1. Animal Development
Chapter 46 & 47

2. Fig. 46-6
Figure 46.6 Parental care in an invertebrate

3. Vocabulary Zygote: Single diploid cell Fertilization:
Sperm & egg combine
Ovulation:
Egg is released from the ovary
Spermatogenesis:
Formation of sperm
Oogenesis:
Formation of the egg

4. Anatomy

5. Anatomy Oviduct Ovary Uterus (Urinary bladder) (Rectum) (Pubic bone)
Cervix
Urethra
Vagina
Figure Reproductive anatomy of the human female
Shaft
Glans
Clitoris
Prepuce
Labia minora
Labia majora
Vaginal opening

6. Fig. 46-10b Oviduct Ovaries Follicles Corpus luteum Uterine wall
Uterus
Endometrium
Cervix
Figure Reproductive anatomy of the human female
Vagina

7. Female Ovaries (at birth) Contain approximately 1 million follicles
Primary oocyte
Started meiosis
Stopped at prophase I (diploid)

8. Female FSH Stimulates production of a follicle
One follicle goes through Meiosis I
Two daughter cells
Secondary oocyte (starts Meiosis II)
Polar body (disintegrates)

9. Female LH stimulates ovary Secondary oocyte leaves ovary Ovulation
Fertilized then completes Meiosis II
Ovum
Polar body
Travels fallopian tube
Implants in uterus (approx. 5-6 days)

11. Fig. 46-12g 2n 2n n n Figure 46.12 Human gametogenesis n n In embryo
Primordial germ cell
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 Human gametogenesis
Completion of meiosis II
Second polar body n
Fertilized egg n

12. Ovulation

13. Menstrual cycle GnRH FSH & LH released Stimulates follicle
Estradiol released
Follicle released (ovulation)
LH increases

14. Menstrual cycle Corpus luteum releases progesterone & estridiol
Corpus luteum disintegrates
Lining sheds
Endometriosis:
Uterine lining in abdomen

16. Menstrual cycle

17. Anatomy

18. Fig. 46-11b (Urinary bladder) (Urinary duct) Seminal vesicle (Rectum)
(Pubic bone)
Vas deferens
Erectile tissue
Ejaculatory duct
Prostate gland
Urethra
Penis
Bulbourethral gland
Glans
Vas deferens
Figure Reproductive anatomy of the human male
Epididymis Testis Scrotum
Prepuce

19. Male Testes are in abdomen (at birth) Descend into scrotum
Temperature of testes is cooler
Normal sperm production
Seminiferous tubules
Contain spermatogonia or germ cells

20. Male Germ cells (diploid) Mitosis One undergoes meiosis
Produce 4 haploid sperm
Produce 100 to 200 million sperm a day
Continues for life

21. Spermatogenesis

22. Fig. 46-12b Epididymis Seminiferous tubule Sertoli cell nucleus
Spermatogonium
Testis
Primary spermatocyte
Cross section of seminiferous tubule
Secondary spermatocyte
Spermatids (two stages)
Figure Human gametogenesis
Lumen of seminiferous tubule
Sperm

23. Fig. 46-12c 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 Human gametogenesis
Early spermatid n n n n
Differentiation (Sertoli cells provide nutrients)
Sperm n n n n

24. Gamete formation

26. Embryonic development
Fertilization
Cleavage
Gastrulation
Neurulation
Organogenesis

27. Fertilization 1. Penetration Sperm digests cells surrounding egg
Contains glycoprotein enzymes
2. Activation
Membrane changes
Prevents other sperm penetrating

28. Fertilization 2. Activation
A. stimulates egg to complete division of Meiosis II
B. stimulates movement of cytoplasm to prepare for cell division of zygote
C. stimulates increase in protein synthesis

29. Fertilization 3. Nuclei fusion Sperm nucleus fuses with egg
Egg is not activated
Does not form zygote

30. Fertilization

31. Cleavage Rapid cell division Blastomeres: Smaller & smaller cells
No increase in volume of cytoplasm
Morula:
Tight mass of approximately 32 cells

32. Fig. 47-6 (a) Fertilized egg (b) Four-cell stage (c) Early blastula
Figure 47.6 Cleavage in an echinoderm embryo
(b) Four-cell stage
(c) Early blastula
(d) Later blastula

33. Cleavage Blastocyst (Blastula) Hollow ball of approx. 500-2000 cells
Blastocyst cavity
Fluid filled
Different regions in blastocyst
Received differing amounts of cytoplasm
Affects further development

34. Cleavage Trophoblast: Outer layer of cells
Surround blastocyst (involved in placenta)
Inner cell mass:
Layer of dividing cells
At one end of Blastocyst
Becomes developing embryo

35. Fig. 47-8-6 Animal pole Blastocoel Vegetal pole Zygote
0.25 mm
0.25 mm
Animal pole
Blastocoel
Figure 47.8 Cleavage in a frog embryo
Vegetal pole
Zygote
2-cell stage forming
4-cell stage forming
8-cell stage
Blastula (cross section)

36. Cleavage Implantation: Blastocyst attaches to endometrium
6 days after fertilization
Human chorionic gonadotropin (HCG)
Hormone released by trophoblast
Maintains corpus luteum

37. Fig. 47-16-2 Epiblast Expanding region of trophoblast
Maternal blood vessel
Epiblast
Hypoblast
Figure Four stages in early embryonic development of a human
Trophoblast

38. Gastrulation Turning inward of cells into blastocyst Forms germ layers
Ectoderm:
Epidermis/neural tissue
Mesoderm:
Muscle/skeletal/vasculature
Endoderm:
Gut lining, respiratory tract, liver

39. Fig. 47-14 ECTODERM MESODERM ENDODERM
Epidermis of skin and its derivatives (including sweat glands, hair follicles) Epithelial lining of mouth and anus Cornea and lens of eye Nervous system Sensory receptors in epidermis Adrenal medulla Tooth enamel Epithelium of pineal and pituitary glands
Notochord Skeletal system Muscular system Muscular layer of stomach and intestine Excretory system Circulatory and lymphatic systems
Reproductive system (except germ cells)
Dermis of skin Lining of body cavity Adrenal cortex
Epithelial lining of digestive tract Epithelial lining of respiratory system Lining of urethra, urinary bladder, and reproductive system Liver Pancreas Thymus Thyroid and parathyroid glands
Figure Adult derivatives of the three embryonic germ layers in vertebrates

41. Gastrulation

42. Gastrulation Chorion: Surrounds embryo Gas exchange Amnion:
Encloses the embryo
Protective amniotic fluid
Yolk sac:
Formation of blood cells

43. Gastrulation Ectoderm Endoderm Amnion Chorion Mesoderm Yolk sac
Figure Four stages in early embryonic development of a human
Extraembryonic mesoderm
Atlantois

44. Neurulation Development of dorsal nerve cord Notochord (spinal column)
Forms from mesoderm soon after gastrulation
Neural grove (spinal cord/brain)
Crease down the axis of the embryo
Neural tube (ectoderm)
Hollow cylinder

45. Neural cord

46. Neurulation
Neural crest
Cells pinch off from neural tube
Migrate to parts of embryo
Peripheral nerves, teeth, skull bones

47. Outer layer of ectoderm
Fig b-4
Outer layer of ectoderm
Neural crest cells
Neural tube
Figure 47.12b Early organogenesis in a frog embryo
(b) Neural tube formation

48. Organogenesis Below neural tube Somitomeres:
Small sections of mesoderm
Somites
Smaller sections of mesoderm
Develop into muscles, vertebrae, connective tissues

49. Organogenesis Mesoderm surrounds the endoderm Separates into 2 layers
One lines the inner body wall
One lines the outside of the gut
Between layers becomes body cavity

51. Human development 266 days divided into trimesters First trimester
First cleavage 30 hours
Second cleavage 60 hours
Third cleavage 72 hours

52. Human development Gastrulation second week Neurulation third week
Organogenesis
Heart beats at 4 weeks (heard at end of first trimester)
Fetus at 8 weeks
All major organs are developed
5 cm in length

53. Fig a
Figure Human fetal development
(a) 5 weeks

54. Human development Second trimester Large growth
Baby about 30 cm in length
Lanugo: fine hair covering body
Placenta now controls progesterone levels

55. Fig b
(b) 14 weeks

56. Fig c
(c) 20 weeks

57. Human development Third trimester Large growth of fetus
Developing nerves

58. Human development Birth Labor
Estrogen stimulates the production of oxytocin receptors on the uterus
Prostaglandins start labor
Posterior pituitary releases oxytocin
Uterine contractions expel fetus

59. Fig. 46-18 Estradiol Oxytocin + from ovaries
from fetus and mother’s posterior pituitary
Induces oxytocin receptors on uterus
Positive feedback
Stimulates uterus to contract
Stimulates placenta to make +
Prostaglandins
Stimulate more contractions of uterus

60. Expulsion: delivery of the infant
Fig
Expulsion: delivery of the infant 2

61. Delivery of the placenta
Fig
Uterus
Placenta
(detaching)
Umbilical
cord
Delivery of the placenta 3

62. Placenta

63. Fig. 46-16 Maternal arteries Maternal veins Placenta
Maternal portion of placenta
Umbilical cord
Chorionic villus, containing fetal capillaries
Fetal portion of placenta (chorion)
Maternal blood pools
Figure Placental circulation
Uterus
Umbilical arteries
Fetal arteriole
Fetal venule
Umbilical cord
Umbilical vein