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Hormonal Control in Females
• PUBERTY, DRAWING Puberty. Illustration of the changes observable at puberty in
both boys and girls (genitals, weight and height, secondary sex characteristics and
other characteristics developped specifically due to the secretion of testosterone in
boys and estrogen in girls.
The Ovarian (Menstrual) Cycle
• A regular periodic building and
destruction of the inner lining of
the uterus (endometrium) in
correlation with ovulation.
• Average cycle: 28 days
• Day 1 of the cycle is the first day
of menstrual flow
4 Phases of the Cycle
• 1. Flow Phase: (days 1-5)
– Menstruation.
• 2. Follicular Phase: (days 6-13)
– The follicle develops.
– The endometrium thickens and develops.
• 3. Ovulation: (day 14)
– Oocyte (ovum) bursts from the follicle.
• 4. Luteal Phase: (days 15-28)
– Corpus luteum develops.
– Endometrium thickens.
– If there is no fertilization, the corpus luteum will
degenerate and progesterone levels will drop. This will
cause the shedding of the endometrium (menstruation)
and the cycle will repeat itself.
Toxic Shock Syndrome
• What causes it?
• TSS is a strain of staph, the bacterium Staphylococcus Aureus
• illness that is caused by a toxin released by the bacteria is toxic
to the body’s organs
• Hyper-absorbent tampons may facilitate the infection because
their prolonged intra-vaginal use enhances the bacterial
growth. Wearing a diaphragm or sponge for more than 24
hours is not recommended because of possible risk of TSS.
• Prevention?
• Change tampons/pads regularily
• Does menstruation make women moody?
Hormonal Control of the cycle
• FSH: (think Fish=
)
• Stimulates follicle growth and development.
• Stimulates the follicles to release estrogen.
• LH:
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Stimulates follicle growth and development.
Triggers ovulation.
Maintains corpus luteum development.
Stimulates progesterone secretion
Hormonal Control of the cycle
• Estrogen:
– Secreted from the developing follicle.
– Stimulates endometrium thickening.
– Stimulates the development of female secondary sex
characteristics.
– Stimulates the production of LH.
– Inhibits the production of FSH.
Hormonal Control of the cycle
• Progesterone: Secreted by the
corpus luteum.
– Maintains endometrium thickening.
– Stimulates the enlargement of the
mammary glands.
– Inhibits FSH production (pituitary).
– Inhibits uterine contractions
Menstrual cycle Hormone simulation
http://www.abpischools.org.uk/page/
modules/hormones/horm4.cfm?coSit
eNavigation_allTopic=1
• Do Section 14.3 Review p. 502
• Do Chapter 14 Review p. 504-505
QUIZ-•Male and Female
parts and
Hormones
Section 15.1 – Fertilization
and Embryonic
Development
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•
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Fertilization, Pregnancy and Birth
Fertilization:
The ovum remains fertile up to 15 hours after ovulation.
Sperm cells can live (in the right environment) up to 72 hours after
ejaculation.
• This means that if fertilization is to occur, intercourse must take place no
longer than 72 hours before or 15 hours after ovulation.
Fertilization
• The ovum is transported through the fallopian tubes
toward the uterus.
• Fertilization must occur within the fallopian tubes due to
the short life span of the ovum.
• Sperm cells move from the vagina to the uterus due to
contractions at orgasm. They use their flagella to swim
into the fallopian tubes.
• Many sperm cells are needed to dissolve the ovum
membrane.
Fertilization
SpermRace
Game
• Only one sperm penetrates through the outer layer of the
ovum.
• Acrosome reaction - When a sperm comes in contact with
the egg, the acrosome (an enzyme-filled vacuole at the tip
of the sperm cell) bursts and releases enzymes that digest
the coating of the egg.
• Cortical reaction - Once the membranes have fused, a
chemical reaction occurs in the egg membrane, making it
impossible for other sperm cells to enter the egg.
• Nuclei of the sperm and ovum unite to form a zygote.
Cleavage and Implantation:
• The zygote continues to grow and move down the fallopian tube and into
the uterus.
• Within 30hrs of conception, the first cell division occurs creating 2 cells,
which will divide again to make 4 cells, which will divide again…
• At 16 cells it is called a morula and is a sphere
• 3-5 days after fertilization, the morula reaches the uterus and begins to
fill with uterine fluids
Cleavage and Implantation:
• It soon develops into a hollow fluid-filled ball of cells called a
blastocyst.
• The trophoblast (outerlayer) forms and will soon become the
chorion layer which will eventually become the placenta
• The inner cell mass will develop into the embryo
• Between days 5-7, the embryo attaches to the endometrium
with the help of enzymes produced by the trophobalst
• Implantation is completed by the 10th to 14th day
• The Great Sperm Race
hCG
• Around the time of implantation, the trophobalst produces the
hormone hCG – human chorionic gonadotropin
• http://ca.youtube.com/watch?v=DqX7VxW3wL0
• hCG maintains the corpus luteum like LH past the time the
corpus luteum would normally degenerate so, estrogen and
progesterone continue to “maintain pregnancy”
• high hCG production for 2 months, then it drops off but not
completely until birth
• Placenta eventually takes over to produce estrog. & progest.
Implantation
Gastrulation: formation of germ layers
• This disk will form 3 layers (endoderm, ectoderm,
mesoderm). This is called gastrulation as the 3 layers
are called the primary germ layers (embryo is now a
gastrula)
• Differentiation of cells begins allowing certain cell to
have certain functions
Gastrulation
• Embryonic development, computer artwork. This shows the process of gastrulation,
where cells at one position on the embryo create a groove (blastopore) and migrate
into the center.
• The cells then differentiate into the 3 germ layers; the ectoderm, endoderm and
mesoderm. The ectoderm forms epidermis and nervous tissue, the endoderm forms
the digestive tract, glands and lungs and the mesoderm forms the connective tissue,
including blood vessels and cartilage.
Using p. 513, list what each primary germ
layer becomes:
Ectoderm
• Nervous system
• Epidermis
Mesoderm
• Skeleton
• Muscles
• Reproductive structures
Endoderm
• Lining of the digestive tract
• Lining of the respiratory tract
• Endocrine glads
Neurulation 3-8 weeks
• Video
• Feeding the Growing Fetus
• Fertilization through Gastrulation
• birds
Structures that Support the Embryo
• Shark embryo