Female Reproduction 1 Flashcards
what are the 4 layers of the ovary?
Germinal Epithelium
Tunica Albuginea
Cortex
Medulla
When does Oocyte formation occur?
Only during fetal development
How do primordial germ cells become primary oocytes?
Primordial germ cells–>Oogonia–>proliferate–>enter meiosis–>arrest in prophase of 1st meiotic division
What are the features of a Primordial follicle?
Primary oocyte
Simple squamous follicular epithelium
Dormant
What activates primordial follicles?
Follicle stimulating hormone (FSH)
What do follicular cells produce when they are activated? and what does this do?
Aromatase–converts precursor steroids into estrogen–drives follicular cell mitosis
What are characteristics of unilaminar primary follicles?
Primary oocyte growing rapidly
Epithelium-simple cubodial
What are characteristics of Multilaminar primary follicles?
Primary oocyte growing larger
Epithelium-Stratified cubodial
NOW a GRANULOSA
zona pellucida
Filopodia from granulosa cells-penetrate zone pellucid to contact oocyte microvilli
Gap junctions- for transport/signaling across the granulosa and zone pellucida
What are characteristics of Secondary (astral) follicles?
Granulosa cells--proliferate and con'd to produce estrogen Follicular liquid (secreted by Granulosa cells)--rich in hyaluronic acid/steroid binding proteins- Forms ANTRUM
Primary oocyte + stratified cuboidal epithelium + one or more fluid filled spaces
What are characteristics of Graafian (mature) follicles?
Follicular liquid swells the follicle to 2-cm diameter
Stigma-whitish, transparent bulge on the ovary surface
Secondary follicle that pushes the ovary surface outward
What is the function of the theca externa?
Supportive outer layer of smooth muscle/fibroblasts/collagen
What is the function of the theca interna?
Highly vascular inner layer with steroid hormone-producing cells–for estrogen production by granulosa
What is Atresia and when does it occur?
Programmed cell death of ovarian follicles
Can occur at any time during follicular development
What is corpus fibrosum?
Large atretic follicles collapse and their BM thickens into a transient, collagenous scar
How does ovulation start, what hormone is involved?
Luteinizing hormone–stimulates ovulation by triggering changes that weaken the follicle wall and increase follicular liquid production
What occurs prior to ovulation?
primary oocyte completes asymmetric first meiotic division–one nucleus is extruded as a tiny cell—1st polar body
The oocyte commences the second meiotic division–but arrests at metaphase–secondary oocyte
What occurs 24 hours after ovulation if fertilization occurs?
The secondary oocyte completes a highly asymmetric second meiotic division
Produces second polar body and mature ovum
What occurs 24 hours after ovulation if fertilization doesn’t occur?
Secondary oocyte degenerates
After the secondary oocyte is expelled from the ovary to the peritoneal space its an Oocyte complex, what is this composed of?
Secondary oocyte
Zona pellucida
corona radiata
What is the corpus luteum?
ruptured follicle after ovulation–caused by LH
Granulosa cell of the collapsed follicle differentiate into steroid hormone-producing cells– luteinized granulosa cells
Theca interna differentiate into luteinized theca cells that continue to produce steroid hormones
Both of these hypertrophy
Lipochrome pigments accumulate in luteinized granulosa cells
What is the function of the corpus luteum?
Produces progesterone and estrogen
What does progesterone do?
Stimulates the uterine lining to prepare for embryo implantation
What happens to the corpus luteum in absence of pregnancy?
Undergoes luteolysis
Macrophages engulf debris and a large dense CT scar is formed—corpus albicans
What happens to the corpus luteum in the presents of pregnancy?
human chorionic gonadotropin (HCG) produced by the developing placenta mimic LH–sustains the corpus luteum through the beginning of pregnancy.
