Reproductive Hormones & the Menstrual Cycle (Kara)

Note: Important terms are bolded throughout the page :)

Reproductive Hormones

What are reproductive hormones responsible for?
- Th
- development and maintenance of the male and female reproductive systems.
Where do these hormones come from?
- Sex glands or gonads
  - A gonad produces gametes
  - Gametes are used to unite one sex cell with another from the opposite sex to form a new organism
  - The sex cell for males are the testes
  - The sex cell for females are ovaries
What's the point?
- The sex glands are responsible for the production of our sex hormones as well as the production of egg and sperm cells.
- There are 3 different steroid hormones that the glands produce
  - Androgen: Dominant in males
  - Estrogen: Dominant in females
  - Progestin: Dominant in females
  - Males and females produce all 3 of these hormones, but produce different amounts
  - These hormones control the development of male and female reproductive systems, sexual characteristics and sexual behaviors

Male reproductive system

The male version of gonads are testes.
- Testes are responsible for the secretion of the hormone androgen.
What hormones are in involved in the male reproductive system?
- Androgen: Steroid hormones that control the development and maintenance of the male reproductive system.
  - Testosterone: Primary androgen and it is the male sex hormone
- Gonadotropin-releasing hormone: Released by the hypothalamus, in the brain.
  - This hormone controls the release of the luteinzing hormone (LH) and the follicle-stimulating hormone (FSH) from the pituitary gland
- FSH: Controls the combination and release of the male and female sex hormones in the gonads.
  - Stimulates Sertoli cells to release proteins and other substances that are necessary for spermatogenesis
- LH: Responsible for the building and release of testosterone in the testes
  - Stimulates the Leydig cells to releases testosterone which results in sperm production.

How do males control the testosterone levels in their bodies?
- If testosterone levels are too low, the hypothalamus increases the release of Gonadotropin
- If the levels are too high, the excess inhibits the release of LH
  - The overabundance also results in Sertoli cells releasing inhibin which inhibits the release of FSH.
  - With LH and FSH hormones being inhibited the testosterone levels drop to the optimum level.

Figure 1:

Faiman, C. (2012, June). [Online image]. Retrieved April 10, 2017, from http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/endocrinology/male-hypogonadism/

Female Reproductive system

The women's version of gonads are their ovaries.
- Women have two ovaries located in the abdomen.
- The ovaries produce eggs (ova), estrogen and progestin.
What hormones involved in the female reproductive system?
- Estrogen: Stimulates and controls the development and maintenance of the female reproductive system.
  - Estradiol: Primary estrogen that stimulates the maturation of sex organs. It also is responsible for the development of sexual characteristics such as: developing breasts, widening of the pelvis, growth of body hair, and the development of the sex drive.
- Progestin: responsible for the release of the hormone progesterone
  - Progesterone: The primary progestin that prepares and maintains the uterus for the implantation of a fertilized egg. It also aids in the growth and development of an embryo.
- Gonadotropin (see male reproductive system for defintion)
  - FSH: Responsible for building and releasing progesterone in the ovaries
- These hormones are also responsible for oogensis.
  - Oogensis: Process where the ovaries produce and release eggs

Figure 2:

Emanuele, M., Wezeman, F., & Emanuele, N. V. (2003, June). Alcohol’s Effects on Female Reproductive Function [Online image]. Retrieved April 10, 2017, from https://pubs.niaaa.nih.gov/publications/arh26-4/274-281.htm

Watch this video for

a quick summary of

how hormones

relate to the ovarian

cycle

Clore, J. (2010, April 02). "The Ovarian Cycle" Retrieved April 10, 2017, from https://www.youtube.com/watch?v=lYaZRR3G6pg

Controlling reproduction with hormones

When we understand our reproductive systems we can maximize and minimize our chances of reproduction
Hormonal birth control
- Estrogen and/or progesterone are administered in pill form, injection or in patches
- Females take birth control to control menstruation and prevent ovulation
- Some side effects of birth control are:
  - Nausea
  - Weight gain
  - Lighter periods
  - Sore breasts
  - Headaches
Always consult your doctor before taking hormonal birth control

The Menstrual cycle

What is the menstrual cycle?
- It involves all the changes in the uterus over one ovarian cycle
- Occurs in a sexually mature female
- Prepares the uterus for the implantation of a fertilized egg
- This cycle, on average, happens every 28 days
- Occurs from puberty until menopause
- There are 3 phases: the follicular phase, ovulation phase and luteal phase
- Follicular phase: An egg follicle on the ovary prepares for egg release. This phase is when women are most fertile and most likely to get pregnant
- Ovulation phase: Once an egg follicle develops to maturity it will release an egg. The egg travels through the Fallopian tube. If sperm is present, it will be fertilized here. If no sperm is present the egg will break apart and be released
- Luteal phase: Starts after ovulation. Also called the premenstrual phase. Therefore this phase is responsible for premenstrual symptoms (PMS)
  - PMS: Mood swings, bloating, tender breasts, acne, abdominal cramps, back cramps, leg cramps, less energy, nausea, diarrhea, constipation etc.

Figure 3:

Menstrual Cycle - Phases, Mechanism, Causes, Prevention and Myths. (2016, April 13). Retrieved April 10, 2017, from http://www.medindia.net/patients/patientinfo/menstrual-cycle.htm

Figure 4:

Marsden, H. (2016, November). 10 amazing cartoons that show the reality of periods [Online image]. Retrieved April 10, 2017, from https://www.indy100.com/article/period-comics-girls-menstruation-women-pms-cartoons-symptoms-tampons-7396851

Breakdown of the cycle

Menstrual flow is the result of the uterus shedding its endometrium
Blood and broken down tissue products are released through the vagina
When the flow stops (after about 4-7 days) the endometrium begins to develop again
About 14 days into the cycle, ovulation occurs
- Oocytes (an immature egg) develop more as the endometrium thickens
After ovulation occurs the uterine lining will continue to grow
If no fertilization occurs, the absence of the hormone progesterone results in the arteries contracting
- These arteries supply blood to the uterine lining
- The contraction cuts off the blood supply and causes the uterine lining to break down and disintegrate
Because the uterus is contracting and doesn't have progesterone to stop the contracting, the endometrium sheds the lining and this results in the blood flow.
Prostaglandins, a hormone released by the degenerating endometrium, adds to the contractions
- This is why some women complain about painful cramps, nausea, vomiting and headaches during their menstrual cycle
On average most women lose 20-80 ml of blood in each cycle

Menopause

The menstrual cycle usually ends when a women is about 40 or 50
Not only does the menstrual cycle end, but the high levels of sex hormones also drops dramatically
Because of the huge drop in estrogen levels, most women feel nasty side effects. Some of these side effects are:

Menstrual irregularities

Menstruation is normally irregular for the first few years of menstruation
They also become irregular when a women begins menopause
Each women's menstrual cycle is different
- Therefore each women has a different sense of menstrual irregularity
Causes of menstrual irregularities
- Stress
- Lack of exercise/Too much exercise
- Unhealthy diet/Eating disorders
- Smoking/Alcohol/Drugs
- Emotions
- Traveling
How to avoid irregularites
- Adapt a healthy lifestyle
- Avoid stress as much as possible
- If tirregularites persist, see a doctor

Menstrual conditions

Amennorhea: When monthly periods are missed for 3 months or more. Usually occurs during pregnancy and in girls who haven't begun menstruation yet.
Mennorhagia: Bleeding lasts longer than 7 days and over 80 ml of blood is released.
Ploymennorhea: Periods occur less than 21 days apart.
Oligomennorhea: Periods occur more than 36 days apart
Dysmennorhea: Severly painful menstruation

If you are interested in what happens after the

egg is fertilized, watch the video down below. It

walks you through the process of fertilization.

Parents. (2016, October 17). "How Sperm Meets Egg|Parents" Retrieved April 10, 2017, from http://www.parents.com/pregnancy/stages/fetal-development/sperm-meets-egg-weeks-1-to-3-of-pregnancy/

References

Book:

Fraser, D., & DiGiuseppe, M. (2012). Nelson Biology 12: University Preparation. Toronto, Ont.: Nelson Education.

Websites:

Menstrual Cycle - Phases, Mechanism, Causes, Prevention and Myths. (2016, April 13). Retrieved April 10, 2017, from http://www.medindia.net/patients/patientinfo/menstrual-cycle.htm
Gamete. (n.d.). Retrieved April 10, 2017, from http://www.dictionary.com/browse/gamete
WebMD. (n.d.). Normal Menstrual Cycle - Normal Menstrual Cycle. Retrieved April 10, 2017, from http://www.webmd.com/women/tc/normal-menstrual-cycle-normal-menstrual-cycle#1
WebMD. (n.d.). Missed or Irregular Periods - Topic Overview. Retrieved April 10, 2017, from http://www.webmd.com/women/tc/missed-or-irregular-periods-topic-overview
Crosta, P. (2015, November 12). What Is Ovulation? What Is The Ovulation Calendar? Retrieved April 10, 2017, from http://www.medicalnewstoday.com/articles/150870.php
Amenorrhea. (2014, May 09). Retrieved April 10, 2017, from http://www.mayoclinic.org/diseases-conditions/amenorrhea/basics/definition/con-20031561

Images:

Faiman, C. (2012, June). [Online image]. Retrieved April 10, 2017, from http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/endocrinology/male-hypogonadism/
Emanuele, M., Wezeman, F., & Emanuele, N. V. (2003, June). Alcohol’s Effects on Female Reproductive Function [Online image]. Retrieved April 10, 2017, from https://pubs.niaaa.nih.gov/publications/arh26-4/274-281.htm
Marsden, H. (2016, November). 10 amazing cartoons that show the reality of periods [Online image]. Retrieved April 10, 2017, from https://www.indy100.com/article/period-comics-girls-menstruation-women-pms-cartoons-symptoms-tampons-7396851

Videos:

Parents. (2016, October 17). "How Sperm Meets Egg|Parents" Retrieved April 10, 2017, from http://www.parents.com/pregnancy/stages/fetal-development/sperm-meets-egg-weeks-1-to-3-of-pregnancy/
Clore, J. (2010, April 02). "The Ovarian Cycle" Retrieved April 10, 2017, from https://www.youtube.com/watch?v=lYaZRR3G6pg

Report abuse