Female Anatomy
What hormone do follicles and the corpus luteum produce?
Estrogen (follicles) & Progesterone (Corpus luteum)
What are the hormones that regulate reproduction?
What is the primary ovarian structure and dominant hormones during the luteal phase?
Corpus luteum and progesterone
What causes the surge of GnRH?
Estrogen
What is the intermediate structure from ovulation to a functional corpus luteum?
Corpus Hemorrhagicum
Bonus: What stage of the estrous cycle contains a corpus hemorrhagicum?
How is the mare different in regards to the ovary?
Medulla is the outer layer
Cortex is the inner layer
Ovulation can only occur at the ovulation fossa
The Corpus luteum can not be palpated
What is the primary ovarian structure and dominant hormone during the follicular phase?
Developing follicle and Estrogen
What are some differences between the menstrual cycle and the estrous cycle?
Menstrual cycle: (50/50; longer fertile period; sloughing of the endometrium; menopause)
Estrous cycle: (20/80; low fertile period)
When is the follicular phase initiated?
After luteolysis, progesterone secretions decrease removing the negative feedback progesterone had on the hypothalamus allowing for GnRH to be secreted in higher amplitudes and frequencies.
What will occur if the female does not become pregnant?
The regression of the corpus luteum caused by luteolysis and will become the corpus albicans.
Label the layers of the ovary:
What are the 4 stages of the estrous cycle?
Define anestrus and provide examples of when a female would experience anestrus?
Refers to when a female does not display estrus
pregnancy, poor nutrition, prepubertal, and seasonal
Name the 5 events of folliculogenesis and briefly explain them:
Why does the corpus luteum weigh more than an ovulatory follicle?
Large luteal cell undergo hypertrophy and small luteal cells undergo hyperplasia making the structure more dense. The corpus luteum also has a high metabolic demand that needs more oxygen then other organs in the body leading to hyperemia to meet that standard.
What are the layers of the uterus and what are they composed of:
Bonus: What other structure within the female reproductive anatomy have these layers?
List the different estrous cycles, explain what they are, and one species that associated with the cycle:
List 3 functions of progesterone in the female:
Inhibits estrus and parturition
Blocks myometrial contraction
Stimulates endometrial secretions of nutrients for embryo
Decreases basal GnRH from hypothalamus
Regresses CL if female is not pregnant
Why can the oocyte resume maturation after gap junctions are destroyed?
The LH surge break down gap junctions which then removes the meiotic inhibition signal from the gap junctions. Meiosis can then resume leading to a haploid oocyte with the first polar body. This haploid oocyte then can be fertilized.
Explain the difference between small and large luteal cells:
Large luteal cells:
- granulosa cells
- produce progesterone, oxytocin, and relaxin
- have PGF2a receptors
-developed from hypertrophy
Small luteal cells:
- theca cells
-produce progesterone
-receptor for oxytocin
-developed from hyperplasia
Label all parts of the Tertiary Follicle and provide details of the structures:
Theca layer (have LH receptors)
Basement membrane
Granulosa layer (have FSH receptors)
Antrum
Cumulus oophorus (granulosa cells that SURROUND the oocyte)
Corona radiata (specialized granulosa cells that are DIRECTLY attached to the zona pellicuda and contain gap junctions)
Zone pellicuda (muco-protein surrounding the oocyte and early embryo)
Describe how photoperiod during the longs days affect mares and ewes?
Label the graph of the bovine estrous cycle:
Complete the following regarding ovulation chart:
Explain the hormone profile of estrogen and progesterone during the luteal phase of the estrous cycle:
Progesterone starts to increase in production due to the formation of the Corpus luteum. Increase production of progesterone will cause a negative feedback on the hypothalamus suppressing the secretion of GnRH. The suppression of GnRH will lead to the suppression of LH and FSH. The suppression of these hormones will prevent final follicular development and ovulation.
Progesterone will promote the development of the mammary glands, cause the secretion for "uterine milk" to support the embryo, decrease myometrial contractions, and stimulates the production of a a thick mucous from the cervix to prevent sperm entry. This is to prepare an environment for the embryo to develop in.