lm2 –lc1 · 2009. 8. 19. · lm2 –lc1 integumentary system normal anatomy and basic responses....
TRANSCRIPT
LM2 – LC1
Integumentary System
Normal Anatomy and Basic Responses
Presenter
Presentation Notes
This is Learning Component 1 in the Learning module on Integumentary System (Learning Module 2).
Skin
Normal Structures
Presenter
Presentation Notes
First, we will review some normal histology of the skin. The epidermis of birds is very thin over most of the body, however in certain regions such as the food pads, and the combs and wattles, the epidermis is thicker. This variation and other normal features are illustrated in the following slides (slides 3, and 4).
Presenter
Presentation Notes
Specialized structures like beaks are characterized by extensive keratin that provides the hard structure for this specialized epithelium. A. Normal Beak B. Normal beak at higher magnification. The arrow shows the extensive keratinized surface. C. Some areas of the body, foot pads for example, have much thicker epidermis than other regions of the body such as skin of the wing or skin covering breast. D. Skin from the shank show a scale with its characteristic keratinized projection from surface epithelium.
Presenter
Presentation Notes
Normal skin. Note the relatively thin epidermis (E), the dermis (D), and subcutaneous fat (SQF). A feather follicle (FF) is prominent. A branch of a cutaneous nerve (N) is shown. B. Normal skin showing two feather follicles (FF). E is epidermis and it is thin with very little keratin on the surface. C. Normal skin show epidermis (E), Dermis (D), a longitudinal section of a feather with its dermal papilla (DP). A Herbst corpscle (HC) is adjacent to the feather. A section of cutaneous muscle (M) is present. D. Structures of a normal feather are shown. E = epidermis, D = dermis, EFF = epidermis of the feather follicle, FS = feather sheath, B = barbs, PE = pulp epithelium, and FP = feather pulp. FF is a smaller feather follicle. See Figure I004 on page 411 of the 3dr edition of Avian Histopathology for another example of the structures of a feather follicle.
Responses of Skin to Injury
Examples of Basic Responses
Presenter
Presentation Notes
We will review some of the basic responses of skin to injury. These responses are not disease specific, but are typical of some of the lesions that are common to many diseases.
Questions to Guide Evaluation
• Is Anything on the Epithelial Surface?– Excess Keratin– Crusts
• Is Surface Epithelium Intact?– Vesicles, Erosions or Ulcers
• Is Surface Epithelium Increased in Thickness?– Hyperplasia = Acanthosis
• Is Dermis and/or SQ Tissue Expanded?– If So, By What?
Presenter
Presentation Notes
These questions will help guide you through a systematic examination of the skin and its associated structures. Beginning with the surface, look for the presence of excess keratin or debris. Necrosis of the epidermis that does not extend beneath the basement membrane is defined as an erosion. An ulcer extends through all layers of the epidermis. Increased thickness of the epithelium due to increased numbers of cells (hyperplasia) is called acanthosis. Expansion of the dermis and underlying connective tissue may be due to inflammation or to tumor cells.
Another Question to Guide Evaluation
• Are Any Special Features Seen?– Viral Inclusions
• I/C Inclusions of Fox Virus
– Bacteria
– Fungi
– Parasites
Features
• Crust and Vesicles – Slide 9
• Normal Structure of a Wattle and Ulcer– Slide 10
• Crust, Ulcer, Hyperplasia (Acanthosis), Hydropic (Ballooning) Degeneration and I/C Pox Virus Inclusions– Slide 11
• Normal Eyelid and Cellulitis (Blepheritis)– Slide 12 & 13
Presenter
Presentation Notes
Slides 9 – 12 illustrate features frequently found when evaluating skin lesions. Shown are crust and vesicles (slide 9); a normal wattle and a wattle with an ulcer (slide 10); crust, ulcer, epithelial hyperplasia or acanthosis, hydropic or ballooning degeneration,and large eosinophilic I/C inclusions of pox virus (slide 11); and a normal eyelid for comprison with an eyelid with fibrinoheterophilic cellulitis or blepheritis (slide 12).
Presenter
Presentation Notes
This figure shows a series of higher magnification (A-D) of comb from chickens with Candidiasis. The dilated blood vessels in the dermis are normal for the comb. Note the increased keraqtin and debris on the surfacte that forms a crust. Outline of fungal hyphae can be seen in A Note the degeneration of squamous epithelial cells and the formation of vesicles (*).
Presenter
Presentation Notes
Shown are three images (A-C) of normal wattle with dense collagenous tissue in the core (*). Image D shoes a small area of necrosis that extends through all epidermal layers and is an ulcer (arrow).
Presenter
Presentation Notes
Image A shows skin with a large amount of necrotic material forming a crust on the surface C). Epidermis is hyperplastic at A; dermis is expanded (DI). More normal epidermis (E) and dermis (D) are shown in upper right corner. Image B shows and ulcer (arrow) with numerous bacterial colonies and an ares of epidermal hyperplasia (*). Inage C shows hyperplastic squamous epithelial cells with ballooning degeneration and I/C inclusions (arrow). Image D is a higher magnification of C and shows the large eosinophilic I/C inclusions of pox virus (arrow) and ballooning degeneration (*).
Presenter
Presentation Notes
Image A show a normal lower eyelid from a broiler chicken with epidermis (E) and conjunctival epithelium (CE) resting on the tarsal plate (*). Image B shows an eyelid with fibrinoheterophilic cellulitis that is expanding the connective tissue (black horizonal bar). E is epidermis and CE is the conjunctival epithelium that is hyperplastic. Image C is a higher magnification of the expanded S/Q connective tissue of the eyelid. Image D shows that the expansion of S/Q connective tissue is due to a fibrinoheterophilic exudate and by increased numbers of lymphohistiocytic cells (*) around blood vessels.
Presenter
Presentation Notes
Images A – D are higher magnifications of slide 12 (Blepheritis) to show the fibrinoheterophilic exudate (A, B, and D) and the perivascular lymphohistiocytic cells (C).