Anatomy of male and female reproductive system, Functions of male and female reproductive system, sex hormones, physiology of menstruation, fertilization, spermatogenesis, oogenesis, pregnancy and parturition

1. Reproductive system
Miss. Gayatri K. Bahatkar
Assistant Professor
P. R. Patil Institute of Pharmacy, Talegaon sp.

2. • The human reproductive system includes the male reproductive
system which functions to produce and deposit sperm; and the
female reproductive system which functions to produce egg cells, and
to protect and nourish the fetus until birth.

3. Female Reproductive System
• The female reproductive system functions to produce gametes and
reproductive hormones, just like the male reproductive system;
however, it also has the additional task of supporting the developing
fetus and delivering it to the outside world. Unlike its male
counterpart, the female reproductive system is located primarily
inside the pelvic cavity. Recall that the ovaries are the female gonads.
The gamete they produce is called an oocyte.

5. Function
• Producing gametes ( eggs or ova )
• Certain sex hormones
• Maintaining fertilized egg as they developed into mature feteuses and
become ready for delivery
• Secreting sex hormones
• Providing a site for fertilization
• Fertility
• Mensuration
• reproduction

6. External Female Genitals
• The external female reproductive structures are referred to collectively as
the vulva. The mons pubis is a pad of fat that is located at the anterior, over
the pubic bone. After puberty, it becomes covered in pubic hair. The labia
majora (labia = “lips”; majora = “larger”) are folds of hair-covered skin that
begin just posterior to the mons pubis. The thinner and more pigmented
labia minora (labia = “lips”; minora = “smaller”) extend medial to the labia
majora. Although they naturally vary in shape and size from woman to
woman, the labia minora serve to protect the female urethra and the
entrance to the female reproductive tract.
• The superior, anterior portions of the labia minora come together to
encircle the clitoris (or glans clitoris), an organ that originates from the
same cells as the glans penis and has abundant nerves that make it
important in sexual sensation and orgasm. The hymen is a thin membrane
that sometimes partially covers the entrance to the vagina.

7. Vagina
• The vagina is a muscular canal (approximately 10 cm long) that serves
as the entrance to the reproductive tract. It also serves as the exit
from the uterus during menses and childbirth. The outer walls of the
anterior and posterior vagina are formed into longitudinal columns,
or ridges, and the superior portion of the vagina—called the fornix—
meets the protruding uterine cervix.
• The walls of the vagina are lined with an outer, fibrous adventitia; a
middle layer of smooth muscle; and an inner mucous membrane with
transverse folds called rugae. Together, the middle and inner layers
allow the expansion of the vagina to accommodate intercourse and
childbirth.

8. Ovaries
• The ovaries are the female gonads. Paired ovals, they are each about 2 to 3
cm in length, about the size of an almond. The ovaries are located within the
pelvic cavity, and are supported by the mesovarium, an extension of the
peritoneum that connects the ovaries to the broad ligament. Extending from
the mesovarium itself is the suspensory ligament that contains the ovarian
blood and lymph vessels. Finally, the ovary itself is attached to the uterus via
the ovarian ligament.
Oogenesis
• Gametogenesis in females is called oogenesis. The process begins with the
ovarian stem cells, or oogonia. Oogonia are formed during fetal
development, and divide via mitosis, much like spermatogonia in the testis.
Unlike spermatogonia, however, oogonia form primary oocytes in the fetal
ovary prior to birth. These primary oocytes are then arrested in this stage of
meiosis I, only to resume it years later, beginning at puberty and continuing
until the woman is near menopause (the cessation of a woman’s
reproductive functions). The number of primary oocytes present in the
ovaries declines from one to two million in an infant, to approximately
400,000 at puberty, to zero by the end of menopause.

9. • The process of producing eggs in the ovaries of a fetus carrying XX
chromosomes is called oogenesis. Eggs are haploid gametes, and their
production occurs in several steps that involve different types of cells,
• Oogenesis is completed long before birth. It occurs when diploid germ
cells called oogonia (singular, oogonium) undergo mitosis. Each such
cell division produces two diploid cells. One is called the primary
oocyte, and the other is retained to help maintain a reserve of
oogonia. The primary oocyte, in turn, starts to go through the first cell
division of meiosis (meiosis I). However, it does not complete meiosis
I until puberty.

11. Folliculogenesis
• Again, ovarian follicles are oocytes and their supporting cells. They grow and
develop in a process called folliculogenesis, which typically leads to ovulation of
one follicle approximately every 28 days, along with death to multiple other
follicles. The death of ovarian follicles is called atresia, and can occur at any point
during follicular development.
• Folliculogenesis begins with follicles in a resting state. These small primordial
follicles are present in newborn females and are the prevailing follicle type in the
adult ovary. Primordial follicles have only a single flat layer of support cells, called
granulosa cells, that surround the oocyte, and they can stay in this resting state for
years—some until right before menopause.
• After puberty, a few primordial follicles will respond to a recruitment signal each
day, and will join a pool of immature growing follicles called primary follicles.
Primary follicles start with a single layer of granulosa cells, but the granulosa cells
then become active and transition from a flat or squamous shape to a rounded,
cuboidal shape as they increase in size and proliferate. As the granulosa cells
divide, the follicles—now called secondary follicles—increase in diameter, adding
a new outer layer of connective tissue, blood vessels, and theca cells—cells that
work with the granulosa cells to produce estrogens.

13. Maturation of a Follicle
• Beginning in puberty, about once a month, one of the follicles in an ovary
undergoes maturation, and an egg is released. As the follicle matures, it
goes through changes in the numbers and types of its cells. The primary
oocyte within the follicle also resumes meiosis. It completes meiosis I,
which began long before birth, to form a secondary oocyte and a smaller
cell, called the first polar body. Both the secondary oocyte and the first
polar body are haploid cells. The secondary oocyte has most of the
cytoplasm from the primary oocyte and is much larger than the first polar
body, which soon disintegrates and disappears. The secondary oocyte
begins meiosis II, but only completes it if the egg is fertilized.
Release of an Egg
• It typically takes 12 to 14 days for a follicle to mature in an ovary, and for
the secondary oocyte to form. Then, the follicle bursts open and the ovary
ruptures, releasing the secondary oocyte from the ovary. This event is
called ovulation. The now-empty follicle starts to change into a structure
called a corpus luteum. The expelled secondary oocyte is usually swept into
the nearby Fallopian tube by its waving, fingerlike fimbriae.

14. Uterine Changes
• While the follicle is maturing in the ovary, the uterus is also undergoing changes to
prepare it for an embryo if fertilization occurs. For example, the endometrium gets
thicker and becomes more vascular. Around the time of ovulation, the cervix
undergoes changes that help sperm reach the oocyte to fertilize it. The cervical
canal widens, and the cervical mucus becomes thinner and more alkaline. These
changes help promote the passage of sperm from the vagina into the uterus and
make the environment more hospitable to sperm.
Fertilization — or Not
• Fertilization of an egg by a sperm normally occurs in a Fallopian tube, most often in
the part of the tube that passes above the ovary In order for fertilization to occur,
sperm must “swim” from the vagina where they are deposited, through the
cervical canal to the uterus and then through the body of the uterus to one of the
Fallopian tubes. Once sperm enters a Fallopian tube, tubular fluids help carry them
through the tube toward the secondary oocyte at the other end. The secondary
oocyte also functions to promote fertilization. It releases molecules that guide the
sperm and allow the surface of the egg to attach to the surface of the sperm. The
egg can then absorb the sperm, allowing fertilization to occur.

16. The Menstrual Cycle
Menses' Phase
• The menses phase of the menstrual cycle is the phase during which
the lining is shed; that is, the days that the woman menstruates.
Although it averages approximately five days, the menses phase can
last from 2 to 7 days, or longer. the menses phase occurs during the
early days of the follicular phase of the ovarian cycle, when
progesterone, FSH, and LH levels are low. Recall that progesterone
concentrations decline as a result of the degradation of the corpus
luteum, marking the end of the luteal phase. This decline in
progesterone triggers the shedding of the stratum functionalize of the
endometrium.

18. Proliferative Phase
• Once menstrual flow ceases, the endometrium begins to proliferate again, marking
the beginning of the proliferative phase of the menstrual cycle. It occurs when the
granulosa and theca cells of the tertiary follicles begin to produce increased
amounts of estrogen. These rising estrogen concentrations stimulate the
endometrial lining to rebuild.
Secretory Phase
• In addition to prompting the LH surge, high estrogen levels increase the uterine
tube contractions that facilitate the pick-up and transfer of the ovulated oocyte.
High estrogen levels also slightly decrease the acidity of the vagina, making it more
hospitable to sperm. In the ovary, the luteinization of the granulosa cells of the
collapsed follicle forms the progesterone-producing corpus luteum, marking the
beginning of the luteal phase of the ovarian cycle. In the uterus, progesterone from
the corpus luteum begins the secretory phase of the menstrual cycle, in which the
endometrial lining prepares for implantation. Over the next 10 to 12 days, the
endometrial glands secrete a fluid rich in glycogen. If fertilization has occurred, this
fluid will nourish the ball of cells now developing from the zygote. At the same
time, the spiral arteries develop to provide blood to the thickened stratum
functionalize.

19. The Breasts
• Whereas the breasts are located far from the other female reproductive organs,
they are considered accessory organs of the female reproductive system. The
function of the breasts is to supply milk to an infant in a process called lactation.
The external features of the breast include a nipple surrounded by a pigmented
areola, whose coloration may deepen during pregnancy. The areola is typically
circular and can vary in size from 25 to 100 mm in diameter. The areolar region is
characterized by small, raised areolar glands that secrete lubricating fluid during
lactation to protect the nipple from chafing. When a baby nurses, or draws milk
from the breast, the entire areolar region is taken into the mouth.
• Breast milk is produced by the mammary glands, which are modified sweat
glands. The milk itself exits the breast through the nipple via 15 to 20 lactiferous
ducts that open on the surface of the nipple. These lactiferous ducts each extend
to a lactiferous sinus that connects to a glandular lobe within the breast itself
that contains groups of milk-secreting cells in clusters called alveoli. The clusters
can change in size depending on the amount of milk in the alveolar lumen. Once
milk is made in the alveoli, stimulated myoepithelial cells that surround the
alveoli contract to push the milk to the lactiferous sinuses.

20. From here, the baby can draw milk through the lactiferous ducts by suckling. The
lobes themselves are surrounded by fat tissue, which determines the size of the
breast; breast size differs between individuals and does not affect the amount of
milk produced. Supporting the breasts are multiple bands of connective tissue
called suspensory ligaments that connect the breast tissue to the dermis of the
overlying skin.

21. Male reproductive system
• The male reproductive system includes a group of organs that make up the
reproductive system and urinary system in men and people assigned male
at birth (AMAB).
• The male reproductive system contains internal and external parts. Internal
parts are inside your body, and external parts are outside your body.
Together, these organs help you urinate (pee), have sexual intercourse and
make biological children.
The organs that make up the male reproductive system perform the
following:
• Produce, maintain and transport sperm cells and semen. Sperm cells are
male reproductive cells. Semen is the protective fluid around sperm.
• Discharge sperm.
• Produce and secrete male sex hormones.

23. Male reproductive system function
• The entire male reproductive system depends on hormones.
Hormones are chemicals that stimulate or regulate activity in your
cells or organs. The primary hormones that help the male
reproductive system function include:
• Follicle-stimulating hormone (FSH). Your pituitary gland makes FSH.
FSH is necessary to produce sperm (spermatogenesis).
• Luteinizing hormone (LH). Your pituitary gland also makes LH. LH is
necessary to continue the process of spermatogenesis.
• Testosterone. Testosterone is the main sex hormone in people AMAB.
It helps you develop certain characteristics, including muscle mass
and strength, fat distribution, bone mass and sex drive (libido).

24. External parts of the male reproductive system
• Most of the male reproductive system is on the outside of your abdominal cavity or
pelvis. The external body parts of the male reproductive system include the penis,
scrotum and testicles. Another name for these parts is genitals or genitalia.
Penis
The penis is the male organ for sexual intercourse. It contains many sensitive nerve
endings, and it has three parts:
• Root. The root is the base of your penis. It attaches to the wall of your abdomen.
• Body (shaft). The body has a shape like a tube or cylinder. It consists of three internal
chambers: the two larger chambers are the corpora cavernosa, and the third chamber
is the corpus spongiosum. The corpora cavernosa run side by side, while the corpus
spongiosum surrounds your urethra. There’s a special, sponge-like erectile tissue
inside these chambers. The erectile tissue contains thousands of spaces. During sexual
arousal, the spaces fill with blood, and your penis becomes hard and rigid (erection).
An erection allows you to have penetrative sex. The skin of the penis is loose and
stretchy, which lets it change size when you have an erection.
• Glans (head). The glans is the cone-shaped tip of the penis. A loose layer of skin
(foreskin) covers the glans. Healthcare providers sometimes surgically remove the
foreskin (circumcision).

25. Scrotum
• The scrotum is the loose, pouch-like sac of skin that hangs behind the penis. It holds the
testicles (testes) as well as nerves and blood vessels.
• The scrotum protects your testicles and provides a sort of “climate-control system.” For
normal sperm development, the testes must be at a temperature that’s slightly cooler than
body temperature (between 97 and 99 degrees Fahrenheit or 36 and 37 degrees Celsius).
Special muscles in the wall of the scrotum let it contract (tighten) and relax. Your scrotum
contracts to move your testicles closer to your body for warmth and protection. It relaxes
away from your body to cool them.

26. Testicles
• The testicles (testes) are oval-shaped organs that lie in your scrotum.
They’re about the size of two large olives. The spermatic cord holds
the testicles in place and supplies them with blood. Most people
AMAB have two testicles, on the left and right side of the scrotum.
The testicles make testosterone and produce sperm. Within the
testicles are coiled masses of tubes. These are the seminiferous
tubules. The seminiferous tubules produce sperm cells through
spermatogenesis.
Epididymis
• The epididymis is a long, coiled tube that rests on the back of each
testicle. It carries and stores the sperm cells that your testicles create.
The epididymis also brings the sperm to maturity — the sperm that
emerge from the testicles are immature and incapable of fertilization.
During sexual arousal, muscle contractions force the sperm into the
vas deferens.

27. Spermatogenesis
• Spermatogenesis occurs in the seminiferous tubules that form the bulk of
each testis. The process begins at puberty, after which time sperm are
produced constantly throughout a man’s life. One production cycle, from
spermatogonia through formed sperm, takes approximately 64 days. A new
cycle starts approximately every 16 days, although this timing is not
synchronous across the seminiferous tubules. Sperm counts—the total
number of sperm a man produces—slowly decline after age 35, and some
studies suggest that smoking can lower sperm counts irrespective of age.
• The process of spermatogenesis begins with mitosis of the diploid
spermatogonia. Because these cells are diploid (2n), they each have a
complete copy of the father’s genetic material, or 46 chromosomes.
However, mature gametes are haploid (1n), containing 23 chromosomes—
meaning that daughter cells of spermatogonia must undergo a second
cellular division through the process of meiosis.

29. Structure of Formed Sperm
• Sperm are smaller than most cells in the body; in fact, the volume of a
sperm cell is 85,000 times less than that of the female gamete.
Approximately 100 to 300 million sperm are produced each day,
whereas women typically ovulate only one oocyte per month as is true
for most cells in the body, the structure of sperm cells speaks to their
function. Sperm have a distinctive head, mid-piece, and tail region.

30. Internal parts of the male reproductive system
• There are several internal (accessory) organs in the male reproductive
system. They include:
Vas deferens
• The vas deferens is a long, muscular tube that travels from the epididymis
into the pelvic cavity, just behind the urinary bladder. The vas deferens
transports mature sperm to the urethra in preparation for ejaculation.
Ejaculatory ducts
• Each testicle has a vas deferens that joins with seminal vesicle ducts to form
ejaculatory ducts. The ejaculatory ducts move through your prostate, where
they collect fluid to add to semen. They empty into your urethra.
Urethra
• The urethra is the tube that carries pee from your bladder outside of your
body. If you have a penis, it also ejaculates semen when you reach orgasm.

31. Seminal vesicles
• The seminal vesicles are sac-like pouches that attach to the vas deferens
near the base of the bladder. Seminal vesicles make up to 80% of your
ejaculatory fluid, including fructose. Fructose is an energy source for
sperm and helps them move (motility).
Prostate gland
• The prostate is a walnut-sized gland that rests below your bladder, in
front of your rectum. The prostate adds additional fluid to ejaculate,
which helps nourish sperm. The urethra runs through the center of the
prostate gland.
Bulbourethral (Cowper) glands
• The bulbourethral glands are pea-sized structures on the sides of your
urethra, just below your prostate. They create a clear, slippery fluid that
empties directly into the urethra. This fluid lubricates the urethra and
neutralizes any acids that may remain from your pee.