fallopian tube
• The function of the Fallopian tube is to convey the ovum
from the ovary to the uterus. It is done by peristalsis.
• Fertilisation of the ovum generally takes place in the upper
portion of the Fallopian tube (ampulla).
• Each Fallopian tube (10-20 cm) consists of the parts as
shown in the flowchart.
Isthmus
The isthmus is short, narrow thick-walled portion that follows the
ampulla.Fallopian tubeUterine part
The uterine part passes through the uterine wall and communicates
with the uterine cavity.Infundibulum isafunnel-shaped fimbriated free end of the oviduct. It
opens into the body cavity by an aperture called ostium. Margin of the
funnel bears motile, finger-like processes called fimbriae. Fimbriae
have folds lined with cilia that produceaslow current towards
ostium for the passage of liberated ovum towards inside of oviduct.InfundibulumAmpulla
The ampulla is the widest and the longest part of Fallopian tube.uterus
• It is an inverted pear-shaped large distensible part of female
reproductive system which is specialised for anchoring and
nourishing the developing foetus. Uterus is attached to
pelvic wall by means of ligaments.
interplay of ganulosa and thecal cells• During the initial first of week of menstrual cycle, there is a division of labour between the actions of FSh and Lh on the
follicles.
• FSh acts on the granulosa cells, and Lh acts on the theca cells. The reasons are that granulosa cells have FSh receptors but no
Lh receptors and theca cells have just the reverse. FSh stimulates the granulosa cells to multiply and produce estrogen, and it
also stimulates enlargement of the antrum. Some of the estrogen produced diffuses into the blood and maintains a relatively
stable plasma concentration. Estrogen also functions as a paracrine or autocrine agent within the follicle, where, along with
FSh and growth factors, it stimulates the proliferation of granulosa cells, which further increases estrogen production.
• The granulosa cells, require help to produce estrogen because they
are deficient in the enzymes required to produce the androgen
precursors of estrogen. The granulosa cells are aided by the theca
cells.
• Lh acts upon the theca cells, stimulating them not only to proliferate
but also to synthesise androgens. The androgens diffuse into the
granulosa cells and are converted to estrogen by an enzyme
expressed in granulosa cells called aromatase. Thus, the secretion
of estrogen by the granulosa cells requires the interplay of both
types of follicle cells and both pituitary gonadotropins.Theca cells
synthesise
androgensGranulosa cells
convert androgens
to estrogenDiffusionLH FSHOvarian follicleFig.:Control of estrogen synthesis during the early and
middle follicular phases.• The walls of the uterus are composed of three layers of
tissues. The perimetrium is an outer thin covering of
peritoneum. The myometrium is a middle thick layer of
smooth muscle fibres which shows strong contraction during
delivery of the baby. The endometrium is inner glandular
layer that lines the uterine cavity. It is the endometrium that
undergoes cyclical changes during menstrual cycle.
• morphologically uterus is differentiated into three regions
fundus, body and cervix.
UterusCervix isasmall narrow cylindrical inferior extremity
of uterus which is about 2.5 cm in length.The cervix
communicates alone with the body of the uterus by an
aperture called internal os and with the vagina below
by external os.The cavity of the cervix between the
internal os and external os is called cervical canal.Fundus is upper dome-shaped region of the uterus
which lies above the level of entry of oviducts.Body is the main part of uterus. Body of uterus is
broad towards the fundus and narrows down towards
the cervix.FundusBodyCervixvagina
• The vagina is a tube, about 10 cm long, that extends from
the cervix to the outside of the body. It provides a passage
for the menstrual flow, serves as the receptacle for sperm