1. Reproduction and Development
Chapter 26

2. Asexual Reproduction

3. Cost of Sexual Reproduction
Specialized cells and structures must be formed
Special courtship and parental behaviors can be costly
Nurturing developing offspring, either in egg or body, requires resources (usually from mother)

4. Stages of Development Eggs and sperm form
Gamete formation
frog egg
Sperm and an egg fuse to form zygote
Fertilization
frog sperm
Mitotic cell divisions produce daughter cells
Cleavage
Cell divisions, migrations, and rearrangements produce primary tissues
Gastrulation
midsectional views
Specialized organs and tissues form in prescribed spatial patterns at prescribed times
Organ Formation
top view
side view
Growth, tissue
Specilazation
Organs grow and assume specialized functions
Fig. 27-4, p.464

5. Primary Tissues Ectoderm Endoderm Mesoderm
Outer most primary tissue, Nervous Tissue, outter portions of body covering
Endoderm
Source of gut inner linning and organs derived from it
Mesoderm
Forms between outter and inner primary tissues, gives rise to muscles, most of the skeleton,circulatory, repro., excre.,connective tissue of gut and integumentary

6. Development of the Leopard Frog
transformation to adult nearly completed
adult,
three years old
sexual reproduction (meiosis through fertilization)
organ formation
tadpole
cleavage
zygote

7. Development of the Leopard Frog
Fig. 27-5b-j, p.465

8. Morphogenesis Programmed growth of tissues and organs
Cells migrate along prescribed routes
Sheets of cells expand and fold
Cell deaths shape body parts

9. Male Reproductive System
bladder
seminal vesicle
vas deferens
prostate gland
bulbourethral gland
urethra
epididymis
scrotum
testis
penis

10. A Sperm’s Journey Testes Epididymis Vas deferens Ejaculatory ducts
Produces immature sperm
Epididymis
Matures and stores sperm
Vas deferens
Ejaculatory ducts
Urethra

11. Male Components and Accessory Glands
PROSTATE GLAND
EJECULATORY DUCT
SEMINAL VESICLE
urinary bladder
URETHRA
urethra
anus
anterior
posterior
BULBOURETHRAL GLAND
VAS DEFERENS
PENIS
erectile tissue
EPIDIDYMIS
TESTIS
Fig. 27-7, p.467

12. Sperm Formation
Spermatogonium (2n) divides by mitosis to form primary spermatocyte (2n)
Primary spermatocyte divides by meiosis to form 4 haploid spermatids (n)

13. secondary spermatocyte immature sperm (haploid)
Sperm Production
MITOSIS
MEIOSIS I
MEIOSIS II
lumen
Sertoli cell
spermato-gonium (diploid)
secondary spermatocyte
late spermatid
immature sperm (haploid)
early spermatids
primary spermatocyte
Fig. 27-9b, p.468

14. A Mature Sperm Spermatids mature to become sperm
Head
Midpiece
Tail
Glandular products + sperm = semen

15. Hormonal Control Testosterone Follicle-stimulating hormone (FSH)
Produced by Leydig cells in testes
Controlled by luteinizing hormone (LH)
Follicle-stimulating hormone (FSH)
Starts sperm production
LH and FSH
produced by pituitary, controlled by hypothalamus

16. Female Reproductive Organs
ovary
ovary
oviduct
uterus
uterus
oviduct
vagina
clitoris
vagina

17. The Uterus Myometrium Endometrium Cervix
Thick layer of smooth muscle in walls
Endometrium
Uterine lining
Cervix
Connects uterus and vagina

18. Menstrual Cycle
The fertile period for a human female occurs on a cyclic basis
Menstrual cycle lasts about 28 days on average

19. Menstrual Cycle Follicular phase Ovulation Luteal phase Menstruation
Uterine lining regenerates
Oocyte matures
Ovulation
Oocyte released from ovary
Luteal phase
Hormones thicken endometrium

20. The Ovarian Cycle Girl is born with primary oocytes already in ovaries
Oocytes are suspended in meiosis 1
Meiosis resumes, one oocyte at a time, with the first menstrual cycle

21. Female Hormonal Control
Hypothalamus
GnRH
Rising estrogen stimulates surge in LH
Anterior pituitary
Progesterone,
estrogens LH
FSH
Ovary
follicle growth,
oocyte maturation
Estrogen
Corpus luteum
forms

22. Fertilization Sperm penetrates egg cytoplasm
Secondary oocyte undergoes meiosis II, forms mature egg
Egg nucleus and sperm nucleus fuse to form diploid zygote

23. Fertilization oviduct ovary Ovulation uterus follicle cell
opening of cervix
egg nucleus
vagina
zona pellucida
Fig , p.472

24. Contraception Effectiveness