Sexual Behaviour Flashcards
What is sexual dimorphism?
the difference in forms of sexes
How is external sex defined?
defined in both medical and lay terms by outward appearance of individual by birth (external genitalia)
How is internal sex defined?
defined by internal reproductive organs
What is the chromosomal sex for a genetic male?
XY
What is the chromosomal sex for a genetic female?
XX
What are primary sexual characteristics?
different genitals
What are secondary sexual characteristics?
apparent during puberty
change in figure and voice
What is sexual behaviour associated with?
mate selection
What is sexual identity?
does not always coincide with a person’s anatomical sex
How many pairs of chomosomes do humans have and how many in total?
23 pairs
46 in total
How many pairs of autosomes do humans have and how many pairs of sex chromosomes do they have?
22 pairs of autosomes
1 pair of sex chromosome
What does meiosis lead to?
leads to gametes such as sperm (X and Y) and ova (X and X) being developed
In the 7th week in males, what does the Dry gene on Y chromosome trigger?
the synthesis of Sry protein
What does the Sry protein do?
stimulates the medulla of the primordial gonad to develop into a testis
produces 2 hormones: androgen testosterone and AMH
What do females not have without the Y chromosome?
they have no SRY gene
no Sry protein is produced
Females are homo…
homogametic
(one type of gamete)
Males are hetero…
heterogametic
(two types of gamete)
In other specifies such as moth and butterflies, females are…. and males are….?
females are heterogametic
males are homogametic
system is reversed
What are the 3 stages of human embryonic development?
cells divide
migrate
specialise
after 6 weeks of conception, all embryos are what?
still physically identical
What are Müllerian ducts?
have the potential to develop into female internal organs
What are Wolffian ducts?
have the potential to develop into male sexual organ
At end of 2nd month of pregnancy, what 4 structures begin to develop?
1- glans
2- urethral fold
3- lateral body
3- labioscrotal swelling
What is puberty?
transitional period between childhood and adulthood
how many stages of puberty?
5
In girls what stage does breast development start?
in stage 2
8-14 years old
What releases growth hormones?
the anterior pituitary
growth hormones act on bone and muscle tissue
What is LH and FSH known as?
gonadotropic hormones
controls development of primary sexual characteristics and internal systems
What is the male-specific sexual maturation?
FSH and LH
testes: start to produce sperm, increase in release of testosterone
Some testosterone is converted into dihydrotestosterone which triggers growth of penis
What is the female-specific sexual maturation?
FHS and LH
Ovaries: stimulated to release estradiol
overtime release first ova , menstrual cycle begins
estrogen and progesterone co-ordinate cycle
What does ACTH trigger?
the adrenal cortex to then release adrenal hormones
What does the release of adrenal hormones mean?
means development of secondary sexual characteristics
Gonadal and adrenal sex hormones are what?
steroids
How is the brain masculinised?
by perinatal estradiol that has been aromatised from testosterone
How do females brains not get masculinised by estradiol?
alpha fetoprotein binds to and deactivated circulating estradiol
what is testosterone immune to?
alpha fetoprotein - can’t get past blood brain barrier and testosterone travels to the brain
What are organisational effects?
prenatal
development of nervous system
What are activational effects?
puberty and adulthood
activation of nervous system
What is behavioural masculinisation?
Androgen-stimulated development of the brain areas
respond to testosterone in adulthood
produce male sexual behaviour
What is behavioural defeminisation?
The inhibitory effects of androgens on the development of
female brain areas
stop the production of female sexual behaviour
