Reproduction & Development (PB Lecture18 – Spring 2008 Althoff, reference Ch. 36)

• Animal Reproduction

• Human Reproduction

• Animal Development

Modes of Reproduction

______________budding (in Hypha)parthenogenesis (in some insects, lizards, salamanders)spontaneous fission (planaria)

_____________ “true” hermaphoditism (rare, few insects)

_____________ fertilization—union of gametes from two different individuals

HYDRA LIFE CYCLE

BUDDING….by Hydra (who also

carrying on sexual reproduction)

Asexual Reproduction

____________________--females (of some species) reproduce without fertilization…resulting in haploid offspring.

Some species can do this AND sexual reproduction

example: Aphids can do both: no wasted energy or gametes in midst of plenty

Aphid “taps” into phloem tissue of plants(the “sugar” pipeline)….so, rich source of energy and other nutrients allows for optimum production of young…without having to find a mate !!!!

Some species… it is a ________ world only, thus, considered _________species

FISH: mollies and platies LIZARDS: whiptails

Planaria

Spontaneous(binary)fission

Sexual Reproduction: the norm among Animalia species

Some species have “both sets” of sex organs(hermaphroditic: earthworms example)

Just one set of sex organs ( or ) is the norm Two basic categories:

______________ fertilization—most primitive

______________ fertilization—most advanced

Human Reproduction

Reproductive system consists of 2 components:(1) _______: testes or ovaries which

produce gametes and sex hormones(2) ________________:

a) males: conduct (move) gametes b) females: house embryo/fetus

TESTIS

PENIS

Bladder

Urethra

EPIDIDYMIS

VAS DEFERENS

SEMINAL VESICLE

PROSTATEGLAND

testes epididymis vas deferens bulbourethral

gland prostrate

gland seminal

vesicle urethra penis

B.G.

Semen Combination of _________ + secretions from 3

glands:1) seminal vesicles: thick, viscous fluid

containing _________ for possible use by sperm

2) prostrate gland: milky, ________ fluid that a) activates/increases sperm motility

b) protects sperm in vagina’s low pH (3.8 to 4.5) environment

3) bulbourethral glands: muscous secretions with a ____________ effect (some pre- ejaculate fluid)

EPIDIDYMUS

TESTIS

SEMINIFEROUSTUBULES

Site of gamete production

(_________ occurs here)

TESTES: site of gamete production, “__________” environment

SPERMP

____________(a lysosome)

MITOCHONDRIA

OVIDUCT

OVARYUTERUS

CERVIX

VAGINA

OVARIAN CYCLE

28-days in humans

here

occurs at this

stage

OVARYsite of

oogenesis

does NOT take place in the ovary!

1

2

3

45

6 7

Developing, ovulating,…and gone!

Theovary

Follicle Ovulation Evidence of Ovulation

New __________ containing primary oocyte Developing follicle Mature follicle with secondary oocyte ______________ – egg erupts from ovary into

oviduct…”ruptured follicle remains Egg goes into oviduct, “that” follicle is done for

life. But, if pregnancy occurs it will become a _________________ (easily detected) producing primarily ______________

& 7 No pregnancy, then “that” corpora luteum reduces in size and quits producing progesterone

Menstrual Cycle - Under hormonal control

GnRH - gonadotropin-releasing hormone

FSH - follicle stimulating hormone

LH - lutenizing hormone ESTROGEN

PROGESTERONE

WHERE DO THESE HORMONES COME FROM?

________ (HT) _______ (AP) ______ (AP) ___________(OV) _______________

(OV)

HT =hypothalamus

AP = anterior pituitary

OV = ovary (oocyte folliclecorpus luteum

DAY OF MENSTRUAL CYCLE

HO

RM

ON

E C

ON

CE

NT

RA

TIO

N

0 14 28

HO

RM

ON

E C

ON

CE

NT

RA

TIO

N

DAY OF MENSTRUAL CYCLE

0 14 28

DAY OF MENSTRUAL CYCLE

0 14 28

TH

ICK

NE

SS

Uterinelining

menstruation

Post - ovulation

1) SECONDARY OOCYTE (EGG)enters OVIDUCT with action by fimbriae

2) sperm “meets” egg somewhere in oviduct resulting in _______________

3) ___________ results, and travels on

4) ______________ develops and implants in the _________________

5) _____________ develops into ________

= when 3 germs layershave formed. Occurs 3rd week of development

Embryonic layer Adult tissue

Ectoderm

Mesoderm

Endoderm

GERM LAYERS specific tissues/organs

Human embryo at beginning of week 5

SOMITES

The PLACENTA – the most ______________“support” structure for development

PLACENTA Maternal blood and fetal blood never mix… because

exchange occurs across the ___________________ Chorionic villi: ______________ fetal side

______________ maternal side Risk: harmful chemicals moving across placenta to

fetal side…_______________ during EMBRYONIC (0-90 days) stage because various structure first forming

OTHER TIMES (including 3-9 months)different organs “at risk” because they developat different times during pregnancy