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Reproductive_Physiology - Reproductive Physiology...

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Unformatted text preview: Reproductive Physiology Reproductive Physiology Dr. Mickey A. Latour Purdue University, Smith Hall, West Lafayette, IN 47907 Reproduction Reproduction The following topics will be discussed: - Male reproduction Male - Female reproduction - Embryonic Development and Embryonic Implantation Implantation - Gestation and Parturition Gestation Reproduction Reproduction • The role of the male is less complicated than the female. • Whether boar, bull, ram, stallion, tom, or rooster, all males have the same basic function: Reproduction Reproduction • Male reproduction system consist of: (a) the testicles, which produce sperm (b) the duct system, which delivers sperm and semen Reproduction (Terms) Reproduction • Testicles • Seminiferous tubules • Vas deferens • Rete testis • Sperm vs Semen • Acrosome • Epididymis • Bulbourethral gland • Urethra Reproduction Reproduction Testes Glands Penis Retractor Penis Reproduction Reproduction • Pathway for sperm Seminiferous tubules----Rete testis---Epididymis--vas deferens---Urethra Tail Nucleus/Head Acrosome Reproduction Reproduction Controlling the production of sperm • Sperm production is regulated by production of the male hormone, testosterone which is consequently regulated by pituitary hormone, follicle stimulating hormone (FSH) and leuteinizing hormone (LH). • The production of FSH and LH are time dependent, i.e., sexual maturity. Reproduction (Sperm Production) Production) • Scrotum •Cremaster muscle • Pampiniform plexus •Tunica dartos Factors Affecting Sperm Production Factors • Nutrition Vitamin A and protein seem to be the critical nutrients involved in sperm production. •Temperature This is usually a temporary effect. • Age & Genetics •Castration •Cryptorchids Reproduction Reproduction (Terms) Reproduction • Ovaries Is the site of gamete formation (ova). Like the testes, the ovaries receive stimulation from FSH and LH. • Oviduct Connects the ovary to the uterine horn, thus the passage way for the ova. The portion of the oviduct surrounding the ovary is call the infundibulum. • Horns • Cervix • Vagina • Vulva Reproduction Reproduction Reproduction Reproduction Reproduction (Female Hormones) (Female • Gonadotropin-releasing hormone (GnRH) Is produced in the hypothalamus and controls the release of FSH and LH. • FSH Stimulates follicle development within the ovaries. • LH Triggers ovulation/release of the ova. • Estrogen •Progesterone •PGF2α Reproduction Reproduction Estrus cycle • Proestrus the beginning stages of follicle development • Estrus the period where the female is receptive to breeding • Metestrus •Diestrus Reproduction Reproduction Species Cycle(d) Heat (h) Cow Sow Ewe Mare Fowl 21 12-18 20-21 48-72 16-17 24-36 19-23 90-170 nearly every day Time of OvulationSuggested Breeding Time 12-15 after ovulation 18-40 after start of estrus 18-26 after start of estrus 1 d before & 1 d after est. usually occurs at dusk 4-8 h before end of estrus 24 h after start of estrus 12-18 after start of estrus alternate d during estrus at ovulation Reproduction Reproduction Gestation Length: Cow 282 days Sow 114 days Ewe 150 days Mare 336 days Fowl 1 day Reproduction Reproduction Embryo Development and Implantation Fertilization Fertilization Usually occurs within 24 to 36 hours of copulation in mammals. Usually In birds, fertilization occurs within 15 to 20 minutes of ovulation. In For fertilization to occur, the sperm must have to penetrate the For egg (i.e.,undergone capacitation). egg Only one sperm fertilizes the egg via enzymes present on the Only head surface. Following Fertilization Implantation of Embryo Implantation Embryo’s implants in the uterus which is rich in blood and provides Embryo’s fluids to the developing embryo. Following implantation, the embryo begins to develop extraembryonic membranes, called placentation. Chicks are developed completely in the egg laid and are Chicks independent of maternal care. independent Following Fertilization Implantation to Placentation Implantation Development of extra-embryonic membranes (placenta). Placenta functions to: a) provide nutrients and vital gases, b) removal Placenta of waste products, and c) production of hormones to maintain pregnancy pregnancy Chicks develop a placenta like structure and provides an avenue for Chicks nutrients. Embryo Structure Embryo Chorion Embryo Amnion Parturition Parturition Defined as giving birth. • Towards to final days of gestation, estrogen production is increased by the placenta, which in turn stimulates prostaglandins (PGF2α) from the uterine wall. • The PGF2α lowers progesterone levels. While the CL is regression it begins to release relaxin a hormone which relaxes the pelvic muscles and ligaments in the pelvic area. • Around the time of birth, the hormone prolactin increases to stimulate milk synthesis. • The hormone, oxytocin brings about steady contractions during the birth process. Breeding (Artificial Insemination) (Artificial A) more genetic improvement through use of sires B) reduction or elimination of sires (not true for turkeys) C) reduces the risk of spreading certain reproductive diseases ...
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