Exam 3 - Integumentary System Flashcards
The integumentary system is an important _________ ________ which ________ water loss, invasion by ___________, and _________ trauma
Protective barrier; reduces; microorganisms; abrasive
Skin
Covers the outside of the animal; continuous with mucosal membranes at oral, anal, and urogenital orifices, the vestibule of the nostril, and the palpebral fissure
Outer epidermis
keratinized stratified squamous epithelium
Dermis
Dense fibrovascular connective tissue
Subcutaneous layer
Hypodermis
Adipose tissue
Insulator and shock absorber
Which layer of the skin is adipose tissue in
Subcutaneous layer
How is skin characterized
By the mucocutaneous junction
Skin is ________ where it is most exposed and ______ in protected regions
Thickest; thinner
The ___________ ________ consists of layers of dead, flattened cells
Stratum corneum
The __________ _____________ consists of spindle-shaped cells containing basophilic keratohyalin granules
stratum granulosum
The _______ _________ has a spiny appearance because of desmosomes (intercellular bridges) connecting adjacent cells
stratum spinosum
A layer of mitotically active cuboidal or columnar cells ________ _______ follows the contour of the underlying dermis, to which it is closely applied
Stratum basale
The ______ lies beneath the epidermis
Dermis
The _________ _______, which is variably present, comprises cells that are poorly stainable
Stratum lucidum
The skins outer layer is referred to as ______
Epidermis
Epidermis has these the of cells
Stratified squamous epithelium
The skin’s middle layer is referred to as _____
Dermis
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The dermis features _______ _______ which _______ with the overlying epidermis
Dermal papillae; interdigitate
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Blister
Local disruption between epidermis and dermis at the dermal papillae
Callus
Thickened stratum corneum
The skin’s third layer is referred to as _______
Hypodermis
The ________ and the _____ are both made up of thick connective tissue but different types
Hypodermis; Dermis
Hypodermis
Separated dermis from underlying structures
________ connective tissue that allows movement without tearing
Areolar
Variable amounts of fat (________ ________) are present in the hypodermis, with species dependent distribution and relative abundance
panniculus adiposus
Hair
Important for maintenance of body temperature (insulation) and protection from UV light
The three main types of hair
- Primary / Guard Hairs – straight or arched
- Secondary / Wool Hairs / Undercoat – softer, shorter
- Tactile Hairs - whiskers around the face; can also be found
throughout the coat
Primary/Guard hairs
Secondary/Undercoat/Wool hairs
Tactile Hairs
Hair structure
An individual hair arises from a modification of the
epidermis, called the hair follicle
Arrector pili muscle
Tiny, smooth muscle bundle; contraction will straighten hair toward 90°
Dermal papilla
Surrounds the hair bulb
The division of the epithelial cells covering the dermal papilla generates the hair itself
External epithelial root sheath
The follicle invaginates from the surface of the skin as a double-layered root sheath that surrounds the hair and terminates in a hair bulb of epidermal origin
Sebaceous glands
Classified as holocrine glands and secrete an oily secretory
product (called sebum) produced by disintegration of epithelial cells within the glands
How do sebaceous glands work
Contraction of the arrector pili muscle compresses
the glands and aids in emptying them
Open directly onto the skin surface and include: in
the ear canal, around the anus, and in the penis,
prepuce, and vulva, along with the tarsal glands of
the eyelid
Sudiferous glands aka sweat glands
can be found over the entire body of farm animals, including the horse, cow, sheep, and pig, although in pigs they are sparse
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