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Reproduction and Development Chapter 27. Multiple Births Becoming more common Increased use of fertility drugs High order multiple births are risky –Increased.

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Presentation on theme: "Reproduction and Development Chapter 27. Multiple Births Becoming more common Increased use of fertility drugs High order multiple births are risky –Increased."— Presentation transcript:

1 Reproduction and Development Chapter 27

2 Multiple Births Becoming more common Increased use of fertility drugs High order multiple births are risky –Increased risk of miscarriage –Premature delivery –Low birth weights

3 p.461b

4 Impacts, Issues Video Mind-boggling births

5 Methods of Reproduction Sexual reproduction –Meiosis, gamete formation, and fertilization –Offspring show genetic variation Asexual reproduction –Single parent produces offspring –Offspring are genetically identical

6 Asexual Reproduction

7 Cost of Sexual Reproduction Specialized cells and structures must be formed Special courtship and parental behaviors can be costly Nurturing developing offspring, either in egg or body, requires resources (usually from mother)

8 Where embryos develop Early Development

9 Male Reproductive System vas deferens epididymis testis penis seminal vesicle prostate gland bulbourethral gland urethra bladder scrotum

10 A Sperm’s Journey Testes –Produces immature sperm Epididymis –Matures and stores sperm Vas deferens Ejaculatory ducts Urethra

11 Route sperm travel Sperm Travel Route

12 PROSTATE GLAND EJECULATORY DUCT URETHRA SEMINAL VESICLE BULBOURETHRAL GLAND VAS DEFERENS EPIDIDYMIS PENIS TESTIS urethra erectile tissue urinary bladder anus anterior posterior Fig. 27-7, p.467 Male Components and Accessory Glands

13 Male reproductive system Male Reproductive System

14 Glandular Secretions Secretions from epididymis aid sperm maturation Seminal vesicles secrete fructose and prostaglandins Prostate-gland secretions buffer pH in acidic vagina Bulbourethral gland secretes mucus

15 vas deferens epididymis testis penis seminal vesicle prostate gland bulbourethral gland urethra seminiferous tubule Fig. 27-9a, p.468 Sperm Production

16 Sertoli cell spermato- gonium (diploid) primary spermatocyte MITOSISMEIOSIS IMEIOSIS II immature sperm (haploid) late spermatid secondary spermatocyte early spermatids lumen Fig. 27-9b, p.468 Sperm Production

17 Spermatogenesis Spermatogensis

18 A Mature Sperm Spermatids mature to become sperm –Head –Midpiece –Tail Glandular products + sperm = semen

19 Hormonal Control Testosterone –Produced by Leydig cells in testes –Controlled by luteinizing hormone (LH) Follicle-stimulating hormone (FSH) –Starts sperm production LH and FSH –produced by pituitary, controlled by hypothalamus

20 Female Reproductive Organs vagina uterus oviduct ovary vagina clitoris oviduct ovary uterus

21 Female reproductive system Female Reproductive Organs

22 The Uterus Myometrium –Thick layer of smooth muscle in walls Endometrium –Uterine lining Cervix –Connects uterus and vagina

23 Menstrual Cycle The fertile period for a human female occurs on a cyclic basis Menstrual cycle lasts about 28 days on average

24 Menstrual Cycle Follicular phase –Menstruation –Uterine lining regenerates –Oocyte matures Ovulation –Oocyte released from ovary Luteal phase –Hormones thicken endometrium

25 The Ovarian Cycle Girl is born with primary oocytes already in ovaries Oocytes are suspended in meiosis 1 Meiosis resumes, one oocyte at a time, with the first menstrual cycle

26 Ovarian function Ovarian Cycle

27 Ovulation

28 Female Hormonal Control Hypothalamus Anterior pituitary GnRH LHFSH Ovary Estrogen Progesterone, estrogens follicle growth, oocyte maturation Rising estrogen stimulates surge in LH Corpus luteum forms

29 Cycle Overview hypothalamus anterior pituitary FSHLH FSHLH estrogens FOLLICULAR PHASELUTEAL PHASE menstruation ovulation GnRH FSHLH estrogens progesterone GnRH secretion affects LH and FSH secretion by pituitary LH and FSH affect follicle maturation Estrogens and progesterone from ovary affect uterus

30 Menstrual cycle summary Cycle Overview

31 Follicular Phase Female Hormones

32 Ovulation and luteal phase Female Hormones

33 Fertilization Sperm penetrates egg cytoplasm Secondary oocyte undergoes meiosis II, forms mature egg Egg nucleus and sperm nucleus fuse to form diploid zygote

34 zona pellucida follicle cell egg nucleus Ovulation oviduct ovary uterus opening of cervix vagina Fig , p.472 Fertilization

35 Fertilization Fertilization

36 Birth Control Options Prevent fertilization Prevent ovulation Block implantation

37 Contraception Effectiveness

38 Medical Manipulations In vitro fertilization (IVF) –Hormone injections –Removal and fertilization of eggs –Reinsertion of dividing cells Abortion –Spontaneous –Induced

39 Sexually Transmitted Diseases Human papillomavirus infection (HPV) Trichomoniasis Chlamydia Genital herpes Gonorrhea Syphilis AIDS

40 Sexually Transmitted Diseases

41 Bacterial STDs Can be cured with antibiotics –Syphilis –Gonorrhea –Chlamydia Pelvic Inflammatory Disease (PID) –Scarring –Tubal pregnancy –Infertility

42 Viral STDs Cannot be cured HIV/AIDS Genital herpes Genital warts –Human papillomaviruses (HPV) –Can cause cancers

43 Table 27-1, p.475

44 Pregnancy Averages 38 weeks from fertilization Takes 2 weeks for blastocyst to form Weeks 3 to 8: embryonic period Weeks 9 to birth: fetal period

45 endometrium implantation fertilization endometrium uterine cavity blastocoel inner cell mass DAYS 1-2 DAY 3 DAY 4DAY 5DAYS 6-7 Fig a, p.476 trophoblast (surface layer of cells of the blastoyst)

46 Implantation First two weeks of development

47 Human Chorionic Gonadotropin (HCG) Hormone secreted by blastocyst Prevents degeneration of corpus luteum –maintains endometrium –prevents menstruation Can be detected by week 3 with a home pregnancy test

48 The Placenta Interlocking fetal and maternal tissues Nutrients and wastes exchanged across membrane separating bloodstreams

49 4 weeks 8 weeks 12 weeks Fig a, p.478

50 Embryonic Period Weeks 3 to 8 By week 8 –Embryo appears human week 4 length 4mm week 8 length 2 cm

51 Fig a,b, p.480

52 Fetal Period Weeks 9 to birth 22 weeks: fetus cannot survive birth 28 weeks: lungs still developing 36 weeks: survival is 95 percent 38 weeks: full term birth

53 Fetal Period Fetal development

54 Prenatal Care Nutrition – must be provided from maternal diet through placenta Infection – mother’s viruses can affect fetus Drugs and alcohol – harm developing fetus Children of smokers – at risk for heart defects and death

55 Fetal Alcohol Syndrome

56 Birth (Labor) Cervical canal dilates Amniotic sac ruptures Uterine contractions drive fetus from uterus Placenta is expelled as afterbirth

57 Birth Birth

58 Lactation During pregnancy, progesterone and estrogen stimulate gland development After birth, prolactin induces synthesis of enzymes for milk production Oxytocin triggers contractions that expel milk

59 Stages of Human Development: Prenatal Zygote: single cell Morula: solid ball of cells Blastocyst: ball with fluid-filled cavity Embryo: 2 weeks to 8 weeks Fetus: 9 weeks to birth

60 Stages of Human Development: Postnatal Newborn: birth to 2 weeks Infant: 2 weeks to 15 months Child: infancy to 10 or 12 years Pubescent: during puberty Adolescent: puberty to maturation Adult Old age


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