Figure 46.0 Frogs mating

Chap46 Animal

Reproduction

Asexual reproduction

• Budding

• Fragmentation

• Regeneration

Animal reproductive pattern

• Parthenogenesis

• Sequential Parthenogenesis:

• Protogynous (female): Fig 46.3

• Protogynous (male):

Figure 46.2 Sexual behavior in parthenogenetic lizards

(a)

Figure 46.3 Sex reversal in a sequential hermaphrodite

Figure 46.x2 Sea urchin sperm fertilizing an egg

Figure 46.9 Reproductive anatomy of the human female

Figure 46.9 Reproductive anatomy of the human female (continued)

Figure 46.10 Reproductive anatomy of the human male (continued)

Figure 46.10 Reproductive anatomy of the human male

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

Ovary

Primary germ cell in embryo

Differentiation

OogoniumOogoniumin ovary

Mitoticdivision

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

and onset of meiosis II

Primaryoocytewithinfollicle

Secondary oocyte,arrested at meta-phase of meiosis II

Firstpolarbody

OvulationEntry ofsperm triggerscompletion ofmeiosis II

Ovum

Growingfollicle

Mature follicle

Rupturedfollicle

Ovulatedsecondary oocyte

Corpus luteum

Degeneratingcorpus luteum

2n

2n

nn

nn

Figure 46.11

Oogenesis is the development of mature ova

Figure 46.13b Oogenesis

Spermatogenesis is the production of mature sperm

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

Nucleus Mitochondria

Neck

TailPlasma membrane

Head Midpiece

2n

2n

nn

nn nn

n nn n

Figure 46.12

Differentiation andonset of meiosis I

Figure 46.11 Spermatogenesis

Figure 46.12 Structure of a human sperm cell

The reproductive cycle of the human female

Figure 46.13a–e

Control 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 phase0 5 10 14 15 20 25 28

Day

s

1

(a)

(b)

(c)

(d)

(e)

3

6

7 8

4

5

2

10

9

Positive and negative feedback

• Positive : Follicular phase:

LH estrogen

• Negative: Luteal phase:

LH and FSH Estrogen and progesterone

Androgen secretion and sperm productionAre both controlled by hypothalamic and pituitary hormones

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 TestisFigure 46.14

Fertilization of an egg by a sperm, conception Occurs in the oviduct

Figure 46.15a, b

Ovary

Uterus

Endometrium

From ovulation to implantationEndometrium Inner cell mass

Cavity

Blastocyst Trophoblast

(a)

Implantation of blastocyst(b)

Ovulation releases asecondary oocyte, which

enters the oviduct.

1

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 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

The blastocyst implants in the endometriumabout 7 days after conception.

5

Figure 46.16 Placental circulation

Figure 46.18 Human fetal development

Figure 46.18 Hormonal induction of labor

Figure 46.19 The three stages of labor

Mechanisms of some contraceptive methods

Figure 46.20

Male FemaleMethod Event Event Method

Production ofviable sperm

Production ofviable oocytes

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

Sperm transportdown male

duct 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 46.20 Mechanisms of some contraceptive methods

Figure 46.22 Ultrasound imaging