Chapter_19-review_sheet.docx

Chapter 19 The Reproductive Systems: Maintaining the Species The main purpose of the reproductive system is to produce gametes (egg and sperm) and unite them to form a new individual Gametes are produced through the process of meiosis Meiosis is a type of cell division that ensures the gametes will...

Chapter 19 The Reproductive Systems: Maintaining the Species The main purpose of the reproductive system is to produce gametes (egg and sperm) and unite them to form a new individual Gametes are produced through the process of meiosis Meiosis is a type of cell division that ensures the gametes will contain the haploid chromosome number A haploid gamete means that it contains half the number of chromosomes of normal body cells when two haploid gametes (sperm and egg) unite to form a zygote containing the original diploid number The diploid number (46) is the normal and total number of chromosomes Forming gametes is only one function of the reproductive system Other functions include Triggering puberty Maintaining reproductive ability Stimulating secondary sex characteristics Producing hormones involved in sexual maturation and general homeostasis Both male and female reproductive systems are composed of Gonads – organs that produce gametes (testis in male, ovary in female) Ducts – transport gametes and fertilized egg Accessory glands – secrete hormones and other fluids that facilitate gamete production and survival Supporting structures – help deliver and support gametes Spermatogenesis In the male Meiosis is the process that forms four haploid sperm Males produce about 300 million sperm per day from puberty until death Oogenesis In the female Meiosis is the process that forms one haploid egg and up to 3 haploid polar bodies The haploid egg has the potential to be fertilized by one sperm The polar bodies are not viable and are quickly degraded Females are born with all the eggs they will ever have There are 3 main functions of the male reproductive system Produce sperm Store sperm Deliver the sperm to the female reproductive system The male reproductive system is essentially one long tube Sperm is produced at one end - in the testes Sperm moves along the length of the tube - it matures along the route Sperm is released at the end of the tube - as it leaves the body Accessory glands Add secretions to nourish, carry, and protect the sperm before it is released from the male’s body What is the scrotum? What does sperm survival require? Sac of loose skin and smooth muscle that surrounds the testes Sperm survival requires 3 degrees lower temperature than body temperature What are the testes divided into? Where are sperm cells fomed? Divided into compartments called lobules Each lobule contains 2 or 3 seminiferous tubules where sperm cells are formed Define the following terms: spermatogenesis, spermatogonia, sertoli cells and interstitial cells. Spermatogenesis – formation of sperm cells from spermatogonia Spermatogonia – stem cells inside the seminiferous tubule Sertoli cells – support developing sperm cells Interstitial cells – Leydig, produce testosterone Describe the epididymis. Comma shaped organ Site of sperm maturation, spermiogenesis Stores sperm for 1-2 months Define vas deferens Transports sperm from the epididymis to the ejaculatory duct What are seminal vesicles? Pair of pouch-like organs Secretes clear alkaline fluid that contains fructose to nourish the sperm Where is the prostate gland located? What does it secrete? Chestnut size gland found below the bladder Enlarges with age Secretes milky, acidic fluid that increases sperm motility Define bulbourethral glands. Cowper’s Gland Paired, pea-sized glands Secretes alkaline fluid which clears urethra prior to ejaculation, neutralizes acid What is semen? Mixture of sperm and seminal fluid Slightly alkaline, milky appearance, sticky The head of sperm contains nucleus and acrosome. What does the midpiece and tail contain? Head – contains nucleus and acrosome Acrosome – cap, contains enzymes which digest the surface of the egg Nucleus – contains 23 chromosomes Midpiece – contains mitochondria to form ATP Tail – contains flagellum for locomotion Describe and explain the tissues that make up the penis. Copulatory organ in the male Passageway for urine and semen The body of the penis is composed of erectile tissue masses filled with blood sinuses Corpora cavernosa – erectile tissue that contains blood sinuses Corpora spongiosum – tissue that surrounds the urethra and forms the glans penis Glans penis – enlarged distal end of the penis Prepuce – foreskin Gonadotropin-releasing hormone (GnRH) Released by the hypothalamus Triggers the anterior pituitary gland to release LH and FSH Luteinizing hormone (LH) Causes Leydig cells (interstitial cells) to produce and release testosterone These cells reside between the seminiferous tubules LH is also called interstitial cell stimulating hormone (ICSH) Follicle-stimulating hormone (FSH) Stimulates Sertoli cells to secrete androgen-binding protein (ABP) ABP binds to testosterone to keep it near the seminiferous tubules Testosterone then stimulates spermatogenesis As sperm count rises, Sertoli cells produce inhibin, which stops FSH production As inhibin levels drop, FSH production resumes The main functions of the female reproductive system are to Receive sperm Produce and maintain egg cells (oocytes) = gametes Transport oocytes to the site of fertilization Provide nutrition and safe environment for fetal development Give birth – expel offspring to outside Produce female sex hormones Primary female sex organs - gonads – two ovaries Produce eggs (gametes) through a process called oogenesis Produce the hormones estrogen and progesterone Accessory sex organs – internal and external Uterine tubes, uterus, vagina, labia majora and minora, clitoris, vestibule Label the diagram below: Name the organs within the female reproductive system. Ovaries – produce oocytes (eggs), and hormones Uterine tubes – transport fertilized ova, fallopian tubes Uterus – site of fetal development occurs Vagina and external genitalia – constitute the vulva Mammary glands – produce milk Label the diagram below: Ovary – almond sized organs found in upper pelvic region Which hormones are made by the ovary? FSH stimulates the development of the follicle within the ovary A mature follicle is called a Graafian follicle and contains an oocyte Name and describe the stages of follicular development. Primary follicle – contain primary oocyte Secondary follicle – follicle start filling up with fluid Graafian follicle – mature follicle Ovulation – follicle ruptures and release and releases oocyte What comes first, Corpus albicans or Corpus luteum? Describe each process. Corpus luteum – follicle after ovulation, this comes first Fills in with hormone secreting cells Corpus albicans – white scar left after corpus luteum Describe the preovulatory phase. Lasts from day 6 to 13 In the ovary (follicular phase) Developing follicle releases estrogen By day 14, a follicle has matured called Graafian follicle High estrogen levels trigger the secretion of LH In the uterus (proliferation phase) Increasing estrogen levels have repaired and thickened the endometrium Define graafian follicle and estrogen. Mature follicle Female reproductive hormone Give the stages of ovulation. High blood levels of estrogen cause the release of LH LH causes the follicle to rupture and release the oocyte Differentiate between the postovulatory phase when there is fertilization and no fertilization. In the ovary, and in the uterus. Label the diagram below: Define fallopian tube and fimbriae and give their functions. Oviduct – narrow tube that extends from ovary to uterus Site of fertilization Cilia and peristalsis move Ova along Ova reaches uterus after 7 days Fimbrae – moving fingerlike processes that sweep over the ovary Name the parts of the uterus and define each one. Fundus – dome shaped top of the uterus Body – middle portion Cervix – neck of the uterus that opens into the vagina Uterus is the site of fetal development Name the three layers of the uterine wall and what they consist of. Perimetrium – outer layer, made of connective tissue Myometrium – middle layer, made of visceral, smooth muscle Endometrium – inner layer, made of epithelial tissue What is a hysterectomy? Why would someone opt to have this procedure? Surgical removal of the uterus Reasons for surgery Endometriosis, ovarian cysts, excessive bleeding, cancer of cervix, uterus or ovaries Define vagina. Copulatory organ in the female 4 inch muscular tube Serves as the birth canal and site of menstrual flow Vulva – external female reproductive structures and vaginal opening Mons pubis – fatty pad over the pubic bone Labia Majora – outer skin fold Labia Minora – inner skin fold Clitoris – small mass of erectile tissue What are mammary glands and where are they located? Modified sweat glands that produce milk Located in the breasts Name three types of birth control. The only absolute method of birth control is abstinence If no sperm enters the female, pregnancy is impossible Other birth control methods Rely on surgery, hormones, IUDs, spermicides, barriers, or behavior modification Sterilization – cutting and sealing gamete transport tubes to permanently prevent fertilization Vasectomy – vas deferens are cut Tubal ligation – Oviducts are cut Hormonal birth control Hormonal methods are temporary Oral contraceptive (BC Pill) and the topical BC Patch A combination of synthetic estrogens and progestins that alters the natural hormonal rhythms of the female By keeping the estrogen and progestin levels high Inhibit the secretions of FSH and LH from the anterior pituitary gland Without FSH, the follicles in the ovaries do not mature, and no eggs are ready to ovulate – cut out the hormone entirely Intrauterine devices – prevent the union of sperm and egg, and/or implantation Barrier methods – prevent fertilization Diaphragm Cervical cap Contraceptive sponge Male and female condoms Spermicidal preparations – kill sperm and therefore prevent fertilization Each form of birth control has advantages and disadvantages What is fertility awareness? The avoidance of intercourse when fertilization is likely to occur What is the morning-after pill? High doses of hormones taken after unprotected intercourse