CVA - Integument system

• Integument - the cellular layers that cover an organism and form a boundary at the interface between its internal and external environment
• What are the 3 primary layers of the epidermis?

  Stratum corneum, stratum intermedium, stratum basale
• Petromyzontidate

  • Unicellular glands and club cells
  • Cutaneous pigment throughout dermis
  • Slime glands/mucus cells
• Chondrichthyes

  • Series of placoid scales along dermis/epidermis
  • Scales formed from dentin and enamel
• Actinopterygii

  • Unicellular glands/club cells
  • Some photophores or poison glands
  • Cycloid, ctenoid, and ganoid cells
  • Tubercles
• Amphibia

  • Leydig cells
  • poison glands and mucous glands
  • Tubercles on feet
• Reptilia

  • keratinization on spiny scales, connected by hinge regions
  • fission zone/shedding
  • Birds: feathers and uropygial glands
• Mammalia

  • hair/arrector pili muscles
  • Sweat glands
  • antlers/horns
  • Nails, claws, hooves
  • sebaceous glands
  • apocrine (mammary) glands
  • keratinization of all of these
• The integument system may include tissues such as

  • epithelium
  • connective tissue
  • smooth muscle
  • fat
  • nerves
  • glands
• Integument functions in

  • protection
  • osmotic barrier/filter
  • communication
  • sensory receptions
  • camouflage
  • locomotion
  • temp regulation
  • vit d synthesis
• 4 things covers the dermis

  hair, feathers, bones, scales
• Types of exocrine glands?

  holocrine, apocrine, merocrine (eccrine)
• Holocrine gland - secretes liquid from cell destruction
• apocrine gland - secretes liquid but loses a portion of the cell
• merocrine (eccrine) gland - secretes fluid by exocytosis
• A lot of fish have living cells on the outside of their epidermis
• Chromatophore - color bearing cells, only produce specialized proteins called pigments which interact with light to produce colors
• Types of chromatophores

  • melanophores
  • iridophores
  • xanthophores
  • eurythrophores
• Melanophores - have dark pigment (brown/black) contained in organelles called melanosomes
• iridophores - contain purine and guanine platelets creating a silvery appearance (silver/blue)
• Xanthophores - contain yellow pigments
• eurythrophores - contain red pigments
• dermal chromatophore unit - arrangement of 3 or more chromatophores. Combos of chromatophores and dynamics of deeper melanophores result in a wide variety of color patterns
• green - blue light from iridophores reflects back through yellow xanthophores
• Morphological color change - change in coloration by changing the amount of pigment synthesized (slow process)
• Physiological color change - change in coloration by changing the distribution of amount of pigment in melanophores (fast process)
• Structural color changes - color changes by changing the angle in which iridescent colors are displayed (fast process)
• unicellular glands - single cells that acts like a gland for secretion
• Agnthans have all living cells on their skin. No need for a keratinized layer since they don't have to worry about water loss
• In actinopterygii, unicellular glands rupture when the organism is bitten, a release a pheromone that other fish can sense and know the danger
• keratin - diverse filamentous proteins produced in epidermal layer by keratinocytes
• bird feathers

  • flying surfaces
  • reduce airflow along skin
  • insulation
  • water retention
• Mammalian hair

  • insulation
  • water retention
  • defense
  • feeding
  • pheromones