Reproduction and Development Chapters 46 and 47 Campbell 9th

Major vestibular (Bartholin’s) gland Labia minora Labia majora Figure 46.10 Oviduct Ovary Uterus (Urinary bladder) (Pubic bone) (Rectum) Urethra Cervix Body Vagina Glans Clitoris Prepuce Major vestibular (Bartholin’s) gland Labia minora Labia majora Vaginal opening Oviduct Ovaries Figure 46.10 Reproductive anatomy of the human female. Follicles Corpus luteum Uterus Uterine wall Endometrium Cervix Vagina

(Urinary bladder) Seminal vesicle (Urinary duct) (Rectum) (Pubic bone) Figure 46.11b (Urinary bladder) Seminal vesicle (Urinary duct) (Rectum) (Pubic bone) Vas deferens Erectile tissue Ejaculatory duct Prostate gland Figure 46.11 Reproductive anatomy of the human male. Urethra Penis Bulbourethral gland Vas deferens Glans Epididymis Testis Prepuce Scrotum

Gametogenesis Gametogenesis, the production of gametes, differs in male and female, reflecting the distinct structure and function of their gametes Sperm are small and motile and must pass from male to female Eggs are larger and carry out their function within the female © 2011 Pearson Education, Inc.

Oogenesis, the development of a mature egg, is a prolonged process Spermatogenesis, the development of sperm, is continuous and prolific (millions of sperm are produced per day; each sperm takes about 7 weeks to develop Oogenesis, the development of a mature egg, is a prolonged process Immature eggs form in the female embryo but do not complete their development until years or decades later © 2011 Pearson Education, Inc.

Spermatogenesis differs from oogenesis in three ways All four products of meiosis develop into sperm while only one of the four becomes an egg Spermatogenesis occurs throughout adolescence and adulthood Sperm are produced continuously without the prolonged interruptions in oogenesis © 2011 Pearson Education, Inc.

Figure 46.12 Exploring: Human Gametogenesis Figure 46.12a Epididymis Seminiferous tubule Testis Primordial germ cell in embryo Cross section of seminiferous tubule Mitotic divisions Spermatogonial stem cell 2n Mitotic divisions Sertoli cell nucleus Spermatogonium 2n Mitotic divisions Primary spermatocyte 2n Meiosis I Figure 46.12 Exploring: Human Gametogenesis Secondary spermatocyte n n Meiosis II Lumen of seminiferous tubule Spermatids (two stages) Early spermatid Neck n n n n Tail Midpiece Head Differentiation (Sertoli cells provide nutrients) Plasma membrane Sperm cell n n Acrosome n n Nucleus Mitochondria

Primordial germ cell in embryo Mitotic divisions Figure 46.12ab Primordial germ cell in embryo Mitotic divisions Spermatogonial stem cell 2n Mitotic divisions Spermatogonium 2n Mitotic divisions Primary spermatocyte 2n Meiosis I Secondary spermatocyte n n Meiosis II Figure 46.12 Exploring: Human Gametogenesis Early spermatid n n n n Differentiation (Sertoli cells provide nutrients) Sperm cell n n n n

Figure 46.12 Exploring: Human Gametogenesis Figure 46.12b Primary oocyte within follicle Ovary Growing follicle Primordial germ cell In embryo Mitotic divisions 2n Oogonium Mitotic divisions Primary oocyte (present at birth), arrested in prophase of meiosis I Mature follicle 2n Ruptured follicle Completion of meiosis I and onset of meiosis II First polar body n n Secondary oocyte, arrested at metaphase of meiosis II Ovulated secondary oocyte Figure 46.12 Exploring: Human Gametogenesis Ovulation, sperm entry Completion of meiosis II Second polar body Corpus luteum n Fertilized egg n Degenerating corpus luteum

Primary oocyte (present at birth), arrested in prophase of meiosis I Figure 46.12bb Primordial germ cell In embryo Mitotic divisions 2n Oogonium Mitotic divisions Primary oocyte (present at birth), arrested in prophase of meiosis I 2n Completion of meiosis I and onset of meiosis II First polar body n n Secondary oocyte, arrested at metaphase of meiosis II Ovulation, sperm entry Figure 46.12 Exploring: Human Gametogenesis Completion of meiosis II Second polar body n Fertilized egg n

Hormones of Female Reproduction Stop Here and Do the Handout first

Concept 46.4: The interplay of tropic and sex hormones regulates mammalian reproduction Human reproduction is coordinated by hormones from the hypothalamus, anterior pituitary, and gonads Gonadotropin-releasing hormone (GnRH) is secreted by the hypothalamus and directs the release of FSH and LH from the anterior pituitary FSH and LH regulate processes in the gonads and the production of sex hormones © 2011 Pearson Education, Inc.

Hormonal Control of the Female Reproductive Cycles In females, the secretion of hormones and the reproductive events they regulate are cyclic Prior to ovulation, the endometrium thickens with blood vessels in preparation for embryo implantation If an embryo does not implant in the endometrium, the endometrium is shed in a process called menstruation © 2011 Pearson Education, Inc.

Degenerating corpus luteum Figure 46.13 (a) Control by hypothalamus Inhibited by combination of estradiol and progesterone Hypothalamus  Stimulated by high levels of estradiol 1 GnRH  Anterior pituitary Inhibited by low levels of estradiol  2 FSH LH (b) Pituitary gonadotropins in blood 6 LH FSH 3 FSH and LH stimulate follicle to grow LH surge triggers ovulation (c) Ovarian cycle 7 8 Growing follicle Corpus luteum Degenerating corpus luteum Maturing follicle Follicular phase Ovulation Luteal phase Estradiol secreted by growing follicle in increasing amounts Progesterone and estradiol secreted by corpus luteum 4 (d) Ovarian hormones in blood Peak causes LH surge (see ) 5 6 Figure 46.13 The reproductive cycle of the human female. 10 Estradiol 9 Progesterone Estradiol level very low Progesterone and estra- diol promote thickening of endometrium (e) Uterine (menstrual) cycle Endometrium Menstrual flow phase Proliferative phase Secretory phase Days 5 10 14 15 20 25 28

 Hypothalamus GnRH   Anterior pituitary FSH LH Negative feedback Figure 46.14  Hypothalamus GnRH   Anterior pituitary FSH LH Negative feedback Negative feedback Sertoli cells Leydig cells Figure 46.14 Hormonal control of the testes. Inhibin Spermatogenesis Testosterone Testis

Early Development During its first 2 to 4 weeks, the embryo obtains nutrients directly from the endometrium Meanwhile, the outer layer of the blastocyst, called the trophoblast, mingles with the endometrium and eventually forms the placenta Blood from the embryo travels to the placenta through arteries of the umbilical cord and returns via the umbilical vein © 2011 Pearson Education, Inc.

Maternal portion of placenta Figure 46.16 Maternal arteries Maternal veins Placenta Umbilical cord Maternal portion of placenta Chorionic villus, containing fetal capillaries Fetal portion of placenta (chorion) Maternal blood pool Figure 46.16 Placental circulation. Uterus Fetal arteriole Fetal venule Umbilical arteries Umbilical cord Umbilical vein

from fetus and mother’s posterior pituitary Figure 46.18 Estradiol Oxytocin  from ovaries from fetus and mother’s posterior pituitary Activates oxytocin receptors on uterus Stimulates uterus to contract Positive feedback Stimulates placenta to make  Prostaglandins Figure 46.18 Positive feedback in labor. Stimulate more contractions of uterus

Expulsion: delivery of the infant Figure 46.19 Placenta Umbilical cord Uterus Cervix 1 Dilation of the cervix 2 Expulsion: delivery of the infant Figure 46.19 The three stages of labor. Uterus Placenta (detaching) Umbilical cord 3 Delivery of the placenta

The importance of cell-cell communication. Development The importance of cell-cell communication.

8-cell stage (viewed from the animal pole) Figure 47.7 Zygote 2-cell stage forming Gray crescent 0.25 mm 8-cell stage (viewed from the animal pole) 4-cell stage forming Animal pole 8-cell stage Figure 47.7 Cleavage in a frog embryo. 0.25 mm Blastula (at least 128 cells) Vegetal pole Blastocoel Blastula (cross section)

In pairs write the following terms in order. Gastrula Morula Blastula Zygote

Terminology of Stages of Development ZYGOTE MORULA SOLID BALL EMBRYO BLASTULA (BLASTOCYST IN MAMMALS) GASTRULA

Concept 47.2: Morphogenesis in animals involves specific changes in cell shape, position, and survival After cleavage, the rate of cell division slows and the normal cell cycle is restored Morphogenesis, the process by which cells occupy their appropriate locations, involves Gastrulation, the movement of cells from the blastula surface to the interior of the embryo Organogenesis, the formation of organs © 2011 Pearson Education, Inc.

Gastrulation Gastrulation rearranges the cells of a blastula into a three-layered embryo, called a gastrula © 2011 Pearson Education, Inc.

Each germ layer contributes to specific structures in the adult animal The three layers produced by gastrulation are called embryonic germ layers The ectoderm forms the outer layer The mesoderm partly fills the space between the endoderm and ectoderm The endoderm lines the digestive tract Each germ layer contributes to specific structures in the adult animal © 2011 Pearson Education, Inc.

ECTODERM (outer layer of embryo) Figure 47.8 ECTODERM (outer layer of embryo) • Epidermis of skin and its derivatives (including sweat glands, hair follicles) • Nervous and sensory systems • Pituitary gland, adrenal medulla • Jaws and teeth • Germ cells MESODERM (middle layer of embryo) • Skeletal and muscular systems • Circulatory and lymphatic systems • Excretory and reproductive systems (except germ cells) • Dermis of skin • Adrenal cortex Figure 47.8 Major derivatives of the three embryonic germ layers in vertebrates. ENDODERM (inner layer of embryo) • Epithelial lining of digestive tract and associated organs (liver, pancreas) • Epithelial lining of respiratory, excretory, and reproductive tracts and ducts • Thymus, thyroid, and parathyroid glands

MEMBRANES The four extraembryonic membranes that form around the embryo arise from the amniotic egg The chorion functions in gas exchange The amnion encloses the amniotic fluid The yolk sac encloses the yolk The allantois disposes of waste products and contributes to gas exchange © 2011 Pearson Education, Inc.

Organogenesis During organogenesis, various regions of the germ layers develop into rudimentary organs Early in vertebrate organogenesis, the notochord forms from mesoderm, and the neural plate forms from ectoderm © 2011 Pearson Education, Inc.

Figure 47.13 Neural folds Eye Somites Tail bud Neural fold Neural plate SEM 1 mm 1 mm Neural tube Neural crest cells Neural fold Neural plate Notochord Neural crest cells Coelom Notochord Ectoderm Somite Figure 47.13 Neurulation in a frog embryo. Mesoderm Outer layer of ectoderm Archenteron (digestive cavity) Endoderm Neural crest cells (c) Somites Archenteron (a) Neural plate formation Neural tube (b) Neural tube formation

The neural plate soon curves inward, forming the neural tube The neural tube will become the central nervous system (brain and spinal cord) © 2011 Pearson Education, Inc.

Mesoderm lateral to the notochord forms blocks called somites Neural crest cells develop along the neural tube of vertebrates and form various parts of the embryo (nerves, parts of teeth, skull bones, and so on) Mesoderm lateral to the notochord forms blocks called somites Lateral to the somites, the mesoderm splits to form the coelom (body cavity) © 2011 Pearson Education, Inc.

Archenteron (digestive cavity) Figure 47.13c Eye Somites Tail bud SEM 1 mm Neural tube Neural crest cells Notochord Coelom Figure 47.13 Neurulation in a frog embryo. Somite Archenteron (digestive cavity) (c) Somites

The embryonic cells in a limb bud respond to positional information indicating location along three axes Proximal-distal axis Anterior-posterior axis Dorsal-ventral axis © 2011 Pearson Education, Inc.

(b) Wing of chick embryo Figure 47.24b 2 Digits 3 4 Anterior Ventral Figure 47.24 Vertebrate limb development. Proximal Distal Dorsal Posterior (b) Wing of chick embryo

EXPERIMENT Anterior New ZPA Donor limb bud Host limb bud ZPA Posterior Figure 47.25 EXPERIMENT Anterior New ZPA Donor limb bud Host limb bud ZPA Posterior RESULTS 4 Figure 47.25 Inquiry: What role does the zone of polarizing activity (ZPA) play in limb pattern formation in vertebrates? 3 What role does the zone of polarizing activity (ZPA) play in limb pattern formation in vertebrates? 2 2 3 4

Cell Fate Determination Sonic hedgehog is an inductive signal for limb development Hox genes also play roles during limb pattern formation Read Cell Fate Determination and Pattern Formation 1039-1051 © 2011 Pearson Education, Inc. © 2011 Pearson Education, Inc.

Cilia and Cell Fate Ciliary function is essential for proper specification of cell fate in the human embryo Motile cilia play roles in left-right specification Monocilia (nonmotile cilia) play roles in normal kidney development Almost every cell has one that acts as a transporter and an antenna to receive info from other cells © 2011 Pearson Education, Inc.

Figure 47.26 Kartogener’s Syndrome Lungs Heart Liver Spleen Stomach Figure 47.26 Situs inversus, a reversal of normal left-right asymmetry in the chest and abdomen. Large intestine Normal location of internal organs Location in situs inversus

Figure 46.12 Exploring: Human Gametogenesis Figure 46.12a Epididymis Seminiferous tubule Testis Primordial germ cell in embryo Cross section of seminiferous tubule Mitotic divisions Spermatogonial stem cell 2n Mitotic divisions Sertoli cell nucleus Spermatogonium 2n Mitotic divisions Primary spermatocyte 2n Meiosis I Figure 46.12 Exploring: Human Gametogenesis Secondary spermatocyte n n Meiosis II Lumen of seminiferous tubule Spermatids (two stages) Early spermatid Neck n n n n Tail Midpiece Head Differentiation (Sertoli cells provide nutrients) Plasma membrane Sperm cell n n Acrosome n n Nucleus Mitochondria

Figure 46.12 Exploring: Human Gametogenesis Figure 46.12b Primary oocyte within follicle Ovary Growing follicle Primordial germ cell In embryo Mitotic divisions 2n Oogonium Mitotic divisions Primary oocyte (present at birth), arrested in prophase of meiosis I Mature follicle 2n Ruptured follicle Completion of meiosis I and onset of meiosis II First polar body n n Secondary oocyte, arrested at metaphase of meiosis II Ovulated secondary oocyte Figure 46.12 Exploring: Human Gametogenesis Ovulation, sperm entry Completion of meiosis II Second polar body Corpus luteum n Fertilized egg n Degenerating corpus luteum