1. EVOLUTION OF THE MAMMARY GLAND AND SECRETIONS
Why is the mammary gland really a gland of reproduction?

2. MAMMARY GLAND Gland of Reproduction
Development is tied to hormones and physiology of reproduction.
Purpose is to nuture young!!
Huge female expenditure for something outside their own body!
Develop offspring/ species survival!

3. GIVE A 1 WORD DEFINITION FOR THIS COURSE!
MAMMALS!

4. MAMMALS mamma: latin word - breast / milk gland Kingdom: Animals
Phylum: chordata
Sub phylum: vertebrae
Class: mammalia
> 4400 species ( good info on ~150)
Evolved 250 million years ago (dinosaurs- 65)!

6. MAMMALS HAIR? MAMMARY GLANDS!
WHAT ARE 2 DISTINCT FEATURES OF MAMMALS?
HAIR?
MAMMARY GLANDS!

8. SUBCLASS: PROTOTHERIA
NO PLACENTA
Egg laying mammals
Lactation preceded placentation!
One order: Monotremata
3 species?
Mammary glands: no teats!
Tubules with myoepithelial tissue
Young have strong forepaws/ poorly developed hindlimbs

9. Duckbill Platypus

10. Mammary gland:
no teats
tubules
myoepitelial cells
milk forced onto hair

11. Female lays eggs 2 weeks post mating 10 - 14 day incubation period
Young: 350 mg at birth; 3-4 mo.- 1/2 adult wt.

12. Less young but better survival!
WHY MAMMALS?
Less young but better survival!
Protect egg!
Nourish young!
WHY MAMMARY GLANDS?

13. ECHIDNA Lay eggs but transfer to temp. brood pouch 10 day incubation
3-4 month lactation
special areas called areola in pouch: tubules

14. SUBCLASS: THERIA
HAVE PLACENTA!

15. METATHERIA
Give birth to live young but not a true placenta: chorio-vitelline
One order: Marsupials
Pouched animals
3-4 week gestation
Embryo born w/ highly dev. forepaws
Adaptation: animals move/ forage

16. Young born and crawl up into pouch
Why is > 3 important?
Young born and crawl up into pouch
Latches on teat for months (breathes!)
Can have 2 in pouch, 1 latched, 1 not
Different milk in each teat!

17. Can have embryo in utero Lactation results in delayed growth
Why is > 3 important?
Can have embryo in utero
Lactation results in delayed growth
Prolactin inhibits luteal function/ P4
What a baby machine!!!

19. MARSUPIALS
~ 275 SPECIES!

20. EUTHERIAN > 95 % OF ALL MAMMALS TRUE PLACENTA!
Extract nutrients from maternal blood!
21 orders ( see Dr. Anderson paper)
Born more mature
Lactations from 4 days to years!

21. EUTHERIAN

22. EUTHERIAN

23. * development and tissue
FUTURE THOUGHTS
What do mammals have in common:
- hair
- mammary glands
* development and tissue
* secretion products

24. EUTHERIAN
What do boy and girl mammary glands have in common?

25. AS 337 LACTATION BIOLOGY EXTRA CREDIT QUESTION 1 (10 PTS)
Are the SUBCLASSES / orders we talked about in class (monotremes / marsupials/ 21 orders for eutherians) all there or are there some lost subclasses / orders looking for a home? Can you find a lost subclass / order and if so, state what it is and where you found it! (paper or website!) Or any other interesting evolution facts?
DUE ON OR BEFORE CLASS NEXT THURS 1/23
Can give to Mackenzie, Kali, Melissa, Brittany , or me in class or send via .
HAVE A FANTASTIC WEEKEND!!!