Reproductive System Fundamentals Flashcards
What are the main Functions of the Gonads?
The production of gametes and reproductive hormones
What important Releasing Hormone does the Hypothalamus secrete in relation to Reproduction?
Gonadotrophin releasing hormone (GnRH)
Where does Gonadotrophin Releasing Hormone (GnRH) act?
The gonadotroph cells in the anterior pituitary
What are the Two Gonadotrophins that the Anterior Pituitary Gland Gonadotroph Cells make?
Follicle Stimulating Hormone (FSH) and Lutenising Hormone (LH)
Where do Follicle Stimulating Hormone (FSH) and Lutenising Hormone (LH) act?
On the gonads
When acted upon by FSH and LH, what do the Gonads produce?
Steroid reproductive hormones
What sort of Effect do the Steroid Reproductive Hormones produced by the Gonads have on the Anterior Pituitary and the Hypothalamus?
Negative feedback regulation
What are the main Male Steroid Hormones?
Testosterone and 5 α Dihydrotestosterone (5αDHT) which are Androgens
Do Males produce Androgens?
Yes
Do Females produce Androgens?
Yes (primarily testosterone to a lesser extent than males do)
What are the main Female Steroid Hormones?
Oestradiol, Oestrone and Oestriol (Oestrogens) and Progestagens
Do Females produce Oestrogens?
Yes
Do Males produce Oestrogens?
Yes (primarly oestrone to a lesser extent than females do)
Do Females produce Progestagens?
Yes
Do Males produce Progestagens?
No
What is Sex Determination?
The commitment of the bipotential gonad to a testis or an ovary
What is Sex Differentiation?
The phenotypic development of genital structures due to the action of hormones produced following gonadal development
In Mammals, how is Sex Determination usually Controlled?
Via the sex determining region on the Y chromosome (the SRY gene)
If the Y Chromosome and therefore the SRY Gene is Present, will the individual develop Testes (to become a Male) or Ovaries (to become a Female)?
Testes, eventually developing into a Male
If the Y Chromosome and therefore the SRY Gene is Absent, will the individual develop Testes (to become a Male) or Ovaries (to become a Female)?
Ovaries, eventually developing into a Female
The Two Duct Systems in the Undifferentiated Bipotential Gonad are called the ___ Duct and the ___ Duct
The Two Duct Systems in the Undifferentiated Bipotential Gonad are called the Mesonephric (Wolffian) Duct and the Paramesonephric (Mullerian) Duct
What is the Male Duct in the Undifferentiated Bipotential Gonad?
The mesonephric (wolffian) duct
What is the Female Duct in the Undifferentiated Bipotential Gonad?
The paramesonephric (Mullerian) duct
What Two Cell Types in the Testes release Hormones that eventually give rise to the Male Reproductive System from the Bipotential Gland?
Sertoli cells and Leydig cells
What Hormone do Sertoli Cells secrete during Fetal Development? What does this cause?
Anti-mullerian Hormone (AMH), causing mullerian duct regression
What Hormone do Leydig Cells secrete? What does this cause during Fetal Development?
Testosterone, causing wolffian duct development
What Hormones do the Ovaries secrete during Fetal Development?
Oestrogens and Progestagens
Are the Oestrogens and Progestagens directly acting upon the Mullerian and Wolffian ducts?
No, the Mullerian and Wolffian ducts develop and regress by themselves
In an Individual with XY Chromosomes, what would happen if their Androgen Receptors didn’t Function Correctly (Androgen Insensitivity Syndrome)?
The individual would have female genital ducts and/or external genitals, but would possess testes
An increase in ___ release in Early Puberty causes ___ secretion to increase
An increase in GnRH release in Early Puberty causes FSH and LH secretion to increase
During Early Puberty what Time during the Day are Gonadotrphins secreted?
At night
In Late Puberty, Day Time secretions of ___ also Increase
In Late Puberty, Day Time secretions of LH also Increase
___ levels Rise in response to the increase in Plasma LH
Sex Steroids levels Rise in response to the increase in Plasma LH
In Females, what are the Secondary Sexual Characteristics that Develop/Occur during Puberty?
- Breast Enlargement
- Pubic Hair Development
- Height Spurt
- Menarche (Menstruation)
In both Males and Females, Pubic Hair occurs due to exposure of Hair Follicles to what?
Androgens
How much later does the Height Spurt in Males typically occur compared to the Height Spurt in Females?
Approximately 2 years
What is the Average Age of Menarche in Females?
12-13 years old
How long after Menarche does the First Ovulation in Females typically occur? Why is this?
6-9 Months, because the positive feedback mechanisms of oestrogen have not yet developed
Typically how long after Menarche is a regular Ovulatory Cycle established in Females?
1-2 years
In Males, what are the Secondary Sexual Characteristics that Develop/Occur during Puberty?
- Growth of the Testes
- Pubic hair growth
- Growth of the Penis
- Height Spurt
Approximately at what Age does Spermatogenisis begin in Males?
12-13 years old
What is Precocious Puberty? What is it typically dependent on?
The appearance of physical and hormonal signs before the age of:
7 in girls
9 in boys
Typically dependant on GnRH, in extreme cases may be the result of a hypothalamic tumor
Is Precocious Puberty more common in Females or Males?
Females
What is Delayed Puberty? What causes it?
The late appearance of physical and hormonal signs, as late as:
13 years old for females
14 years old for males
Occurs when gonadotrophin signals from the pituitary are insufficient to begin the secretion of steroid hormones
Is Delayed Puberty more common in Females or Males?
Males
Identify the Mesonephros


Identify the Gonadal Ridges


Identify the Paramesonephric (Mullerian) Duct


Identify the Mesonephric (Wolffian) Duct


Identify the Urogential Sinus


Identify the Genital Tubercle


Identify the Urethral Folds


Identify the Urethral Groove


Identify the Labioscrotal Swelling


Identify the Urogenital Sinus


Identify the Anus


Identify the Glans Penis on the Male Genitalia


Identify the Clitoris on the Female Genitalia


Identify the Urethral Folds


Identify the Labioscrotal Swelling


Identify the Perineum


Identify the Anus


Identify the External Urethral Orifice on the Male Genitalia


Identify the Glans Penis on the Male Genitalia


Identify the Penis on the Male Genitalia


Identify the Clitoris on the Female Genitalia


Identify the Clitoris on the Female Genitalia


Identify the Labia Majora on the Female Genitalia


Identify the Labia Minora on the Female Genitalia


Identify the Vaginal Orifice on the Female Genitalia


Identify the External Urethral Orifice on the Female Genitalia


Identify the Vestibule on the Female Genitalia


Identify the Anus

