1. Chapter 41 BIOL 1000 Dr. Mohamad H. Termos
Reproductive Systems
Chapter 41
BIOL 1000
Dr. Mohamad H. Termos

2. Asexual vs. Sexual Reproduction
Biology, 9th ed, Sylvia Mader
Chapter 43
Asexual vs. Sexual Reproduction
Asexual reproduction- parent gives rise to identical offspring; no fusion of gametes
Sexual reproduction- haploid gametes fuse together resulting in genetic variation.
Reproductive Systems

3. Biology, 9th ed, Sylvia Mader
Chapter 43
Asexual Reproduction
Fission: Parent splits into two parts
Budding: Offspring develop as small growths on parent (hydra)
Fragmentation: Part of parent is broken off and develops into a new individual (sponges, starfish)
In sexual reproduction organisms may undergo parthenogenesis, or modification of sexual reproduction. Unfertilized egg can develop into an individual. Example: honey bees (males = haploid, females = diploid
Reproductive Systems

4. Biology, 9th ed, Sylvia Mader
Chapter 43
Sexual Reproduction
Most animals are dioecious or separate sexes where egg of one parent is fertilized by sperm of another
Some animals are monoecious (hermaphroditic); which means they contain both male and female sex organs in a single body. However, the majority practice cross-fertilization with other individuals.
Animals usually produce gametes in specialized organs called gonads (Testes produce sperm, Ovaries produce eggs). Copulation: Sexual union to facilitate the reception of sperm, resulting in internal fertilization.
Many aquatic animals practice external fertilization (Gametes are released and unite outside the bodies of reproducing animals).
Reproductive Systems

5. Biology, 9th ed, Sylvia Mader
Chapter 43
How Animals Reproduce
Oviparous animals deposit eggs in the external environment. Many aquatic animals have a larval stage. Utilize different food source than adults.
Ovoviviparous animals retain their eggs and release young able to fend for themselves
Viviparous- care for developing embryo via a placenta (mammals)
Reproductive Systems

6. Biology, 9th ed, Sylvia Mader
Chapter 43
Oviparous
Reptiles and birds provide eggs with plentiful yolk
Development takes place in shelled egg
Yolk provides nutrients
Parents often tend eggs and young
Reproductive Systems

7. Biology, 9th ed, Sylvia Mader
Chapter 43
Viviparous
Placental mammals are viviparous
Do not lay eggs
Placenta – allows exchange of material between mother and developing embryo
Development occurs inside the female’s body
Care of zygote and embryo
Placental mammals eliminate need for shelled egg
Reproductive Systems

8. Human Male Reproductive System
Biology, 9th ed, Sylvia Mader
Chapter 43
Human Male Reproductive System
The Testes
Paired gonads suspended in scrotum
Sperm: Produced by testes. Mature within epididymis. Eventually enter vas deferens
- Production of Sperm takes place in the seminiferous tubules (Tubes packed with cells undergoing spermatogenesis)
Reproductive Systems

9. Biology, 9th ed, Sylvia Mader
Chapter 43
Testis and Sperm
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
MITOSIS
MEIOSISI
MEIOSISII
spermatogonium
(diploid)
primary
spermatocyte
(diploid)
secondary
spermatocyte
(haploid)
early
spermatid
(haploid)
late
spermatid
(haploid)
immature sperm
(haploid)
acrosome
head
middle piece
tail
nucleus of
Sertoli cell
end piece
c. Spermatogenesis
d. Sperm 9
Reproductive Systems

10. Human Male Reproductive System
Biology, 9th ed, Sylvia Mader
Chapter 43
Penis is organ used for copulation
Semen (seminal fluid) contains:
Sperm
Secretions from:
Seminal vesicles
Prostate gland
Bulbourethral glands
Reproductive Systems

11. Male Reproductive System
Biology, 9th ed, Sylvia Mader
Chapter 43
Male Reproductive System
Reproductive Systems

12. Human Male Reproductive System
Biology, 9th ed, Sylvia Mader
Chapter 43
Hypothalamus has ultimate control of hormones
Gonadotropic-releasing hormone (GnRH) stimulates production of hormones by the anterior pituitary
Follicle Stimulating Hormone (FSH): Promotes spermatogenesis in the seminiferous tubules
Luteinizing Hormone (LH): Controls production of testosterone by the interstitial cells of testes
Hormonal Regulation in Males
Testosterone
Major sex hormone in males
Establishes and maintains secondary sex characteristics
Reproductive Systems

13. Female Reproductive System
Biology, 9th ed, Sylvia Mader
Female Reproductive System
Chapter 43
The Ovaries, Uterus, and Vagina
An oocyte (egg) bursts from an ovary into oviduct through the fimbriae of the oviducts.
Fertilization normally occurs in the oviduct
Ciliary action moves the developing embryo to the uterus
Embryo embeds in the uterine lining (endometrium)
Cervix: Narrow end of the uterus. Opening in the cervix leads to the vaginal canal
Vagina: Contains mucosal lining. Bacteria create an acidic environment. Protects against the growth of pathogenic bacteria
Reproductive Systems

14. Female Reproductive Organs
Biology, 9th ed, Sylvia Mader
Chapter 43
Female Reproductive Organs
Reproductive Systems

15. Biology, 9th ed, Sylvia Mader
The Ovarian Cycle
Chapter 43
Follicle: primary  secondary  vesicular (Graafian) follicle under the influence of FSH and LH
Ovulation: Release of secondary oocyte from a vesicular follicle. Secondary oocyte enters an oviduct. Follicle develops in corpus luteum (Degenerates if pregnancy does not occur)
Reproductive Systems

16. Biology, 9th ed, Sylvia Mader
Chapter 43
The Ovarian Cycle
Follicular Phase: FSH promotes the development of a follicle. Follicle then secretes estrogens
Luteal Phase: LH promotes development of the corpus luteum. Corpus luteum then secretes progesterone
Reproductive Systems

17. Biology, 9th ed, Sylvia Mader
The Uterine Cycle
Chapter 43
Sex hormones affect the endometrium
A twenty-eight-day uterine cycle
Days 1-5:
Arteries that supply the lining of the uterus constrict and capillaries weaken
Endometrium disintegrates
Menses pass out of the vagina during menstruation
Days 6-13:
Endometrium thickens
Ovulation usually occurs on 14th day
Days 15-28:
Endometrium doubles in thickness
Uterine glands mature and produce a thick secretion
Reproductive Systems

18. Female Hormone Levels During the Ovarian and Uterine Cycles
Biology, 9th ed, Sylvia Mader
Chapter 43
Female Hormone Levels During the Ovarian and Uterine Cycles
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Anterior pituitary
Hormone
Levels
FSH LH
Ovarian cycle
Ovarian
Events
developing follicles
mature follicle
Ovulation
corpus luteum
Follicular Phase
Luteal Phase
estrogen
Hormone
Levels
progesterone
Uterine cycle
Endometrium
Menstruation
Proliferative Phase
Secretory Phase
Days 1 3 5 7 9 11 13 15 17 19 21 23 25 27 30
Reproductive Systems

19. Ovarian and Uterine Cycles
Biology, 9th ed, Sylvia Mader
Chapter 43
Ovarian and Uterine Cycles
Reproductive Systems

20. Fertilization and Pregnancy
Biology, 9th ed, Sylvia Mader
Fertilization and Pregnancy
Chapter 43
Embryo begins developing as it travels down the oviduct to the uterus (if fertilized)
Embedded in the uterine lining several days after fertilization
Placenta produces human chorionic gonadotropin (HCG)
Maintains the corpus luteum until placenta begins production of progesterone and estrogen
Detected in pregnancy tests 20
Reproductive Systems

21. Human Female Reproductive System
Biology, 9th ed, Sylvia Mader
Chapter 43
Human Female Reproductive System
Lactation is caused by prolactin
Colostrum is produced until milk production begins
Reproductive Systems

22. Control of Human Reproduction
Biology, 9th ed, Sylvia Mader
Chapter 43
Control of Human Reproduction
Most reliable method is abstinence
Traditional birth control regimens either prevent fertilization or stop a fertilized egg from implanting
Male and female condoms
Contraceptive vaccines
Morning‑After Pills
Reproductive Systems