fallopian tubes

Transcription

fallopian tubes
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Consists of:
Ovaries or paired gonads
Oviducts (Fallopian Tubes)
Uterus
Vagina
Associated Structures (External Genitalia,
Mammary Glands)
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Unlike the male, the human female has a
reproductive system located entirely in the
pelvis
The external part of the female reproductive
organs is called the vulva.
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A female's internal reproductive organs are: the
vagina, uterus, fallopian tubes, and ovaries.
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At the upper corners of the uterus, the fallopian tubes
(oviduct) connect the uterus to the ovaries.
Small almond shaped bodies (3.8 cm in length)
Contains clusters of cells called follicles, each which
produces one egg. Other cells in the follicles nourish
the growing and maturing egg cell (ovum).
The cell contains little yolk. Maturation is slow, and
the ovaries may contain many follicles at different
stages of development.
Ovaries produce, store, and release eggs into the
fallopian tubes in the process called ovulation.
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Called oviduct, uterine tubes or ovarian tubes
The passageway for the ovum between the
ovary and the uterus
Located on each side of the uterus, oviducts are
about 10 to 12.5 cm long.
As the ovum bursts from the ovary into the
pelvic cavity, the oviduct catches it in
structures called fimbriae
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Fimbriae are the fringe-like ends of the
fallopian tubes
Cilia on the inner surfaces of frimbrae and on
the lining of the oviducts move the ovum
towards the uterus
Smooth muscles of the oviducts contract in
peristaltic waves to propel the ovum
The inner layer of the oviducts contains
mucous-secreting cells that may assist in
transporting the ovum and provide nutrients
for the ovum
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Fertilization of the ovum normally occurs
midway in the oviduct
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Implantation happens in the uterus. If
implantation happens in the fallopian tubes it
causes an ectopic pregnancy or tubal
pregnancy
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Hollow, muscular, upside-down pear-shaped
organ
Found in the pelvic cavity above and behind
the bladder
Non-pregnant uterus is about 7.5 cm long and
5 cm wide and 2.5 cm thick
During pregnancy the uterus increases in size
about 16 times the above dimensions
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The fundus is the upper part of the uterus; the
oviducts enter here
The body is the broad central portion
The cervix is the narrow end, which opens into
the vagina
The uterus has three layers; serous, muscular,
and mucous
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The serous layer is called the perimetrium
The muscular layer is called the myometrium;
it is the smooth muscle that increases in size
during pregnancy and contracts during labor
and delivery
The mucous layer is the endometrium, which
forms the maternal portion of the placenta
during pregnancy
At the bottom of the uterus is the cervix. The
cervix has strong, thick walls. The opening of
the cervix is very small (no wider than a
straw). During childbirth, the cervix can
expand to allow a baby to pass.
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The vagina connects with the uterus at the cervix
About 10 cm long
Glandular secretions from mucous membrane moisten
the vagina. Mucus is acidic and retards microbial
growth
Rugae are expandable folds within the vagina walls
that accommodate insertion of the penis and passage of
the fetus during childbirth
Vagina’s functions are to receive sperm, provide an exit
for menstrual flow and to serve as the birth canal
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Mons pubis – rounded part of fat in front,
covered by dense skin and during puberty
becomes covered with hair
Labia majora – two prominent longitudinal
folds of skin and underlying fat that extend
backward from the mons pubis towards the
anus.
Skin of this contains numerous hair follicles
and sweat glands
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Labia minor – two small folds of skin which
unite just above the clitoris to form the prepuce
Between labia major
No hair follicles or sweat glands
Clitoris – Small erectile structure that responds
to sexual stimulation
Similar in structure and origin to the penis
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Vestibule Floor – The labia minor skin folds
can be spread apart to expose the vestibule
floor
Contains Bartholin’s glands, which lubricate
the vagina
Vagina and urethra open in this area
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Modified sweat glands
Located in breasts
Hormones (prolactin and oxytocin) stimulate
them to produce and release milk after
childbirth
Each breast is divided into 15 to 20 lobes of
glandular tissue covered by adipose (fat) tissue
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Structure of the breast include the nipple, the
areola, and the areolar glands
Nipple is a circular projection containing some
erectile tissue
Nipple if surrounded by pigment areola.
Areolar glands make the areolar appear rough.
Secretions prevent the nipples from drying out.
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Egg cells are produced in the ovaries of female
organisms
A diploid cell in the ovaries called the primary
oocyte undergoes meiosis. In the first meiotic
division, a large cell called the secondary
oocyte and smaller cell called the first polar
body are produced.
Oogenesis – production of egg cells in females
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The secondary oocyte undergoes a second
meiotic division, forming a large cell called an
ootid and a second polar body.
Sometimes, the first polar bodies divide into
two second polar bodies.
The ootid develops into the mature haploid egg
cell, or ovum.
The polar bodies do not develop into egg cells.
The ovum contains more cytoplasm than the
polar bodies
The extra cytoplasm is used as food during
early development of a new organism.
Only 1 egg (ovum) gets made during meiosis
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Females have about 2 million oocytes in their
ovaries at birth and only 400-500 are released
during the reproductive years. The rest get
absorbed by the body.
At birth, primary oocytes have already entered
meiosis l, but stay in prophase l until females
enter reproductive age. When a girl begins her
menstrual cycle meiosis continues and eggs are
produced. When a woman hits menopause,
she stops producing eggs.