1. TOPIC:
HORMONAL REGULATION OF MALE AND
FEMALE REPRODUCTIVE SYSTEM
ASSIGNMENT OF PHYSIOLOGY
SUBMITTED BY:
NADIA EIMAN
1st YEAR (2nd SEMESTER)
JUW ID: 23012
SUBMISSION DATE: 18-FEB-23
SUBMITTED TO : MISS HIRA RAEES
COURSE TITLE: PHYSIOLOGY-B
COURSE CODE: 318-T
2. HORMONES:
HORMONAL REGULATION SYSTEM:
Hormones are your body's chemical messengers. They travel in your
bloodstream to tissues or organs. They work slowly, over time, and affect many
different processes, including: Growth and development. Metabolism - how
your body gets energy from the foods you eat.
During hormone regulation, hormones are released, either directly by an
endocrine gland or indirectly through the action of the hypothalamus of the
brain, which stimulates other endocrine glands to release hormones in order to
maintain homeostasis.
Hormonal control of spermatogenesis varies among species. In humans, the
mechanisms are not completely understood.
3. THE ROLE OF HORMONES IN MALE
REPRODUCTION:
Studies from rodent models suggest that gonadotropin hormones
(both LH and FSH) support the process of spermatogenesis by
suppressing the proapoptotic signals and thus promoting
spermatogenic cell survival. The Sertoli cells themselves mediate
parts of spermatogenesis through hormone production. They are
capable of producing the hormones estradiol and inhibin. The
Leydig cells are also capable of producing estradiol in addition to
their main product, testosterone. The male reproductive system is
regulated by the production, stimulation, and feedback of specific
hormones.
4. GONADOTROPIN-RELEASING HORMONE:
Gonadotropin-releasing hormone (GnRH) is mainly made in the preoptic area of the
hypothalamus before traveling to the pituitary gland.
FOLLICLE-STIMULATING HORMONE:
Follicle-stimulating hormone (FSH) is released by the anterior pituitary gland. Its
presence in males is necessary for the maturation of spermatozoa. Follicle-
stimulating hormone stimulates both the production of androgen-binding protein
by Sertoli cells and the formation of the blood-testis barrier.
LUTEINIZING HORMONE:
Luteinizing hormone (LH) is released by the anterior pituitary gland. In the
testes, LH binds to receptors on Leydig cells, which stimulates the synthesis and
secretion of testosterone.
5. TESTOSTERONE:
Testosterone is made in the interstitial cells of the testes. It stimulates the sex
drive and is associated with aggression. Androgen-binding protein is essential
to concentrating testosterone in levels high enough to initiate and maintain
spermatogenesis, which can be 20-50 times higher than the concentration
found in blood. The sequestering of testosterone in the testes is initiated by
FSH, and only testosterone is required to maintain spermatogenesis.
INHIBIN:
Inhibin is secreted by the Sertoli cells and acts to decrease the levels of FSH.
The hormone is released into the circulation when the sperm count is too high.
7. PROCESS OF SPERM PRODUCTION:
SPERMATOGENESIS:
Spermatogenesis is a process forming of spermatozoa form germ
cells (spermatogonium/ spermatogonia) that happened in
seminiferous tubules of the testis. There are 2 process of
spermatogenesis:
• Spermatocytogenesis.
• Spermiogenesis.
8. SPERMATOCYTOGENESIS:
Spermatocytogenesis is the male form
of gametocytogenesis and involves stem cells dividing
to replace themselves and to produce a population of
cells destined to become mature sperm.
SPERMIOGENESIS:
Spermiogenesis is the final stage of spermatogenesis,
during which the spermatids develop into
mature spermatozoa. At the beginning of the stage,
the spermatid is a more or less circular cell
containing a nucleus, Golgi
apparatus, centriole and mitochondria; by the end of
the process, it has radically transformed into an
elongated spermatozoon, complete with a head,
midpiece, and tail.
BY: SHUMAILAA.SHAKOOR
9. THE ROLE OF HORMONES IN FEMALE
REPRODUCTION:
In females, FSH and LH cause estrogen and progesterone to be produced. They
regulate the female reproductive system which is divided into the ovarian cycle
and the menstrual cycle.
FORMATION OF OVUM:
OOGENESIS:
Oogenesis is the process of
formation of female gametes. It is
the type of gametogenesis through
which ova or the female gametes
are formed, and this female
gamete is known as an ovum.
10. HORMONES REGULATING THE FEMALE
REPRODUCTIVE SYSTEM:
In this topic we will discuss the role of important hormones involved in the
regulation of the female menstrual cycle
Gonadotropin-releasing hormone (GnRH)
It produced by a part of the brain called the hypothalamus. When it circulates
in the blood, it causes the release of two important hormones from
the pituitary gland in another specialised part of the brain.
Leutenizing hormone (LH)
is also produced by the pituitary gland in the brain. It stimulates the ovaries to
produce oestrogen and progesterone.
Oestrogen
It is a female reproductive hormone, produced primarily by the ovaries in the
non-pregnant woman. It promotes the maturation and release of an ovum in
every menstrual cycle. It is also produced by the placenta during pregnancy.
11. Progesterone
It is produced by the corpus luteum in
the ovary; its function is to prepare
the endometrium (lining of the uterus)
for the reception and development of
the fertilized ovum. It also suppresses
the production of oestrogen after
ovulation has occurred.
12. • PUBERTY:
• Puberty is the sequence of events in which a child acquires adult physical
characteristics and capacity for reproduction. Circulating LH and FSH
levels are elevated at birth but fall to low levels within a few months and
remain low until puberty. Until puberty, few changes occur in reproductive
target organs.
• AGE OF ONSET OF PUBERTY:
• The age of onset of puberty and the rate of development through different
stages are influenced by different factors. Over the last 150 years, the age at
which puberty begins has been decreasing, primarily because of improved
health and nutrition, but this trend has stabilized.
• PHYSICAL CHANGES OF PUBERTY:
• Physical changes of puberty occur sequentially during adolescence (see
figure Puberty—when female sexual characteristics develop).Breast
budding and onset of the growth spurt are usually the first changes
recognized. Then, pubic and axillary hair appear and the growth spurt
peaks
13. • MECHANISMS
INITIATING PUBERTY:
• Mechanisms initiating puberty are
unclear. Central influences that
regulate release of GnRH include
neurotransmitters and peptides (eg,
gamma- aminobutyric acid [GABA],
kisspeptin). Such factors may inhibit
release of GnRH during childhood,
then initiate its release to induce
puberty in early adolescence. Early in
puberty, hypothalamic GnRH release
becomes less sensitive to inhibition
14. • THE OVARIAN CYCLE:
• The ovarian cycle refers to the monthly series of events in the ovaries,
associated with the maturation and release of an ovum, and the ‘just in case’
preparation for its fertilization and implantation in the uterus.
• THE FOLLICULAR PHASE:
• DAYS 1 TO 14:The sequence shown in Figure 4.1 begins with the secretion
of GnRH from the hypothalamus, which stimulates the pituitary gland to
produce FSH and LH, which in turn act on the ovaries, telling the ovarian
follicles to complete the maturation of an ovum. During this period, a few
ovarian follicles containing immature ova develop and mature under the
stimulation of FSH and LH. Usually by day 14, only one follicle has become
fully mature, and the ovum it contains is ready to be released
• THE LUTEAL PHASE: DAYS 15 TO 28:
• This phase is the period of corpus luteum activity, during which the uterus is
prepared ‘just in case’ of pregnancy. After ovulation has occurred, the corpus
luteum begins to secrete progesterone, as well as a small amount of oestrogen.
Progesterone maintains the uterus in a state ready to receive and nourish an
embryo. The lining of the uterus (the endometrium) becomes thicker, more richly
nourished by blood vessels, and more receptive to the fertilised ovum
15. THE MENSTRAL CYCLE
The menstrual cycle prepares your body for pregnancy. If
you are not pregnant, your hormones send a signal to your
uterus to shed its lining. This becomes your period. Once
you start your period, the cycle starts again.
A menstrual cycle is measured from the first day of your
period to the first day of your next period. The average
length of a menstrual cycle is 28 to 29 days, but every
woman’s cycle is different. For example, teenagers might
have cycles that last 45 days, whereas women in their 20s to
30s might have cycles that last 21 to 38 days.
16. PHASES OF MENSTURAL CYCLE
There are four main phases of the menstrual cycle.
17. MENSTRATION PHASE
• Menstruation is commonly known as a period. When
you menstruate, your uterus lining sheds and flows
out of your vagina.
• Your period contains blood, mucus and some cells
from the lining of your uterus. The average length of
a period is three to seven days.
• Sanitary pads, tampons, period underwear or
menstrual cups can be used to absorb your period.
18. THE FOLECULAR PHASE
The follicular phase starts on the first day of your period
and lasts for 13 to 14 days, ending in ovulation.
The pituitary gland in the brain releases a hormone to
stimulate the production of follicles on the surface of an
ovary. Usually, only one follicle will mature into an egg.
This can happen from day 10 of your cycle. During this
phase, your uterus lining also thickens in preparation for
pregnancy.
19. • Ovulation is when a mature egg is released from an
ovary and moves along a fallopian tube towards
your uterus.
• This usually happens once each month, about two
weeks before your next period. Ovulation can last
from 16 to 32 hours.
• It is possible to get pregnant in the five days before
ovulation and on the day of ovulation, but it’s more
likely in the three days leading up to and including
ovulation.
20. • After ovulation, cells in the ovary (the corpus luteum),
release progesterone and a small amount of oestrogen. This
causes the lining of the uterus to thicken in preparation for
pregnancy.
• If a fertilised egg implants in the lining of the uterus, the
corpus luteum continues to produce progesterone, which
maintains the thickened lining of the uterus.
• If pregnancy does not occur, the corpus luteum dies,
progesterone levels drop, the uterus lining sheds and the
period begins again.
:
21. COMMON MENSTURAL PROBLEMS:
Some of the more common menstrual problem include:
.PREMENSTRUAL SYNDROME( PMS)
Hormonal events before a period can trigger a range of side effects in women at risk .
Including fluid retention, fatigue and irritability.
TREATMENT: exercise
.DYSMENORRHOEA Or painful periods .
It is thought that the uterus is prompted by certain hormones to squeeze harder than
necessary to dislodge its lining .
TREATMENT: pain-relieving medication.
.HEAVY MENSTRUAL BLEEDING ( Menorrhagia )
It is left untreated, this can cause anemia .
TREATMENT: oral contraceptives and hormonal (IUD) to regulate the flow.
.AMENORRHOEA: or absence of menstrual periods .
This is considered abnormal , except during pre – puberty , pregnancy ,lactation and
post menopause
.
22. SUMMARY:
• The hormone controlling the female reproductive
system include GnRH,FSH,LH, all of which are
produce in the brain ; oestrogen and progesterone
produced by the ovaries and the corpus luteum
and HCG, Produced by the placenta during
pregnancy .
