Fig. 46-1

Chapter 46

Animal Reproduction

Fig. 46-2

Fig. 46-3

Asexual reproduction

Female

Sexual reproduction

Female

Generation 1

Male

Generation 2

Generation 3

Generation 4

Fig. 46-4a

Both are females; Parthenogenic

Fig. 46-4b

Ova

ry

size

Ho

rmo

ne

leve

lB

ehav

ior

Estradiol

Ovulation Ovulation

Progesterone

Time

Female Male-like

Female Male-like

The sexual behavior the cycle of ovulation

Fig. 46-5

Eggs

Fertilization

Fig. 46-6

Giant water bugs: parental protection; few offsprings

Fig. 46-7

Accessorygland

EjaculatoryductTestis

Vas deferens

Seminalvesicle

Penis

Ovary

Oviduct

Spermatheca

Vagina

Accessorygland

(a) Male honeybee (drone) (b) Female honeybee (queen)

Fig. 46-8

Genitalpore

(Digestive tract)

Male organs:

Seminalvesicle

Sperm duct(vas deferens)

Vas efferens

Testis

Female organs:

UterusYolk gland

Yolk duct

Oviduct

Ovary

Seminalreceptacle

(Excretory pore)

4

3

2

1

3

2

1

A hermaphrodite 雌雄同體

Fig. 46-10a

(Rectum)

Cervix

Vagina

Vaginal opening

Oviduct

Ovary

Uterus

(Urinary bladder)

(Pubic bone)

Urethra

ClitorisShaftGlansPrepuce

Labia minora

Labia majora

Fig. 46-10b

OvariesOviduct

FolliclesCorpus luteum

Uterine wallUterus

Cervix

Endometrium

Vagina

Fig. 46-11b

Seminal vesicle

(Rectum)

Vas deferens

Ejaculatory duct

Prostate gland

Bulbourethral gland

Vas deferens EpididymisTestisScrotum

(Urinarybladder)

(Urinaryduct)

(Pubic bone)

Erectiletissue

Urethra

Glans

Prepuce

Penis

Spermatogenesis

Fig. 46-12b

Epididymis

Seminiferous tubuleSertoli cellnucleus

Testis

Cross sectionof seminiferoustubule

Spermatogonium

Primary spermatocyte

Secondary spermatocyte

Spermatids(two stages)

SpermLumen ofseminiferous tubule

Fig. 46-12cPrimordial germ cell in embryo

Mitotic divisions

Spermatogonialstem cell

Mitotic divisions

Spermatogonium

Mitotic divisions

Primary spermatocyte

Meiosis I

Secondary spermatocyte

Meiosis II

Earlyspermatid

Differentiation (Sertolicells provide nutrients)

Sperm

2n

2n

2n

n n

n n n n

n n n n

Spermatogenesis

Fig. 46-12e

Ovary

In embryo

Primordial germ cell

Mitotic divisions

Oogonium

Mitotic divisions

Primary oocyte(present at birth), arrestedin prophase of meiosis I

Firstpolarbody

Completion of meiosis I and onset of meiosis II

Secondary oocyte,arrested at metaphase of meiosis II

Ovulation, sperm entry

Completion of meiosis IISecondpolarbody

Fertilized egg

Primaryoocytewithinfollicle

Growingfollicle

Mature follicle

Rupturedfollicle

Ovulatedsecondary oocyte

Corpus luteum

Degeneratingcorpus luteum

2n

2n

nn

n

n

Oogenesis

Fig. 46-12f

Ovary

Primaryoocytewithinfollicle

Rupturedfollicle

Growingfollicle

Mature follicle

Ovulatedsecondary oocyte

Corpus luteum

Degeneratingcorpus luteum

Fig. 46-12g

Primordial germ cell

Mitotic divisions

Oogonium

Mitotic divisions

Primary oocyte(present at birth), arrestedin prophase of meiosis I

Completion of meiosis I and onset of meiosis II

Secondary oocyte,arrested at metaphase of meiosis II

Firstpolarbody

Ovulation, sperm entry

Completion of meiosis IISecondpolarbody

Fertilized egg

2n

2n

nn

n

n

In embryo

Hormone control of the testes

Nurse cells

5 Sertoli cell,

7 Leydig cell,

Fig. 46-14aControl by hypothalamus Inhibited by combination of

estradiol and progesterone

Stimulated by high levelsof estradiol

Inhibited by low levels of estradiol

Hypothalamus

GnRH

Anterior pituitary

FSH LH

Pituitary gonadotropinsin blood

LH

FSH

FSH and LH stimulatefollicle to grow

LH surge triggersovulation

Ovarian cycle

Growing follicle Maturingfollicle

Corpusluteum

Degeneratingcorpus luteum

Follicular phase Ovulation Luteal phase

(a)

(b)

(c)

Da

ys

0 5 10 14 15 20 25 28| | | | | | | |

–

–

+

Fig. 46-14b

Ovarian hormones in blood

Peak causesLH surge

Estradiol level very low

Estradiol Progesterone

Ovulation Progesterone and estradiolpromote thickeningof endometrium

Uterine (menstrual) cycle

Endometrium

0 5 10 14 20 25 28| | | | | | | |

Da

ys

15

Menstrual flow phase Proliferative phase Secretory phase

(d)

(e)

Estrous cycle:Mammals share the same reproductive system, including the regulatory hypothalamic system that releases gonadotropin releasing hormone in pulses, the pituitary that secretes follicle stimulating hormone and luteinizing hormone, and the ovary itself releases sex hormones including estrogens and progesterone.

1.One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle. 2. Another difference is sexual activity. In species with estrous cycles, females are generally only sexually active during the estrus phase of their cycle (see below for an explanation of the different phases in an estrous cycle).

Fig. 46-16

Placenta

Uterus

Umbilical cord

Chorionic villus,containing fetalcapillaries

Maternal bloodpools

Maternalarteries

Maternalveins

Maternalportionof placenta

Fetal arterioleFetal venuleUmbilical cord

Fetalportion ofplacenta(chorion)

Umbilicalarteries

Umbilicalvein

Fig. 46-17

(a) 5 weeks (b) 14 weeks (c) 20 weeks

Fig. 46-17a

(a) 5 weeks

Fig. 46-17b

(b) 14 weeks

Fig. 46-17c

(c) 20 weeks

Fig. 46-18

Estradiol Oxytocin

fromovaries

Induces oxytocinreceptors on uterus

from fetusand mother’sposterior pituitary

Stimulates uterusto contract

Stimulates placenta to make

Prostaglandins

Stimulate morecontractions

of uterus

Po

siti

ve

fee

db

ac

k

+

+

Fig. 46-19-4

3

2

1 Dilation of the cervix

Placenta

Umbilical cord

Uterus

Cervix

Expulsion: delivery of the infant

Uterus

Placenta(detaching)

Umbilicalcord

Delivery of the placenta

Fig. 46-20Male Female

Method Event Event Method

Production of

sperm

Production ofprimary oocytes

Vasectomy Combination birth controlpill (or injection, patch, orvaginal ring)

Sperm transport

down maleduct system

Oocytedevelopmentand ovulation

Abstinence

Condom

Coitusinterruptus(very highfailure rate)

Abstinence

Spermdepositedin vagina

Capture of theoocyte by the

oviduct

Tubal ligation

Female condom

Spermmovement

throughfemale

reproductivetract

Transportof oocyte in

oviduct

Spermicides;diaphragm;cervical cap;progestin alone(as minipill,implant,or injection)

Meeting of sperm and oocyte

in oviduct

Union of sperm and eggMorning-afterpill; intrauterinedevice (IUD)

Implantation of blastocyst in endometrium

1. Describe oogenesis and spermatogenesis; describe three major differences between them

2. Explain how the uterine and ovarian cycles are synchronized and describe the functions of the hormones involved

You should now be able to: