Transcript NVCC Bio 212 - gserianne.com

Marieb’s Human
Anatomy and Physiology
Ninth Edition
Marieb w Hoehn
Chapter 27
Female Reproductive System II
Lecture 20
Hormonal Control, Menstrual Cycle/Estrogens,
the Climacteric, Female Breast
Review of Female Reproductive Cycle
Figure from: Hole’s
Human A&P, 12th
edition, 2010
2
Ovarian Cycle – Preovulatory (Follicular) Phase
Figure from: Martini,
Anatomy & Physiology,
Prentice Hall, 2001
(Graafian)
1.5 cm
Many
(FSH)
Few
Thecal and
granulosa cells
produce
estrogens
(FSH)
One
8-10 days after
beginning of
cycle
10-14 days
LH
Meiosis
II started
Meiosis I
Estrogen
3
Ovarian Cycle – Postovulatory (Luteal) Phase
(Day 14)
LH
LH
Lipids used to
synthesize progestins,
e.g., progesterone
(prepares uterine
lining for
implantation)
12 days post ovulation
If fertilization has
not occurred
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
4
Hormonal Control of the Female Reproductive Cycle
• Ovarian and uterine (menstrual) cycles must
be coordinated
• GnRH (Gonadotropin Releasing Hormone)
is the controlling hormone of reproduction
– Pulse frequency and amplitude (amount)
– Without pulses, LH/FSH secretion (also in
pulses) will stop
– Changes in GnRH pulse frequency are
controlled by estrogen (increase) and progestins
(decrease)
5
Hormonal Regulation of Ovarian Activity
Figure from:
Saladin,
Anatomy &
Physiology,
McGraw Hill,
2007
6
Hormonal Regulation of Ovarian Activity
1-4 GnRH
pulses/day
inhibits LH and FSH
during most of the
reproductive cycle
(Day 10)
16-24 GnRH
pulses/day
36 GnRH
pulses/day
48GnRH
pulses/day
Estrogen is the
predominant
hormone prior to
ovulation (follicular
phase)
Progesterone is the
predominant
hormone after
ovulation (luteal
phase)
Figure from: Marieb, Anatomy & Physiology, Pearson, 2004
7
Pathways of Steroid Hormone Synthesis
Most abundant
Androstenedione is secreted by
thecal cells (LH) of the primary
follicles and then absorbed by the
granulosa cells (FSH) and
converted to estrogens.
Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001
8
Effects of Estrogens (20 sex characteristics)
•development of breasts and ductile system of the
mammary glands
• increased adipose tissue in breasts, thighs, and
buttocks
• increased vascularization of skin
• Maintenance of the function of accessory
reproductive glands/organs
• CNS effects, e.g., sex drive, “feminization”
•Repair/growth of endometrium (following menses)
9
Uterine (Menstrual) Cycle
Figure from: Hole’s Human A&P, 12th edition, 2010
Functional
Basilar
*
Proliferative phase – functional layer of endometrium thickens
under the influence of estrogen
Secretory phase – Arteries elaborate and uterine glands enlarge,
coil, and begin secreting glycogen under progesterone’s influence
10
Menarche and the Menstrual Cycle
• Menarche
– First menstrual cycle (Latin mensis = month)
– Typically begins around age 11-12
– If menarche does not appear by age 16,
considered amenorrhea (rhe(o)- = flow)
• Menstrual cycles
– Occur monthly unless interrupted by illness,
stress, starvation, or pregnancy
– Lack of menstrual period for 6 months or more
is considered amenorrhea (secondary)
– Painful menstruation is called dysmenorrhea –
may result from uterine inflammation or
conditions involving adjacent pelvic structures
11
Overview of Female Reproductive Cycle
Figure from: Hole’s Human A&P, 12th edition, 2010
You should
understand
these events,
and their
timing, for
the exam
12
Events of the Female Reproductive Cycle
Table 22.4 in
Hole’s Anatomy &
Physiology
Good textual
review table for
combined
ovarian and
uterine cycles
Figure from: Hole’s Human
A&P, 12th edition, 2010
13
Male and Female Climacteric
Female climacteric = menopause
• usually occurs in late 40s or early 50s (perimenopause)
• reproductive cycles stop for 6 months to 1 year
• ovaries no longer produce as much estrogen and
progesterone due to depletion of ovarian follicles
• some female secondary sex characteristics may disappear
• sustained rise in GnRH and LH/FSH may produce hot
flashes (LH) and fatigue
• risk of atherosclerosis increases
• hormone therapy may prevent effects on bone tissue
Male climacteric (andropause)
• more gradual than female climacteric
• usually occurs after age 50
• slowly declining levels of testosterone
• sperm (gamete) production continues (even into 80s!)
14
Mammary Glands
Mammary glands as
shown are for women in
last trimester of
pregnancy or who are
nursing.
The areola, a ring of
pigmented skin, covers
large sebaceous glands
that give it a bumpy
appearance. Sebum
reduces chapping and
cracking of the nipple.
Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001
15
Mammary Glands
Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001
Milk production = lactation
Inactive (resting) mammary gland is dominated by a duct
system rather than by active glandular cells. Size of
mammary glands in a nonpregnant/nonlactating woman
reflects amount of adipose tissue present.
16
Review
inhibits LH and FSH
during most of the
reproductive cycle
Estrogen is the
predominant
hormone prior to
ovulation (follicular
phase)
Progesterone is the
predominant
hormone after
ovulation (luteal
phase)
(Day 10)
Estrogen maintains secondary sex
characteristics in females
Figure from: Marieb, Anatomy & Physiology, Pearson, 2004
17
Review
Figure from: Hole’s Human A&P, 12th edition, 2010
18
Review
• Climacteric
– Women
•
•
•
•
Called menopause
Occurs around 40-50 years of age
Cessation of reproductive cycles – no oocytes
Ovaries no longer produce much estrogen
– Men
• Occurs more gradually
• Sperm production continues well into old age
• Levels of testosterone decline gradually
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