The integumentary system : SKIN + APPENDAGES Each of the pink areas is a cell; Most are pink and cells change characteristics . . .get more flatten and full of protein as go through the layers Top layer=dead cells provide hydrophobic barrier to block liquid from coming in . . .. What happens when you go swimming? Cells divide as cells slough off . . .unless lots of friction=calluss or corn Other cells too: melanocytes . . .derived from neural cells, contains melanin makes your skin dark; depending on how much melanin is present with long arms contacts lots of cells and can transfer melanin to cells its in contact with Macrophages (Langerhan cells)=immune system, if barrier broken these cells can ingest (phagocytosize) foreign material N Matrix=border between the epidermis and dermis and allows cell sheet to stay connected to dermis with all it’s proteins FUNCTION: Generate Vitamin D; make chemical that when exposed to sun is converted into Vit. D No sun, no Vit. D . . .low Ca in body, weak bones and many other problems 38th Edition, Gray’s Anatomy (1995) Churchill Livingstone

D. Nails, Horns and Hooves 1. Protection 2. Made of keratin (like epidermis and hair) Daytona Community College, Dr. Doolin (2003)

Where Nails Grow matrix, primates, grip Look at epidermis . .. It’s continuous with the nail structure See site of active growth, the dermal pappilary ridges and epidermal papillary ridges matrix, primates, grip 38th Edition, Gray’s Anatomy (1995) Churchill Livingstone

Claws and Talons Hooves Amniotes: mammals, birds and reptiles and even in some amphibians (African Clawed frog) Hooves curved, birds, mammals Ungulates: ungulates

Horse’s Hooves frog, digital cushion

Atrophy and Dysmorohism in Domestication

Horns and Antlers http://www.honoluluzoo.org/images/rhino_horn.jpg bone + skin mammals, dinosaurs and extinct turtles http://www.fullpassport.com/Trip2000/afphoto/rhinohead.jpg

Bovidae : cattle, antelope, sheep, goats, bison, wildebeasts cornified, life, cattle, antelope, sheep, goats, bison, widebeasts

Elk with “Velvet” on antlers Cervidae: deer, elk moose http://www.caneva.ca/images/photo_elk.gif http://www.nps.gov/yell/tours/thismonth/june2004/images/velvetelk.jpg velvet, vascular, shed annually, deer, elk, moose

Elk with Velvet & Without http://www.nps.gov/yell/tours/thismonth/june2004/images/velvetelk.jpg http://www.elkcompany.us/images/June,_04_037_cropped1.jpg

Baleen of Whales epidermis and dermal papillae, mysticete http://www.zoo.ufl.edu/courses/vertzoo/Images/Mammallab/baleen.jpg

Epidermal Scales and Dermal Armor I know you have talked a lot about dermal scales, especially in fish, but briefly here we are going to consider epidermal scales and dermal armor. Epidermal scales, like dermal scales, are hard and thus mechanically protective. They are the major component of the skin of reptiles, occur on bird legs and occasionally in mammal as shown here on the beaver tail. In reptiles, they are anti desicatory but also assist with heat radiation or accumulation depending on how a reptile like the lizard orients itself to the sun. Dermal bone is often not represented as a surface structure (like the dermal scales of fishes) in mammals and birds but we have an exception with the extinct Glyptodon mammal and the living mammal armidillo. The turtle shell has : dorsal : dermal bone + expanded rib and vertebrae ventral plastron: dermal bone all covered with epithelium (like fish dermal scales) but unlike with fish it is keratinized.

Mucus Aquatic vertebrate….friction, protection from pathogens and predators for terrestrial vertebrates..retain moisture (in lungs) and to provide part of a reasonable mechanical structure for gas exchange https://www.sciencenews.org/article/ingredients-hagfish-slime-revealed aquatic, terrestrial

Color differential reflection and light scattering http://notexactlyrocketscience.files.wordpress.com/2006/12/mathger_lpealeii2.jpg Chromatophores …. Dermis sipous melanophore, iridophore, xanthophore, erythrophore, http://protist.biology.washington.edu/dparichy/choprae.jpg

dermal versus epidermal melanophores flounder squidhttp://notexactlyrocketscience.files.wordpress.com/2006/12/mathger_lpealeii2.jpg dermal versus epidermal melanophores