Adolescent Sexual Development: The Endocrine System, Puberty, Anatomy, and Physiology - PowerPoint PPT Presentation

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Adolescent Sexual Development: The Endocrine System, Puberty, Anatomy, and Physiology

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Title: Adolescent Sexual Development: The Endocrine System, Puberty, Anatomy, and Physiology


1
Adolescent Sexual Development The Endocrine
System, Puberty, Anatomy, and Physiology
  • FCS 438 Adolescents in the Family Context
  • Wendy Hill Williams, MA, LMFT

2
Puberty
  • Puberty is the time in life when a child changes
    into a young man or young woman capable of having
    children
  • Begins earlier in girls than boys (girls usually
    between 8 13 boys between the ages of 9 - 14
    years old)
  • Triggered by the pituitary gland which sends a
    signal to the ovaries or testicles to produce
    testosterone or estrogen
  • Understanding puberty requires an understanding
    of the endocrine system

3
The Endocrine System
  • The endocrine system is a complex system
    consisting of numerous glands that secrete more
    than 50 different hormones into the bloodstream
    to target tissues throughout the body
  • Hormones are chemical substances/messengers that
    affect the activity of almost every cell in the
    human body
  • The hormones of the endocrine system function to
    maintain homeostasis, regulate growth and
    metabolism, promote sexual development and sexual
    function, balance sugar, and perform many other
    physiological and metabolic functions many that
    are essential to life (Daruna, 2004 Farabee,
    2001 Rieser Kemp, 2005).

4
The Major Endocrine Glands of the Human Body
  • Each gland secretes one or more hormones
  • pituitary gland
  • pineal gland
  • thyroid gland
  • parathyroid gland
  • adrenal gland
  • pancreas
  • ovaries or testes

The Internet Encyclopedia of Science
5
The Hypothalamus Pituitary Gland
Many of the chemical processes begin in the
hypothalamus ? the pituitary gland

6
The Hypothalamic-Pituitary-Adrenal Axis and the
Hypothalamic-Pituitary-Gonadal Axis
  • The hormones of the hypothalamic-pituitary-adrenal
    axis (HPA) and the Hypothalamic Pituitary
    Gonadal (HPG) axis are regulated by a negative
    feedback loop, involving the hypothalamus,
    pituitary gland, and the target organs (Daruna,
    2004 Morley 2005).

7
Hypothalamic Pituitary Gonadal Adrenal Axes
8
The Hormones of the Endocrine System
  1. Pituitary gland The Master Gland it secretes
    releasing hormones to target gland and other
    hormones such as oxytocin
  2. Pineal gland secretes melatonin, regulates
    sleep
  3. Thyroid gland secretes thyroxine (T4) and
    triiodothyronine (T3) and calcitonin functions
    in metabolism
  4. Parathyroid glands secretes PTH regulates
    calcium, Vitamin D, and bone metabolism
  5. Adrenal glands the outer cortex secretes
    aldosterone which regulates salt and water
    balance cortisol is secreted by the middle
    cortex and is essential for life the adrenal
    medulla produces epinephrine and norepinephrine -
    the fight or flight response
  6. Pancreas the islet cells of the pancreas
    secrete insulin to balance blood sugar
  7. Ovaries or Testes the gonads produce estrogen,
    progesterone and testosterone and are responsible
    for sexual development and reproduction

9
Major Male Female Sex Hormones
  • Estrogen is the major female hormone
  • Testosterone is the major male hormone
  • Both hormones are present in both genders but in
    different quantities men produce 6-8 mg of
    testosterone daily women produce .5 mg
  • Testosterone plays a role in sexual desire it
    can also increase aggression

10
Primary Sex CharacteristicsRelated to
reproduction and present at birth
  • Men testes and other reproductive organs
  • Women ovaries, uterus, and other reproductive
    organs

11
Secondary Sex Characteristics Appear at puberty
  • Recall that puberty begins when the pituitary
    signals the gonads to produce the sex hormones
    testosterone and estrogen
  • The first sign of puberty is often a growth spurt
    in both boys and girls
  • Boys penis and testicles enlarge, larger
    skeletal structure, stronger muscles, shoulders
    broaden, thicker skin, hair distribution (face,
    chest, back, legs, arms, pubic area and
    underarms), voice deepens, spontaneous erections
    and wet dreams
  • Girls breasts develop, hair develops in pubic
    area and underarms, extra layer of fat beneath
    the skin which makes the womans body softer and
    more rounded, hips widen, and menstruation begins
  • Increased hormone production, overactive oil
    glands and sebum production can clog the pores
    and cause acne in some teens

12
Stages of Puberty
  • The process of puberty begins at different ages
    for each individual
  • Puberty occurs in five stages and can take
    between two five years depending on the person
  • These stages are called The Tanner Stages of
    Development

13
Tanner Stages of Male Development
From Always Changing Fifth Grade Puberty
Education Program (2009)
14
Stage One Up to ages 9 to 13 Stage Two May begin ages 9 to 15 Stage Three May begin ages 11 to 16 Stage Four May begin ages 12 to 17 Stage Five May begin ages 14 to 18
Childhood stage no visible signs of pubertal development Testicles and scrotum grow larger Fine, straight hair starts growing at the base of the penis Testicles and scrotum continue to growPenis grows larger Pubic hair becomes darker, thicker and curlier Vocal cords increase in size, causing voice to deepen Height and weight may start to increase noticeably Growth spurt continues Shoulders begin to broaden and physique becomes more muscular Penis grows in width as well as length Pubic hair coarsens and takes on a triangular shape Underarm hair appears Traces of hair may appear on upper lip and chin Testicles start to produce sperm ejaculation occurs for the first time Adult stage overall look is that of a young man Growth spurt slows down Facial hair growth becomes heavier Body hair growth, especially on the chest, may continue into the 20s
From Always Changing Fifth Grade Puberty
Education Program (2009)
15
Tanner Stages of Female Development
From Always Changing Fifth Grade Puberty
Education Program (2009)
16

Stage One Up to ages 8 to 12 Stage Two May begin ages 8 to 14 Stage Three May begin ages 9 to 15 Stage Four May begin ages 10 to 16 Stage Five May begin ages 12 to 19
Childhood stage no visible signs of pubertal development Height and weight increase rapidly Breast buds appear nipples become raised and this area may be tender Fine, straight hair starts growing close to the labia Height continues to increase Breasts become rounder and fuller Pubic hair becomes darker, thicker and curlier Hips may start to widen in relation to waist, giving a softer, more rounded shape Vagina begins secreting a clear, whitish fluid called vaginal discharge For some girls, ovulation and menstruation begin late in this stage Underarm hair appears The nipple and the dark area around it (areola) may stick out from the rest of the breast Pubic hair starts to form a triangular patch in front and around sides of the genital area For many girls, ovulation and menstruation begin during this stage Adult stage overall look is that of a young woman Areola rejoins breast contour and breast development is complete Pubic hair forms a thick, curly, triangular patch Pubic hair forms a thick, curly, triangular patch Adult height is probably reached Ovulation and menstruation occur regularly
From Always Changing Fifth Grade Puberty
Education Program (2009)
17
Sex Hormones (female)
  • Estrogen the principal female hormone serves
    multiple functions
  • Helps to promote sex differentiation in the fetus
  • Promotes maturation of reproductive organs and
    the development of secondary sex characteristics
    during puberty
  • Has effects on other organs such as the breasts,
    uterus, brain, bone, and other tissues
  • Facilitates the buildup and thickening of the
    lining of the uterus during the proliferative
    phase of the menstrual cycle
  • Progesterone
  • serves multiple functions
  • plays a major role in the luteal phase of
    menstruation, and in maintaining pregnancy

18
Sex Hormones (male)
  • Testosterone principal male hormone, serves
    multiple functions
  • The amount of testosterone seems to correlate
    with sexual response
  • Can cause aggression
  • Promotes development of secondary sex
    characteristics in puberty
  • Facilitates muscle and bone growth (in both men
    and women)
  • Both men and women have testosterone and estrogen
    although not in the same quantities

19
Gonadotropins
  • FSH - Follicle Stimulating Hormone is secreted by
    the pituitary gland and is responsible for
    stimulating the development of the ova in the
    ovary and for sperm production.
  • LH - Luteinizing Hormone is also secreted by the
    pituitary gland and stimulates the production of
    sex hormones by the ovaries and testes. LH
    causes ovulation to occur.

20
Menstruation and the Menstrual Cycle
  • Complex endocrine, ovarian and uterine changes
    characterize each of these phases
  • Menstrual Phase
  • Proliferative Phase
  • Ovulation
  • Luteal Phase

21
Phases of the Menstrual Cycle Regulated by
the Hypothalamic-pituitary-gonadal axis of the
endocrine system The menstrual cycle is
measured from the first day of menstrual flow to
the last day before the next flow begins
  • The Menstrual Phase The sloughing off of the
    uterine lining (the endometrial lining) that
    takes place if conception has not occurred
  • Proliferative Phase The endometrial lining is
    built up to prepare for a possible pregnancy.
    Egg follicles develop. Estrogen plays a vital
    role in this phase
  • Ovulation The release of a developed ovum (egg)
    from the ovary. Usually occurs midway through
    the cycle on day 14 of a 28 day cycle
  • Luteal Phase Postovulatory phase between
    ovulation and the next menstrual cycle

22
Menstrual PhaseDay 1
  • The first day of your period is considered the
    onset of your new cycle
  • The onset of menstruation during which the
    endometrial lining is sloughed off and discharged
    if pregnancy hasnt occurred

23
Proliferative Phase
  • The hypothalamus releases a hormone called
    gonadotropin releasing hormone (GN-RH)
  • The lining of the uterus thickens as the
    pituitary gland increases production of
    gonadotropins
  • GNRH stimulates the pituitary to produce two
    hormones follicle-stimulating hormone (FSH) and
    luteinizing hormone (LH) FSH cause the ovarian
    follicles to mature
  • LH causes the ovary to release a mature ovum and
    stimulates the development of corpus luteum, the
    mass of cells left in the ovary after the
    follicle ruptures and an ovum is released

24
Ovulation Phase
  • Ovulation is the release of mature ovum from the
    ovary and marks the transition from the
    proliferative phase to the luteal phase of the
    menstrual cycle
  • Pregnancy occurs during this phase if a viable
    sperm meets and fertilizes a viable ovum
  • This usually takes place mid-cycle (on day 14 in
    a 28 day cycle)

25

26
Luteal Phase
  • Postovulatory phase lasting from ovulation until
    menstrual flow begins again
  • The corpus luteum is formed during this phase
    producing large amounts of progesterone
  • Progesterone (along with estrogen produced by the
    ovaries) causes the uterus to prepare for the
    possible implantation of a fertilized egg and
    regulates the production and release of other
    hormones in the body
  •  If implantation does not occur, the pituitary
    gland decreases
  • production of LH and FSH causing the corpus
    luteum to degenerate and estrogen and
    progesterone production drop abruptly
  • This causes endometrial cells to die initiating
    the next menstrual phase

27
Conclusion
  • Hormones are vital and necessary chemicals for
    sexual development, maturation, desire,
    reproduction, and some are essential for
    maintaining health and life
  • Sex Hormones involve a complex interplay of the
    hypothalamic-pituitary-gonadal axis to promote
    sexual development, sexual desire and the ability
    to propagate
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