Female Reproductive System Flashcards
1
Q
Ovaries
A
- These organs produce ova (eggs) and certain reproductive hormones.
- The eggs in the ovaries develop within fluid-filled sacs called follicles
2
Q
Oviducts
A
- These tubes move the ovulated and released eggs from the ovaries to the uterus in approximately two days.
- Moreover, the oviducts are the sites of egg maturation and fertilization
3
Q
Uterus
A
- This organ consists of two long horns and a short body.
- The uterus is the site of implantation and placental and foetal development
4
Q
Cervix
A
- This structure is a constricted orifice that serves as a channel from the uterus to the vagina.
- During pregnancy the cervix closes the birth canal and serves as a barrier against the entry of micro-organisms into the uterus
5
Q
Vagina
A
- This hollow organ extends from the cervix to the vulva.
- The inner lining of the vagina is made up of cells that undergo particular changes during the oestrous cycle.
6
Q
Vulva
A
- This structure is composed of the external genitalia, which includes the clitoris (sexual organ) and two vertical lips.
7
Q
FSH
A
Follicle Stimulating Hormone
8
Q
LH
A
Leutenizing Hormone
9
Q
Effects of Oestragen
A
- it stops FSH being produced (inhibitory effects in first 10 days) - so that only one egg matures in a cycle. (see a decline in follicular phase as Oestrogen levels rise)
- at low levels it inhibits LH (negative feedback in first 10 days) release but at higher levels it stimulates the pituitary gland to release the hormone LH
- Stimulates bone and muscle growth
- Stimulates endometrial growth
- Maintain Female secondary characteristics
- Maintain Glands
10
Q
LH surge
A
- In low concentration, Oestrogen inhibits LH secretion
- However, at high concentration, Oestrogen stimulates LH secretion
- Increase in GnRH secretion and Oestrogen stimulate LH secretion and you see a resulting surge of LH
- This will trigger ovulation of the most mature follicle in the ovary! - Only release one per cycle!
- the oocyte (female egg) will then be released
- After the release of the egg (ovulation), LH levels and GnRH levels will fall and FSH (which has a small surge as a side effect of the LH surge)
11
Q
Corpus Luteum
A
- After the follicle ovulates and releases the oocyte, it essentially becomes “dead”
- This is when it develops into a Corpus Luteum and becomes a progestrone producing machine (in addition secretes oestrogen and inhibin)
- Slowly degrades over time
- Inhibin: has a negative feedback and will inhibit the secretion of FSH (follicular phase is over). Don’t need any more follicles to mature JUST yet in the luteal phase. Inhibin halts follicle maturation
- As secondary luteum develops, inhibin secretion supresses FSH secretion
12
Q
Progesterone
A
- VERY IMPORTANT IN LUTEAL PHASE
- has negative feedback on hypothaamus to inhibit the secretion of GnRH
- During ovulation, progesterone levels will increase slowly as oestrogen levels will decrease slowly (somewhat). This will suppress GnRH release whcih will also affect the release of FSH and LH
- Progesterone and Oestrogen stimulate Endometrial growth (lining of uterus) - also is where the egg will implant if it is fertilized
- If there is no fetrilization, the CL will continue to degenerate in the ovary and there will be space for the follicles to mature again
- Hormones that are produced by the corpus luteum will drop as it degrades, including progesterone, whcih means there won’t be inhibition of GnRH release anymore–> this will allow for a new menstrual cycle to occur!
- Also with the decrease in hormones produced by CL, means that the endometrium cannot be maintained in the uterus so therefore it will shed
13
Q
Follicle
A
- start off as primordial follicles
- Made up of: 1 primary oocyte (egg cell), Layer of Granulosa cells around oocyte
- Granulosa cells become more numerous as the follicle matures
- Granulosa cells secrete: oestrogen, inhibin, and progesterone
- At time of ovulation: follicle will eject out the secondary oocyte
14
Q
Two Types of reproductive (Ovarian) Cycles
A
- Oestrus Cycle
- Menstrual Cycle
15
Q
Oestrus Cycle
A
- dynamic process
- gives the female the opportunity to get pregnant
- comprises the recurring physiological changes that are induced by reproductive hormones in most mammalian therian females.
- Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases or by pregnancies.
- Typically, estrous cycles continue until death
*
16
Q
Canine Uterus
(Bitch)
A
- quite small in relation to other species
- Uterine walls are quite narrow and long, but are not convoluted
17
Q
Ovarian Bursa
A
- the peritoneal recess between the medial aspect of the ovary and the mesosalpinx
- In the bitch, the ovary projects and is entrapped in a bursa created by the fusion of the distal mesovarium and the mesosalphinx
- bursa contains enough fat in bitches to conceal the ovary
18
Q
Attachments (Ligaments) of the Reproductive Tract
A
- Broad Ligament: bilateral sheets that anchor organs to abdominal roof and pelvic walls
- Reproductive system is attached to the bones of the pelvis via various ligaments
- the mesometrium: ligament that holds the uterus
- the mesosalphinx: holds the oviduct
-the mesovarium: holds the ovary
- Round Ligament: lateral fold
- Inter-cornual ligament: attaches uterine horns
- important for veterinarians when you do rectal palpation
- can use it to retract uterus and then the ovaries can come into your hand and you can examine them
- Suspensory Ligament: peritoneal fold attaches ovary to abdominal wall adjacent to last rib
19
Q
Vasculature of Reproductive System
A
- Uterine Branch of the ovarian artery
- Ovarian artery (off Aorta)
- Uterine artery (off the internal iliac**)
NOTE: in the mare the uterine artery is from the external iliac
- Vaginal artery
- Ovarian vein
- Uterine vein
- Vaginal vein
20
Q
Structural Parts of the Ovary
A
- Tunica Albuginea- thin connective tissue capsule underlying the germinal epithelium
- Cortex- surrounds the medulla and contains maturing follicles. Can see all different classes of ovarian follicles (primordial follicle, primary follicle, and so on..)
- Medulla- central connective tissue containing vascular supply and nervous innervation that pass through the ovary
21
Q
2 Functions of the Ovary
A
- Produce female gametes through oogenesis and folliculogenesis
- Hormone production (oestrogen and progesterone; also oxytocin , inhibin, activin)
-all the hormones produced by the ovaries
22
Q
Zona Pellucida
A
- The zona pellucida (plural zonae pellucidae, also egg coat or pellucid zone) is a glycoprotein layer surrounding the plasma membrane of mammalian oocytes.
- It is a vital constitutive part of the oocyte.
- The zona pellucida first appears in unilaminar primary oocytes (late primary follicle/secondary follicle)
23
Q
Graafian/Mature Follicle
A
- Antral follicle to Graafian follicle (mature)
- This is the follicle stage that releases the egg upon ovulation
- Afterwards become the structure called the Corpus Luteum
- 2 important cells within the wall of follicle
: important for production of estrogen and then later on progesterone (Granulosal cells and Thecal cells(internal and external thecal))
24
Q
Classifications of Uterus
A
- Duplex (advanced and regular)
- 2 vaginas vs. one vagina (both with 2 cervices and 2 uterine horns)
- Bicornate (longer uterine horns–> pig/bitch) or Bipartite (smaller uterine horns–> cow, ewe, doe)
- Modified Bipartite (Mare)
-Larger Uterine Body with smaller Uterine Horns
- Simplex
-no uterine horn, all uterine body
25
Q
Duplex Uterus
A
- opossum, mouse, rabbit
- two cervixes
- no uterine body
- one or two vaginas
- the uterine horns are completely separated and have separate cervices opening into the vagina
26
Q
Bicornuate (Bipartite) Uterus
A
- cow, ewe, mare, sow, bitch, queen
- 2 uterine horns
- one cervix
- uterine body
- poor to good development of uterine horns
- one vagina
- the horns are largely separate but enter the vagina by a single cervix
27
Q
Simplex Uterus
A
- primate
- one cervix
- uterine body
- no uterine horns
- one vagina
28
Q
Cow
(Uterus)
A
- Bipartite Uterus
- Cervix is 2-5 annular rings
- Uterus lining: 70-120 caruncles
29
Q
Ewe
(uterus)
A
- Bipartite
- Cervix: 3-6 annular rings
- Well Developed Hymen
- Uterus lining: 70-120 caruncles
30
Q
Sow
(uterus)
A
- Bicornuate
- Uterus lining: Longitudinal Folds
- Corkscrew cervix
- Ill defined os cervix
- ill-defined hymen
31
Q
Mare
(uterus)
A
- Bipartite (modified)
- Uterus lining: Conspicuous longitudinal folds
- Cervix: Conspicuous folds
- Clearly defined Os Cervix
- Well developed Hymen
32
Q
Cervix of Different Species
A
- Cow, ewe - cervix has annular rings, ewe has more obstacles
- In cow can do artificial insemination
- but in the sheep it is very difficult, need to go another route
- Mare- longitudinal folds
- Sow - interdigitating prominences, no fornix
- During pregnancy, the cervix is filled with a thick mucus secretion known as the cervical plug, which protects the uterus from infections entering fromt he vagina
33
Q
Functions of the Oviduct
A
- Capture and transport oocytes and convey sperm in ascent
- Site of fertilization (ampulla)
- Nutrition of gametes and zygote
- Times transport of developing zygote to uterus
- Muscle in the Isthmus is thicker
- When egg is released after fertilization the oviduct can catch it
- at the top of the infandibulum is the fimbria
- Fertilization is at the ampula-isthmus junction in most animals!
- in humans it is in the ampulla
34
Q
Vagina
A
- Copualtory Organ
- glands secrete lubrication
- birth canal
- glands secrete pheromones: important to attract a mate
- Site of expulsion of urine
- anterior of the vagina is columnar but becomes stratified as you get to the outside
- columnar epithelium in anterior
- stratified squamous epithelium in posterior
35
Q
Menstrual Cycle Hormones
A
- LH surge is responsible for two things:
- Follicular Rupture (ovulation)
- Resumption of meiosis
36
Q
Classification of Oestrus Cycles
A
- By Phase/hormones present:
Follicular Phase: Oestrogen-dominant
Luteal Phase: Progesterone-Dominant
- Vaginal Cytology
-Pro-Oestrus (oestrogen dominant)
-Oestrus (Oestrogen Dominant)
-Metoestrus (Transitional Period)
-Dioestrus (Progesterone dominant)
- Based on Changes in the Cytology of the endometrium:
-Proliferative Phase: Oestrogen Dominant
Secretory Phase: Progesterone Dominant
42
Q
Rules of receptors on Follicles
A
- Theca cells always have LH receptors , never FSH receptors
- Granulosa cells always have FSH receptors, LH receptors are acquired from mid-follicular phase onwards
- Dominant follicle survives fall in circulating levels of FSH by being able to respond to LH through the acquisition of LH receptors
57
Q
Endometrial Cups
A
- Endometrial cups form during pregnancy in mares and are the source of equine chorionic gonadotropin (eCG) and a placenta-associated structure, which is derived from the fetus.
- Their purpose is to increase the immunological tolerance of the mare in order to protect the developing foal
58
Q
Polyhedral Trophoblasts Cells
(Mare Endometrial Cup)
A
- Large polyhedral cells of chorionic origin, mostly bi-nucleate in morphology- produce equine Chorionic Gonadotropin (eCG) previously called PMSG
- Lymphocytes sit around the periphery of the trophoblast cells and will eventually invade the cups. It is speculated that the lymphocytes may destroy the cup cells but experimental data supporting this is limited
60
Q
Ewe Placentome and placenta
A
EPITHELIOCHORIAL.
NON DECIDUATE or INDECIDUATE.
VILLOUS
COTYLEDONARY with CONCAVE PLACENTOMES.
The fetal cotyledon and the maternal caruncle comprise the placentome
63
Q
Ewe Placentome
A
65
Q
Cow Placentome
A
EPITHELIOCHORIAL.
NON DECIDUATE or INDECIDUATE.
VILLOUS
COTYLEDONARY with CONVEX PLACENTOMES.
The fetal cotyledon and the maternal caruncle comprise the placentome.
66
Q
Placental Area
(cow placentome)
A
- chorionic villi
- maternal crypts
68
Q
Cat Placenta
A
ENDOTHELIOCHORIAL.
DECIDUATE.
LABYRINTHINE.
ZONARY.
69
Q
4 Layers Present in Endothelialchorial
A
- Maternal endothelium lining blood vessels.
- Fetal chorion.
- Fetal stroma.
- Fetal endothelium lining blood vessels.
73
Q
Chorionic VIlli of Chorion Wall
A
76
Q
Maternal Recognition of Pregnancy in Cow/Sheep
A
- Dramatic ↑ in oxytocin receptor number which coincides with time animal goes through luteolysis- these respond to oxytocin produced by CL release of PGF2α luteal regression.
- If animal= pregnant then oxytocin receptors stay ↓ due to type 1 interferon (tau) secreted by the embryo, ensuring progesterone secretion remains high
80
Q
MRP in the Sow
A
Conceptus secreted MRP signal= oestradiol, acts in 3 ways
-
Changes the direction in which PGF2α is secreted
* (secreted uterine lumen instead of vein in an exocrine (excrete by way of a duct) fashion rather than endocrine) overall ↓ in prostaglandin secretion - Oestradiol causes the CL to gain ↑ LH receptors - so becomes more sensitive to LH & produces more progesterone (luteotrophic action).
-
Oestradiol also ↑ secretion of PGE2 (prostaglandin E2) from the uterus which binds to CL & stimulates progesterone production
* Overall: Antiluteolytic and luteotrophic
81
Q
MRP in the Mare
A
- Continues to ovulate even when pregnant
- Luteolysin is still thought to be PGF2α
- There’s downregulation of oxytocin receptors but no idea what causes this & oxytocin doesn’t come from CL but from the endometrium itself.
- Fetus stays round & migrates until day 17 before implanting- distributing MRP signal around the uterus. Prevention of this migration= abortion- -In every other species that we know, when it gets to the oviduct it wants to attach and start to develop a placenta. In the mare, that is not the case
- the conceptus is circular and goes round and round the uterus
- if you prevent this motion or immobilize it, it aborts
- Around day 35 endometrial cups form, which equine chorionic gonadotrophin induces secondary ovulations which allows accessory CL to be formed (eCG ↓ at ~ day 100)
- Embryo secretions:
- Secretes PGE2 (for oviduct transport) shortly after fertilisation & enters the uterus around day 6.
- Secretes PGF2α & PGE2 for transuterine motility
- Around day 10 it starts secreting oestrogens (suggested MRP signal- but unproven)
- Conceptus secretes signal for luteal survival (don’t know what though)
- At day 17 conceptus secretes molecule ↑ in uterine tone fixation
- There must be a factor secreted that maintains the primary CL until the secondary CL forms & can take over, but still unknown.
- Secondary (accessory) CL will secrete progesterone until the placenta takes over (~day 100)
