1. Chapter 46: Animal Reproduction

2. Overview Asexual (one parent) Sexual (fusion of haploid gametes)
fission (parent separation)
budding (corals)
gemmules (porifera)
fragmentation & regeneration (inverts)
Sexual (fusion of haploid gametes)
gametes (sex cells)
zygote (fertilized egg)
ovum (unfertilized egg)
spermatozoon (male gamete)
Hermaphrodatism (rare mates)
Video: Hydra Budding

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

4. Mechanisms of sexual reproduction
Fertilization
(union of sperm and egg)
external
Internal
Spermatheca: stores sperm from copulation in some insects
Pheromones
chemical signals that influence the behavior of others (mate attractants)

5. Mammalian reproduction, I
The Human Male
Testes: male gonads
Seminiferous tubules: sperm formation
Leydig cells: hormone production
Scrotum: outside body temp.
Epididymis: sperm development
Vas deferens: sperm propulsion
Seminal vesicles: semen
Prostate gland: anticoagulant; nutrients
Bulbourethral glands: acid neutralizer
Penis/urethra: semen delivery

6. Mammalian reproduction, II
Oviduct
Ovary
The Human Female
Ovaries: female gonads
Follicle: egg capsule
Corpus luteum: hormone secretion
Oviduct: fertilization
Uterus/endometrium: womb/lining
Cervix/vagina: sperm receptacle
Uterus
(Urinary bladder)
(Rectum)
(Pubic bone)
Cervix
Urethra
Vagina
Shaft
Glans
Clitoris
Prepuce
Labia minora
Labia majora
Vaginal opening
Oviduct
Ovaries
Follicles
Corpus luteum
Uterus
Uterine wall
Endometrium
Cervix
Vagina

7. Animation: Male Hormones
Spermatogenesis
Animation: Male Hormones
Puberty until death!
Seminiferous tubules: location
Primordial germ cell (2N): differentiate into….
Spermatogonium (2N): sperm precursor
Repeated mitosis into….
Primary spermatocyte (2N)
1st meiotic division
Secondary spermatocyte (1N)
2nd meiotic division
Spermatids (1N): Sertoli cells….
Sperm cells (1N)

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

9. Animation: Post Ovulation
Oogenesis
Animation: Ovulation
Animation: Post Ovulation
As embryo until menopause...
Ovaries
Primordial germ cells (2N)
Oogonium (2N)
Primary oocyte (2N)
Between birth & puberty; prophase I of meiosis
Puberty; FSH; completes meiosis I
Secondary oocyte (1N); polar body
Meiosis II; stimulated by fertilization
Ovum (1N); 2nd polar body

10. Animation: Post Ovulation
The female pattern
Estrous cycle (many mammals)
Menstrual cycle (humans and many otherprimates):
Ovarian/Menstrual cycles:
follicular phase: follicle growth
ovulation: oocyte release
luteal phase: hormone release
Animation: Post Ovulation

11. The blastocyst implants
Fig 3
Cleavage
Cleavage continues 4
Ovary 2
Fertilization
Uterus
The blastocyst implants 5 1
Ovulation
Endometrium
(a) From ovulation to implantation
Figure Formation of the zygote and early post-fertilization events
Endo- metrium
Inner cell mass
Cavity
Trophoblast
Blastocyst
(b) Implantation of blastocyst

12. Embryonic & fetal development
Orgasm: rhythmic contractions of reproductive structures
Gestation: pregnancy
1st trimester:
organogenesis
fetus (week 8; all adult features)
HCG hormone (menstruation override; pregnancy test detection)
Parturition: birth
Labor: uterine contractions
Lactation: prolactin & oxytocin

13. Fig
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

14. from fetus and mother’s posterior pituitary
Fig
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 +
Figure A model for the induction of labor
Prostaglandins
Stimulate more contractions of uterus

15. Contraception and Abortion
Contraception: deliberate prevention of pregnancy
Contraceptive methods fall into three categories:
Preventing release of eggs and sperm
Keeping sperm and egg apart
Preventing implantation of an embryo
Rhythm method (natural family planning): 10-20% = baby
Coitus interruptus = unreliable
Barrier methods: less than 10% = baby
A condom fits over the penis
A diaphragm is inserted into the vagina before intercourse
Intrauterine devices: less than 1% = baby
Female birth control pills: less than 1% = baby

16. Figure 46.20 Mechanisms of several contraceptive methods
Male
Female
Method
Event
Event
Method
Production of sperm
Production of primary oocytes
Vasectomy
Combination birth control pill (or injection, patch, or vaginal ring)
Sperm transport down male duct system
Oocyte development and ovulation
Abstinence
Abstinence
Condom
Female condom
Coitus interruptus (very high failure rate)
Sperm deposited in vagina
Capture of the oocyte by the oviduct
Tubal ligation
Spermicides; diaphragm; cervical cap; progestin alone (as minipill, implant, or injection)
Sperm movement through female reproductive tract
Transport of oocyte in oviduct
Figure Mechanisms of several contraceptive methods
Meeting of sperm and oocyte in oviduct
Morning-after pill; intrauterine device (IUD)
Union of sperm and egg
Implantation of blastocyst in endometrium

17. Detecting Disorders During Pregnancy
Amniocentesis and chorionic villus sampling are invasive techniques in which amniotic fluid or fetal cells are obtained for genetic analysis
Noninvasive = usually ultrasound imaging
Genetic testing of fetus poses ethical questions, can present parents with difficult decisions

18. Treating Infertility
Modern technology can provide infertile couples with assisted reproductive technologies
In vitro fertilization (IVF): mixes eggs with sperm in culture dishes, returns embryo to uterus at 8 cell stage
Also medications to encourage ovulation like clomed