The Role of Chromosomes and Hormones Flashcards
What are chromosomes?
Chromosomes are strands of DNA found in the nucleus of living cells that carry information in the form of genes
What are genes?
Short sections of DNA that determine the characteristics of a living thing
How many chromosomes are there in the human body?
There are 46 chromosomes divided into 23 pairs, the last of these, the 23rd pair, determine biological sex
What are the chromosomal structures for male and female and why?
For females it’s XX whereas for males it’s XY this is because of how they appear when viewed under a microscope
How is a babies sex determined?
All normal egg cells have an X chromosome whereas some sperm cells have an X chromosome some have a Y chromosome. The sex of the baby depends on whether the sperm that fertilises the egg has an X or Y chromosome.
What does the Y-chromosome carry and what does it do?
A gene called the sex determining region Y - this causes testes to develop in an XY embryo - which then produce androgens (male sex hormones) this causes the embryo to develop into a male
What is a hormone?
A chemical substance circulating in the blood that controls and regulates the activity of certain cells or organs
Which are the two key times at which gender development is influenced by hormones?
Prenatally in the room and during puberty
How are hormones influential prenatally in the womb?
They act upon brain development and course development of the reproductive organs
How are hormones influential during puberty?
The best of hormonal activity triggers the development of secondary sexual characteristics such as pubic hair
How does the role of hormones differ in males and females?
Males and females produce many of the same hormones but in different concentrations – some hormones however are exclusive to one gender
What is testosterone?
A hormone from the androgen group that’s produced mainly in the mail testes (and in small amounts in the female ovaries)
When does testosterone become active and what does it do?
It begins to be produced at around eight weeks of foetal development and controls the development of male sex organs
What studies have been done into the effect of testosterone on human behaviour and what did they find?
Nanne Van de Poll et al. 1988 - showed that female rats became more physically and sexually aggressive when injected with testosterone
What is oestrogen?
The primary female hormone, playing an important role in the menstrual cycle and reproductive system
What does oestrogen do?
Oestrogen determines female sexual characteristics and menstruation. It may cause some women to experience heightened emotionality and irritability during the menstrual cycle
What is it called when the effects of the oestrogen on the menstrual cycle become diagnosable as a disorder?
This is known as pre-menstrual tension or pre-menstrual syndrome
What is oxytocin?
I hormones which causes contraction of the uterus during labour and stimulates lactation
What does oxytocin do?
Produced in large quantities in women, oxytocin stimulates lactation, and reduces the stress hormone cortisol and facilitating bonding – sometimes referred to as the love hormone
When is oxytocin produced most?
It is produced in massive quantities during labour and childbirth causing the mother to be in love with the new baby
How has the difference in oxytocin between men and women fuelled stereotypes?
The idea that men are less interested in intimacy within the relationship has grown because of it but evidence suggests that both sexes produced oxytocin in roughly equal amounts in activities like kissing and sexual intercourse
What is a strength of the role of chromosomes and hormones?
There is evidence to support the role of chromosomes and hormones – David Reimer – James Dabbs et.al (1995) found that offenders with the highest level of testosterone in a prison were more likely to have committed violent or sexually motivated crimes - Studies of transgender individuals show male-female ppl with decreasing aggression and vice versa
What are weaknesses of the role of chromosomes and hormones?
Contradictory evidence – Ray Tricker et al. (1996) found that 43 males given either a week injection of testosterone or placebo showed no significant differences in aggression after 10 week period
Supporting studies like those in to transgender individuals have small sample sizes of unusual ppl - low generalisability
Some people believe premenstrual syndrome is a social construction not a biological fact used only as a way of privileging certain groups over others
Oversimplifies a complex concept – biological accounts the reduced gender chromosomes and hormones ignore alternative explanations of gender development – the cognitive approach would draw attention to changing thought processes that underpin gender development
