Biological Transitions - Puberty Flashcards

1
Q

What is puberty?

A

The period during which an individual becomes capable of sexual reproduction

  • Females start menstruating and males start being able to ejaculate sperm
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2
Q

What are 3 pre-through-post-pubertal changes that adolescence go through?

A
  • Biological
  • Cognitive
  • Social
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3
Q

What 2 systems of the brain are the changes being driven by?

A

The Endocrine system
The Central Nervous System

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4
Q

What does the onset of puberty depend on?

A

Hormones

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5
Q

What are organizational effects?

A

The prenatal effects of hormones causing differentiation and organization of physiological systems

  • Your brain is being altered by hormones before you’re even born - exposed to in utero
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6
Q

What are the activational effects?

A

The effects of hormones upon these previously organized systems

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7
Q

What are the critical hormones?

A
  • Androgens - Testosterone
  • Estrogen and progesterone
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8
Q

Do both males and females produce both types of hormones?

A

Yes, but the quantity is dfferent

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9
Q

Is there a critical period during development when hormones have an organizational effect on both physiology and on brain wiring?

A

Yes.

  • The presence or absence of the appropriate hormones during this critical period determines the appearance and behavior of the adult
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10
Q

True or False: Everyone embryo starts out as Bi-Potential

A

True.

The embryo could be male or female

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11
Q

Is it the X or Y chromosome that is going to decide if the embryo is going to be a male or female?

A

The direction an embryo takes is determined by the presence or absence of a Y chromosome

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12
Q

What does the Y chromosome contain?

A

The Y chromosome contains a tiny little gene called the Sex Determining Region of the Y Chromosome (SRY gene) that is responsible for producing a protein called Testes Determining Factor (TDF)

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13
Q

What is TDF?

A

Testes Determining Factor

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14
Q

What happens when the SRY gene activates TDF?

A

the bipotential tissue begins to masculinize and will develop into testes, which produce Androgens (particularly Testosterone) that stimulates the development of the penis

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15
Q

What happens in the absence of the TDF?

A

the bipotential tissue develops as female sex organs: the ovaries and vagina (Historically, this led some to erroneously conclude that female was the “default” sex)

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16
Q

What is Androgen Insensitivity Syndrome (AIS)?

A

A genetic male who is resistant to androgens

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17
Q

What is Complete Androgen Insensitivity Syndrome (CAIS)?

A

the penis and other male body parts fail to develop so that at birth, the child is sexed as female

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18
Q

What is Partial Androgen Insensitivity Syndrome (PAIS)?

A

may appear with predominantly female, predominantly male, or ambiguous external genitalia

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19
Q

True or False: Most cases of AIS are genetic and inherited from the father

A

FALSE.

They are genetic but they are inherited from the mother

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20
Q

True or False: AIS males are almost always infertile

A

TRUE

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21
Q

Can PAIS lead to gender dysphoria?

A

Yes because the brain has partially masculinized

22
Q

Are people with AIS typically raised as male or female?

A

They are typically raised as females

  • In CAIS, despite the presence of a Y chromosome, this is fine, masculinization of the brain has not occurred
23
Q

What is 5-alpha Reductase Deficiency?

A

Genetic male who develops testes and produces testosterone but is unable to effectively convert Testosterone to the substance required for the proper development of the penis (dihydrotestosterone)

  • Often sexed as females at birth
24
Q

What happens during puberty of individuals who have 5-alpha Reductase Deficiency?

A
  • an increase in Testosterone production leads to the development of typical male sex characteristics
  • Gender dysphoria is VERY common in this case because the brain WAS masculinized…
25
Q

What are the primary sexual characteristics present at birth?

A

Internal genitalia such as testes and ovaries

External genitalia such as penis and vagina

25
Q

What are the 3 primary physical changes that occur during puberty due to the activational effects of hormones?

A
  • Further development of Primary Sex Characteristics

-Development of Secondary Sex Characteristics

  • Rapid acceleration in growth: The Adolescent “Growth Spurt”
26
Q

What are the secondary sexual characteristics that emerge during the pubertal phases for males?

A

Facial hair, muscle growth, pubic hair, body odor

27
Q

What are the secondary sexual characteristics that emerge during the pubertal phases for females?

A

Breasts, rounding of hips, pubic hair, body odor

28
Q

What is the adolescent growth spurt?

A

The dramatic increase in height and weight that occurs during puberty

  • Usually occurs in spurts and during a short amount of time
  • Pituitary hormones prompt growth (Adolescent growth spurt)
29
Q

What is peak height velocity?

A

The point at which the adolescent is growing most rapidly

30
Q

What may occur due to the adolescent growth spurt?

A

Body dissatisfaction

  • Increased in height is accompanied by increase in weight
31
Q

What are boys muscle-to-fat ratio by the end of puberty?

A

3 to 1

  • Boys feelings around their looks revolve around how muscular they are
32
Q

What are girls muscle-to-fat ratio by the end of puberty?

A

5 to 4

  • Leads girls to become overly concerned about their weight
  • Early matures are most susceptible to feelings of body dissatisfaction
33
Q

What is the timing of the activation effects of hormones dependent on?

A

The function of the Endocrine System

34
Q

What does the endocrine system do?

A
  • In general, the endocrine system produces, circulates, and regulates hormone levels in the body
  • The levels of sex hormones (i.e., androgens, estrogen) circulating in the body are controlled by a feedback loop
35
Q

What does the hypothalamus do?

A
  • Monitors levels of sex hormones to maintain the correct set point
  • Inhibits the pituitary gland unless sex hormones levels fall below a set point
36
Q

What is adrenarche?

A
  • The maturation of the adrenal gland that began in middle childhood (we don’t know why) is completed during adolescence
37
Q

What does adrenarche result in?

A

Sometimes called the “puberty of the adrenal gland”

– it results in a steady increase in the production of sex hormones (i.e. androgens and estrogens) that result in the development of pubic hair, oily skin, oily hair, and body odor

38
Q

What is the HPG axis?

A

The Hypothalamic-Pituitary-Gonadal Axis

39
Q

What initiates the activations of the HPG axis?

A

Just before puberty, the pituitary begins to secrete hormones but we don’t know exactly why

  • Presence of mature sexual partners
  • Sufficient nutritional resources
  • Physically healthy enough to begin reproducing
40
Q

Which chemicals are involved in the activation of the HPG axis?

A
  • Kisspeptin
  • Leptin
  • Melatonin
41
Q

What is kisspeptin?

A

A chemical produced by mature kisseptin neurons, believed to trigger the onset of puberty

42
Q

What is Leptin?

A

A brain chemical produced by the fat cells that may play a role in the onset of puberty through stimulating kisspeptin neurons (It’s typical function is to increase appetite!)

43
Q

What is melatonin?

A

A hormone secreted by the brain that contributes to sleepiness and that triggers the onset of puberty through its impact on kisspeptin neurons

44
Q

What are some somatic development because of the effects of hormonal changes during puberty?

A
  • Individual enters puberty looking like a child; shortly thereafter has the physical appearance of a young adult
  • The average individual grows about 10 inches taller, matures sexually, and develops an adult proportioned body
  • The brain changes in size, structure, and function at puberty
45
Q

True or False: There is a specific average age at onset and duration of puberty.

A

FALSE.

There is NO specific average age at onset OR duration of puberty

46
Q

True or False: There is no relation between the age at which puberty begins and the rate of pubertal development

A

TRUE

47
Q

Are there ethnic differences in the time and rate of pubertal maturation?

A

There ARE ethnic differences in the timing and rate of pubertal maturation:

Black females (1st); Mexican American females (2nd); White females (3rd).

  • Difference is probably not due differences in income, weight, or area of residence
  • Likely related to environmental (i.e. chemical) and/or genetic factors
48
Q

Are the timing and tempo of puberty inherited?

A

Largely inherited

  • Genetic disposition is best thought of as an upper and lower age limit, not a fixed absolute
49
Q

What are two key environmental influences that can cause individual differences in pubertal maturation?

A

Nutrition and Health

  • Puberty occurs earlier among those who are better nourished
  • Delayed puberty is more likely among individuals with a history of protein and/or caloric deficiency
  • Chronic illness and excessive exercise also linked with delayed puberty
50
Q

Does familial influence have an effect on pubertal timing?

A

Social factors in the home environment may influence the onset of maturation, especially in girls

  • Tension in the family (i.e., absence of father, conflict-ridden households, sexual abuse): All are stressors
  • Stressors can directly impact the production of hormones!
  • The presence of a stepfather, which may expose the adolescent girl to pheromones that stimulate pubertal maturation
51
Q

What are pheromones?

A

A class of chemicals secreted by animals that stimulate certain behaviors in other members of the species.