What is menstruation?
Menstruation is the shedding of the endometrium lining in the uterus (by loss of blood) that occurs when pregnancy does not occur.
Menstruation is also known as a period.
How long is a menstrual cycle or period?
Can be anywhere from 21 - 36 days long.
When does a menstrual cycle start and end?
Starts on the first day of bleeding, ends right before the next period starts.
What is ovulation?
When an egg (or ovum) is released from an ovary into the fallopian tube in order for pregnancy to occur.
If a menstrual cycle is 28 days, then ovulaton will occur at about day 14.
What is the HPO cycle in regards to menstruation?
The HPO cycle are the steps that make ovulation occur.
They include the hormones that get released by the Hypothalamus.
What are the 3 steps in the HPO cycle?
Hypothalamus > Pituitary > Ovarian Cycle
- Hypothalamus makes GnRH that sends a message to the anterior pituitary
- Anterior pituitary makes FSH and LH that sends a message to the ovaries
- Ovaries make estradiol and progesterone that makes the uterus ready for pregnancy
These are the steps that make ovulation occur.
Which neurotransmitter is released from the hypothalamus that tells the anterior pituitary to make FSH (follicle stimulating hormone) and LH (luteinizing hormone)?
The hypothalamus is located in the brain.
GnRH
(Gonadotropin releasing hormone)
Which hormone is released by the anterior pituitary that makes a follicle from which an egg will emerge?
The anterior pituitary is located in the brain.
FSH
(Follicle stimulating hormone)
What is a follicle?
A follicle is the sac in the ovary that contains an egg/ovum.
Which hormone is released by the anterior pituitary that makes the corpus luteum and triggers ovulation?
LH
(Luteinizing hormone)
What is the corpus luteum?
A corpus luteum is the collection of cells that’s left over in the ovaries after the egg leaves the ovary.
What two hormones does the corpus luteum produce?
The corpus luteum is located in the ovaries.
- progesterone
- estradiol (a type of estrogen)
What is the function of progesterone during the menstrual cycle?
Progesterone stabilizes the endometrium lining (uterine lining) in order for fertilization to occur.
What is the function of estradiol during the menstrual cycle?
Estradiol makes the endometrium lining (uterine lining) thickened or “fluffy” for a baby to grow.
If fertilization does not occur (woman does not become pregnant) which hormone levels will decrease which sends a message back to the hypothalamus to begin producing GnRH to start the menstrual cycle over again?
This is called a positive feedback loop.
Progesterone and estradiol
If fertilization does occur (woman becomes pregnant), which hormone will be present?
HCG
(Human chorionic gonadotropin)
What hormone does the placenta make in order to keep the endometrium stable as pregnancy progresses?
Progesterone
Why is it important to know when ovulation occurs?
Ovulation is the time that a woman is able to get pregnant.
The woman will either:
1. want to avoid getting pregnant or
2. want to get pregnant during this time
What is one way to determine if a woman is ovulating in regards to the menstrual cycle?
If the menstrual cycle is very regular, then ovulation will occur about halfway through.
Ex: If a menstrual cycle is 28 days, then ovulation will occur at about day 14.
What is one way to determine if a woman is ovulating in regards to abdominal discomfort?
If the woman gets abdominal discomfort, especially on one side, ovulation may be occurring.
This is from stretching of the follicle.
What is one way to determine if a woman is ovulating in regards to cervical mucus?
If the woman gets a very sticky cervical mucus, ovulation is most likely occurring.
What is one way to determine if a woman is ovulating in regards to body temperature?
If the woman’s body temperature drops and then quickly increases, ovulation is most likely occurring.
