1. Human Reproduction Male Reproductive Anatomy
Spermatogenesis and Male Hormones
Male Reproductive Technologies and Birth Control
Female Reproductive Anatomy
Oogenesis and Female Hormones
Uterine and Ovarian Cycles
Development of the Fetus
Parturition and Lactation
Teratogens and Birth Defects
Reproductive Technologies

2. Reproduction ensures the survival of a species
Sexual reproduction produces offspring with new and unique characteristics that may increase their chance of survival.

3. Reproduction 2 types of gametes (sex cells)
Males: 1 billion sperm each day from the ages 13-90
Females: born with 400, 000 eggs, 400 mature from ages 12 to 50 (menopause)
The average gestational period for a human is 266 days.

4. Male Reproductive System
The male reproductive structures are responsible for:
producing sperm
storing sperm
delivering sperm
to the female

5. Male Reproductive System

6. Male Reproductive System
Scrotum
holds the testes away from the body to keep them cool.
Sperm production only occurs at temperatures about 3 degrees below body temperature.

7. Male Reproductive System
Testis
descend about 2 months before birth
hang outside the internal body to maintain a temperature of ~35OC to give sperm max survival ability
2 types of cells in the Testis:
1) Interstitial cells- testosterone producing cells
2) Seminiferous tubules- cells that carry out spermatogenesis (=making of sperm)

8. Male Reproductive System
Epididymis – holds sperm for about 2-4 days while they mature

9. Male Reproductive System
Vas Deferens
conducts sperm during ejaculation
vasectomy: the vas deferens cut and tied off, to prevent conduction of sperm.

10. Male Reproductive System
Ejaculatory Duct –propels semen and sperm through the urethra.
Urethra –conduction of urine and semen out of the penis.
a sphincter muscle closes off the bladder, preventing urine from exiting the urethra.

11. Male Reproductive System
Penis
male organ for copulation. Beneath the skin, lies the urethra surrounded by spongy protective tissue that expands to form the glans penis.
Prepuce (foreskin) – is a loose sheath of skin covering the glans penis of uncircumcised males. The foreskin produces an oily secretion known as smegma.

12. Seminal Fluid -as sperm moves through the vas deferens, it mixes with seminal fluid to help it do its job. This forms semen
Seminal fluid (semen) is produced by three different glands:
1) Seminal Vesicles
fluid high in fructose that provides food energy sperm need to swim
Prostaglandins which cause contractions of muscles in the female reproductive tract to help move sperm in

13. Seminal Fluid 2) Prostate Gland 3) Cowper’s Gland
milky white alkaline fluid that neutralizes the acidity of the vagina
3) Cowper’s Gland
buffered fluid that cleanses and neutralizes the acidity in the urethra

14. Spermatogenesis
Spermatozoa – are the smallest cells in the body. They have very little cytoplasm in the head, and a large tail (flagellum).
The sperms head contains the DNA, the body contains tons of mitochondria to move the tail. Acrosome is an enzymes which helps sperm penetrate egg

15. Steps of Spermatogenesis
1) Spermatogonia – undifferentiated germ cells that have 46 chromosomes (2n)
2) Primary Spermatocytes – larger cells that undergo meiosis I (1n)
3) Secondary spermatocytes – cells that undergo meiosis II
4) Spermatids – cells with 23 chromosomes, that are ready to mature in the epididymis
5) Spermatozoa – mature sperm cells
6) Sperm  ready to go to the urethra!

16. Sertoli Cells- nourish sperm cells Formation of sperm broken down:

17. Regulation of the Male Reproductive Hormones

18. Terminology
Erection
parasympathetic nerve impulses dilate the arteries of the penis, allowing blood to flow rapidly into the highly vascular penile tissue
veins are compressed preventing blood from leaving the penis.

19. Terminology
Ejaculation – occurs when sexual stimulation forces semen to the urethra, where rhythmical muscle contractions cause the semen to be expelled/eject from the penis.
Infertility – the inability to produce viable sperm.
Impotency – the inability to achieve a sustained erection. Cure: Viagra© and Cialis ©

20. Male Reproductive Hormones
GnRH : gonadotropic releasing hormone
released from hypothalamus
stimulates the anterior pituitary to release LH and FSH
LH : luteinizing hormone
stimulates the interstitial cells (cells in between seminiferous tubules) of the testes to produce testosterone

21. Male Reproductive Hormones
Testosterone – responsible for male secondary sex characteristics (pubic hair, armpit hair, thick jaws, voice changes, muscle mass, broad shoulders, aggression) required for sperm production
FSH: follicle stimulating hormone
stimulates production of sperm in the seminiferous tubules

22. Male Reproductive Hormones
Inhibin
produced by Sertoli cells when sperm count is high
Sends feedback to inhibit FSH and GnRH

24. Sperm Production

25. Female Reproductive Structures
The female reproductive structures are responsible for
reception of sperm
producing an egg
nourishing and protecting the fetus
delivering the baby

26. Female Reproductive Structures

27. Female External Structures (Vulva)
Labia majora – large, fatty, hair covered folds that protect the genitals
Labia minora – smaller folds of skin inside the labia that are kept moist by secretions
Clitoris – small shaft of erectile tissue

28. Female Internal Structures
Vagina
intercourse : accepts the penis
birth canal during labor
pH is generally acidic

29. Female Internal Structures
Cervix
Thick muscular tissue
plugs closed with mucous during pregnancy
prevents material from getting into the uterus, and holds the baby in

30. Female Internal Structures
Uterus (womb)
pear shaped muscular organ (5 cm wide)
houses the developing fetus during pregnancy (30 cm wide)
strong contractions help push the baby out during birth
main body is known as the fundus
Inner layer of the uterus is called the endometrium. Here there is tons of blood vessels, tissue, and mucous. If no fertilization occurs it is expelled from the uterus (=menstration)

31. Hysterectomy: removal of the uterus

32. Female Internal Structures
Ovaries
produce the ovum from follicles found in the outer cortex

33. Female Internal Structures
Oviducts /Fallopian tubes
conduction of the ovum (egg) from the ovaries to the uterus
where fertilization usually takes place (sperm meets the eggs)
If egg implants here = ectopic pregnancy
frequency

34. Female Internal Structures
Fimbriae
small fingerlike projections at the ends of the oviducts that sweep to draw the egg into the fallopian tube

35. Female Internal Structures
Tubal Ligation- sterilization is females, fallopian tubes are severed and thus sperm and egg can not join.

36. Ovarian Structures Follicle cells that support and protect the ovum
secrete estrogen to mature the ovum
become a corpus luteum following ovulation.
Ovum – egg cell, viable for about 24 hours after release.

37. Ovarian Structures Corpus Luteum
cells remaining after a follicle has ruptured during ovulation
secretes progesterone and some estrogen for about 3 months if fertilization and pregnancy occurs
deteriorates after about 14 days if fertilization does not occur.

38. Oogenesis

39. Regulation of the Female Reproductive Hormones
GnRH – stimulates the anterior pituitary to produce FSH and LH
FSH – stimulates development of the follicle and the production of estrogen within the ovary

40. Regulation of the Female Reproductive Hormones
LH – causes ovulation, development of the corpus luteum which secretes progesterone

41. Reproductive Hormones
Estrogen
secreted by the follicles in the ovaries
causes maturation of the egg
stimulates growth of the endometrium (uterus lining)
Female secondary sex characteristics
Inhibits FSH

42. Reproductive Hormones
Progesterone
secreted by the corpus luteum
continues preparation of endometrium
inhibits both FSH and LH to prevent ovulation
prevents uterine contractions
firms the cervix

43. P 525 Fig 6

44. The Uterine and Ovarian Cycles (Menstrual cycle)

45. Day 1-5: Menstruation/Flow Phase
Estrogen and progesterone levels are low
endometrium is sloughed off and shed (menstration)
Day 1-13: Follicular Phase
Increased FSH secreted from ant. pit. promotes development of the follicle to day 6 or 7.
follicle releases estrogen, which promotes growth of the endometrium. Estrogen peaks at day 12 to mature the new follicle. Day 13 there is a very small spike in LH and FSH as well

46. Day 14: Ovulation
An increase in LH and FSH causes the follicle to rupture (=ovulation) and let the ovum to be released
FSH is lowered
Day 15 – 22: Luteal Phase
LH promotes formation of the corpus luteum from the left over ruptured empty follicle
corpus luteum produces progesterone, inhibits GnRH, LH and FSH, preventing subsequent ovulation.
Estrogen levels continue to be high which continues the thicken the endometrium
- ovum eventually implants into the endometrium

47. If no fertilization and implantation occurs by day 22, the corpus luteum degenerates, then progesterone levels drop, estorgen levels drop, and the endometrium begins to break down
Many birth control pills are high in progesterone which prevents ovulation
cancer

49. No Fertilization  corpus luteum degenerates, estrogen and progesterone levels drop, and menstruation occurs.

50. The Uterine Cycle
Menstrualcycle

51. Fertilization Fertilization
-union of sperm (1n) and secondary oocyte (1n) in the fallopian tube
Only one spermatozoa will fertilize an egg
Now called a zygote (2n)

52. Early Embryonic Development
12 hours: Zygote formed –fertilized egg, divides by cleavage, mitosis with no increase in size
36 hours: 1st division (2 cells)
40hours: 4 cells
60h: 8 cells
Day 3: Morula – solid ball of cells the same size as the fertilized egg (32 cells)

53. Early Embryonic Development
Day 4-5: Blastocyst forms:
hollow ball of 64 cells filled with fluid,
outer layer forms the chorion, inner layer forms the embryo
Implants to endometrium day 6-10

54. Early Embryonic Development

55. Implantation (around day 6)
embryo embeds itself in the endometrium.
To save itself from being shed, blastocyst produces HCG (human chorionic gonadotropic hormone): maintains the corpus luteum for about 2-3 months.
***Reminder: corpus luteum produces progesterone and estrogen to maintain the endometrium and prevent ovulation

56. hCG Pregnancy Test ELISA
HCG detected in blood or urine with a pregnancy test
hCG Pregnancy Test ELISA

57. Gastrulation

58. Early Embryonic Development
Day 7-12: Gastrula forms
the blastocyst pushes in (invaginates) and forms the 3 primary germ layers
the hollow space forms a primitive gut

59. 3 Germ Layers created are:
Ectoderm – nervous system and epidermis of the skin
(hair, nails,retina, lens, inner ear, lining of the nose, mouth, anus and tooth enamel)
Neurula- notochord/neural tube forms from the ectoderm layer (forms in 3rd to 4th week)

60. Germ Layers

61. Germ Layers Mesoderm – skeleton, muscles, reproductive organs
(connective tissue,cartilage, blood, blood vessels, kidneys)
Endoderm –lining of the digestive and respiratory system, endocrine glands
(trachea, bronchi, lungs, gallbladder, urethra, liver, pancreas, thyroid,bladder)

62. Gastrulation
BERP: Overview

63. Embryo at 4 weeks

64. Extra Embryonic Membranes
Placenta
The chorion cells and the endometrium cells fuse to form the placenta
forms around the fetus
exchange of gases, delivery of nutrients and removal of wastes for the fetus

65. Extra Embryonic Membranes
no direct blood shared between the mother and the fetus
Produces progesterone and estrogen at about 4 months

66. Extra Embryonic Membranes
Amnion – inner membrane filled with fluid to provide protection, maintain temperature, swallowing (amniotic sac)
Chorion-outer membrane, contributes to placenta
Extraembryonic coelom – fluid filled space between amnion and chorion

67. Extra Embryonic Membranes
Allantois – collects nitrogenous wastes and forms the umbilical cord and placenta blood vessels
Yolk Sac – surrounds embryo, first site of blood cell formation (until liver is formed), becomes part of the primitive gut

69. How Old Are You? Gestational age
-calculated from the first day of the mother’s last menstrual period.
–length of pregnancy is 40 weeks

70. How Old Are You? Fertilization age –actual age of the fetus
- estimated to be about two weeks before the date of the last menstrual period.
To calculate due date: LMP –3 months + 7 days
calculator

71. Trimesters 1rst : until end of third month 2nd: 4-6months
3rd : 7-9 months

72. Developmental Milestones
1 week – fertilization, cleavage, blastocyst
2 weeks – implantation, chorion secretes HCG, 3 germ layers form

73. Developmental Milestones
3 weeks – nervous system is evident, heart begins to form (2 tubes), heart beats around day 22
4-5 weeks – limb buds appear, eyes, ears and nose develop, umbilical cord is attached to placenta

74. Developmental Milestones
6-8 weeks – fetus is recognizable as a human, all organ system are developed, reflexes begin (size = 1.5”, 0.5 g)
8th week = fetus

75. 9-16 weeks – heartbeat is audible with a stethoscope, bone replaces cartilage, eyelashes formed, fetus can suck and swallow (size = 6”, 0.5 lb)

76. Developmental Milestones
17-28 weeks – movement is felt by mother, eyelids open (size = 12”, 3lb)
Week 28: premature baby has 10-20% chance of survival

77. Developmental Milestones
32 weeks: fetus moves to head down position and lungs mature
(has 50% survival rate if born)

78. Developmental Milestones
after about 32 weeks significant weight gain
40 weeks: full term (size = 21”, 7.5 lbs)
See summary chart on page 534

79. Developmental Milestones

80. Conception to Birth, Anatomical Travelogue
Virtual Development
Conception to Birth, Anatomical Travelogue
Visible Embryo

81. Teratogens
Teratogens - chemical substances or infections that cause specific birth defects

82. Teratogens
-Thalidomide-prescribed for morning sickness in the late 50’s and early 60’s
-rubella during the first 12 weeks of pregnancy: eye problems, hearing problems and heart damage.

83. Parturition: Birth Hormones:
-relaxin: made by placenta, loosens pelvis ligaments
-prostaglandins – contractions
-oxytocin from Post. Pit - contractions

84. Parturition
Stage 1 – dilation and effacement(thinning) of the cervix, mucous plug dislodges, uterine contractions open the cervix
Stage 2 – delivery of the baby, cervix is dilated to about 10 cm, intense contractions every 1-2 min push the baby down the birth canal
Stage 3 – delivery of the placenta

85. Parturition
The average labor lasts about 12 hours, but can range from 1 hour to 36 hours.
caesarean section may be required.
involves removing the baby from an incision in the front of the abdomen.

86. Lactation
prolactin stimulates the glandular tissue in the breasts to produce fluids, colostrum, and milk.
Colostrum is a rich fluid containing mostly sugar and proteins. This first milk is believed to play a role in early immunity.

87. Lactation
Regular suckling stimulates the pituitary gland to release oxytocin
causes weak uterine contractions to return it to its pre pregnancy shape
causes “let down” of milk
1.5 L of milk each day

89. Reproductive Technologies and Health
Pap Smear – a sample of cervical cells are taken and examined for abnormal growth (cancer)
Ultrasound – uses sound waves to view the baby in the womb
Ultrasound Scan Fetal Video Clips

90. Reproductive Technologies and Health
Amniocentesis – sampling of the cells from the amniotic fluid at about 16 weeks to check for genetic abnormalities
Amniocentesis Flash Animation - Mountain View Bay Area Sunnyvale Cupertino Palo Alto Standford

91. Reproductive Technologies and Health
Chorionic Villus Sampling – sampling of cells from the chorion at about 5 weeks to check for genetic abnormalities

92. Fertility Technologies
IVF – in vitro (in glass) fertilization – fertilizing the egg in a petri dish, and implanting the embryo 2-4 days later
Life Changine Science - Program 3: IVF
AID – artificial insemination by donor, sperm is artificially placed in the vagina.

93. Fertility Technologies
Egg Screening – testing and selecting eggs to be fertilized, fertility drugs produce eggs that are collected using a needle biopsy
TSE – testicular sperm extraction
removal of sperm via biopsy (not ejaculation)
ICSI – intracytoplasmic sperm injection
sperm head is injected directly into the egg

94. Fertility Technologies
GIFT – gamete intra-fallopian transfer
sperm and egg are transferred to the fallopian tube for fertilization
AH – assisted hatching
a chemical solution is dripped over the egg to allow the sperm to penetrate more easily

95. Fertility Technologies
Embryo Transfer – implantation of an embryo (at blastocyst stage) into the womb or fallopian tube, may be frozen or unfrozen
Fertility Drugs – induce ovulation, usually many ova are produced at one time, often results in multiples