11.1 Sex And Hormones

Question 0

Male and female mammals start with the same ____ during an early stage of prenatal development.

Answer 0

anatomy

Question 1

Females have two X ____, where as males have an X and a Y ____.

Answer 1

chromosomes

Question 2

Both have a set of ____ ducts (precursors to femail internal structures) and a set of ____ ducts (precursors to male internal structures), as well as unidentified gonads that are on their way to becoming either testes or ovaries.

Answer 2

Müllerian : Wolffian

Question 3

The males Y-chromosome includes the ___ (sex-determining region on the Y-chromosome) ___, which causes those primitive gonads to develop into testes, the sperm-producing organs.

Answer 3

SRY gene

Question 4

The developing testes produce ____ (hormones that are more abundant in males) that increase the growth of the testes, causing them to produce more androgens and so forth.

Answer 4

androgens

Question 5

Androgens also cause of the primitive Wolffian ducts, precursors for other male reproductive structures, to develop into ____ ____ (sack like structures that store semen) and the ___ ____ (a duct from the testes to the penis).

Answer 5

seminal vesicles : vas deferens

Question 6

The testes also produce ____ ____ ____ (MIH), which causes the Müllerian ducts to degenerate.

Answer 6

Müllerian inhibiting hormone

Question 7

Because females do not have the SRY gene, their gonads develop into ____ instead of testes, and their Wolffian ducts degenerate.

Answer 7

ovaries

Question 8

Because a female’s ovaries do not produce MIH, females Müllerian ducts develop and mature into ____, ____, and the upper vagina.

Answer 8

oviducts, uterus

Question 9

The males testes then produce more androgens than ____ (hormones that are more abundant in females,).

Answer 9

oestrogens

Question 10

Androgens and oestrogens are ____ ____, containing four carbon rings, derived from cholesterol.

Answer 10

steroid hormones

Question 11

We are often warned about the risks of excessive ____, but a moderate amount is necessary for generating these important hormones.

Answer 11

cholesterol

Question 12

Steroids exert their effects in ____ ways. First, they bind to membrane receptors, like neurotransmitters, exerting rapid effects. Second, they enter cells and activate certain kinds of proteins in the cytoplasm. Third, they bind to receptors that bind to chromosomes, where they activate or inactivate certain genes.

Answer 12

three

Question 13

Androgens and oestrogens are categories of ____; neither androgen nor oestrogen is a specific chemical its self.

Answer 13

chemicals

Question 14

The most widely known androgen is ____. The most common type of oestrogen is ____.

Answer 14

testosterone : estradiol

Question 15

_____, another predominantly female hormone, prepares the uterus for the implantation of a fertilised ovum and promotes the maintenance of pregnancy.

Answer 15

Progesterone

Question 16

Androgens promote the development of typically ____ features, such as facial hair. Oestrogens promote typically female features, such as breast development.

Answer 16

masculine

Question 17

For many years, biologists assumed that hormones account for all the biological differences between males and females. Later research demonstrated that some differences depend directly on control by the X and Y chromosomes ____ of hormones.

Answer 17

independently

Question 18

At least three gene on the Y-chromosome (found only mean) are active in specific brain areas, and at least one gene on the X chromosome is active only in the ____ brain.

Answer 18

female

Question 19

Genes on the X and Y chromosomes produce ____ differences in addition to those that we can trace to androgens and oestragens.

Answer 19

sex

Question 20

Biologist distinguish between the organising and activating effects of ___ ____.

Answer 20

sex hormones

Question 21

____ ____ produce long-lasting structural effects. The most prominent organising effects occur during a sensitive stage of early development determining whether the body develops female or male anatomy.

Answer 21

Organising effects

Question 22

____ ____ are more temporary, when a hormone increases some activity that lasts only while the hormone is present. Activating effects occur at any time in life.

Answer 22

Activating effects

Question 23

Differentiation of the ____ ____ and several aspects of brain development depend mainly on the level of testosterone.

Answer 23

external genitals

Question 24

The human sensitive period for genital formation is about the ____ and ____ months of pregnancy.

Answer 24

third and fourth

Question 25

Drugs that tend to ____ or demasculinise early development include alcohol, marijuana, haloperidol (and antipsychotic drug), phthalates (chemicals common in many manufactured products), and cocaine.

Answer 25

feminise

Question 26

In short, male development is vulnerable to many sources of ____.

Answer 26

interference

Question 27

In addition to controlling differences in the external genitals, sex hormones early in life influence development in parts of the ____, ____, and other brain areas.

Answer 27

hypothalamus, amygdala

Question 28

One area in the anterior hypothalamus, known as the ____ ____ ____, is larger in males than in females and contributes to the control of male sexual behaviour.

Answer 28

sexually dimorphic nucleus

Question 29

Parts of the female hypothalamus generate a cyclic pattern of hormone release, as in the human ____ ____.

Answer 29

menstrual cycle

Question 30

Any time in life, not just during a sensitive period, current levels of testosterone or oestradiol exert activating effects, _________.

Answer 30

temporarily modifying behaviour

Question 31

Changes in ____ ____ influence sexual behaviour within 15 minutes. Behaviours can also influence hormonal secretions.

Answer 31

hormonal secretions

Question 32

Sex hormones facilitate sexual activity. Testosterone is essential for male sexual arousal. A combination of estradiol and progesterone is the most effective combination for females. Arousal also depends on _________.

Answer 32

previous experience

Question 33

____ is the inability to have an erection. The most common cause is impaired blood circulation, especially in older men. Other common causes include neurological problems, reactions to drugs, and psychological tension.

Answer 33

Impotence

Question 34

Testosterone reduction has sometimes been tried as a means of controlling ____ ____, including exhibitionists, rapists, child molesters, and those who commit incest.

Answer 34

sex offenders

Question 35

One major practical problem is getting sex offenders to continue taking drugs that block testosterone. Another drawback is the side-effects of ____ ____, including weight gain, diabetes, and depression.

Answer 35

testosterone depravation

Question 36

A woman’s hypothalamus and pituitary interact with the ovaries to produce the ____ ____, a periodic variation in hormones and fertility over the course of about 28 days.

Answer 36

menstrual cycle

Question 37

After the end of the menstrual cycle, the anterior pituitary releases ____ ____ ____ (FSH), which promotes the growth of a follicle in the ovary.

Answer 37

follicle-stimulating hormone

Question 38

The follicle in the ovary nurtures the ____ (egg cell) and produces several types of oestrogen, including estradiol.

Answer 38

ovum

Question 39

The increased release of estradiol causes an increased release of FSH as well as a sudden surge in the release of ____ ____ (LH) from the anterior pituitary. FSH and LH combine to cause the focal to release an ovum.

Answer 39

luteinising hormone

Question 40

The remnant of the follicle (now called the corpus luteum) releases the hormone ____, which prepares the uterus for the implantation of a fertilised ovum.

Answer 40

progesterone

Question 41

Toward the end of the menstrual cycle, the levels of LH, FSH, estradiol, and progesterone all ____.

Answer 41

decline

Question 42

If the ovum is not fertilised, the lining of the uterus is cast off (____), and the cycle begins again.

Answer 42

menstruation

Question 43

The most widely used birth-control pill is the ____ ____, containing oestrogen and progesterone.

Answer 43

combination pill

Question 44

The ________ combination thickens the mucus of the cervix, making it harder for a sperm to reach the egg, and prevents an ovum, if released, from implanting in the uterus.

Answer 44

oestrogen-progesterone

Question 45

Changes in hormones over the menstrual cycle also alter women’s ____ ____.

Answer 45

sexual interest

Question 46

The ____ ____, consisting of the days around the middle of the menstrual cycle, is the time of maximum fertility and high oestrogen levels. According to two studies, women not taking birth-control pills initiate more sexual activity during that period than at other times of the month.

Answer 46

periovulatory period

Question 47

In addition to sex hormones, the pituitary hormone ____ is also important for reproductive behaviour. Oxytocin stimulates contractions of the uterus during delivery of a baby, and it stimulates the mammary gland to release milk.

Answer 47

oxytocin

Question 48

Sexual pleasure also releases oxytocin, especially at ____. People typically experience a state of relaxation shortly after orgasm as a result of oxytocin release.

Answer 48

orgasm

Question 49

Strong release of oxytocin facilitates formation of ____ ____ between mating partners.

Answer 49

pair bonds

Question 50

Oxytocin also facilitate other ____ ____. When people inhaled nasal spray containing oxytocin, as compared to a placebo, they become more accurate at recognising familiar faces.

Answer 50

social behaviours

Question 51

People sometimes call oxytocin a “love hormone”, but as you can see, that term is misleading. It might enhance your attraction towards someone you already love, but it doesn’t make you love or trust ____.

Answer 51

everyone

Question 52

A female mammals ____ changes in many ways when she becomes a mother. In addition to nursing and caring for the young, she eats and drinks more than usual, and becomes less fearful and more aggressive, especially in defence of her young.

Answer 52

behaviour

Question 53

____ is necessary for milk production and certain aspects of maternal behaviour, such as retrieving young when they wander away from the nest.

Answer 53

Prolactin

Question 54

Prolactin also inhabits sensitivity to ____, enabling the mother to eat far more than usual.

Answer 54

leptin

Question 55

In addition to secreting hormones, the female changes her pattern of hormone receptors. Late in pregnancy, her brain increases at sensitivity to estradiol in the areas responsible for ____ ____.

Answer 55

maternal behaviour

Question 56

The hormonal changes increase the mother’s attention to their young after delivery. Hormones increase activity in the medial preoptic area and anterior hypothalamus, areas that are necessary for ____ maternal behaviour.

Answer 56

rats’

Question 57

Another key hormone is ____, synthesised by the hypothalamus and secreted by the posterior pituitary gland. ____ is important for social behaviour in many species, partly by facilitating olfactory recognition of other individuals.

Answer 57

vasopressin

Question 58

Hormonal changes are necessary for a woman to _______, and oxytocin levels correlate with several aspects of motherly attention to an infant.

Answer 58

nurse a baby

Question 59

However, hormonal changes and not necessary for human parental behaviour. After all, many people ____ children and become excellent parents.

Answer 59

adopt