Chapter 41 ~ Animal Reproduction

Overview Asexual (one parent) fission (parent separation) budding (corals) gemmules (porifera) fragmentation & regeneration (annelids) Sexual (fusion of haploid gametes) gametes (sex cells) zygote (fertilized egg) ovum (unfertilized egg) spermatozoon (male gamete)

Sequential hermaphroditism reversal of gender during lifetime Reproductive cycles Parthenogenesis unfertilized egg development; haploid, sterile adults (honeybees) Hermaphroditism both male & female reproductive systems; sessile & burrowing organisms (earthworms) Sequential hermaphroditism reversal of gender during lifetime protogynous (female 1st) protandrous (male 1st)

Mechanisms of sexual reproduction Fertilization-union of sperm and egg • external • internal Pheromones-chemical signals that influence the behavior of others (mate attractants)

Mammalian reproduction, I The Human Male Testes~ male gonads Seminiferous tubules~ sperm formation Leydig cells~ hormone production Scrotum~ outside body temp. (~2 degrees lower) Epididymis~ sperm development Vas deferens~ sperm propulsion Seminal vesicles~ semen Prostate gland~ anticoagulant; nutrients Bulbourethral glands~ acid neutralizer Penis/urethra~ semen delivery One ejaculation 2-5mL and 1 mL contains 50-130 million sperm These 3 secretions with sperm make the semen. 60% of semen is mucous and fructose

Male Reproductive Structures The penis is composed of 3 cylinders of spongy erectile tissue derived from veins and capillaries. Sexual arousal – erectile tissue fills with blood and there is as an increase pressure which seals the veins and the penis becomes engorged D:\ImageLibrary40-55\46-AnimalReproduction\46-08a-MaleReproductive.mov D:\ImageLibrary40-55\46-AnimalReproduction\46-08b-MaleHormones.mov

Biology, 9th ed, Sylvia Mader Animation Chapter 43 Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Reproductive Systems

Male Reproductive System Biology, 9th ed, Sylvia Mader Chapter 43 Male Reproductive System Reproductive Systems

Mammalian reproduction, II The Human Female Ovaries~ female gonads Follicle~ egg capsule Corpus luteum~ hormone secretion Oviduct~ fertilization Uterus/endometrium~ womb/lining Cervix/vagina~ sperm receptacle

Female Reproductive Structures D:\ImageLibrary40-55\46-AnimalReproduction\46-15a-FemaleReproductive.mov

Ovulation D:\ImageLibrary40-55\46-AnimalReproduction\46-15b-Ovulation.mov

Post-ovulation D:\ImageLibrary40-55\46-AnimalReproduction\46-15c-PostOvulation.mov

Biology, 9th ed, Sylvia Mader Animation Chapter 43 Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. Reproductive Systems

Know the 3 major differences between Spermatogenesis and Oogenesis Spermatogenesis is the making of sperm and it starts in the seminiferous tubules. 4 viable sperm will be made. Oogenesis is the making of an egg and it starts in the ovary. Only 1 viable egg will be made. Between birth & puberty; prophase I of meiosis Puberty; FSH; completes meiosis I Meiosis II; stimulated by fertilization Know the 3 major differences between Spermatogenesis and Oogenesis Cytokinesis unequal Sperm cells consistently produce sperm, females born with all Oogenesis has long periods of wait

The female pattern Estrous cycles/estrus (many mammals) Menstrual cycle (humans and many other primates): Menstrual Flow Phase- Proliferative Phase – endometrium begins to regenerate Secretory Phase – endometrium continues to thicken. If no fertilization occurs shedding of lining and cycle begins again Ovarian Cycle- follicular phase~follicle growth ovulation~ oocyte release luteal phase~ hormone release

Figure 46.15 The reproductive cycle of the human female

Hormones Hormonal coordination of the menstrual and ovarian cycles involves five hormones. Gonadotropin releasing hormone (GnRH) secreted by the hypothalamus. Follicle-stimulating hormone (FSH) secreted by the anterior pituitary. Luteinizing hormone (LH) secreted by the anterior pituitary. Estrogens secreted by the ovaries and stimulates ovulation. Progesterone secreted by the ovaries.

1st and 2nd Trimester Gestation~ pregnancy 1st Fertilization occurs in oviduct and 24 hours later starts dividing, organogenesis 5 days later blastocyst implants in endometrium Embryo until 8th week and then called fetus Embryo secretes hormones to signal presence HCG hormone (menstruation override; pregnancy test detection) 2nd Hormone levels subside and placenta starts to secrete progesterone which maintains through pregnancy

3rd Trimester and Labor 3rd Labor (uterine contractions) Birth brought on by many hormones. Thought is now that the baby initiates labor by secreting oxytocin. Labor (uterine contractions) 1st – Thinning of cervix and opening 2nd – Pushing and delivery of baby 3rd – Delivery of placenta Parturition~birth Lactation~prolactin & oxytocin

41.4 Control of Human Reproduction Biology, 9th ed, Sylvia Mader Chapter 43 41.4 Control of Human Reproduction Traditional Birth Control Methods The most reliable method of birth control is abstinence Not engaging in sexual intercourse Traditional birth control regimens either prevent fertilization or stop a fertilized egg from implanting Male and female condoms Contraceptive vaccines Morning‑After Pills Reproductive Systems

Control of Human Reproduction Biology, 9th ed, Sylvia Mader Chapter 43 Control of Human Reproduction Morning-After Pills Medications that can prevent pregnancy after unprotected intercourse Preven – upsets normal uterine cycle Makes it difficult for the embryo to implant within the endometrium Plan B Ulipristal acetate Reproductive Systems

Control of Human Reproduction Biology, 9th ed, Sylvia Mader Chapter 43 Control of Human Reproduction Morning-After Pills Mifepristone, also known as RU‑486, causes the loss of an implanted embryo It blocks the progesterone receptors of the endometrial cells. Without functioning receptors for progesterone, the uterine lining sloughs off carrying the embryo with it. Taken in conjunction with a prostaglandin to induce uterine contractions, it is 95% effective. Reproductive Systems

Various Birth Control Methods Biology, 9th ed, Sylvia Mader Chapter 43 Various Birth Control Methods Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. Intrauterine device placement Intrauterine devices uterus cervix female condom b. Female condom placement Female condom c. Male condom placement Male condom (a): © Saturn Stills/Photo Researchers, Inc.; (b): © Getty RF; (c): © The McGraw-Hill Companies, Inc. Lars A. Niki, photographer Reproductive Systems

Control of Human Reproduction Biology, 9th ed, Sylvia Mader Chapter 43 Control of Human Reproduction Reproductive Technologies Infertility Inability of a couple to achieve pregnancy after one year of regular, unprotected intercourse May be attributed to the male (40%), the female (40%), or both (20%) Artificial Insemination by Donor (AID) In Vitro Fertilization (IVF) Gamete Intrafallopian Transfer (GIFT) Surrogate Mothers Intracytoplasmic Sperm Injection (ICSI) Reproductive Systems

41.5 Sexually Transmitted Diseases Biology, 9th ed, Sylvia Mader Chapter 43 AIDS Human Immunodeficiency Virus (HIV) Attacks helper T cells Transmitted by sexual contact No cure Genital Warts Human Papillomaviruses (HPVs) No cure, but can be treated effectively 41.5 Sexually Transmitted Diseases Reproductive Systems

Sexually Transmitted Diseases Biology, 9th ed, Sylvia Mader Chapter 43 Genital Herpes Herpes Simplex Virus Type I - Cold sores and fever blisters Type II - Ulcerations on genitals Viral Hepatitis A - Sewage-contaminated drinking water B - Blood transfusions and bodily fluids Sexually Transmitted Diseases Reproductive Systems

Sexually Transmitted Diseases Biology, 9th ed, Sylvia Mader Chapter 43 Sexually Transmitted Diseases Bacterial STDs Chlamydia Chlamydia trachomatis Gonorrhea Neisseria gonorrhoeae Syphilis Treponema pallidum Reproductive Systems

Sexually Transmitted Diseases Biology, 9th ed, Sylvia Mader Chapter 43 Sexually Transmitted Diseases Vaginal Infections Vaginitis – vaginal inflammation Gardnerella vaginalis Candida albicans Reproductive Systems