Reproductive systems

1. Reproductive systems

2. دستگاه توليد مثلي مرغ

3. Hen Ovary Magnum Vagina Infundibulum Cloaca Isthmus Uterus

4. Female Reproductive Tract • Ovary • Infundibulum - site of fertilization • Magnum - albumin addition • Isthmus - membranes • Uterus - shell gland • Vagina - transport to exterior • Sperm storage occurs at various sites in tract in some species

5. Female Reproductive Tract • Ovary • Infundibulum - site of fertilization • Magnum - albumin addition • Isthmus - membranes • Uterus - shell gland • Vagina - transport to exterior • Sperm storage occurs at various sites in tract in some species

6. Compare Mammalian and Poultry Reproduction

7. Ovary: Produces the ovum Infundibulum: Receives yolk from ovary, where sperm is stored, and fertilization takes place Magnum: Secretes the thick white of the egg 3 Hours Isthmus: 2 shell membranes are placed around the yolk and thick white 1 ¼ Hours Uterus: Thin white and outer shell are added to the egg 20 Hours Vagina: Completed egg is stored for a short time til laid Total: 25-27 Hours

8. Infundibulum ≤ 1 hour Captures ova Secretes outer membrane First albumen Magnum 2 – 3 hours Albumen Avidin Ovalbumin Lysozyme Isthmus ± 1 hour Inner Outer Shell Membranes Shell gland 20 – 26 hours Plumping Shell deposition Vagina Just a few minutes Sperm storage Cuticle Pigment Oviduct Fast Facts Virtual ChickenThe Female Reproductive Tract Time ova spends in each section

9. Role of the Avian Female Reproductive Tract Manufacture ova and egg components Ova Yolk Albumen Shell Site of fetilization Sperm is stored and transported within the female tract Virtual ChickenThe Female Reproductive Tract

10. Ovary -- 2 functions Produce ova germinal disk - will become the embryo when fertilized Yolk-nutrition for the growing embryo Endocrine function Estrogen, androgens, and progesterone Oviduct Transport Packaging Virtual ChickenThe Female Reproductive Tract

11. Ovary Structure Outer cortex contain the ovarian follicles >12000 follicles Oocytes Steroid producing cell layers Granulosa Theca Inner Medulla Virtual ChickenThe Female Reproductive Tract

12. Ovarian Follicle Virtual ChickenThe Female Reproductive Tract

13. White yolk Core of the yolk Female pronucleus (female genetic material) Yellow yolk Deposited in layers on white yolk Yellow because of fat soluble pigments from feed Female pronucleus rises through yellow yolk on stalk Virtual ChickenThe Female Reproductive Tract Yolk Formation and Maturation of the Ovum

14. Rapid deposition of yellow yolk for 7-10 days prior to ovulation Yolk material is formed as droplets or spheres much like fat droplets in milk. Yolk formation is estrogen dependent Yolk components formed in liver Particles of “Very Low Density Lipoproteins” (VLDL) 12% protein 88% lipid Virtual ChickenThe Female Reproductive Tract Yolk Formation and Maturation of the Ovum

15. Proteins Apo-B, Apo-VLDL-II Vitellogenin Phosvitin, Lipovitellin Plasma proteins Albumin IgG (antibodies to protect chick) Virtual ChickenThe Female Reproductive Tract Yolk Formation and Maturation of the Ovum

16. Lipids Triglycerides (70 – 75%) Can be somewhat manipulated by changing hen’s diet Mainly palmitic, oleic acids Phospholipids (20-25%) Cholesterol (only 4%!) Virtual ChickenThe Female Reproductive Tract Yolk Formation and Maturation of the Ovum

17. 4 membranes enclose the yolk (from inside to out) Vitelline membrane Perivitelline membrane Middle continuous layer Extravitelline layer Blastodisc Location of the embryo Floats on white yolk Virtual ChickenThe Female Reproductive Tract Yolk Formation and Maturation of the Ovum

18. Ovulation Structure of the follicle causes expulsion of the ovum Stigma: avascular area Collagen structure weaker Proteolytic enzymes -digest and weaken the membranes Myofibrils - contract and cause the membranes to rupture Virtual ChickenThe Female Reproductive Tract

22. Follicle stimulating hormone (FSH) Granulosa cell differentiation Progesterone production Luteinizing hormone (LH) Androgens Estrogens Virtual ChickenThe Female Reproductive Tract Endocrine Control of Development

23. Steroidogenesis: Controlled by pituitary hormones: FSH and LH Estrogen and androgen Estrogen production dominates as the follicle begins to accumulate yolk then declines as follicle nears maturation Androgen and progesterone production maximum about 3 days prior to ovulation Androgen production ends at just before ovulation Progesterone production continues after ovulation Virtual ChickenThe Female Reproductive Tract Hormone production by follicles

24. In mammals, the parts of the follicle remaining after ovulation become the “corpus luteum” and continues to produce progesterone to support pregnancy In birds, steroidogenic capacity is retained by the postovulatory follicle for 24 hours Probably has no function since birds don’t get pregnant Gone by 6 days Virtual ChickenThe Female Reproductive Tract Post Ovulatory Follicle

25. Interval between consecutive ovulations Controlled by circadian rhythms Clock reset at dusk: open period for oviposition begins 15 hours after dusk Open period: Oviposition and ovulations occur during an 8 hour period Ovulation 30 – 45 minutes after oviposition LH release controls ovulation Virtual ChickenThe Female Reproductive Tract Ovulatory Cycle

27. Follicular Hierarchy Follicles develop in an orderly hierarchy Control of the order of follicle development is not well understood Recruitment of follicles into the hierarchy: May be adrenal regulated The Adrenal glands are essentially embedded in ovary Nerve endings on thecal cells If nerves are cut: many follicles mature at once Virtual ChickenThe Female Reproductive Tract

30. 1 4 2 3

31. 1 Infundibulum 4 Uterus 2 Magnum 5 Vagina (with egg inside) 3 Isthmus