Physiology of Human Reproduction SystemPhysiology of Human Reproduction System

Dr. Nur Aida Sri WahyuniDepartment of Physiology

Medical Faculty of Sriwijaya University

Dr. Nur Aida Sri WahyuniDepartment of Physiology

Medical Faculty of Sriwijaya University

Introduction Introduction

• The objective of this lecture will be to create an understanding of reproduction from the physiological perspective.

• The objective of this lecture will be to create an understanding of reproduction from the physiological perspective.

Introduction Introduction

• Sexual reproduction is the formation of a new individual following the union of two gametes.

• Genetic material transmission via chromosome in gametes

• Character transmission:– Morphologic– Physiologic– Patologic

• Sexual reproduction is the formation of a new individual following the union of two gametes.

• Genetic material transmission via chromosome in gametes

• Character transmission:– Morphologic– Physiologic– Patologic

Gametes Gametes • Male : spermatozoa • Female : ovum• Fertilization occurs at tuba fallopii• Gametes need:

– Motility to be able to meet and unite– Food to nourish the develoving embryo

• Male : spermatozoa • Female : ovum• Fertilization occurs at tuba fallopii• Gametes need:

– Motility to be able to meet and unite– Food to nourish the develoving embryo

Sex determinationSex determination

• Since fertilization happen• Ovum (22 A+ X) unites with sperm (22

A + X or Y)• Sex determination depends on sex

chromosom carried by sperm.

• Since fertilization happen• Ovum (22 A+ X) unites with sperm (22

A + X or Y)• Sex determination depends on sex

chromosom carried by sperm.

Development of sex organ in embryonal phase

Development of sex organ in embryonal phase

• week 4th – Urogenital ridge ___ gonad ___ cortex &

medulla• Week 6th

– Male : cortex ___ regresi; medulla____ testis – Female : cortex ___ ovary: medulla ___regresi

• Week 7th – Ductus primordial: ductus mulleri & ductus

wolfii

• week 4th – Urogenital ridge ___ gonad ___ cortex &

medulla• Week 6th

– Male : cortex ___ regresi; medulla____ testis – Female : cortex ___ ovary: medulla ___regresi

• Week 7th – Ductus primordial: ductus mulleri & ductus

wolfii

• Birth to child – Reproduction organ inactive– Pituitary: secret TSH, ACTH, GH for

growing child while LH and FSH inactive

• Adolescence – Rapid growth stature– Secondary sex characteristics develop– Sex Reproduction act

• Birth to child – Reproduction organ inactive– Pituitary: secret TSH, ACTH, GH for

growing child while LH and FSH inactive

• Adolescence – Rapid growth stature– Secondary sex characteristics develop– Sex Reproduction act

Sex Organ of maleSex Organ of male

• The male reproduction system has two major function:– Production of sperm– Delivery these to the reproductive tract of

the female

• The male reproduction system has two major function:– Production of sperm– Delivery these to the reproductive tract of

the female

Male Reproductive SystemMale Reproductive System• Testes – where

spermatogenesis takes place

• Epididymis – where sperm mature

• When sperm leaves the body, it will go up the vas deferens, past the following glands:– Bulbourethral gland– Prostate gland– Seminal vesicles

• Testes – where spermatogenesis takes place

• Epididymis – where sperm mature

• When sperm leaves the body, it will go up the vas deferens, past the following glands:– Bulbourethral gland– Prostate gland– Seminal vesicles Slide 8 of 18

Sex Organ of maleSex Organ of male

Sex Organ of maleSex Organ of male

• Sperm production___ spermatogenesis_ takes place in the testes

• Each testis is packed with tubulus seminiferus (laid end to end, they would extend more than 20 m) where spermatogenesis occurs.

• Sperm production___ spermatogenesis_ takes place in the testes

• Each testis is packed with tubulus seminiferus (laid end to end, they would extend more than 20 m) where spermatogenesis occurs.

Pathway of SemenPathway of Semen

• Epididymis Vas Deferens Urethra

• A vasectomy is a procedure in which the vas deferens is cut so that the man will no longer be able to father children.

• Epididymis Vas Deferens Urethra

• A vasectomy is a procedure in which the vas deferens is cut so that the man will no longer be able to father children.

Slide 10 of 18

Spermatogenesis Spermatogenesis

• The walls of tubulus seminiferus consists of diploid spermatogonia (2n), stem cells that are the precursors of spermatozoa

• The walls of tubulus seminiferus consists of diploid spermatogonia (2n), stem cells that are the precursors of spermatozoa

Spermatogonia Spermatogonia

• Divide by mitosis to produce more spermatogonia or..

• Differentiate into spermatocytes– It distributes one of each duplicated

chromosome to each daughter cell.

• Divide by mitosis to produce more spermatogonia or..

• Differentiate into spermatocytes– It distributes one of each duplicated

chromosome to each daughter cell.

Spermatogenesis Spermatogenesis

• Meiosis of each spermatocyt produces 4 haploid spermatids. This process takes over 3 weeks to complete.

• Then the spermatids differentiate into spermatozoa, losing most of their cytoplasma in their process.

• Meiosis of each spermatocyt produces 4 haploid spermatids. This process takes over 3 weeks to complete.

• Then the spermatids differentiate into spermatozoa, losing most of their cytoplasma in their process.

Spermatogenesis Spermatogenesis

Spermatozoa Spermatozoa

• Sperm cells consists of– Head, which has

• Acrosome• Contains a haploid set of chromosomes in a

compact, inactive state.

– Midpiece, containing mitochondria and a single centriole

– Tail

• Sperm cells consists of– Head, which has

• Acrosome• Contains a haploid set of chromosomes in a

compact, inactive state.

– Midpiece, containing mitochondria and a single centriole

– Tail

Spermatozoa Spermatozoa

• An adult male manufactures over 100 million sperm cells each day.

• The sperm cells gradually move into epidydimis where they undergo further maturation.

• The acidic environment in the epidydimis keeps the mature sperm inactive.

• An adult male manufactures over 100 million sperm cells each day.

• The sperm cells gradually move into epidydimis where they undergo further maturation.

• The acidic environment in the epidydimis keeps the mature sperm inactive.

Spermatozoa Spermatozoa • In addition to making sperm, the testis

is an endocrine gland. Its principal hormone, testosteron, is responsible for the development of the secondary sex characteristics of men.

• Testosteron is essensial for making sperm

• Testosteron is made in the interstitial cells (leydig cell) that lie between the tubulus seminiferus.

• In addition to making sperm, the testis is an endocrine gland. Its principal hormone, testosteron, is responsible for the development of the secondary sex characteristics of men.

• Testosteron is essensial for making sperm

• Testosteron is made in the interstitial cells (leydig cell) that lie between the tubulus seminiferus.

SpermatozoaSpermatozoa• The spermatozoa leave the testis carrying

23 chromosomes but not yet capable of fertilization.

• Their maturation is completed through their journey in the 6 meters of the epididymis and when mixed with the seminal plasma from the epididymis, seminal vesicle and prostate gland.

• The spermatozoa leave the testis carrying 23 chromosomes but not yet capable of fertilization.

• Their maturation is completed through their journey in the 6 meters of the epididymis and when mixed with the seminal plasma from the epididymis, seminal vesicle and prostate gland.

After semen is ejaculated, the sperms reach the cervix by their

own motility within seconds leaving behind the seminal

plasma in the vagina

After semen is ejaculated, the sperms reach the cervix by their

own motility within seconds leaving behind the seminal

plasma in the vagina

At time of ovulation, the cervical mucous is in the most favourable condition for sperm

penetration and capacitation as:1. It becomes more copious, less viscous and its

macromolecules arrange in parallel chains providing channels for sperms passage.

2. Its contents from glucose and chloride are increased.

At time of ovulation, the cervical mucous is in the most favourable condition for sperm

penetration and capacitation as:1. It becomes more copious, less viscous and its

macromolecules arrange in parallel chains providing channels for sperms passage.

2. Its contents from glucose and chloride are increased.

• The sperms ascent through the uterine cavity and Fallopian tubes to reach the site of fertilization in the ampulla by:

1.Its own motility, and by2.Uterine and tubal peristalsis which is

aggravated by the prostaglandins in the seminal plasma.

• The sperms ascent through the uterine cavity and Fallopian tubes to reach the site of fertilization in the ampulla by:

1.Its own motility, and by2.Uterine and tubal peristalsis which is

aggravated by the prostaglandins in the seminal plasma.

• The sperms reach the tube within 30-40 minutes

• But they are capable of fertilization after 2-6 hours. • This period is needed for sperm

capacitation.

• The sperms reach the tube within 30-40 minutes

• But they are capable of fertilization after 2-6 hours. • This period is needed for sperm

capacitation.

Capacitation of spermsCapacitation of spermsCapacitation of spermsCapacitation of sperms• is the process after which the sperm

becomes able to penetrate the zona pellucida,that surrounding the ovum and fertilize it.

• The cervical and tubal secretions are mainly responsible for this capacitation.

• is the process after which the sperm becomes able to penetrate the zona pellucida,that surrounding the ovum and fertilize it.

• The cervical and tubal secretions are mainly responsible for this capacitation.

• Capacitation is believed to be due to :1.Increase in the DNA concentration in

the nucleus,2.Increase permeability of the coat of

sperm head to allow more release of hyaluronidase

• Capacitation is believed to be due to :1.Increase in the DNA concentration in

the nucleus,2.Increase permeability of the coat of

sperm head to allow more release of hyaluronidase

Male Reproductive HormonesMale Reproductive Hormones

Slide 11 of 18

• See hormone chart in notes• GnRH released from

hypothalamus causes the release of LH and FSH from the pituitary gland

• LH– Causes Leydig cells in the

testes to produce testosterone

• FSH– Causes Sertoli cells in the

testes to make inhibin to inhibit FSH

• See hormone chart in notes• GnRH released from

hypothalamus causes the release of LH and FSH from the pituitary gland

• LH– Causes Leydig cells in the

testes to produce testosterone

• FSH– Causes Sertoli cells in the

testes to make inhibin to inhibit FSH

Female Reproductive System

Female Reproductive System

• Ovaries – where oogenesis takes place

• Oviduct (Fallopian Tube) – where fertilization takes place

• Uterus – where the embryo grows and develops

• Vagina – birth canal

• Ovaries – where oogenesis takes place

• Oviduct (Fallopian Tube) – where fertilization takes place

• Uterus – where the embryo grows and develops

• Vagina – birth canal

Slide 12 of 18

Sex organ of femaleSex organ of female

• The responsibility of the female mammal for succesfull reproduction is considerably greater than male

• She must:– Manufacture eggs– Be equipped to receive sperm– Provide an environment conducive to fertilization

and implantation– Nourish the developing baby not only before

birth but also after

• The responsibility of the female mammal for succesfull reproduction is considerably greater than male

• She must:– Manufacture eggs– Be equipped to receive sperm– Provide an environment conducive to fertilization

and implantation– Nourish the developing baby not only before

birth but also after

Oogenesis Oogenesis

• Eggs formation takes place in ovarium• In contrast to male, the initial steps in

egg production occur prior to birth. Diploid stem cells (oogonia) divide by mitosis to produce more oogonia and primary oocyte (oosit primer). By the time fetus is 20 weeks old, the process reaches its peak and all the oocytes that she will ever posses have been formed (±4 million).

• Eggs formation takes place in ovarium• In contrast to male, the initial steps in

egg production occur prior to birth. Diploid stem cells (oogonia) divide by mitosis to produce more oogonia and primary oocyte (oosit primer). By the time fetus is 20 weeks old, the process reaches its peak and all the oocytes that she will ever posses have been formed (±4 million).

Oogenesis Oogenesis

• By the time she is born, 1-2 million remain.

• Each has begun the first steps of meiotic division (meiosis) and then stopped.

• No further development occurs until years later when the girl become sexually mature. Then oosit primer recommence their development, usually one at a time and once a month.

• By the time she is born, 1-2 million remain.

• Each has begun the first steps of meiotic division (meiosis) and then stopped.

• No further development occurs until years later when the girl become sexually mature. Then oosit primer recommence their development, usually one at a time and once a month.

Oogenesis Oogenesis

• Oosit primer grows much larger and complete the meiosis I, forming a large secondary oocyte and a small polar body that receives little more than one set of chromosomes. Which chromosomes end up in the egg and which in the polar body is entirely a matter of chance

• Oosit primer grows much larger and complete the meiosis I, forming a large secondary oocyte and a small polar body that receives little more than one set of chromosomes. Which chromosomes end up in the egg and which in the polar body is entirely a matter of chance

Oogenesis Oogenesis

• In human (and most vertebrates), the first polar body does not go on to meiosis II, but the secondary oocyte does proceed as far as metaphase of meiosis II and then stops.

• Only if fertilization occurs will meiosis II ever be completed.

• Entry of the sperm restarts the cell cycle, breaking down MPF (Metaphase Promoting Factor) and turning on APC (Anaphase Promoting Complex)

• In human (and most vertebrates), the first polar body does not go on to meiosis II, but the secondary oocyte does proceed as far as metaphase of meiosis II and then stops.

• Only if fertilization occurs will meiosis II ever be completed.

• Entry of the sperm restarts the cell cycle, breaking down MPF (Metaphase Promoting Factor) and turning on APC (Anaphase Promoting Complex)

Oogenesis Oogenesis

• The ripening follicle also serves as an endocrine gland. Its cells make a mixture of steroid hormone collectively known as estrogen.

• Estrogen is responsible for the development of the secondary sexual characteristics of mature women.

• Estrogen continues to be secreted throughout the reproductive years of women. During this period, it plays an essential role in the monthly menstrual cycle.

• The ripening follicle also serves as an endocrine gland. Its cells make a mixture of steroid hormone collectively known as estrogen.

• Estrogen is responsible for the development of the secondary sexual characteristics of mature women.

• Estrogen continues to be secreted throughout the reproductive years of women. During this period, it plays an essential role in the monthly menstrual cycle.

The ovum:The ovum:The ovum:The ovum:The ovum leaves the ovary after

rupture of the Graafian follicle, carrying 23 chromosomes and surrounded by the zona pellucida and corona radiata.

The ovum leaves the ovary after rupture of the Graafian follicle,

carrying 23 chromosomes and surrounded by the zona pellucida and corona radiata.

The ovum is picked up by the fimbrial end of the Fallopian

tubes and moved towards the ampulla by the :

1. Ciliary movement of the cells and 2. Rhythmic peristalsis of the tube.

The ovum is picked up by the fimbrial end of the Fallopian

tubes and moved towards the ampulla by the :

1. Ciliary movement of the cells and 2. Rhythmic peristalsis of the tube.

The ovum:The ovum:The ovum:The ovum:

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