Hormonal Control in Males

Hypothalamus

GnRH

FSH

Anterior pituitary

Sertoli cells Leydig cells

Inhibin Spermatogenesis Testosterone

Testis

LH

Neg

ativ

e fe

edb

ack

Neg

ativ

e fe

edb

ack

– –

–

(a) Control by hypothalamus

Hypothalamus

GnRH

Anterior pituitary

1

Inhibited by combination ofestradiol and progesteroneStimulated by high levelsof estradiol

Inhibited by low levels of estradiol

2 FSH LH

Pituitary gonadotropinsin blood

(b)6

FSH

LH

FSH and LH stimulatefollicle to grow

LH surge triggersovulation

3

Ovarian cycle 8(c) 7

Growing follicle Maturingfollicle

Corpusluteum

Degeneratingcorpus luteum

Follicular phase Ovulation Luteal phase

Estradiol secretedby growing follicle inincreasing amounts

Progesterone andestradiol secretedby corpus luteum

4

Ovarian hormones in blood

Peak causesLH surge

(d)5

Estradiol Progesterone 910

Estradiol levelvery low

Progesterone and estra-diol promote thickeningof endometrium

Uterine (menstrual) cycle

Endometrium

(e)

Menstrual flow phase Proliferative phase Secretory phase

Day

s

0 5 10 14 20 25 28| | |

15| | | | |

–

–

+Hormonal Control in Females

Control 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| | | | | | | |

–

–

+

Horm

onal C

ontrol in

Fem

ales (E

xpan

ded

View

)

Ovarian hormones in blood

Peak causesLH surge

Estradiol level very low

Estradiol Progesterone

Ovulation Progesterone and estra-diol promote 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)

Hormonal Control in Females (Expanded View)

Ovary

Uterus

Endometrium(a) From ovulation to implantation

(b) Implantation of blastocyst

Cleavage

Fertilization

Ovulation

Cleavage continues

The blastocystimplants

Trophoblast

Inner cell mass

Cavity

Blastocyst

Endo-metrium

1

2

3

4

5

Hormones During Pregnancy

Maternal Fetal Blood Flow

Placenta

Uterus

Umbilical cord

Chorionic villus,containing fetalcapillaries

Maternal bloodpools

Maternalarteries

Maternalveins

Maternalportionof placenta

Fetal arterioleFetal venuleUmbilical cord

Fetalportion ofplacenta(chorion)

Umbilicalarteries

Umbilicalvein

Placental Crossing

Fig. 46-17

(a) First Trimester (b) Second Trimester (c) Third Trimester

Fig. 46-17a

(a) First Trimester

Fig. 46-17b

(b) Second Trimester

Fig. 46-17c

(c) Third Trimester

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

+

+

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

Birthing Process

Fig. 46-19-1

PlacentaUmbilical cord

Uterus

Cervix

Dilation of the cervix1

Fig. 46-19-2

Expulsion: delivery of the infant2

Fig. 46-19-3

Delivery of the placenta

Uterus

Placenta(detaching)

Umbilicalcord

3

Male Female

Method Event Event Method

Production ofsperm

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 oocytein oviduct

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

Implantation of blastocyst in endometrium

Methods Of Birth Control

In-Vitro Fertilization

Ethics of In-Vitro Fertilization

• Advantages of IVF: there are as many reasons for this treatment as there are people seeking this treatment. – over comes infertility

– allow families for people who must be sterilised e.g.. radiography/chemo therapy cancer patients

• Disadvantages of IVF:– what happens to unwanted embryo's

– what happens to orphaned embryo's

– should infertility be by-passed