Chapter 17: Sex and the Brain

Question 1

How many autosomes are there and how many sex chromosomes?

Answer 1

44 autosomes

2 sex chromosomes

Question 2

How is the gender of a human determined?

Answer 2

Gender is determined by the X or Y contribution of the father.

Question 3

What is SRY?

Answer 3

It is a gene on the Y-Chromosome called: sex-determining region of the Y-Chromosome.

Question 4

What does SRY code?

Answer 4

It codes for a protein called testis-determinig factor (TDF)

Question 5

Which two key structures do the uncomitted gonads possess?

Answer 5

Müllerian duct and thee Wolffian duct.

Question 6

If the fetus has a Y chromosome and an SRY gene, testosterone is produced. Which duct develops into the male internal reproductive system?

Answer 6

Wolffian Duct.

The Müllerian Duct is prevented from developing by a hormone called Müllerian-inhibiting factor.

Question 7

Which endocrine glands release sex hormones, which is regulated by the pituitary?

Answer 7

The ovaries and the testes.

Question 8

What are male hormones called, what are female hormones called?

Answer 8

Androgens

Estrogens

Question 9

Testosterone is turned into estardiol by an enzyme called?

Answer 9

Aromatase

Question 10

An increase of testosterone is correlated with…?

Answer 10

Social challanges, anger and conflict

Question 11

Name two gonadotropins.

Answer 11

Luteinizing hormone LH

Follice-stimulating hormone FSH

Question 12

What does Gonadotropin-releasing hormone GnRH do?

Answer 12

It is a hormone released by the hypothalamus and causes the anterior pituitary to release LH and FSH.

Question 13

Why is GnRH often referred to as LHRH?

Answer 13

LHRH for Leteinizing hormone-releasing hormone, because it causes much greater increase in LH than FSH.

Question 14

In males, Luteinizing hormone stimulates the testes to produce….?; And Follicle-stimulating hormone is involved in the……?

Answer 14

LH stimulates the testes to produce testosterone.

FSH is involved in the maturation of sperm cells within the testes.

Question 15

How is it possible that psychological factors can decrease male fertility by inhibiting gonadotropin secretion and sperm production?

Answer 15

Because the hypothalamus get cortical input.

Question 16

What does LH and FSH cause in females?

Answer 16

LH and FSH causes the secretion of estrogens from the ovaries.

Question 17

In the absence of gonadotropins, the ovararies are…?

Answer 17

Inactive which is the case during childhood.

Question 18

The timing and duration of of LH and FSH secretion determine the nature of the….?

Answer 18

Menstrual Cycle / Reproductive Cycle.

Question 19

What happens during the follicular phase?

Answer 19

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)

Question 20

Name the full sexual response cycle.

Answer 20

arousal, plateau, orgasm, resolution

Question 21

Engorgement and erection are controlled primarly by…?

Answer 21

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.

Question 22

Sildenafil (Viagra) works by enhancing the effects of…?

Answer 22

Nitric Oxide

Question 23

Name two examples of Polgamy.

Answer 23

Polygyny, Polyandry

Question 24

What is meant by the term sexual dimorphism?

Answer 24

Differences between male and female because of the sex.

Question 25

What is the motor neuron pool called that controlls the Bulbocavernosus (muscles sorrounding the base of the penis and the opening of the vagina)?

Answer 25

Onuf's Nucleus (is a bit dimorphic)

Question 26

Which steroid triggers the mascunalization of the developing nervous system?

Answer 26

Estrogen binding to estradiol receptors

Question 27

What did McCarthy and Amateau find regarding fetal and neonatal rats that were exposed to COX(cycoloxygenase) inhibitors.

Answer 27

Males showed reduced copulatory behavior as adults. | Female ratsexhibited male-like copulatory behaviors

Question 28

Give an example of organizational effects of a steroid and an activational effect of a steroid.

Answer 28

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

Question 29

During lactation the representation of the ventral skin in femal rats expands. This is an example for....?

Answer 29

somatosenry map plasticity

Question 30

What did Toran-Allerand find?

Answer 30

Estradiol treatment of tissue from hypothalamus of newborn mice causes a great degree of neurite outgrowth.

Question 31

Estradiol seems to important for...?

Answer 31

Forming neuronal circuitry during brain development.

Question 32

What is polyandry?

Answer 32

One female mates with many males but that male mates only with one female

Question 33

What is polygyny?

Answer 33

Male mates with many females but the female only with one male

Question 34

What does the male prairie vole prevent from bonding to the female vole?

Answer 34

Vasopressin antagonists given before mating.

Question 35

In prairie voles: vasopressin is important for the .... to form a bond and oxytocin is important for the .... to form a bond

Answer 35

vasopressin: male oxytocin: female

Question 36

Name three examples for sexual dimorphisms of the central nervous system

Answer 36

Onufs nucleus sexually dimorphic nucles (in rats) Interstitial nuclei of the anterior hypothalamus (controversial)

Question 37

Name two sexual dimorphisms of cognition.

Answer 37

Women better at verbal tasks | Men better at spatial rotation task

Question 38

Name two general ways by which steroids can influence neurons

Answer 38

Directly influence: affect transmitter synthesis, transmitter release or postsynaptic transmitter receptors Indirectly influence: Gene transcrption