Female Physio

Question 1

Hormone released from the hypothalamus that signals LH and FSH release from the anterior pituitary.

Answer 1

GnRH

• must be released in a pulsatile manner
• a continuous release inhibits LH secretion

Question 2

Main cell type that LH binds in the ovary and the function.

Answer 2

LH binds theca interna cells to stimulate testosterone (T) production from cholesterol.

Question 3

Main cell that FSH binds in the ovary and the function.

Answer 3

FSH binds granulosa cells to:

1. Convert T into Estradiol (E2)
2. Stimulate production of inhibin (negative feedback for FSH secretion)
3. Induce LH receptor production

Question 4

Function of E2 on the hypothalamus-pituitary-gonad axis in the early and middle follicular phases.

Answer 4

Suppresses GnRH, FSH, and LH release.

Question 5

Function of E2 in the late follicular phase.

Answer 5

Once the follicle reaches a Graffian follicle stage, the high levels of estradiol serve two functions:

1. Stimulate a surge of GnRH release from the hypothalamus
2. Increase sensitivity of the gonadotrophs in the anterior pit. to GnRH

This allows the LH surge to occur leading to ovulation.

Question 6

Main source of progesterone secretion.

Answer 6

Birth Control

Question 7

Main endogenous source of progesterone

Answer 7

Corpus Luteum

Question 8

Functions of progesterone.

Answer 8

Inhibits GnRH and LH secretion

Prevents uterine contraction

Thickens cervical mucous

Question 9

Function of Inhibin.

Answer 9

Negative feedback for FSH release.

-mainly to prevent recruitment and development of more than one follicle into Graafian follicles

Question 10

Length of the 2 phases of the ovarian cycle.

Answer 10

1. Follicular Phase: 11-20 days

2. Luteal Phase: 14 days

Question 11

Name the 5 stages of the follicular maturation of the ovarian cycle.

Answer 11

1. Primordial
2. Primary
3. Secondary
4. Tertiary
5. Graafian

Question 12

In which follicular phase does the zona pellucida form and from where?

Answer 12

Primary follicle

-secreted by granulosa cells

Question 13

In which follicular phase do theca interna cells form?

Answer 13

Secondary Follicle

Question 14

In which follicular phase do the FSH and LH receptors emerge on the ovarian cells?

Answer 14

Secondary Follicle

Question 15

In which phase do the ovarian cells begin secreting hormones?

Answer 15

Secondary Follicle

Question 16

What are the corona radiate and cumulus oophorus?

Answer 16

CR: granulosa cells that surround the oocyte in the Graafian follicle
CO: stalk of granulosa cells that connect the corona radiate and oocyte to the rest of the follicle

Question 17

In which follicular phase to LH receptors form on granulosa cells?

Answer 17

Graffian Follicle

Question 18

Direct cause of ovulation

Answer 18

LH surge

LH surge occurs 24-36 hours after peak estrogen levels, then ovulation occurs 24hrs after LH surge

Question 19

How is the corpus luteum regulated in a woman that is not pregnant?

Answer 19

Ovulation of the oocyte creates the corpus luteum from the LH surge. The levels of LH remain elevated for about 14 days and this hormone maintains the corpus luteum.

The corpus luteum secretes progesterone to prevent recruitment of any other follicles and maintain the uterine endometrium by suppressing uterine contraction.

However, progesterone has negative feedback on LH secretion and as the progesterone levels rise, the suppression of LH causes the corpus luteum to degenerate.

Question 20

What causes a rise in the FSH and LH levels in the beginning of the menstrual cycle?

Answer 20

There are low levels of E2 since the follicles are still in the primordial phase, so no inhibition of FSH release.

The corpus luteum has degenerated so there is no progesterone to inhibit LH release. (it also secretes a minor amount of E2)

Question 21

When does the menstrual cycle begin?

Answer 21

First day of menses is designated as Day 1

Question 22

Name the 3 phases of the endometrial cycle.

Answer 22

Menstrual Phase: days 1-5ish
Proliferative Phase: days 6-14ish
Secretory Phase: days 15-28ish

Question 23

Hormone that controls the proliferative phase of the endometrial cycle and its function.

Answer 23

Estradiol

-thins cervical mucous, induces proliferation of the cells, glands, and blood vessels

Question 24

Hormone that controls the secretory phase of the endometrial cycle and its function.

Answer 24

Progesteron

• secretes glycogen (energy store for potential fertilized egg implantation)
• prevents uterine contraction
• thickens cervical mucous

Question 25

Function of estradiol in the secretoary phase of the endometrial cycle.

Answer 25

Induces progesterone receptors in the endometrial cells.

Question 26

Optimal site of fertilization of the oocyte.

Answer 26

Once the oocyte has traveled about 1/3 the length of the fallopian tube from the ovary

Question 27

What is capacitation?

Answer 27

Biochemical changes that occur to the sperm while in the female reproductive tract. 2 changes occur: 1. Tail begins "whiplike" action 2. Plasma membrane altered to enhance passage thru the granulosa cell layer and degrade the zona pellucida of the oocyte.

Question 28

What is the acrosomal reaction?

Answer 28

Sperm attaching to the zona pellucida and passing thru it to fuse with the membrane of the oocyte.

Question 29

What is the cortical reaction?

Answer 29

Once the sperm cell membrane fuses with the oocyte cell membrane, a reaction occurs in the zona pellucida that prevents other sperm from fusing. The zona pellucida becomes more solid and any sperm receptors are internalized.

Question 30

When does the oocyte become a zygote?

Answer 30

When the genetic material from the sperm and oocyte fuse

Question 31

What occurs after the formation of the zygote?

Answer 31

It travels the rest of the way down the fallopian tube over the course of 3-4 days. During this time mitotic divisions occur leading to about a 16-32 cell morula.

Question 32

What occurs after the formation of the morula?

Answer 32

The solid mass of cells "hollows" leading to a cyst with an inner cell mass and a single cell layer surrounding the fluid chamber called the trophoblast. This stage is called the blastocyst.

Question 33

What occurs after formation of the blastocyst?

Answer 33

This is the stage where implantation into the endometrium occurs. secretion of proteolytic enzymes to allow the blastocyst to fully incorporate into the endometrium.

Question 34

What is the area of the endometrium that immediately surrounds the implanted blastocyst?

Answer 34

Decidua

Question 35

Describe the formation of the placenta.

Answer 35

The trophoblast cells of the blastocyst secrete proteolytic enzymes that degrade many of the blood vessels in the decidua leading to a "pool" of blood. The trophoblast then proliferates a very specific cell type that will serve as the mother/fetus blood barrier. These cells are called the chorion. The chorion extends out into the pool of blood. Then the fetus extends capillaries out into the chorion to participate in nutrient and gas exchange with maternal blood. The area of the chorion between the fetal (umbilical) capillaries and the maternal (uterine) capillaries is called a chorionic villus (there are multiple chorionic villi). This whole thing is called the placenta.

Question 36

What is the function of Human Chorionic Gonadotropin (hCG) and where does it come from.

Answer 36

Trophoblast (syncytiotrophoblast) cells from the blastocyst secrete hCG. It maintains the corpus luteum for about 10 weeks so that progesterone and E2 levels remain high to provide maintenance of the endometrium.

Question 37

What maintains the levels progesterone and E2 after hCG drops and the corpus luteum regresses after 10 weeks gestation?

Answer 37

Placenta secretes both. E2: stimulates growth of the ducts of mammillary glands in the breast. Progesterone: maintains cervical endometrium and forms the mucous plug in the cervix.

Question 38

How is a due date determined?

Answer 38

40 weeks from the FDLNMP

Question 39

Function of estrogens in parturition.

Answer 39

1. Synthesis of gap junctions in the myometrium to allow uterine contraction as a unit. 2. Increase in oxytocin receptors on the myometrium 3. Increase PG formation that will also increase uterine contraction

Question 40

Describe the (+) feedback of parturition.

Answer 40

The induction of labor stimulus is still unknown, but once the placenta stops producing progesterone, the uterus undergoes contractions. This pushes the baby toward the cervix and stretches the opening of the cervix. The dilation of the opening sends a signal to the posterior pituitary to release oxytocin which cause more uterine contraction.

Question 41

Describe the (+) feedback of delivery.

Answer 41

As the baby moves through the cervix and vagina, the stretching stimulates contraction of the abdominal wall muscles.

Question 42

What physiological changes occur in the urterus with delivery of the placenta?

Answer 42

Uterine contractions continue until the placenta is removed. Once the placenta is removed the last of the uterine contractions close off the blood vessels that supplied the placenta to prevent any more blood loss.

Question 43

Function of Estrogens and Progesterone in lactation.

Answer 43

E's: growth of glandular ducts | P: growth of alveoli (acini of apocrine cells that secrete breast milk)

Question 44

Function of prolactin and oxytocin in lactation.

Answer 44

PRL: induces milk production in apocrine cells of the mammillary alveoli OXY: induces secretion of milk from alveoli into ducts