Endocrine L4: Reproduction Flashcards
Sex determined by chromosomes – XX, XY from fertilisation – ‘_____’
genetic sex
What are genetic sex?
Sex determined by chromosomes – XX, XY from fertilisation
All embryos have ‘______’ gonads, Wolffian ducts & Müllerian ducts
bi-potential
Not gender specific –> Can turn into male or female Initially –> gonads have both sex –> turn into one
If male, gonads differentiate into testes from seventh week of gestation, ovaries form after ninth week – ‘_____’
gonadal sex
What is gonadal sex?
If male, gonads differentiate into testes from seventh week of gestation, ovaries form after ninth week
When does gender get developed = after 9 weeks The baby either develops as a male or stay as a female If you have no changes –> develop into a female (eg. didn’t have changes or it didn’t work) Only when things change, start to develop into a male Default development = ____ (female/male)
female
After 8 weeks gestation testosterone production by testes causes development of Wolffian ducts into male internal reproductive organs, dihydrotestosterone (DHT) causes masculinisation of external genitalia - ‘______ ‘
phenotypic sex
What are phenotypic sex?
After 8 weeks gestation testosterone production by testes causes development of Wolffian ducts into male internal reproductive organs, dihydrotestosterone (DHT) causes masculinisation of external genitalia
_____ (testes/ovaries) become dormant after birth, _____ (testes/ovaries) quiescent until onset of puberty
Testes; ovaries
Onset of puberty influenced by _____, _____, ______ and ______
bodyweight/obesity, genetics, health, melatonin
- Need to reach a certain body weight –> puberty is getting earlier now because children are growing quicker and have high body weight
- Severe obesity can delay puberty
- If parents went into puberty early
Pre-pubertal increase in pulses of ________ trigger production of gonadotrophins (LH & FSH) from anterior pituitary, which trigger gonadal activity
gonadotrophinreleasing hormone (GnRH)
____ and _____ are the same hormones for males and females and work on testes or ovaries
FS; FSH
Production of ____ steroids cause development of secondary sexual characteristics and fertility
sex
Produced within gonads = secondary changes (body shape, voice changes and fertility)
Growth spurt associated with increase ____/_____ and sex steroids
growth hormone/IGF-I
Why does growth hormone affect puberty?
Will stop you growing = cause epiphyses to close = stop you from getting taller (initially get growth spurt)
How does the control of reproduction occur?
- Hypothalamus (centrally controlled) produces pulses of GnRH
- Stimulates pulsatile release of LH and secretion of FSH
How does the negative feedback control work?
How does the male reproduction of hormones work?
What does testis structure and spermatogenesis?
What are 2 types of cells in testicular function?
- Leydig cells
- Sertoli cells
What are Leydig cells?
produce testosterone and small amounts of other steroids
- eg oestradiol &dihydrotestosterone (DHT) in response to LH
What is the function of testosterone?
either acts on adjacent Sertoli cells or is released in the blood, actions outside testes
What are Sertoli cells?
(with support from testosterone & FSH)
- maintain tight junctions (to create seminiferous tubules)
- nourish germ cells & support spermatogenesis (Maturation of sperm)
- secrete androgen binding protein (ABP)
- secrete inhibin
- convert testosterone to DHT or oestradiol (Lipophilic hormone (carried around on a binding protein))
What is the mechanism of actions for androgens?
Problems with liver = less binding proteins = more testosterone floating around in the liver
For males, once they get going, they keep going (eg. produced for the rest of their lives)
- Can be fertile well into their 90s