Female and Male Reproductive System Notes

Female Reproductive System

Internal Female Genitalia

• 1 Vagina

• 1 Uterus

• 2 Uterine (Fallopian) Tubes/ Oviduct

• 2 Ovaries

Female External Accessory Reproductive Organs

• Labia majora: Enclose and protect other external genital organs.

• Labia minora: Protect the opening of the vagina and urethra.

• Clitoris: Produces feeling of pleasure during sexual simulation.

• Vestibular glands: Secrete fluids that lubricate the vestibule.

Organs of the Female Reproductive System

• Suspensory ligament of ovary with ovarian blood vessels and nerves

• Uterine tube

• Ovary

• Ovarian ligament

• Body of uterus

• Secondary oocyte

• Infundibulum

• Fimbriae

• Broad ligament

• Ureter

• Endometrium

• Myometrium

• Perimetrium

• Cervix

• Cervical orifice

• Vagina

• Secondary oocyte

• Zona pellucida

• Corona radiata

• First polar body

Ovaries

• The two ovaries are solid, ovoid structures.

• The primary reproductive organs (gonads)

• Ovaries Functions:

  • Release 1 immature gamete (oocyte or ova) per month (ovulation)

  • Produce hormones (estrogen and progesterone)

  • Site where oogenesis occurs.

Ligaments of the Ovary

• Several structures help hold each ovary in position.

  • The broad ligament

  • The suspensory ligament

  • The ovarian ligament: a rounded, cordlike structure connects the ovary to the side of the uterus.

Uterine Tubes/ Fallopian Tubes/ (Oviducts)

• Each tube, about 10 centimeters long, extends laterally from both sides of the uterus to the ovary.

• Functions:

  • Pathway of the egg (ova) (from the ovaries to the uterus).

  • Site where fertilization occurs (normal site of fertilization).

• Composed of four parts:

  • Isthmus

  • Ampulla

  • Infundibulum

  • Fimbriae: finger or fringe-like projections at the end of the fallopian tubes.

• Fimbriae Function: help to direct ova into fallopian tubes.

Uterus

• The uterus is hollow, muscular, and shaped like an inverted pear.

• The size of the uterus changes greatly during pregnancy.

• Functions of the uterus:

  • Site where the blastocyst (fertilized egg) implants itself.

  • Site where the fetus develops and grows.

• Composed of three parts:

  • The fundus: The superior rounded region of the uterus above the entrance of the uterine tubes.

  • The body

  • The cervix: lower one-third, or neck, of the uterus. Function of the cervix: Connects the uterus to the vagina.

Uterine Wall

Endometrium

• A thin, inner, glandular endometrium (mucosa)

• Contributes about 10% of uterine mass

• Functions:

  • Site for blastocyst implantation/ Glandular and vascular tissues support physiological demands of growing fetus

  • It is removed (sloughed) during menstruation.

Myometrium

• Has a thick muscular myometrium

• Function:

  • Responsible for uterine contraction

Perimetrium

• Is an incomplete serous membrane

• Covering the uterus and cervix

Menstruation

• Is the process of endometrial sloughing

• Lasts 1–5 days

• Sheds 35–50 ml blood

• Menarche is the first menstrual cycle begins at puberty (age 11–12).

Vagina

• The vagina is a fibromuscular tube, about 9 centimeters long, extending from the uterus to the outside of the body.

• Functions:

  • Passageway for elimination of menstrual fluids (blood).

  • Receives spermatozoa during sexual intercourse.

  • Forms inferior portion of birth canal.

Parts and Functions of the Female Reproductive System

Functions of The Female Reproductive System

• Produces sex hormones (estrogen and progesterone)

• Produce functional gametes (female sex cells) (ovum, egg, oocyte)

• Transports eggs to site of fertilization.

• Protects and supports developing embryo ( provide a favorable environment for a developing fetus)

• Gestation and delivery of fetus

• Nourishes newborn infant.

Oogenesis

• Process of ovum formation in ovaries.

• When a primary oocyte undergoes oogenesis, it gives rise to a secondary oocyte in which the original chromosome number is halved (from 46 to 23).

Follicle Maturation

• At puberty, FSH initiates follicle maturation.

• During maturation of the Primary follicle, the primary oocyte enlarges, the follicular cells proliferate, and a fluid-filled cavity (antrum) appears.

• A mature follicle called Graafian follicle contains a secondary oocyte

Ovulation

• Ovulation is the process of releasing the secondary oocyte from the mature follicle (Graafian) in the ovary.

• Egg is released about day 14 of the female reproductive cycle.

• Luteinizing Hormone plays a role in triggering ovulation.

Fertilization

• Fertilization is the union of secondary oocyte and sperm cell.

• It takes place in the fallopian tube.

• The product of fertilization is a cell with 46 chromosomes called zygote

Pregnancy (Gestation)

• The Period from fertilization of the ovum (egg) until birth.

• The secondary oocyte changes from fertilization to implantation are:

  • After fertilization, the product is a zygote that undergoes mitosis.

  • On day 4, a solid ball of cells (morula) forms

  • On day 7, it becomes a hollow ball called a blastocyst.

  • The blastocyst implants in the uterine wall.

  • The blastocyst (trophoblast) part secretes human chorionic gonadotropin (hCG).

  • From 2 to 8 weeks, it is called Embryo

  • From 8 to 39/40 Weeks, it is called Fetus

Developmental Changes of Ovulated Fertilized Egg (Secondary Oocyte)

• Fertilized egg; Fertilization after the Egg meets sperm

• Zygote is formed and starts Cell division

• Morula formed on day 4

• Blastocyst-Passed down fallopian tube into uterus

• Implantation- blastocyst attaches to endometrium

• Embryo develops

• Fetus

Pathway of Ovulated Unfertilized Egg (Secondary Oocyte)

• Fimbria

• Move through the fallopian tube

• To Uterus

• Shed with endometrium

• To Cervix

• To Vagina

• Menstruation

Female Reproductive Cycle

• Changes in the ovaries are called the ovarian cycle which is subdivided into 3 phases:

  • Follicular phase (day 1- day 14)

  • Ovulation phase in (day 14)

  • Luteal phase (day 15- day 28)

• The parallel changes in the uterus are called the uterine cycle, which is subdivided into 3 phases:

  • Menstruation phase (day 1 – day 5)

  • Proliferative phase (day 6- day 14)

  • Secretory phase (day 15- day 28)

Ovarian Cycle

• Immature follicle

  • Primary oocyte

  • Granulosa cells

• Zona pellucida develops around the primary oocyte

• Fluid-filled antrum develops

• Graafian Follicle

  • Polar body

  • Secondary oocyte

  • Ovarian connective tissue

• Ovulation. Follicle ruptures, releasing the secondary oocyte with its polar body and granulosa cells

• Corpus luteum forms from ruptured follicle

  • Secretes progesterone

• Corpus Albicans

• Corpus luteum degenerates if pregnancy does not occur

Follicular Phase (Days 1-14) - Ovarian cycle

• Occurs from approximately day 1-14.

• The ovaries are simultaneously preparing to ovulate again.

• The pituitary gland releases a hormone called FSH – follicle-stimulating hormone.

• This hormone causes several ‘follicles’ to rise on the surface of the ovary.

• These fluid-filled “bumps” each contain an egg.

• Eventually, one of these follicles becomes dominant and within it develops a single mature egg; the other follicles shrink back.

• Granulosa cells of the maturing follicle produce the hormone estrogen, which increases over the follicular phase and peaks in the day or two prior to ovulation.

Menstruation phase day 1 – day 5 - Uterine cycle

• Occurs from approximately day 1-5.

• Menstrual bleeding does happen in the early part of the menstrual phase

Proliferative phase day 6- day 14 - Uterine cycle

• Occurs from approximately day 6-14.

• Estrogens cause the lining of the uterus (endometrium) to become thicker and more glandular and enriched with blood

Ovulatory Phase (Day 14) - Ovarian cycle

• High levels of estrogen stimulate the production of gonadotropin-releasing hormone (GnRH), which in turn stimulates the Anterior pituitary gland to secrete luteinizing hormone (LH).

• On about day 12, surges in LH and FSH cause the Ovulation.

• Ovulation is the release of the mature egg (secondary oocyte) from the ovary happens on about day 14.

• Once the egg is released, the follicle seals over and forms a yellow structure called the corpus luteum.

• After release, the egg enters the fallopian tube where fertilization may take place if sperm are present.

• If the egg is not fertilized, it disintegrates after about 24 hours.

Luteal Phase (Days 15-28) - Ovarian cycle

• After the release of the egg, levels of FSH and LH decrease.

• The corpus luteum produces progesterone.

• If fertilization has occurred, the corpus luteum continues to produce progesterone for 3 months, which prevents the endometrial lining from being shed.

• If fertilization has not occurred, the corpus luteum disintegrates into Corpus Albicans, which causes progesterone levels to drop and signals the endometrial lining to begin shedding.

Secretory phase (days 15- 28) - Uterine cycle

• Progesterone causes the endometrium to become more vascular and glandular.

• It also stimulates the uterine glands to secrete more glycogen and lipids (secretory phase).

• The endometrial tissues fill with fluids containing nutrients and electrolytes, which provide a favorable environment for embryo development.

• If no fertilization, the endometrial lining to begin shedding.

Important Female Hormones

Summary of Important Female-Related Terms

Placenta

• The placenta is a vascular structure, formed by the cells surrounding the embryo and cells of the endometrium that anchors to the uterine wall and exchange gases, nutrients and wastes between the embryo’s blood and maternal blood.

• This structure provides oxygen and nutrients to the growing fetus and removes waste products from fetus blood.

• The placenta attaches to the wall of the uterus, and the fetus's umbilical cord arises from it.

Amniotic Fluid

• Surrounds the developing fetus to protect it against shocks.

Parturition

Birth (childbirth)/Delivery

• Natural Delivery vs. C-Section

Puberty

• Puberty is the stage in the human lifecycle where boys and girls start to produce gametes (eggs and sperm).

• Changes at puberty include (Secondary sex characteristics):

  • Menstruation

  • Pubic hair

  • Hip widening

  • Breast growth

  • Underarm hair

Male Reproductive System

General Terms

• Gonads: organs that produce gametes and hormones/ ovaries and testes

• Ducts: receive and transport gametes egg’s and sperm

• Accessory glands: secrete fluids into ducts

• Perineal structures: collectively known as external genitalia

The Structure of the Male Reproductive System

• Ureter

• Urinary bladder

• Abdominal muscle

• Bladder

• Pubic symphysis

• Ampulla

• Seminal vesicle

• Ejaculatory duct

• Bulbourethral gland

• Bulb of penis

• Crus of penis

• Epididymis

• Testis

• Penis

• Urethra

• Glans penis

• Prostate gland

• Vas deferens

• Corpus cavernosum

• Corpus spongiosum

• Urethra

• Foreskin

• Penis glans

• Navicular fossa

• Urethral opening (Meatus)

• Scrotum

• Anus

• Coccyx bone

• Rectum

• Pelvic floor muscle

External Genitalia

• The external accessory organs of the male reproductive system are the penis and the scrotum which encloses two testes.

Scrotum

• Is a pouch of skin that encloses testes.

• Scrotum Functions:

  • Encloses, protects, and regulates the temperature of testes at which spermatogenesis occurs.

Penis

• A cylindrical erectile organ

• encloses the distal portion of the urethra far from the urinary bladder

• Penis Functions:

  • Conveys urine and semen through the urethra to the outside.

  • Introduces semen into the female vagina

• Penis is divided into 3 regions:

  • root

  • body

  • Glans (enlarged tip of the penis)

• The body is composed of three columns of erectile tissues:

  • Pair of corpora cavernosa

  • Single corpus spongiosum

Glans Penis

• Glans penis is a cone-shaped part at the end of the penis bears the urethra opening (external urethral orifice/ meatus) contains sensory receptors for sexual stimulation.

Prepuce

• A loose fold of skin called prepuce (foreskin) surrounding the tip of the penis covering the glans.

• Prepuce Is removed by the surgical procedure called Circumcision.

Testes

• Egg-shaped (ovoid) structures about 5 cm in length and 3 cm thick.

• Both testes, each suspended by a spermatic cord, are within the scrotum.

• Testes are the Primary sex organs (i.e., gonads) of the male reproductive system.

• Testes Functions:

  • The site of Sperm production.

  • The site of testosterone and inhibin hormones production.

Structure and Function of the Testes

• A tough, white, fibrous capsule called the Tunica albuginea encloses each testis contains 250 lobules.

• A lobule contains one to four highly coiled, convoluted seminiferous tubules.

Seminiferous tubules

• Each is about 70 cm long when uncoiled.

• These tubules unite to form the rete testis.

Seminiferous tubules includes

• Spermatogenic cells that give rise to the sperm cells.

• Sertoli cells (Sustentacular Cells) produce inhibin hormone.

• Interstitial cells (Leydig cells) produce and secrete male sex hormones.

Epididymis

• Are narrow, tightly coiled tubes about 6 meters long if uncoiled.

• Sperm cells need 10 – 14 days here before they are capable of fertilization.

• Epididymis Functions:

  • Promotes sperm maturation/development.

  • Stores sperm cells

  • Conveys / transport sperm to ductus deferens

Vas Deferens

• Also called ductus deferens

• Muscular tube about 45 cm long

• Begins at the tail of the epididymis

• Ascends through inguinal canal: as part of the spermatic cord

• Near its termination, the ductus deference dilates into a portion called the Ampulla.

• Vas Deferens Function: Conveys / transports sperm cells to the ejaculatory duct.

Accessory Male Reproductive Glands

• Secrete fluids into ejaculatory ducts and urethra:

  • Seminal vesicles

  • Prostate gland

  • Bulbourethral/ Cowper’s glands

Seminal vesicle (seminal glands)

• Are convoluted saclike structures about 5 cm long, each attached to the ampulla.

• Secrete an alkaline fluid.

• The fluid helps regulate the pH of the tubular content.

• Neutralizes vagina acidity, helping to sustain the sperm inside the vagina.

• Includes fructose that provides energy to sperm cells.

• Includes prostaglandins which stimulate the muscular contraction of the female reproductive organ, aiding the movement of the sperm toward the oocyte.

• 50 – 55% of semen volume

Prostate Gland

• Is a chestnut-shaped structure about 4 cm across and 3 cm thick that surrounds the proximal portion of the urethra. Inferior to the urinary bladder.

• Releases secretion into the urethra where it will mix with the sperm cells and secretion of the seminal glands.

• The prostate secretes a thin, milky fluid that contains citrate, which is a nutrient for sperm.

• It contains enzymes break down semen in the vagina.

• It is slightly acidic

• Forms 20–30% of semen volume.

• Gives a milky appearance.

Bulbourethral Gland

• The bulbourethral glands (Cowper’s Glands) are two small structures, about 1 cm in diameter.

• Secrets mucus-like fluid that lubricates the end of the penis in preparation for intercourse.

Ejaculatory Duct

• Is a short passageway (2 cm): at the junction of the ampulla and seminal vesicle duct.

• Penetrates wall of prostate gland.

• Empties into the urethra.

Male Urethra

• Is a common pathway used by urinary and reproductive systems

• Pathway for the urine and the semen to the exterior

• Extends 18–20 cm from urinary bladder to tip of penis

General Terms

• Emission: is the movement of sperm cells from the testes and secretions from the prostate gland and seminal vesicles into the urethra, where they mix to form semen.

• Semen: sperm mixed with accessory glands secretions.

• Ejaculation: The process in which semen is expelled from the body, forcing the semen through the urethra to the outside.

Characteristics of Semen

• The fluid that the urethra conveys to the outside during ejaculation is called semen.

• Consists of

  • Sperm cells from testes and secretion of:

    • Prostate gland fluids

    • Seminal gland fluids

    • Bulbourethral gland fluids

• It is slightly alkaline (pH about 7.5)

• The volume of semen released at one time varies from 2 to 5 ml.

• The average number of sperm cells in the fluid is about 120 million per ml.

• Sperms usually survive only up to 6 days after being expelled to the outside.

• The ability to fertilize the oocyte lasts 24 – 48 hr after entering the female tract.

Pathway of Sperm

• Testes where its produced

• Epididymis store

• Vas deferens be released

• Ejaculatory duct when its done

• Urethra in Penis it will come out

Structure and Function

The Male Reproductive System Functions

• The purpose of the organs of the male reproductive system is to perform the following functions:

  • To produce, maintain, and transport sperm (the male reproductive cells) and protective fluids (semen).

  • Transport and discharge the sperms from male to female organs.

  • To produce and secrete male sex hormones responsible for maintaining the male reproductive system.

Hormonal Control Of Spermatogenesis and Masculinity

• Hypothalamus produces Gonadotropin-releasing hormone GnRH

• Anterior pituitary Gland

  • Luteinizing Hormone LH

  • Follicle Stimulating Hormone FSH

• Interstitial Cells/ Leydig cells Secrete Testosterone

• Sustentacular Cells/ Sertoli Cells Stimulate Spermatogenic Cell

• Inhibin spermatogenesis

Hormonal Control of Spermatogenesis

• In the human male reproductive system, spermatogenesis starts at the age of puberty due to sign increase in the secretion of gonadotropin-releasing hormone from the hypothalamus.

• The increased level of GnRH then acts on the anterior pituitary gland and stimulates the secretion of the two gonadotropins: Luteinizing Hormone LH and Follicle Stimulating Hormone FSH.

• LH promotes the development of interstitial cells (Leydig cells)

• The interstitial cells (Leydig cells) secrete testosterone (male sex hormone). Then in the presence of FSH and testosterone, the Sustentacular Cells (Sertoli cells) stimulate spermatogenic cells to undergo spermatogenesis.

• FSH stimulates the Sustentacular Cells (Sertoli cells) to grow mature and respond to the effect of testosterone.

• The Sustentacular Cells (Sertoli cells) secrete Inhibin hormone which prevents over secretion of FSH.

Hormonal Control Of Spermatogenesis

Cells

Spermatogenesis

• Spermatogenesis occurs in testes

• Is the process of sperm production, takes 65-75 days in the human male.

• Begins at Spermatogonia cell in seminiferous tubules

• Proceeds toward lumen

• begins at puberty and is continuous throughout life.

Spermatogenesis: Sperm production

• Spermatogonium

• Primary spermatocyte

• Secondary spermatocyte

• Spermatid

• Spermatozoa (sperm)

• Sertoli (sustentacular) cell

• Leydig (interstitial) cells

Structure of the Sperm Cell

Head

• It is spherical in shape consisting of a large nucleus and a dome-shaped acrosome present on the nucleus.

• Nucleus contains genetic information and (23) chromosomes. (Haploid).

• The acrosome is a small cap-like covering over the head that contains enzymes which aid/ support the sperm cell in penetrating the layers surrounding the oocyte during fertilization.

Middle piece (Midpiece)

• It is a tubular structure in which mitochondria are spirally arranged.

• Mitochondria are called the powerhouse of sperm because it gives energy to the sperm to swim in the female genital tract.

Tail

• It arises from the middle piece, and it is the end part of the sperm. It contains axial filaments.

• Function: The tail helps the sperm to swim in the female genital tract. It is the main part of the sperm that provides movement.

Puberty

• Puberty is the process of developing/transforming into an adult, which includes the maturation of the physical body (outside) and emotional/mental state (inside).

• The stage in human life where boys start to produce mature sperm cells.

Puberty-Male

• Occurs at 10 – 14 years where Testosterone production increased.

• Changes at puberty include male (secondary sex characteristics):

  • Muscle and bone growth

  • Larynx enlargement – voice deepens

  • Hair growth on: Face, under arms, chest, Abdomen, Pubis

  • Penis, scrotum, and prostate enlargement

  • Maturation of seminiferous tubules

  • Spermatozoa production

  • Thickening of the skin and becomes oilier.