1. Reproductive System Female Anatomy and Hormones

2. 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

3. 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”

4. 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

5. 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

6. 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

7. 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!

8. 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

9. 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)

10. Female Anatomy and Hormones
Estrous is divided into 4 phases
Hormones released during these phases differ greatly
Proestrus
Estrus
Metaestrus
Diestrus

11. 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

12. 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.

13. Female Anatomy and Hormones
Proestrus
LH rates increase the day prior to estrus

14. 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

15. Female Anatomy and Hormones
Estrus
Follicle releases the egg 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

16. 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

17. 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

18. Female Anatomy and Hormones
Diestrus – (If open)
Lasts days
Without pregnancy the uterus will release prostaglandin and the animal will renter proestrus

19. 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!