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Reproductive System Female Anatomy and Hormones. Female Anatomy and Hormones. The vulva is the external opening to the urogenital tract Leads to the vagina Urine exits through the urethra into the caudal vagina and then the vuvla. Female Anatomy and Hormones.
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Female Anatomy and Hormones • The vulva is the external opening to the urogenital tract • Leads to the vagina • Urine exits through the urethra into the caudal vagina and then the vuvla
Female Anatomy and Hormones • The vagina then leads to the cervix • A firm structure that protects the opening of the uterus • During birth and “heat” the cervix can “open”
Female Anatomy and Hormones • The uterus • Has a short body the joins the two horns of the uterus • It is “Y” shaped • A hallow muscular walled organ line with epithelium that can expand dramatically to support the developing fetus
Female Anatomy and Hormones • The uterine horns branch into smaller tubes called the oviduct or fallopian tubes • These tubes lead to the ovaries • At the end of these tubes is a thin membranous tissue called the infundibulum • Wraps around the ovary to catch the released ovum
Female Anatomy and Hormones • The ovaries are located caudally to the kidneys • Has a large blood supply to keep the system working properly and to support embryo growth
Female Anatomy and Hormones • Ovaries produce ovum (eggs) through meiosis during embryo development • Precursor cells undergo the first step of meiosis then stop • The number is limited but is a larger supply then what she will use in her lifetime • Males: undergo mitosis of the precursor cells daily!
Female Anatomy and Hormones • Estrous versus Estrus • Estrous cycle: • Begins at puberty (sexual maturity) • Prepares a female to become pregnant • Cycles but varies by species • All controlled by hormones produces by the reproductive and endocrine system • Estrus: • Time of sexual receptiveness • “Heat” • Tells the male that the female is receptive to breeding • Varies in length by species
Female Anatomy and Hormones • Terms to Know: • Polyestrous: Continue to cycle until they become bred • Seasonally Polyestrous: Cycle only during certain times of the year • Anestrous: Not cycling (Milking)
Female Anatomy and Hormones • Estrous is divided into 4 phases • Hormones released during these phases differ greatly • Proestrus • Estrus • Metaestrus • Diestrus
Female Anatomy and Hormones • Proestrus • Timing: approx 3 days before heat • Prostaglandin is released by the uterus into the bloodstream • Ovary contains a corpus luteum (CL) that produces progesterone • Prostaglandin causes the CL to regress lowering the levels of progesterone in the blood stream
Female Anatomy and Hormones • Proestrus • Declining Progesterone cause the pituitary gland to secrete FSH and LH • Higher FSH causes the ovaries to develop a follicle –fluid filled sac around the egg • The follicle releases estrogen in response to the FSH • Estrogen is what is responsible for behavioral changes in the female prior to heat.
Female Anatomy and Hormones • Proestrus • LH rates increase the day prior to estrus
Female Anatomy and Hormones • Estrus • Short period of time: 8-30 hours – most tend to cycle short • Signs of Estrus: • Standing to be bred • Mounting • Bellowing • Restlessness • Excitability • Mucus discharge • Reddish and swollen vuvla
Female Anatomy and Hormones • Estrus • Follicle releases the egg 10-14 hours after onset of estrus • Ovulation - Marks day 1 of the estrous cycle • Infundibulum catches the egg and transports it to the oviduct • If animal has been bred, sperm should be present in the fallopian tubes to fertilize the eggs (fertilization) • Follicle collapses after ovulation- leaving a mark on the ovary
Female Anatomy and Hormones • Metestrus • Follows ovulation: lasts 3-4 days • Estrogen declines and LH causes the former follicle to create a Corpus Luteum (CL) – • CL produces progesterone • Stimulates the uterus to prepare to nourish the embryo • The embryo continues to travel down the fallopian tubes towards the uterus
Female Anatomy and Hormones • Diestrus (if pregnant) • Embryo moves into the uterus and implants (conception) • CL produces large amounts of progesterone to stimulate the growth of the lining of the uterus • If pregnant, the uterus will not release prostaglandin and the CL will not regress • Progesterone is essential to maintaining the pregnancy
Female Anatomy and Hormones • Diestrus – (If open) • Lasts 12-15 days • Without pregnancy the uterus will release prostaglandin and the animal will renter proestrus
Show Me What You Know… • With a partner…create a “cycle” chart that shows what occurs during estrous • Must be included: • 4 Stages of Estrous • Hormones • Where these hormones are created Be creative when making this chart! 50 Points will be given for this assignment – Most creative will earn 25 extra bonus points!