Chapter 46

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

PowerPoint TextEdit Art Slides for Biology, Seventh Edition

Neil Campbell and Jane Reece

Chapter 46Chapter 46

Animal Reproduction


Figure 46.2 Asexual reproduction of a sea anemone (Anthopleura elegantissima)


Figure 46.3 Sexual behavior in parthenogenetic lizards

Time

Ova

rysi

zeH

orm

ones

Beh

avio

r

Ovulation Ovulation

ProgesteroneEstrogen

Female-like

Male-like

Female-like

Male-like

(a) Both lizards in this photograph are C. uniparensfemales. The one on top is playing the role of a male. Every two or three weeks during the breeding season, individuals switch sex roles.

(b) The sexual behavior of C. uniparens is correlated with the cycle of ovulation mediated by sex hormones. As blood levels of estrogen rise, the ovaries grow, and the lizard behaves like a female. After ovulation, the estrogen level drops abruptly, and the progesterone level rises; these hormone levels correlate with male behavior.


Figure 46.1 Earthworms mating


Figure 46.5 External fertilization

Eggs


Figure 46.9 Reproductive anatomy of the human female

Glans

(Rectum)

Cervix

Vagina

Bartholin’s gland

Vaginal opening

Ovary

Oviduct

Labia majora

Labia minora

(Urinary bladder)

(Pubic bone)

Uterus

Urethra

Shaft

Prepuce Clitoris


Vagina

Uterus

Cervix

OvariesOviduct

Uterine wallEndometrium

Follicles

Corpus luteum


Figure 46.13b Oogenesis


Figure 46.9x Ovary (left) and follicle (right)


Figure 46.10 Reproductive anatomy of the human male

Erectile tissueof penis

Prostate gland

(Urinarybladder)

Bulbourethral gland

Vas deferensEpididymisTestis

Seminalvesicle(behind bladder)

Urethra

Scrotum

Glans penis


Seminal vesicle

(Rectum)

Vas deferens

Ejaculatory duct

Prostate gland

Bulbourethral gland

(Urinarybladder)

(Pubic bone)

Erectiletissue of

penis

Urethra

Glans penis

Prepuce

Vas deferens Epididymis

Testis

Scrotum



Activity

• Work in groups to tell me about the travel of a group of sperm to see the legendary follicle

• Each member of your group will need to choose a role from below:

• Leader, Reporter, Recorder, Noise monitor

• Start out in the seminiferous tubules and work your way to the follicle

• Be sure to include structure and function

• This is a G rated classroom


EpididymisSeminiferous tubule

Testis

Cross sectionof seminiferoustubule

Sertoli cellnucleus

Lumen ofSeminiferous tubule

Spermatogonium

Primary spermatocyte(in prophase of meiosis I)

Secondary spermatocyte

Earlyspermatids

Spermatids(at two stages ofdifferentiation)

Differentiation(Sertoli cells providenutrients)

Meiosis II

Meiosis I completed

Mitotic division,producing large numbersof spermatogonia

Sperm cells

Acrosome

NucleusMitochondria

Neck

TailPlasma membrane

Head Midpiece

2n

2n

n n

nnnn

n n n n

Differentiation andOnset of meiosis I

Figure 46.12 Human Spermatogenesis


Figure 46.12 Structure of a human sperm cell


Figure 46.11 Human Oogenesis

Ovary

Primary germ cell in embryo

Differentiation

OogoniumOogoniumin ovary

Mitoticdivision

Primary oocyte,arrested in prophaseof meiosis I(present at birth)

Completion of meiosis Iand onset of meiosis II

Primaryoocytewithinfollicle

Secondary oocyte,arrested at meta-phase of meiosis II

Firstpolarbody

Ovulation

Entry ofsperm triggerscompletion ofmeiosis II

Ovum

Growingfollicle

Mature follicle

Rupturedfollicle

Ovulatedsecondary oocyte

Corpus luteum

Degeneratingcorpus luteum

2n

2n

nn

nnSecondpolarbody


Figure 46.13 The reproductive cycle of the human femaleControl by hypothalamus Inhibited by combination of

estrogen and progesteroneStimulated by high levelsof estrogenInhibited by low levels ofestrogen

Hypothalamus

Anterior pituitary

GnRH

FSH LH

Pituitary gonadotropinsin blood

LH

FSHFSH and LH stimulatefollicle to grow

LH surge triggersovulation

Ovarian cycle

Growing follicle Maturefollicle

Corpusluteum

Degenerating corpus luteum

Estrogen secretedby growing follicle inincreasing amounts

Progesterone andestrogen secretedby corpus luteum

Follicular phase Luteal phaseOvulation

Ovarian hormonesin blood

Peak causes LH surge

Estrogen Progesterone

Estrogen levelvery low

Progesterone and estro-gen promote thickeningof endometrium

Uterine (menstrual) cycle

Endometrium

Menstrual flow phase Proliferative phase Secretory phase

0 5 10 14 15 20 25 28

Day

s

1

(a)

(b)

(c)

(d)

(e)

3

6

7 8

4

5

2

9

10


Activity

• Work in pairs to compare the timing of the menstrual and ovarian cycles

• Answer:

– “Why does it make sense that each phase occurs when it does?”


Figure 46.14 Hormonal control of the testes

Stimuli from otherareas in the brain

Hypothalamus

GnRH from thehypothalamus reg-ulates FSH and LH

release from theanterior pituitary.

FSH acts on theSertoli cells of the

seminiferoustubules, promotingspermatogenesis.

LH stimulates the Leydig cells to maketestosterone, whichin turn stimulatessperm production.

Anteriorpituitary

Negativefeedback

Leydig cellsmake

testosteronePrimary andsecondary sexcharacteristics

Sertoli cells

Spermatogenesis Testis


Figure 46.15 Formation of the zygote and early postfertilization events

Ovary

Uterus

Endometrium

From ovulation to implantationEndometrium Inner cell mass

Cavity

BlastocystTrophoblast

Ovulation releases asecondary oocyte, whichenters the oviduct.

1

The blastocyst implants in the endometriumabout 7 days after conception.

5

Cleavage continues. By the time the embryoreaches the uterus, it is a ball of cells.It floats in the uterus forseveral days, nourished byendometrial secretions. It becomes a blastocyst.

4

Fertilization occurs. A sperm enters the oocyte; meiosis of

the oocyte finishes; and the nuclei of the ovum and sperm

fuse, producing a zygote.

2

Cleavage (cell division)begins in the oviduct

as the embryo is movedtoward the uterus

by peristalsis and themovements of cilia.

3

(a)

Implantation of blastocyst(b)


Figure 46.16 Placental circulation

Placenta

Umbilical cord

Chorionic villuscontaining fetalcapillaries

Maternal bloodpools

Uterus Fetal arterioleFetal venuleUmbilical cord

Maternal portionof placenta

Fetal portion ofplacenta (chorion)

Umbilical arteriesUmbilical vein

Maternalarteries

Maternalveins


Figure 46.17 Human fetal development

5 weeks. Limb buds, eyes, the heart, the liver, and rudiments of all other organs have started to develop in the embryo, which is only about 1 cm long.

(a) 14 weeks. Growth and development of the offspring, now called a fetus, continue during the second trimester. This fetus is about 6 cm long.

(b) 20 weeks. By the end of the second trimester (at 24 weeks), the fetus grows to about 30 cm in length.

(c)


Figure 46.18 A model for the induction of labor

Estrogen Oxytocin

fromovaries

from fetusand mother'sposterior pituitary

Induces oxytocinreceptors on uterus

Stimulates uterusto contract

Stimulatesplacenta to make

Prostaglandins

Stimulate morecontractions

of uterus

Pos

itive

fee

dbac

k


Figure 46.19 The three stages of labor

PlacentaUmbilicalcordUterusCervix

Dilation of the cervix

Expulsion: delivery of the infant

UterusPlacenta(detaching)

Umbilicalcord

Delivery of the placenta

1

2

3


Figure 46.20 Mechanisms of some contraceptive methodsMale Female

Method Event Event Method

Production ofviable sperm

Production ofviable oocytes

Vasectomy Combinationbirth control pill (or injection,patch, orvaginal ring)Sperm transport

down maleduct system

Ovulation

Abstinence

Condom

Coitusinterruptus(very highfailure rate)

Spermdepositedin vagina

Capture of theoocyte by the

oviduct

Abstinence

Tubal ligation

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

Sperm movementthrough female

reproductivetract

Transportof oocyte in

oviduct

Meeting of sperm and oocytein oviduct

Morning-after pill (MAP)Union of sperm and egg

Implantation of blastocyst in properly prepared

endometrium

Birth

Progestin alone


Figure 46.21 Ultrasound image

Head

Body

Head

Body


46.21 Ultrasound Of Fetus 1


46.21 Ultrasound Of Fetus 2

Documents

Chapter 46