III. Accessory Digestive Organs A. Pancreas 1. pancreatic duct 2. enzymes - trypsin - lipase - amylase - nucleases digestion is basically completed by intestinal enzymes

3. bicarbonate ions (HCO3-) 4. hormones - insulin - glucagon

B. Liver 1. bile - pigments and bile salts - emulsification 2. gallbladder 3. detoxification 4. glucose  glycogen insulin vs. glucagon

I. Animal Reproduction A. Asexual 1. fission 2. budding 3. parthenogenesis

B. Sexual 1. gametes  zygote

2. hermaphroditism - most are not self-fertilizers

3. sex determination a. Y chromosome (many animals, all mammals) - indifferent gonads in embryo

b. Z and W chromosomes (birds and some fish) - male is ZZ, female is ZW - egg carries either Z or W c. most ants and bees - females are from fertilized eggs (are diploid) - males are from unfertilized eggs (are haploid)

4. types of sexual reproduction a. oviparity - externally laid eggs - birds, most reptiles and amphibians

b. ovoviviparity - internal eggs - some reptiles, many fish (including most sharks)

c. viviparity - developing young nourished by mother (such as with a placenta) - most mammals, some snakes and lizards, some fish

II. External Fertilization A. Bony fish B. Amphibians

III. Internal Fertilization Several types 1. birds 2. reptiles

3. mammals - monotremes - marsupials

- placental - estrous cycle

IV. Males A. Sperm 1. production and secretion a. testes - descend

b. seminiferous tubules (site of sperm production) c. epididymis - sperm stored and mature - become motile

d. vas deferens e. urethra

2. scrotum - temperature regulation 3. testosterone

B. Penis 1. 3 cylinders of cavernous tissue - usually retractable 2. dilation of arterioles/closure of venules 3. ejaculation - around 2-5 ml of semen - 50-130 million sperm per ml - < 20 million per ml = infertile