01-12: Prep for Pregnancy Flashcards
What are the layers of the uterus wall?
- Myometrium
- Endometrium
What is the structure of the uterine endometrium?
- Columnar surface epithelium
- Uterine glands (secrete glycogen)
- Connective tissue stroma (support framework)
- Spiral arterioles
What are the 2 layers of the uterine endometrium?
- Functional layer
- Basal layer
What are the characteristics of the functional layer of the uterine endometrium?
- Undergoes most profound changes during the menstrual cycle
- Swept off during menstruation
What is the mucosal surface of the cervix characterized by?
numerous crypts (pockets that provide space for the sperm passing through the uterus)
What does the cervix epithelium produce?
glycoprotein-rich cervical mucous
Cervix mucous composition features
- mucous composition varies throughout uterine cycle
- thinnest (most watery) mucous composition is around time of ovulation
What kind of epithelium lines the vagina?
Stratified, Non-keratinized squamous epithelium
What does the vaginal epithelium secrete?
glycogen (throughout the menstrual cycle)
What does the glycogen (secreted by the vaginal epithelium) do?
breaks down products that contribute to the vaginal fluid low pH
What is the pH of vaginal fluid?
4.3-4.4
What 4 hormones control the menstrual cycle?
- FSH
- LH
- Estradiol
- Progesterone
How many days is each menstrual cycle?
28 days
What controls the hormones of the menstrual cycle?
hypothalamus»_space; anterior pituitary
What areas of the reproductive system are affected by the menstrual cycle hormones?
- ovarian follicle
- uterine endometrium/myometrium
What are the 2 sub-cycles of the menstrual cycle?
- Ovarian cycle
- Endometrial cycle
During which days does the follicular phase (ovarian cycle) occur?
Days 1-14
During which phase is there development of the mature Graafian follicle and secondary oocyte in the ovary?
Follicular phase of ovarian cycle
How does the Graafian follicle develop?
Hypothalamus»_space; FSH-releasing factor»_space; anterior pituitary»_space; FSH production
Which hormone is responsible for the proliferation phase of the endometrium?
estradiol
What secretes estradiol?
granulosa cells of the developing follicle
On which day does ovulation occur?
day 14
What are the stimuli for ovulation?
- Rise in FSH
- Sharp rise in LH
In what stage of the ovarian cycle is an egg released from the Graafian follicle?
ovulation
What surround the egg at ovulation?
the corona radiata (layer of follicle cells)
When is the egg arrested?
meiosis II (metaphase II)
When will the egg complete meiosis II?
fertilization
What accompanies the egg during the ovarian cycle?
polar body
- very small
- nucleated sister cell
- product of meiosis I
What part of the follicle remains behind during ovulation?
the outer part of the Graafian follicle
What is the outer part of the Graafian follicle made of?
thecal cells
What cells secrete progesterone?
thecal cells
During which phase of the ovarian cycle do the residual theca and granulosa cells of the follicle (left over after ovulation) secrete estrogen and progesterone?
luteal phase
What forms the corpus luteum?
the residual theca and granulosa cells
Why are progesterone and estradiol necessary in the luteal phase?
to maintain the implantation of the fertilized oocyte
What happens to the corpus luteum if fertilization does not occur?
- corpus luteum regresses
- decrease in progesterone
- decrease in estradiol
- result = beginning of next menstrual phase
What is inhibin released by?
granulosa cells
What does inhibin inhibit the secretion of?
gonadotropins (FSH)
What causes the regression of the corpus luteum?
the inhibition of the secretions of gonadotropins (FSH)
What does the endometrial cycle refer to?
cyclic changes in the endometrium
How long does the endometrial cycle last?
28 days
When does the endometrial cycle begin?
first day of menstruation
When does the endometrial cycle end?
28 days after the start of menstruation
What are the 3 phases of the endometrial cycle?
- menstrual phase
- proliferation phase
- secretory phase
What days are the menstrual phase?
Days 1-4/5
What days are the proliferation phase?
Days 4-14
What days are the secretory phase?
Days 15-28
During which phase of the endometrial cycle does the endometrial build-up from the previous cycle slough off (menstrual flow)?
menstrual phase
What does menstruation begin with?
1- vasoconstriction of the spiral arteries that have been supplying the endometrium
2- local ischemia
What mediates the vasoconstriction of the spiral arteries of the endometrium?
prostaglandins
What invades the area of the endometrium and continues the process of endometrial breakdown?
inflammatory cells
What maintains the bleeding until the endometrial lining is sloughed off?
factors that inactivate the clotting process
By day 14 in the proliferation phase, what does the endometrial thickness increase to due to endometrial growth?
1-2mm»_space; 8-10mm
What grows with the expanding endometrium in the proliferation phase?
- BV
- Glands
Where do cells that initiate endometrium growth come from?
the bases of the glands that formed in the previous endometrium that were deep enough to survive the loss of the previous endometrium
What are the basal cells of the endometrium?
everything that doesn’t get sloughed off
What is the proliferation phase in the endometrial cycle due to?
granulosa cells of the developing ovarian follicle secreting increased levels of ESTRADIOL
When in the proliferation phase of the endometrial cycle is there a sharp rise in estradiol levels?
near the end of the proliferation phase
In which phase of the endometrial cycle does the level of estrogen decrease and the endometrial growth stop?
secretory phase
What happens to the mucous glands during the secretory phase of the endometrial cycle?
- develop more fully
- begin secretion
What do the spiral arterioles near the mucous glands do during the secretory phase?
- expand
- heavily vascularize the area
How is the secretory phase of the endometrial cycle controlled?
rising levels of progesterone secreted by granulosa and theca cells of the ovarian follicle
What is the function of the endometrial cycle?
prepares the lining of the uterus to receive the fertilized egg
On which day of the endometrial cycle does implantation of the fertilized egg occur?
7 days after ovulation
Day 21
Stages if no fertilization occurs
1- decreased levels of estradiol and progesterone
2- vasoconstriction of spiral arterioles supplying endomtrium
3- endometrium sloughing off
4- beginning of next cycle
All oogonia are committed to ______________ prior to birth
meiosis I
How many oogonia cells are in the early female embryo?
7 million
How many oogonia cells are there shortly after birth?
500,000
How many eggs will actually be ovulated during a woman’s reproductive years?
400-450 eggs
At menopause, there are no follicles left to produce _______ and _________
estradiol and progesterone
In males, LH is secreted by the anterior pituitary and binds to LH receptors on the interstitial cells of __________________
Leydig
What causes LH/FSH to be secreted by the anterior pituitary in males?
Hypothalamus»_space; GnRH»_space; Anterior pituitary»_space; LH/FSH secretion
What do the Leydig cells synthesize testosterone from?
cholesterol
What carries testosterone to the sertoli cells and secondary sexual tissues?
the blood
What does testosterone bind to on the sertoli cells?
cytoplasmic receptors
What are the secondary sexual tissues for males?
- prostate
- seminal vesicle
- epididymis
- ductus deferens
- penis
- scrotum
What does FSH bind to on the sertoli cells?
surface FSH receptors
What are the functions of sertoli cells?
- convert testosterone»_space; estrogens (compared with granulosa cells)
- synthesize Leydig cell stimulatory factor
- produce androgen-binding protein
- produce inhibin (compared with granulosa cells)
What does the androgen-binding protein produced by the sertoli cells bind to?
testosterone
*Carried to the fluid part of the seminiferous vesicles
What is the function of the androgen-binding protein?
important for aspects of spermatogenesis
Males vs. Females
- the systems are similar
- responses to the systems are different
- the receptors for hormones are located on different cells
How do the testis continue to produce sperm throughout the lifetime of the individual?
because sperm cells responsible for the production of sperm (sptermatogonia cells) remain viable for the individual’s lifetime
What is the fertilization age?
embryo age from time of fertilization
What is the menstrual age?
embryo age from start of mother’s last menstrual period
How many weeks greater is the menstrual age than the fertilization age?
2 weeks