Female Reproductive System Flashcards
What are the female reproductive organs?
Ovaries
Uterine tubes (infundibulum, ampulla and isthmus)
Uterus
Vagina
Ovaries
Produces ova and hormones like estrogen and progesterone
Ampulla
Site of fertilization
Uterus
Site of implantation and embryo development
Vagina
Site of copulation
Ovary structure
Covered by germinal epithelium
Under epithelial is tunica albuginea (dense CT)
Parenchyma divided into cortex and medulla (BVs)
Ovary cortex
Contains follicles (primordial, primary, secondary, tertiary) and corpus luteum
Cow cortex and medulla
Cortex in periphery and covered by germinal epithelium
Medulla in center
Ovulation can occur at any point on cortex surface
Mare cortex and medulla
Cortex in center
Medulla in periphery
Has ovulation fossa located ventrally covered by germinal epithelium
Ovulation can occur only at the ovulation fossa
Spermatogenesis
- Spermatogonia remain dormant until puberty, divide at regular interval until death
- One spermatogonium gives rise to 64 sperm in each cycle of Spermatogenesis
- Meiosis 1 and 2 completed before sperm release
- Spermatids undergo metamorphosis
Oogenesis
- Oogonia completed mitosis (proliferation) in embryo and entered meiosis 1
- Meiosis 1 is completed
- Meiosis 2 is completed after sperm penetration
- Ootids don’t undergo metamorphosis, one oogonium gives rise to one ootid (ovum)
Where meiosis 1 arrested?
Diakinesis
This is why females have fixed number of germ cells and are oocyte-1 @ birth
When is meiosis 1 completed?
Before ovulation in ruminants and sow
After ovulation for mare and dog
Primordial follicle
Oocyte 1 surrounded by flat follicular cells
Roughly 10,000 @ puberty in cattle
Decrease with age
What is the origin of primordial follicle?
Germinal epithelium
Primary follicle structure
One or multiple layers of follicle cells
Growing follicle without antrum
Primary follicle
Activated primordial follicles
Flat follicular cells divide, enlarge and become cuboidal
Zona pellicuda formed and surrounds oocyte 1
Secondary follicle
Growing follicle with antrum
Follicle (granulosa) cells increase
Antrum formed with granulosa cell secretion
Granulosa cells
Surrounded by theca cells (CT cells) that are divided into theca interna (secretory) and theca externa
Tertiary (mature Graafian)
Large antrum surrounded by layers of granulosa cells
Oocyte 1 surrounded by corona radiata attached to granulosa cells by cumulus oophorus
Two-cell mechanism of estrogen secretion during _________ of ovarian cycle
Follicular phase
Two-cell mechanism of estrogen
- Theca cells have LH receptors and secrete testosterone
- T diffuses into granulosa cells
- Granulosa cells have FSH receptors and synthesize aromatase enzyme
- Aromatase converts T into E that diffused into the antrum and general circulation
What does a surge in estrogen lead to?
LH surge (positive feedback) that leads to ovulation
Granulosa luteal cells
Large luteal cells
80-85% of all luteal cells
Under LH, secrete progesterone