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CHAPTER 36: ANIMAL REPRODUCTION Diploid 46 Haploid 23 Gametos o gonads: 23+23= 46 Gonads: organ where reproductive cells are formed (in males: testes) (in females: ovaries) Hormones: GnRH: gonadotropin releasing hormone- hypothalamus: puberty. Stimulates to LH (stimulates anterior pituitary to produce LH and FSH) LH: leuteinizing hormone: stimulates interstitial cells to produce testosterone FSH: follicle stimulating hormone: stimulates Sertoli cells and spermatogonia to begin spermatogenesis. Secondary sexual characteristics that develop during puberty: Hypothalamus: GnRH: stimulates pituitary: LH y FSH: production of gametes (sperm or egg): production of hormones (testosterone and estrogen) MEN WOMEN Penis and testes enlarge Pubic, underarm and facial hair appears Larynx enlarges (deepening voice) Muscular development increases Enlarged breasts Pubic and underarm hair Begin menstruating COPULATION Blood pressure increases: erection Blood flow to vagina, labia and clitoris Movements stimulate touch receptors on the penis, Female orgasm (possible) stimulation of penis. triggering ejaculation Contraction of vagina Male orgasm: causes ejaculation and feelings of pleasure Increase cardiac frequency CREATION OF SEXUAL CELLS Spermatogenesis: spermatogonia: meiosis: primary Oogenesis: oogonia: primary oocyte stops at prophase I spermatocyte: secondary spermatocyte: 4 spermatids (3rd moth of fetus): meiosis (puberty): secondary oocyte and 3 polar body The human male reproductive tract Testis (male gonad): produces sperm and testosterone • Seminiferous tubules (inside): produce sperm • Interstitial cells: produce testosterone • Spermatogonia: diploid cell from which sperm arise: • Sertoli cells: regulate spermatogenesis and nourish developing sperm Epididymis and vas deferens (ducts): • store sperm; conduct sperm from testes to penis Urethra (duct): • conducts semen from vas deferens and urine from urinary bladder to the tip of the penis Penis: •deposits sperm in female reproducti ve tract Seminal vesicles (glands) •secrete fluid into semen Prostate gland: Bulboureth ral glands: • secretes fluids into semen •secrete fluid into semen Accessory Structures Scrotum: sac that contains the testes: maintains temperature of spermatozoids Spermatogenesis: process by which sperm cells form spermatogonium experience a series of developmental events that leads to the production of haploid sperm Spermatozoa: mature sperm o Head: haploid nucleus Acrosome: contains enzymes that dissolve protective layers around the egg enabling its entrance o Midpiece: mitochondria/energy o Tail: flagellum: movement Sperm production regulated by negative feedback: sertoli cells secrete hormone: inhibin: inhibits GnRH, LH and FSH production Semen: sperm mixed with fluid secretions from seminal vesicle, prostate gland, bulbourethral glands: o FUNCTIONS: Transport spermatozoids provides energy that powers swimming neutralizes vagina´s pH Ejaculation: muscles encircling the epididymis, vas deferens and urethra contract forcing semen out of the penis and into vagina Developmental options: mitosis-spermatogenesis The female reproductive tract Ovary (gonad): •produces eggs, estrogen and progesterone Fibria Uterine tube: Uterus: Cervix: Vagina: •(opening of uterine tube): bears cilia that sweep egg into oviduct •conducts egg to uterus; site of fertilization •muscular chamber where fetus develops •closes off lower end of uterus. Ring of connective tissue that holds developing baby in uterus •receptacle for semen; birth canal Semen: pH básico Vagina: pH ácido Polar body: discarded set of chromosomes Zygote: fertilized egg Clitoris: derived from the same embryological tissue as the tip of the penis, becomes engorged with blood (in front of the vagina) Corpus luteum: formed by follicle cells that enlarge and become glandular. It secretes estrogen and progesterone. No fertilization = breaks down Endometrium: inner lining of the uterus that is richly supplied with blood vessels Placenta: transfers oxygen, carbon dioxide, nutrients and wastes between fetus and mother Menstruation: flow of tissue and blood that results from the breakdown of endometrial blood vessels FERTILIZATION sperm and egg nuclei unite (haploid nuclei of sperm and egg fuse: diploid nucleus) Corona radiate (follicle cells) and zona pellucida (inner jellylike layer) form a barrier between the sperm and the egg Sperm enters, triggers 2 changes: o Release chemicals into the zona pellucida reinforcing it and preventing further sperm from entering o Egg undergoes its second meiotic division Contraceptives Prevent ovulation: suppress LH, continuous supply of estrogen and progesterone. •Birth control pill: synthetic hormones. Daily •Contraceptive patch: synthetic hormones. weekly •Injections: synthetic hormones 3 months •Nuva Ring: around cervix. Impregnated estrogen and progesterone. 1 month Barrier methods (preventing sperm and egg from meeting) •Abstinence: 100% efectivo •Condom (male and female) •Today sponge: impregnated with spermicide (in vagina) •Diaphragm/ cervical cap: cérvix. reusable •Rhytm: measure body temperature. Estimate time of ovulation. •Spermicide: kill spermatozoids Gongorrhea Syphilis Chlamydia Bacteria Neisseria gonorrcheae Bacteria: Treponema pallidum Bacteria Clamydia trachomatis HIV virus Males: inflammation of the urethra, discharge of pus from the penis Begins with sore at the site of infection Inflammation of the urethra (m), urethra and cervix (f) Acquired immune deficiency syndrome Can lead to infertility blocking uterine tubes. Spread damaging organs (skin, kidneys, heart, brain) Infect and block uterine tubes: sterility Genital herpes AIDS Herpes 1 and Herpes 2 (virus) Genital warts Human papilloma virus Prevent Implatation •IUD (intrauterine device): plastic device with hormones or copper in uterus through cervix •Morning after pill: 2; abortiva •Sterilization (permanent): interrupt paths •Vasectomy: vas deferens •Tubal ligation: uterine tube Trichomoni asis Trichomonas vaginalis (protist) Crab lice Parasite (arachnid): Pthirus pubic Human papilloma virus Human papilloma virus Genital warts Painful blisters on the genitals and surrounding skin Attacks the immune system, leaving the victim vulnerable to infections (can be fatal) Growths or bumps that appear on the external genitalia, Warts are risk factor for cervical cancer (women) Discharge caused by inflammation in response to the parasite Severe itching, Irritating, spread infectious diseases Sometimes warts in the throat Cervical cancer (and cancer of the vulva, vagina, penis, anus, oropharynx) Copulation: behavior by which the male deposits sperm directly into the reproductive tract of the female Menstrual Cycle Day 1 • Increase of GnRH: release of LH and FSH Day 28 Day 5 • No more estrogen and progesterone = endometrium dies • FSH develops follicles: secrete estrogen. Day 24 Day 7 • No fertilization: corpus luteum dissolves. • MORE ESTROGEN = • Development of follicle and oocyte • Growth of endometrium • More GnRH Day 21 Day 14 • Corpus luteum: estrogen and progesterone: inhibit GnRH: less FSH and LH • Endometrium keeps developing • Ovulation • Remnants of follicle = corpus luteum • LH: • Resumption of meiosis I: formation of secondary oocyte and first polar body