Chapter 17: Sex and the Brain Flashcards
How many autosomes are there and how many sex chromosomes?
44 autosomes
2 sex chromosomes
How is the gender of a human determined?
Gender is determined by the X or Y contribution of the father.
What is SRY?
It is a gene on the Y-Chromosome called: sex-determining region of the Y-Chromosome.
What does SRY code?
It codes for a protein called testis-determinig factor (TDF)
Which two key structures do the uncomitted gonads possess?
Müllerian duct and thee Wolffian duct.
If the fetus has a Y chromosome and an SRY gene, testosterone is produced. Which duct develops into the male internal reproductive system?
Wolffian Duct.
The Müllerian Duct is prevented from developing by a hormone called Müllerian-inhibiting factor.
Which endocrine glands release sex hormones, which is regulated by the pituitary?
The ovaries and the testes.
What are male hormones called, what are female hormones called?
Androgens
Estrogens
Testosterone is turned into estardiol by an enzyme called?
Aromatase
An increase of testosterone is correlated with…?
Social challanges, anger and conflict
Name two gonadotropins.
Luteinizing hormone LH
Follice-stimulating hormone FSH
What does Gonadotropin-releasing hormone GnRH do?
It is a hormone released by the hypothalamus and causes the anterior pituitary to release LH and FSH.
Why is GnRH often referred to as LHRH?
LHRH for Leteinizing hormone-releasing hormone, because it causes much greater increase in LH than FSH.
In males, Luteinizing hormone stimulates the testes to produce….?; And Follicle-stimulating hormone is involved in the……?
LH stimulates the testes to produce testosterone.
FSH is involved in the maturation of sperm cells within the testes.
How is it possible that psychological factors can decrease male fertility by inhibiting gonadotropin secretion and sperm production?
Because the hypothalamus get cortical input.
What does LH and FSH cause in females?
LH and FSH causes the secretion of estrogens from the ovaries.
In the absence of gonadotropins, the ovararies are…?
Inactive which is the case during childhood.
The timing and duration of of LH and FSH secretion determine the nature of the….?
Menstrual Cycle / Reproductive Cycle.
What happens during the follicular phase?
LH but especially FSH have an effect of increasing the growth of a small number of follicles, these enclose and maintain the ova (egg cells)
Name the full sexual response cycle.
arousal, plateau, orgasm, resolution
Engorgement and erection are controlled primarly by…?
Axons of the parasympathetic division of the ANS.
Within the sacral spinal cord, the parasympathetic neurons can be excited by either mechanosensory activity from the genitals or by axons descending from the brain.
Sildenafil (Viagra) works by enhancing the effects of…?
Nitric Oxide
Name two examples of Polgamy.
Polygyny, Polyandry
What is meant by the term sexual dimorphism?
Differences between male and female because of the sex.
What is the motor neuron pool called that controlls the Bulbocavernosus (muscles sorrounding the base of the penis and the opening of the vagina)?
Onuf’s Nucleus (is a bit dimorphic)
Which steroid triggers the mascunalization of the developing nervous system?
Estrogen binding to estradiol receptors
What did McCarthy and Amateau find regarding fetal and neonatal rats that were exposed to COX(cycoloxygenase) inhibitors.
Males showed reduced copulatory behavior as adults.
Female ratsexhibited male-like copulatory behaviors
Give an example of organizational effects of a steroid and an activational effect of a steroid.
Testosterone: Organizational effects of the hormone is to alter very young genitals and brain circuitry, leading to distinctly male genitals and masculine behaviors later in life
Activational Effects occur later, the hormone has to circulate again for example during sexual activity providung activational effects on the nervous system, for example when the testosterone level rises in the body of a male songbird
During lactation the representation of the ventral skin in femal rats expands. This is an example for….?
somatosenry map plasticity
What did Toran-Allerand find?
Estradiol treatment of tissue from hypothalamus of newborn mice causes a great degree of neurite outgrowth.
Estradiol seems to important for…?
Forming neuronal circuitry during brain development.
What is polyandry?
One female mates with many males but that male mates only with one female
What is polygyny?
Male mates with many females but the female only with one male
What does the male prairie vole prevent from bonding to the female vole?
Vasopressin antagonists given before mating.
In prairie voles: vasopressin is important for the …. to form a bond and oxytocin is important for the …. to form a bond
vasopressin: male
oxytocin: female
Name three examples for sexual dimorphisms of the central nervous system
Onufs nucleus
sexually dimorphic nucles (in rats)
Interstitial nuclei of the anterior hypothalamus (controversial)
Name two sexual dimorphisms of cognition.
Women better at verbal tasks
Men better at spatial rotation task
Name two general ways by which steroids can influence neurons
Directly influence: affect transmitter synthesis, transmitter release or postsynaptic transmitter receptors
Indirectly influence: Gene transcrption
