The Reproductive The Reproductive SystemSystem

IntroductionIntroduction Reproduction is the mechanism by which the Reproduction is the mechanism by which the

thread of life is sustainedthread of life is sustainedSingle cell duplicates its genetic materialSingle cell duplicates its genetic material

Genetic material is passed from generation to Genetic material is passed from generation to generationgeneration

Groups of OrgansGroups of Organs Gonads – (testes and ovaries)Gonads – (testes and ovaries)

Produce gametes (sperm cells and ova)Produce gametes (sperm cells and ova) DuctsDucts

Transport, receive, or store gametesTransport, receive, or store gametes Accessory sex glandsAccessory sex glands

Produce material that support gametesProduce material that support gametes

The Male The Male Reproductive Reproductive

SystemSystem

Organs of the Male Organs of the Male Reproductive SystemReproductive System

ScrotumScrotum TestesTestes EpididymusEpididymus Vas deferensVas deferens UrethraUrethra PenisPenis

The Male Reproductive The Male Reproductive SystemSystem

The ScrotumThe Scrotum Pouch that supports the testesPouch that supports the testes Consists of skin and superficial fasciaConsists of skin and superficial fascia InternallyInternally

Divided into 2 sacsDivided into 2 sacs Each contains 1 testisEach contains 1 testis

Muscle fibers regulate temperature of testesMuscle fibers regulate temperature of testesProduction and survival of sperm require a Production and survival of sperm require a temperature that is lower than normal body temp.temperature that is lower than normal body temp.

The TestesThe Testes Paired oval glandsPaired oval glands DevelopmentDevelopment

High on embryo’s abdominal wallHigh on embryo’s abdominal wall

Begin descent into scrotum during latter ½ of 7Begin descent into scrotum during latter ½ of 7thth monthmonth

Cryptorchism – testes do not descendCryptorchism – testes do not descend

Descent of TestesDescent of Testes

Descent of TestesDescent of Testes

Descent of TestesDescent of Testes

Structure of a TestisStructure of a Testis Divided into internal compartmentsDivided into internal compartments

Each contains tightly coiled seminiferous tubulesEach contains tightly coiled seminiferous tubules Spermatogenesis = production of spermSpermatogenesis = production of sperm

The TestesThe Testes

Seminiferous TubulesSeminiferous Tubules

A Few Concepts with A Few Concepts with Regards to the Regards to the

Formation of GametesFormation of Gametes In sexual reproduction, a new organism is produced by the In sexual reproduction, a new organism is produced by the union and fusion of sex cells called union and fusion of sex cells called gametesgametes

A A zygotezygote results from the union and fusion of gametes results from the union and fusion of gametesContains a mixture of chromosomes (DNA) form the 2 parentsContains a mixture of chromosomes (DNA) form the 2 parents

Zygote repeatedly divides (mitosis), develops into a new Zygote repeatedly divides (mitosis), develops into a new organismorganism

Gametes differ from all other body cells in that they contain ½ Gametes differ from all other body cells in that they contain ½ the number of chromosomesthe number of chromosomes

Human cells have 23 chromosomes (Human cells have 23 chromosomes (haploidhaploid, or , or nn) = 1 set) = 1 set

Or 46 chromosomes (Or 46 chromosomes (diploiddiploid, or , or 2n2n) = 23 pairs, or 2 sets) = 23 pairs, or 2 sets MeiosisMeiosis = a process of cell division by which gametes are = a process of cell division by which gametes are

produced in the testes and ovaries; receive the haploid produced in the testes and ovaries; receive the haploid chromosome number (n)chromosome number (n)

SpermatogenesisSpermatogenesis

Migration of Spermatozoa Migration of Spermatozoa (Ducts)(Ducts)

Sperm are stored in the Sperm are stored in the epidymusepidymus, , Then transported through the Then transported through the vas deferensvas deferens, , Leave the body through the Leave the body through the urethraurethra Seminal fluidsSeminal fluids ( (semensemen) are added to the ) are added to the

sperm by accessory glandssperm by accessory glandsseminal vesiclesseminal vesicles

prostate glandprostate gland

bulbourethral glandbulbourethral gland

Accessory GlandsAccessory Glands

SemenSemen Mixture of sperm and secretions from accessory Mixture of sperm and secretions from accessory

glandsglands Average volume for each ejaculationAverage volume for each ejaculation

2.5 – 5 ml2.5 – 5 ml Average # sperm/ejaculation Average # sperm/ejaculation

50 – 100 million/ ml. 50 – 100 million/ ml.

= 125 – 500 million/ejaculation= 125 – 500 million/ejaculation Only a small % reach ovumOnly a small % reach ovum

Many sperm cells act on ovum to dissolve the barrierMany sperm cells act on ovum to dissolve the barrier

Only 1 enters the ovumOnly 1 enters the ovum

SpermatozoaSpermatozoa Produced at the rate of about 300 million/dayProduced at the rate of about 300 million/day Once ejaculatedOnce ejaculated

Life expectancy of about 48 hours in the female Life expectancy of about 48 hours in the female reproductive tractreproductive tract

StructureStructureHead with Head with acrosomeacrosome

MidpieceMidpiece

TailTail (flagellum) (flagellum)

Structure of SpermStructure of Sperm

The Female The Female Reproductive SystemReproductive System

Organs of the Female Organs of the Female Reproductive SystemReproductive System

Ovaries Ovaries (paired)(paired) Fallopian tubesFallopian tubes UterusUterus VaginaVagina

The Female Reproductive The Female Reproductive SystemSystem

The Female Reproductive The Female Reproductive SystemSystem

OvariesOvaries Located in the upper pelvic cavityLocated in the upper pelvic cavity OogenesisOogenesis = formation of haploid = formation of haploid ovumovum by by

meiosismeiosisEssentially the same as spermatogenesis, but Essentially the same as spermatogenesis, but division of cytoplasm is unevendivision of cytoplasm is uneven

OogenesisOogenesis

Process of Ova Process of Ova DevelopmentDevelopment

Before birth, many primordial Before birth, many primordial folliclesfollicles formed formedBegin meiosis, but stop at chromosome duplicationBegin meiosis, but stop at chromosome duplication

At puberty, every monthAt puberty, every monthFSH causes ovaries to enlargeFSH causes ovaries to enlarge

Primordial follicles maturePrimordial follicles mature

OocyteOocyte becomes larger becomes larger

Follicle cells divideFollicle cells divide

Follicle fills with fluid, oocyte pressed to 1 sideFollicle fills with fluid, oocyte pressed to 1 side

Ova DevelopmentOva Development

Ova DevelopmentOva Development

Ova DevelopmentOva Development

OvulationOvulation Ovum undergoes 1Ovum undergoes 1stst meiotic division meiotic division Ovum is released into peritoneal cavityOvum is released into peritoneal cavity Ovum is propelled to the fallopian tubeOvum is propelled to the fallopian tube

If not fertilized, it degeneratesIf not fertilized, it degenerates

If fertilized, 2If fertilized, 2ndnd meiotic division occurs meiotic division occurs

OvulationOvulation

Formation of Corpus Formation of Corpus LuteumLuteum

Fallopian TubesFallopian Tubes PairedPaired Extend laterally from uterus, toward ovary, but Extend laterally from uterus, toward ovary, but

not attachednot attached FunctionFunction

Transport ovaTransport ova

Fertilization occursFertilization occurs Ectopic pregnancyEctopic pregnancy

Development of embryo or fetus outside the Development of embryo or fetus outside the uterine cavityuterine cavity

UterusUterus FunctionsFunctions

Site of menstruationSite of menstruationImplantation of fertilized ovumImplantation of fertilized ovumDevelopment of fetus during pregnancyDevelopment of fetus during pregnancyLaborLabor

LocationLocationBetween the bladder and rectumBetween the bladder and rectum

StructureStructureBodyBodyCervixCervix

3 layers3 layersEndometriumEndometrium MyometriumMyometriumPerimetriumPerimetrium

Papanicolaou test = Papanicolaou test = Pap smearPap smear

Fallopian Tubes and the Fallopian Tubes and the UterusUterus

The Uterine WallThe Uterine Wall

Changes in the Changes in the EndometriumEndometrium

VaginaVagina FunctionFunction

Passageway for menstrual flowPassageway for menstrual flow

Receptacle for penis during intercourseReceptacle for penis during intercourse

Lower portion of the birth canalLower portion of the birth canal StructureStructure

MuscularMuscular

Lined with mucous membraneLined with mucous membrane

pH is lowpH is low

The Female Reproductive The Female Reproductive CycleCycle

Ova Ova ((oocytesoocytes) are produced in the ) are produced in the ovaries ovaries ((oogenesisoogenesis))

Approximately every 28 days one ovum is expelled Approximately every 28 days one ovum is expelled from the ovary (from the ovary (ovulationovulation))

An ovum transported through the An ovum transported through the fallopian tubefallopian tube to to the the uterusuterus where it becomes embedded in the where it becomes embedded in the uterine lininguterine lining

FertilizationFertilization occurs in the fallopian tube occurs in the fallopian tube If the egg is not fertilized, the uterine lining If the egg is not fertilized, the uterine lining

detaches and is shed in detaches and is shed in menstruationmenstruation If the egg is fertilized, the uterine lining is held in If the egg is fertilized, the uterine lining is held in

place and supported by progesteronesplace and supported by progesterones