1. BSC1010- Intro to Biology I
K. Maltz
Chapter 51

2. Reproduction Two types
Sexual Reproduction- 2 gametes (not necessarily 2 parents)
Asexual reproduction- Single parent; no fusion of genetic material
In asexual reproduction, the offspring are clones of the parent
Sexual reproduction allows for genetic mixing and greater gene variation
Asexual reproduction has some advantages, too.
Can reproduce in isolation
Can reproduce rapidly
And they can produce a large number of offspring
prevalent in species in stable environments

3. Asexual Reproduction Mostly in invertebrates Three types
Budding- parent produces outgrowth that becomes offspring organism
Regeneration- whole new organism from fragment of parent
Parthenogenesis- offspring from unfertilized egg
Budding is usually in cnidarians such as hydras
Regeneration is usually in worms (flat worms) and echinoderms (sea stars)
Parthenogenesis can occur in some fish and reptiles

4. Examples Budding- Cnidarians Regeneration- Enchinoderms
Parthenogenesis- Daphnia
Sessile- non-motile
Daphnea = water flea

5. Parthenogenesis vs. Normal Fertilization
In sexual reproduction 2 gametes come together to combine dna producing a zygote which develops into an embryo

6. Hermaphroditism
Synchronus hermaphroditism- can fertilize own eggs or join with another to reproduce (ex earthworms)
Sequential hermaphroditism- sex reversal (expression of specific genes, but not at the same time) (ex fish)

7. Gametogenesis
2o spermatocyte
1o spermatocyte
2o oocyte
oogonium
Sperm- acrosome with nucleus inside, midpiece with mitochondrion, flagellum tail
1o oocyte
egg
First polar body

8. Gametogenesis
antrum

9. Cells
Cell phases
Seminiferous tubule
Leydig with testosterone

10. Fertilization Eggs continually release a chemoattractant molecule
When a sperm gets close the sperm cell’s metabolism increases and it swims faster, following the concentration gradient
When the sperm reaches the egg, the cumulus mass around the egg breaks down the sperm acrosome
This in turn releases enzymes from the acrosome that break down the zona pellucida
The plasma membrane of the egg fuses with the sperm head
A metabolic change occurs within the egg to prevent more sperm from fertilizing

11. Now What? The resulting fertilized egg can develop in several ways
Oviparity- animal develops in shell (birds)
Viviparity- animal develops inside the mother (humans)
Ovoviviparity- eggs have very thin covering develop inside mother but gain no nutrients from mother (some sharks, lizards, snakes)

12. Male Reproductive Structure
Go from testes into epididymis to vas deferens to ejaculatory duct.
ED connects with urethra
Seminal vesicles secrete fructose and motile factors
All of this requires testosterone
Hypothalamus releases gonadotropin releasing hormone to signal anterior pituitary to release Leutinizing hormone and follicle stimulating hormone
They activate the testes
LH works on Leydig and FSH works on sertoli
Leydig secrete testosterone, which also stimulates sertoli to start spermatogenesis
Testosterone also stimulates secondary sex characteristics in puberty
Prostate and bulbourethral secretes an alkaline fluid that protects sprem from acidic fluid in urethra and femal tract
Sexual arousal causes release of Nitrous oxide in penis causing vasodilation

13. Female Reproductive Structure

14. Follicle and Oocyte Development

15. Menstrual Cycle

16. Placental Structure
Embryo 1st 8 weeks, after 8 weeks called fetus

17. Hormonal Control Partuition- birth
Oxytocin- posterior pituitary hormone that stimulates contraction of uterine muscles
In the 3rd trimester the placenta secretes a lot of estrogen (particularly estradiol), which enhances sensitivity to oxytocin
The fetus’s head pushes on the cervix, which signals the hypothalamus to release oxytocin
Prostaglandins from the uterus and positive feedback continue the contractions

18. Labor

19. Birth Control Methods
Male sterilization called vasectomy cuts vas deferens
Tubal ligation in females tie and cut fallopian tubes.
Keep on mind these are all when used PROPERLY, birth control pill is especially hard to use perfectly