Orno Test2

Orno Test2 - Avian Integument (Bird skin) Feathers have...

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Avian Integument (Bird skin) Feathers have evolved from reptilian scales to protect the bird’s body o Provides a highly adaptive external barrier from the environment Skin similar to other vertebrates o 2 layers Epidermis Outer surface of the skin Stratum corneum o Stratified – layers of cells Flattened Produce a great deal of keratin which is a tough fibrous protein Highly resistant to physical and chemical breakdown Takes the place of the nucleus when it reaches the corneum Stratum basale – where the skin cells develop o Called columnar cells o Where mitosis occurs at a high rate o Pushed upward from newer cells being produced down below and then begin to flatten out Stratum transitivum o Transitional layer between the germinativum layer and corneum layer Dermis Supports and nourishes the epidermis Tougher thicker fibrous layer of Vascularized o Allows the bird to regulate its body heat
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Contains nerves, muscles, and blood vessels On the innermost side, you’ll find a lot of stored fat o Absorbs shock o Good for food storage o Good for insulating the body from heat loss o Has a low conductance factor, so it doesn’t release to much heat o Cells have an ability called lipogenesis Produces fat bodies in the cells composed of neutral lipids that are used to coat the plumage along with the secretions from the uropygial gland Skin is thin compared to other vertebrates o Particularly true about birds like owls and goatsuckers (common nighthawk, chuck will’s widow, whippoorwill, etc.) Other glands o Anal glands Produce a secretion called a mucopolysacharide Plays a role in fertilization Important for birds like the Japanese Quail as a territorial maek o Ceruminous glands Secrete wax into the external ear canal Way to keep bacteria from intering the canal o Lipid gland Lipoids oil and protect the skin o Uropygial gland Produces oily secretions that are rubbed on the feathers Found in most birds, but it’s clearly lacking in some like many of the large cursorial birds, frogmouths, pigeons, parrots, etc.
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Most highly developed in aquatic birds like ducks, geese, petrels, etc. Cormorants and Anhingas do not have this gland Derivatives of the Skin o Dense and compact scales Found in most birds covering the feet and legs Produced on the inside of the epidermis at about the same rate that they’re worn away on the outside Provide an efficient covering for the outside of the body that is tough, flexible, and easy to clean o Beaks Extremely varied and specialized to fit the feeding habit Appear as a mass of emidermal cells covering a bony core Called ramphotheca o Comes from the stratum corneum Harder and thicker around the tip Ex. Steppe Eagle o Tomia = sharpened edges of the beak used for cutting In ducks, it’s only the very tip of the beak that is hard o The sides of the bills are full of nerve endings that are
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This note was uploaded on 09/19/2011 for the course 1 101 taught by Professor Larrydavid during the Spring '11 term at South Carolina.

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Orno Test2 - Avian Integument (Bird skin) Feathers have...

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