fallopian tubes (also called oviducts) in the upper pelvic cavity. They are held in place by several ligaments. Ovaries differentiate from tissues which will become the abdominal wall early in fetal development. The ovaries produce eggs called oocytes at regular intervals during the reproductive years. Eggs have 1/2 the number of chromosomes as the parent. Reproductive-BIO 102 HANDOUT

They also produce the hormones estrogen and progesterone The distal ends of the fallopian tubes are funnel shaped and have fingerlike projections called fimbriae. These create waves or currents which sweep the egg from the ovary into the pelvic cavity into the fallopian tube. They do not touch the ovary itself. The egg is propelled toward the uterus by the cilia on the walls of the fallopian tubes. If fertilization by a sperm occurs, it usually takes place in the distal third of the fallopian tube. Eggs take about 3-4 to 7-10 days to reach the uterus. Reproductive-BIO 102 HANDOUT

The uterus is a hollow, pear shaped, muscular organ which is located between the bladder and the rectum. It will “incubate” the fertilized egg. Its narrow, lower end is called the cervix. The middle part of the uterus is called the body and the upper part is called the fundus. Reproductive-BIO 102 HANDOUT

Uterine layers Endometrium: inner layer; lining of epithelial tissue, glands, connective tissue and blood vessels This is the layer that sloughs off during menstrual flow. A fertilized egg will implant into this layer. After implantation, the endometrium helps form the placenta which provides nourishment, waste removal, and gas exchange to the fetus. Reproductive-BIO 102 HANDOUT

Myometrium: middle, smooth muscle layer, expands during pregnancy, constricts during labor Perimetrium: Outermost layer Cervix: narrow opening in lower part of uterus that permits sperm to enter uterus and allows fetus to exit during birth joins vagina, a muscular tube that extends from cervix to exterior serves as birth canal and female organ for intercourse. Vestibular glands secrete lubricating mucus permits passage of menstrual blood to outside Reproductive-BIO 102 HANDOUT

The Breasts are considered to be part of the reproductive organs are really modified sweat glands which produce milk to nourish newborn infants. milk production (lactation) is stimulated by estrogen and progesterone only when birth has actually occurred. the nipple is at the center of each breast. It contains smooth muscles that can contract and cause the nipple to become erect. Reproductive-BIO 102 HANDOUT

Surrounding the nipple is the pigmented areola. Internally, the breasts contain mammary glands that produce milk. The glands consist of many milk producing lobules. Contractile cells around each lobule allow the milk to be released and ducts deliver the milk to the nipple. Most of the breast consists of adipose tissue so breast size doesn’t indicate the potential for milk production. Reproductive-BIO 102 HANDOUT

Menstrual Cycle Each month the ovaries and uterus go through a pattern of changes called the menstrual cycle. Typically lasts 28 days; is controlled by hormones Menstrual cycles begin at puberty and end at menopause A complete menstrual cycle consists of 2 linked cycles (they both must occur): an ovarian and a uterine cycle Ovarian cycle (condensed): oocytes mature and are released Immature follicle develops; GnRH, FSH and LH increase Reproductive-BIO 102 HANDOUT

Estrogen and progesterone secreted Follicle matures; now called Graafian follicle Increasing estrogen causes surge of LH so that ovulation occurs—the egg is released (typically at the middle of the cycle) and swept toward the fallopian tube A corpus luteum forms from the ruptured follicle site and secretes large amounts of estrogen and progesterone to prepare the endometrium for the possible pregnancy If no pregnancy occurs, estrogen and progesterone levels decline and another menstrual cycle begins. Reproductive-BIO 102 HANDOUT

If the egg is fertilized, it moves down the fallopian tube and implants in the uterine endometrium The developing embryo secretes its own hormones to enable the corpus luteum to continue to secrete estrogen and progesterone until the placenta develops. The placenta will take over the job of secreting progesterone and estrogen as well as become a nutrient/waste filter between the maternal and fetal circulation. Reproductive-BIO 102 HANDOUT

Uterine cycle: prepares uterus for pregnancy Menstrual phase: With no pregnancy, days 1–5, estrogen and progesterone decrease, endometrial lining degenerates, menstruation occurs Proliferative phase: days 6–14, estrogen and progesterone increase, endometrial lining begins to proliferate Ovulation: day 14 Secretory phase: corpus luteum produces progesterone and estrogen, endometrium continues to proliferate, uterine glands mature and produce glycogen as a potential energy source for an embryo Reproductive-BIO 102 HANDOUT

Maintenance of Menstrual Cycle
Cycles of hormones of pituitary and reproductive structures: Positive feedback: In proliferative phase, increasing estrogen causes surge in LH Negative feedback: In secretory phase, steady levels of estrogen and progesterone inhibit LH and FSH release Reproductive-BIO 102 HANDOUT

Polycystic ovary syndrome (PCOS)
common hormonal disorder among women of reproductive age. The name of the condition comes from the appearance of the enlarged ovaries containing numerous small cysts in most, but not all, women with the disorder Ovaries produce excessive amounts of male androgens Signs and symptoms vary: Menstrual abnormality. Excess androgen. Elevated levels of male hormones (androgens) may result in excess facial and body hair (hirsutism), adult acne or severe adolescent acne, and male-pattern baldness Polycystic ovaries. Enlarged ovaries containing numerous small cysts Reproductive-BIO 102 HANDOUT

Causes Exact cause unknown; these factors thought to play a role: Excess insulin. Low-grade inflammation. Heredity. If your mother or sister has PCOS, you might have a greater chance of having it, too. Abnormal fetal development. excessive exposure to male hormones (androgens) in fetal life may prevent genes from working the way they're supposed to. No specific test to definitively diagnose; diagnosis is made by exclusion, rule out other possible disorders. Reproductive-BIO 102 HANDOUT

Treatment: treatment focuses on management of individual concerns, such as infertility, hirsutism, acne or obesity. Regulate the menstrual cyclelow-dose birth control pills that contain a combination of synthetic estrogen and progesterone. an oral medication for type 2 diabetes that lowers insulin levels. This drug improves ovulation and leads to regular menstrual cycles. also slows the progression to type 2 diabetes if you already have prediabetes and aids in weight loss if you also follow a diet and an exercise program. Reproductive-BIO 102 HANDOUT

Help you ovulate. If trying to become pregnant, you may need medication to help you ovulate. Reduce excessive hair growth: birth control pills to decrease androgen production or medication that blocks the effects of androgens on the skin. Surgery If medications don't help you become pregnant, an outpatient surgery called laparoscopic ovarian drilling is an option for some women with PCOS. part of the ovaries are destroyed to try to restore regular ovulation cycles Reproductive-BIO 102 HANDOUT

Infertility: Inability to Conceive
Many causes of infertility: Number and quality of sperm, pelvic inflammatory disease (PID), endometriosis Enhancing fertility: Options: artificial insemination, in vitro fertilization, GIFT (Gamete intrafallopian transfer- no in vitro procedures used; harvested eggs are mixed with sperm are transferred into the fallopian tube to hopefully fertilize an egg and implant in the uterus) and ZIFT (Zygote intrafallopian transfer—oocytes fertilized in vitro are immediately transferred to the fallopian tube with the hopes the zygote will implant), fertility-enhancing drugs, surrogate mothers Reproductive-BIO 102 HANDOUT

Sexually Transmitted Diseases (STDs): Worldwide Problem
Bacterial: gonorrhea, syphilis, chlamydia Viral: HIV, hepatitis B, genital herpes, genital warts Other: yeasts (Candida), protozoan (Trichomonas), arthropod (pubic lice) Prevention: Strategies: choose partner wisely, communicate, use suitable barriers, get tested and treated Reproductive-BIO 102 HANDOUT

Syphillis Most people don’t notice early symptoms. Without treatment, it can lead to paralysis, blindness and death. Can be cured with antibiotics Signs: First sign is usually a firm, round, painless sore on the genitals or anus. The disease spreads through direct contact with the sore. Later, may see a rash on the soles, palms, or other parts of the body as well as swollen glands, fever, hair loss or fatigue. In late stages, symptoms come from damage to organs such as the heart, brain, liver, nerves and eyes. Reproductive-BIO 102 HANDOUT

Gonorrhea spreads easily and can lead to infertility. Antibiotics stop the infection Symptoms: burning during urination and discharge. In men, may see penile discharge, swollen testicles In women: vaginal discharge, pelvic pain, spotting. Symptoms may be confused with a urinary tract or vaginal infection Late in the infection, may see skin rashes or spread of the bacteria to the joints and blood. Reproductive-BIO 102 HANDOUT

Reproductive System rev 12-12

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