Bio 1108 Reproductive System

Male and Female Anatomy

Figure 16.2a Male reproductive organs.

Ampulla ofductus deferens

Ductus (vas) deferens

(a)

Bulbourethral glandProstateRectumEjaculatory duct

Seminal vesicle

Epididymis

ScrotumTestis

Shaft of the penisSpongy urethra

External urethral orifice

PrepuceGlans penis

Urogenital diaphragmMembranous urethra

UreterUrinary bladderProstatic urethraPubis

Erectile tissue of the penis

Male Anatomy

1. Testis-M, FP2. Epididymus-M3. Ductus deferens-M, FP4. Seminal vesicle-M5. Prostrate-M6. Urethra –M, FP7. Penis-M, FP

Microscopesperm

M=ModelsFP= Fetal Pig

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The Path of SpermTestisEpididymisDuctus DeferensUrethra

Rete testis

Ductus (vas)deferens

Epididymis

Blood vesselsand nerves

Septum

Spermatic cord

Seminiferoustubule

Tunicaalbuginea

Lobule

Ductus (vas)Deferens is inside

Produces sperm

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2

3

BLADDERURETHRAPENISTESTESDUCTUS DEFERENS

URETHRAPENISTESTESVas Deferens (model-inside cord)

Testes

Vas deferens

Urethra

Penis

BLADDER

bladder

Male Reproductive Systembladder

TestesVas deferensUrethraPenisBLADDER

TEST

ES

TEST

ES

PENIS

PENIS

BLADDER

BLADDERVAS DEFERENS VAS DEFERENS

EPIDIDYMIS

PROSTRATE

SEMINAL VESICLE

Urinary bladder

Prostate

Prostatic urethra

Orifices of prostatic ducts

Membranous urethra

Root of penis

Shaft (body) of penis

(b)

Ureter

Ampulla of ductus deferens

Seminal vesicle

Ejaculatory Duct

Bulbourethral gland

Ductus deferens

Erectile tissue of penis

Epididymis

Testis

Spongy urethra

Glans penisPrepuce

External urethral orifice

Seminiferoustubule

Spermatogonium(stem cell)

Basement membrane

Mitosis

Growth

Entersprophase ofmeiosis I

Meiosis Icompleted

Meiosis IIM

eios

isSp

erm

ioge

nesis

Sper

mat

ogen

esis

Sperm

Lumen ofseminiferoustubule

Latespermatids

Earlyspermatids

Secondaryspermatocytes

Primaryspermatocyte

Daughter celltype A (remainsat basementmembraneas a stem cell)Daughter cell type B(moves toward tubulelumen)

Spermatogenesis: Sperm Production Starts at PubertyLocated in the Seminiferous Tubules

1. Mitosis of Spermatogonium1. Produces 2 cells

2. One remains for Mitosis3. The other continues

2. Meiosis I: genetic variation introduced

3. Meiosis II

Following Meiosis I and II:All spermatids have and half the amount of DNA- n, they are haploid. Spermiogenesis -last stage of sperm development:Sperm develop a flagella

next EPIDIDYMIS

How One cell of 2n (diploid) DNA becomes four cells of n (haploid) DNA

Figure 16.5 Structure of sperm.

(a)

(b)

Plasma membrane

Tail

Axial filamentof tail

Mitochondria

Proximal centriole

NucleusAcrosomeDistal

centriole

Midpiece

NeckHead

GnRH

FSH LH

Testosterone

Supporting cell

Hypothalamus

Anteriorpituitary

Testosterone

FSH andtestosteronestimulatespermproduction

Spermatogeniccells

Spermatogenesis

Seminiferoustubule in testis

Primary and secondarysex characteristics

StimulatesInhibits

KEY:

The hypothalamus releasesgonadotropin-releasinghormone (GnRH).

FSH stimulates spermatogeniccells to produce sperm.

GnRH stimulates theanterior pituitary to releasegonadotropins—FSH and LH.

LH stimulates the interstitialcells to release testosterone,which serves as the final triggerfor spermatogenesis.Testosterone then enhancesspermatogenesis.

Rising level of testosteroneexerts feedback inhibition on thehypothalamus and pituitary.

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1Hormonal Control of Sperm Production:It begins in the Brain . Hormones are produced released to the blood. Hormones travel by the blood to target tissues.

GNRH travels to the pituitary and stimulates the release of LH. The LH travels to the Testis. Testosterone increases in the Seminiferous Tubules. FSH released by the pituitary travels to the Testis.

• LH stimulates Testosterone production. Testosterone Levels Increase.

• FSH Stimulates Sperm Production. Number of Sperm increase.

• For Sperm development to occur the testosterone levels must increase.

Negative Feedback when there are too many Sperm.

Female Anatomy

Uterosacralligament

Rectum

CervixVaginaAnus

Greater vestibular gland

(a)

Labium majusLabium minusHymen

ClitorisUrethraMons pubisPubic symphysisUrinary bladder

Round ligamentUterus (fundus)FimbriaeOvary

Uterine tubeInfundibulum

Suspensory ligamentof ovary (part of broadligament)

Female Anatomy

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THE Path of the Egg1. Ovary2. Uterine Tube3. Uterus4. Vagina

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Microscopefollicle

OVARY Uterine Tube

VAGINA BLADDERURETHRA UTERUS

Figure 16.8b The human female reproductive organs.

(b)Vagina

Cervical canal

Wall ofuterus

EndometriumMyometriumPerimetrium

Round ligament of uterus

FimbriaeInfundibulum Uterine

tube

Lumen (cavity)of uterus

Fundusof uterus

Ovary

Uterine (fallopian) tube

Suspensoryligament of ovary

OvarianbloodvesselsBroadligament

Ovarian ligamentBody ofuterus

Ureter

UterosacralligamentCervix

Uterine bloodvessels

OVARY UTERINE HORNVAGINA BLADDERURETHRA

OVARY UTERUSVAGINA BLADDERURETHRA

Uterine horns

bladder

ovary

vagina

Urogenital sinus

Female reproductive system

bladder

ovary

vagina

Urogenital sinus

Female Reproductive Organs

URETHRA

OVARY UTERINE HORNVAGINA BLADDERURETHRA

OVARY UTERUSVAGINA BLADDERURETHRA

Before birth

Mitosis

Growth

Childhood

Meiotic Events

Oogonium (stem cell)

Primary oocyte

Primary oocyte(arrested in prophase I;present at birth)

(ovary inactive)

Follicle Developmentin Ovary

Follicle cellsOocyte

Primaryfollicle

Primaryfollicle

Primaryfollicle

Growingfollicle

Maturevesicular(Graafian)follicle

Ovulatedsecondaryoocyte

Secondary oocyte(arrested in metaphase II)

Ovulation

Sperm

Ovum

Meiosis II completed(only if spermpenetration occurs)

Secondpolar body

Polar bodies(all polar bodiesdegenerate)

Meiosis II of polar body(may or may not occur)

First polar body

Meiosis I (completed by oneprimary oocyte each month)

Monthly frompuberty to menopause

Primary oocyte (stillarrested in prophase I)

n n n n

n

2n

2n

2n

2n

Oogenesis: Ovum Production Starts in fetal stageLocated in the Ovary

1. Mitosis of Oogonium: Produces 2 n cells2. Meiosis I starts but then stops. Genetic

Variation is introduced.2. 2 million Primary Oocytes

3. All Primary Oocytes are surrounded by cells forming Primary Follicles that will

remain in Suspended Animation untilAge 10 to 14 years

4. With the onset of Puberty, every 28 Days a few of the Primary Follicles undergo Meiosis I (finish what was started) and Meiosis II (starts but then stops).

2. Primary Oocyte becomes Secondary Oocyte

5. Secondary Oocyte is released by the Ovary.2. Meiosis II is completed with

fertilization by Sperm. How One cell of 2n DNA becomes One cell of n DNA with 3 Polar Bodies

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Age 10 to 14 years to 50’s

Birth to Puberty

Fetus

Suspended Animation 3

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4.2

Figure 16.7 Sagittal view of a human ovary showing the developmental stages of an ovarian follicle.

Growing folliclesPrimary follicle

Degeneratingcorpus luteum

Corpus luteum

Developingcorpus luteum

Rupturedfollicle

Ovulation Secondary oocyte

Germinalepithelium

Bloodvessels

Antrum

Coronaradiata

Mature vesicular(Graafian) follicle

Every 28 Days a few of the Primary Follicles undergo Meiosis I (finish what was started) and Meiosis II (starts but then stops). Primary Oocyte becomes Secondary Oocyte . Secondary Oocyte is released by the Ovary

Figure 16.12a Hormonal interactions of the female cycles.

(a) Fluctuation of gonadotropin levels: Fluctuating levels of pituitary gonadotropins (FSH and LH) in the blood regulate the events of the ovarian cycle.

Plas

ma

horm

one

leve

l

LH

FSH

Day 0Day 14: Ovulation-

release of Secondary OOCYTE from Mature

Follicle

Day 28

Primary follicle stimulated

Figure 16.12b Hormonal interactions of the female cycles.

(b) Ovarian cycle: Structural changes inthe ovarian follicles during the ovarian cycleare correlated with (d) changes in theendometrium of the uterus during theuterine cycle.

Primaryfollicle

Secondaryfollicle

Vesicularfollicle

Corpusluteum

Ovulation Degeneratingcorpus luteum

Lutealphase

Ovulation(Day 14)

Follicularphase

After Ovulation: 24 hour window for fertilization by sperm

Spike in temperature

Day 14 -15

Figure 16.16a Cleavage is a rapid series of mitotic divisions that begins with the zygote and ends with the blastocyst.

Sperm

Uterine tubeOvary

Uterus

Endometrium

Cavity ofuterus

Ovulation

Oocyte(egg)

Fertilization(spermmeets andenters egg)

Zonapellucida

(a) Zygote (fertilized egg)

Day 14

Day 17

Figure 16.12c Hormonal interactions of the female cycles.

(c) Fluctuation of ovarian hormone levels: Fluctuating levels of ovarian hormones (estrogens and progesterone) cause the endometrial changes of the uterine cycle. The high estrogen levels are also responsible for the LH/FSH surge in (a).

Estrogens

Progesterone

Plas

ma

horm

one

leve

l

Preparing the Uterus for the Blastocyst

Day 14: Ovulation-release OOCYTE

Day 17: Blastocyst arrives at Uterus

(d) The three phases of the uterine cycle:•Menstrual: Shedding of the functionallayer of the endometrium.•Proliferative: Rebuilding of thefunctional layer of the endometrium.•Secretory: Begins immediately afterovulation. Enrichment of the bloodsupply and glandular secretion ofnutrients prepare the endometrium toreceive an embryo.

The menstrual and proliferative phases occurbefore ovulation, and together correspond tothe follicular phase of the ovarian cycle. Thesecretory phase corresponds in time to theluteal phase of the ovarian cycle.

Menstrualflow

Basa

l lay

erFu

nctio

nal l

ayer

Endometrialglands

Menstrualphase

Proliferativephase

Secretoryphase

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Blood vessels

28 Days

Day 14: Ovulation-release OOCYTE

Day 17: Blastocyst arrives at Uterus

Menstrual Phase Suspended: No Menses

Fertilization of Oocyte by Sperm

(d) The three phases of the uterine cycle:•Menstrual: Shedding of the functionallayer of the endometrium.•Proliferative: Rebuilding of thefunctional layer of the endometrium.•Secretory: Begins immediately afterovulation. Enrichment of the bloodsupply and glandular secretion ofnutrients prepare the endometrium toreceive an embryo.

The menstrual and proliferative phases occurbefore ovulation, and together correspond tothe follicular phase of the ovarian cycle. Thesecretory phase corresponds in time to theluteal phase of the ovarian cycle.

Menstrualflow

Basa

l lay

erFu

nctio

nal l

ayer

Endometrialglands

Menstrualphase

Proliferativephase

Secretoryphase

1 105 2515 20

Blood vessels

28 Days

Day 14: Ovulation-release OOCYTE

Menstrual Phase occurs: Menses

No Fertilization