Ovarian and Uterine Cycle Flashcards
TRUE OR FALSE:
Both ovaries and testes contain nurse and steroid-secreting types of cells
TRUE
- both gonads contain nurse (support), steroid-secreting, and germ cells
TRUE OR FALSE:
Both ovaries and testes release gametes into ducts/tubules within the internal reproductive tract.
TRUE
TRUE OR FALSE:
Both ovaries and testes release gametes into internal tubule systems within the gonad.
FALSE
- While both ovaries and testes release gametes, the statement about releasing them into internal tubule systems within the gonad is not accurate for both.
- In females, the ovaries release eggs (ova) into the fallopian tubes not internal tubule systems within the gonad.
- In males, the testes release sperm into a system of ducts that includes the epididymis, vas deferens, and ejaculatory duct, not directly into internal tubule systems within the gonad.
TRUE OR FALSE:
Gametogenesis involves the proliferation of support cells in both ovaries and testes.
FALSE
- gametogenesis involves the maturation of gametes in the ovaries and testes
TRUE OR FALSE:
Both ovaries and testes only release one (or occasionally) two gametes at one time.
FALSE
- testes release many sperm at once, while ovaries only release a single ovum at a time
TRUE OR FALSE:
Both ovaries and testes can maintain the release of gametes throughout adulthood as long as sex steroid levels are maintained.
FALSE
What are the internal genitalia of the female reproductive system
- ovaries (gonads)
- uterine (Fallopian) ducts
- uterus
- vagina
What are the external genitalia of the female reproductive system
- mons pubis
- clitoris
- labia
Why is the vagina considered both an internal and external genitalia of the female reproductive system
It is structurally internal but during embryonic development it was formed outside?
What is the role of internal genitalia in the female reproductive system
to help move, protect, and nourish an ovum/zygote before and after fertilization
What are the functions of the female reproductive system
- manufacture gametes (ova)
- provide nourishment and protection to a developing embryo
Describe the function of the following female reproductive structure:
Ovaries
make the ova (oogenesis)
Describe the function of the following female reproductive structure:
Uterus
site of embryonic and fetal development
Describe the function of the following female reproductive structure:
Clitoris
erectile tissue; responsible for pleasurable sensations associated with the sexual response
Describe the function of the following female reproductive structure:
Vagina
responsible for receiving sperm and for pleasurable sensations associated with the sexual response
- birth canal
Describe the function of the following female reproductive structure:
Uterine tubes/Fallopian tubes
site of fertilization
What does bipotential gonad mean
- has the potential to become either male or female
- depending on the signals from SRY -> may push towards male or female reproductive system
- bipotential refers to the capability of a structure to differentiate into either male or female reproductive organs
During the embryonic period, there are two ducts, which one degrades and which ones develops into the female reproductive system
- Wolffian duct degrades
- Mullerian duct becomes part of the female reproductive system
True or False:
The Fallopian tube is attached to the ovary
FALSE
- the Fallopian tube is not attracted to the ovary
- there are like little hand-like projections that sweep the ovaries
What are the three classes of cells organized into clusters/layers in ovarian follicles
- Steroid-secreting cells
- Germ cells
- Nurse (support) cells
Describe the regions of a mature ovary
- cortical and medullary regions
- ovarian hilum
- germinal epithelium
- tunica albuginea
What is the ovarian hilum of the ovary
a ligament like structure that connects the ovaries to the rest of the reproductive tract
What is the germinal epithelium of the ovary
outer epithelium surrounding the ovary
What is the tunica albuginea of the ovary
part of the layer surrounding the ovary, but is a layer of dense connective tissue just beneath the germinal epithelium
What is the cortex and medulla of the ovary
cortex = outside
medulla = middle region
Where do oocytes develop
Oocytes develop within follicles in the ovarian cortex
- housed in follicles
What type of cells do oocytes form from
Oocytes form from germ cells within ovarian follicles, surrounded by two classes of support cells
- develop within follicles in the ovarian cortex
What are germ cells called in the female reproductive system
oogonia/oocytes
What are support/nurse cells called in the female reproductive system
granulosa cells
What are steroid-secreting cells called in the female reproductive system
theca/thecal cells
Compare and contrast the names of the three functional classes of cells in the male vs female reproductive system
Male
- Spermatogonia/spermatocytes
- Sertoli cells
- Leydig cells
Female
- Oogonia/oocytes
- Granulosa cells
- Theca/thecal cells
Describe the layering of the three types of cells in the ovaries
Inside = primary oocyte
Middle = granulosa cells
Outside = theca cells
How many oocytes form from oogenesis
ONE gamete and 2-3 non-functional polar bodies
What is oogenesis
Process by which ova are produced
- process that involves both mitosis and meiosis
Trace the steps of oogenesis
- Start with oogonium/oogonia
- undergoes mitosis and divides into two offspring cells with 46 chromosomes - Becomes a primary oocyte
- only one of the offspring cells from mitosis enters meiosis I
- formation of tetrads
- becomes a secondary oocyte - Secondary oocyte forms 1 gamete (ovum) with 23 chromosomes
- the other 3 become polar bodies that do not progress (will degrade)
When does oogenesis begin
Begins during embryonic development, continues during the ovarian cycle and is not fully complete until fertilization
What is an oocyte
Oocyte = immature egg cell
Oogonia = germ cell (very immature)
Ovum = mature egg cell
Ova = multiple mature eggs
Describe how it goes from
oogonia -> oocyte -> ovum
Oogonia -> oocyte = oogenesis
Oocyte -> ovum = maturation and fertilization by sperm
How long is oogenesis
~14 days (shorter than spermatogenesis)
True or False:
Oogenesis occurs in parallel with development and growth of the follicle surrounding an individual oocyte
TRUE
Trace the path of oogenesis and follicle development
- Get primary oocytes by 5 months of development
- primordial ovarian follicles in egg nest - Formation of primary ovarian follicle
- development of primary oocyte, theca cells, and granulosa cells - Formation of secondary ovarian follicle
- development of zona pellucida
- protective layer around oocyte - Formation of a tertiary ovarian follicle
- develops antrum containing follicular fluid
What is the zona pellucida
Protective layer around the oocyte
What condition must be met in order for a follicle to be considered a tertiary follicle
- needs antrum
- space with fluid
- space with no cells
- contains a secondary oocyte
- ready for ovulation
How many follicles reach the tertiary stage of development
Usually only 1 follicle per cycle reaches this stage
TRUE OR FALSE:
Oocyte activation and maturation is accompanied by cell proliferation and differentiation in its surrounding follicular cells (granulosa and thecal cells)
TRUE
What is ovulation
The rupturing of the follicle, release of the secondary oocyte and transformation into the corpus luteum
What is the corpus luteum
Follicular granulosa cells that are converted into corpus luteum after ovulation
When does ovulation usually occur
~day 14 of the ovarian cycle
What does atretic mean
Follicles that do not complete the process of ovulation become ATRETIC during the LUTEAL phase of the cycle
- non-functional and the oocyte cannot be reactivated
Approx how many oogonia do you have at birth and at puberty
During early embryonic development, you get ~7 million oogonia
At birth, the number goes down to 2 million oogonia
By puberty, only about 400,000 oocytes remain (~20% of what you started with)
What is one major side effect of ovarian atresia
Loss of fertility
What is the HPG axis
hypothalamus
pituitary
gonad
What controls oogenesis and ovarian hormonal secretions
the HPG axis controls oogenesis and ovarian hormonal secretions
- levels of HPG hormone secretion vary across the ovarian cycle
What is the role of FSH in the ovarian cycle
- stimulates follicle proliferation
- stimulates secretion of aromatase by granulosa cells
- stimulates secretion of regulatory hormone inhibin
What is the role of LH is the ovarian cycle
- stimulates meiosis
- stimulates ovulation
- stimulates corpus luteum formation
- stimulates secretion of testosterone by thecal cells
- stimulates secretion of progesterone by corpus luteum
What is aromatase
enzyme that converts testosterone to estrogen
How does inhibin provide negative feedback for FSH secretion
- GnRH from hypothalamus goes to anterior lobe of pituitary gland
- Pituitary gland produces and secretes FSH
- FSH acts on ovaries
- Granulosa cells in ovaries releases inhibin
- Inhibin provides negative feedback on FSH from anterior pituitary
Hoes estrogen control LH secretion
- GnRH from hypothalamus goes to anterior lobe of pituitary gland
- Pituitary gland produces and secretes FSH
- FSH acts on ovaries
- Granulosa cells produce estrogens that cause the secretion of LH (causes ovulation/corpus luteum formation)
COMES DOWN TO THE LEVEL OF ESTROGEN THAT WE HAVE
- low estrogen = negative feedback = inhibits secretion of LH
- high estrogen = positive feedback = increased secretion of LH
Why do estrogen levels rise despite negative feedback on LH from Days 1-10
Because of follicular cell proliferation (more cells that can secrete = more hormones)
What role does progesterone have in negative feedback of GnRH secretion
1.1. GnRH from hypothalamus goes to anterior lobe of pituitary gland
2. Pituitary gland produces and secretes LH
3. LH acts on ovaries
4. LH causes ovulation and corpus luteum formation
5. Corpus luteum secretes progesterone
6. High levels of progesterone shuts off GnRH release
- acts on hypothalamus
How are progesterone, estrogen, and inhibin different in their feedback loops
Progesterone = negative feedback on GnRH secretion (acts on hypothalamus)
Estrogen = can be positive or negative feedback on LH secretion (acts on anterior pituitary)
Inhibin = negative feedback on FSH secretion (acts on anterior pituitary)
How do oral contraceptive pills work
Use synthetic forms of estrogen and/or progesterone to suppress ovulation through negative feedback
What is the result of ovulation
Release of a mature secondary oocyte from its follicle into the peritoneal cavity
- ovaries are not directly attached to the uterine tubes
- still surrounded by protective layer
How do oocytes move from the ovaries to towards the uterus
Released oocytes enter the uterine (Fallopian) tube and are moved toward the uterus
- a ciliated epithelial layer creates currents that pull the oocyte into the tube and propel it toward the uterus
- lined with epithelial layer that has cilia
- fluid current sucks whatever is floating in the opening into the uterine tube
- pulls it into the uterine tube and to the uterus
Where does fertilization take place
in the uterine tube
What is the uterus
a hollow organ with a thick, muscular wall and a glandular lining that can grow and shrink
What are the three layers of the uterus
- Perimetrium
- Myometrium
- Endometrium
What is the perimetrium
protective outer membrane
What is the myometrium
smooth muscle
What is the endometrium
secretory inner membrane
What are the two layers of tissues and two different types of arteries in the endometrium
- functional layer
- basal layer
- simple columnar epithelium
- stroma (connective tissue)
Differentiate the functional layer from the basal layer of the endometrium
The two layers refer to parts of the stroma (connective tissue) with different functions
- functional layer = closer to lumen
- basal layer = closer to walls
Differentiate spiral arteries from the straight arteries in the endometrium
Spiral arteries are found in the functional layer
Straight arteries are found in the basal layer
Which layer of the endometrium changes across the uterine/menstrual cycle
Functional layer
What are the three phases of the uterine cycle and when do they occur
- Menstrual phase (Days 1-7)
- Proliferative phase (7-14 => ovulation occurs in the ovarian cycle on day 14)
- Secretory phase (days 14-28)
What happens in the menstrual phase
Because fertilization did not occur, there is no need for the endometrium, so it is shed (in the form of a period)
What happens in the proliferative phase
Functional layer grows and expands
What happens in the secretory phase
Secretes lots and lots of mucus + pooling of blood
What is the main secretion of the uterine glands during the secretory phase
Mucus
What role does estrogen and progesterone have in the ovarian/uterine cycle
estrogen = proliferation
progesterone = maintenance and secretion
How does the female sexual response involve the autonomic nervous system
ORGASM
- activation of smooth muscle in the uterus and vagina
AROUSAL
- engorgement of erectile tissue
- lubricating secretions from vaginal glands
**both parasympathetic and sympathetic divisions appear to be necessary for female arousal responses
How does the female sexual response involve the somatic nervous system
ORGASM
- rhythmic activation of several pelvic floor muscles
