Integument System Flashcards
Functions of the skin (9)
Protection Prevent water loss and electrolytes Temperature regulation Sensation Movement Immune Function Excretion Ca Homeostasis Energy Storage
Functions of hair (5)
Insulation Camouflage Social display Sense/protect Sex recognition
Epidermis (4)
Ectodermal origin
Avascular
Thick barrier
Stratified Squamous keratinized
Dermis (4)
Mesodermal
CT
Vascular and nervous
Supports epidermis
Hypodermis
Subcutis, loose CT below dermis
NOT PART OF THE SKIN
Thick skin has what present
Merocrine sweat glands
T or F
Thick skin is hairless
TRUE
Thin skin has (2)
Hair follicles with arrector pili muscle
Sebaceous and sweat glands
What part of the skin brings blood vessels near epithelium
Dermal papillae
Sites of epidermis
Footpad, nasal planun and scrotum
What is the principal component of dermis
CT
Papillary layer of dermis (3)
Loose CT
Type 1 and 3 collagen
Mas cells, macrophages, vessels and nerves
Reticular layer of dermis(4)
Dense irregular CT
Type 1 collagen
Network of elastic fibers
Blood vessels, nerves
Skin elasticity is
Network of elastic fibers in reticular layer of dermis
Cells in epidermis
Keratinocytes
Non keratinocytes
Keratinocytes
Most common cell
95% of total cells in epidermis
Non keratinocytes (4)
Langerhans cells
Markel’s cells
Melanocytes
Variable number of intraepithelial lymphocytes
Mention the adherent cells in epidermis (2)
Desmosomes
Hemidesmosomes
Hemidesmosomes
Attach basal cells to basal lamina
Basic plan of epidermal layers (2)
Generate constant supply of cells
Replace cytoplasm with keratin, waterproof, flattened cells, provide many layers of this oily cellular barrier
Layers of epidermis (7) from top to base
Cinderella Loss her Glass Slipper at the Ball
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale
Stratum basale
Epidermal dermal junction of single cuboidal to columnar cells
Desmosomes binds what
Neighboring cells together
Where in epidermis is the are of mitotic activity
Stratum basale
Stratum spinosum (what type of cells)
Cuboidal or slightly flattened
Stratum granulosum (3)
3-5 layers
cells begin to flatten
May be difficult to see in skin
Where can you find keratohyalin granules
Stratum granulosum
Stratum granulosum stain
Basophilic
Lamellar granules of Granulosum
secreted by cells to from waterproof lipid sheets (intracellular cement)
What is the last living layer and has no mitotic activity
Granulosum
What happens to nucleus of cells in granulosum layer
They start disappearing
In a section of the thick skin, it looks as a translucent layer is what layer of epidermis
Lucidum
only in thick
Are there cellular organelles in the lucidum layer of epidermis?
NO
Cells are fully keratinized
What is eleidin
Protein chemically related to keratin present in cytoplasm of lucidum layer
How thick can the stratum corneum be?
15-20 layers thick depending on location in footpads
How is the epidermis of the thick skin
Keratinized squamous epithelium
Non nucleated cells (dead keratinized cells)
In the thick skin the stratum lucidum cells have
Pyknotic nuclei
What is keratinization
Process by which keratinocytes differentiate
What is cornification
Production of stratum corneum by terminal epidermal differentiation
Langerhans cells help with
IS
Merkel’s cells are
Sensory cells
Melanocytes have a ____ function
Protective
Where are the Langerhans cells found
Stratum basale and spinosum
Intra-epidermal macrophages
Bone marrow derived from monocytes
Immunological role of Langerhans cells in skin (2)
Antigen presenting cells
Internalized surface bound antigen for processing and presenting at its cell surface to T lymphocytes
Merkel’s cells are present where
Thick skin near stratum basale
Melanocytes are present where
Stratum Basale
What cells produce melanin
Melanocytes
What cells protect cells from effects of UV radiation
Melanocytes
Melanocytes need ____ to function properly
Tyrosinate
Eumelanin
Most common type of melanin
BROWN BLACK PIGMENT
Pheomelanin
Red/brown polymer largely responsible for red hair and freckles
What happens if there is no Tyrosinase
No pigment
No melanin
so ALBINO
Sensory nerve of dermis
Free nerve endings to stratum granulosum called nociceptors
Encapsulated nerve endings of dermis (3)
Meissner’s corpuscles
Pacinian corpuscles
Raffini corpuscle (sense stretching)
Medulla of hair
Loose cuboidal cells, air filled in areas
Cortex of hair follicles
Dense compact keratinized cells parallel to hair shaft
Cuticle of hair
Single layer of flat keratinized cells
What carries the blood supply to cells of hair
Dermal papilla
External glassy membrane of root sheath
Basal lamina external to root sheath
External root sheath is continuous to
Epidermis
The cuticle of hair follicle is formed by
Overlapping keratinized cells with free edges oriented in opposite direction from hair cuticle toward hair bulb
Types of hair follicles
Primary and secondary
Primary hair follicle characteristics (2)
What is present
Large diameter
Rooted deep in epidermis
Sebaceous glans, arrector pili, muscle, sweat glands
Secondary hair follicles
What is has
Smaller diameter
Rooted nearer the surface
Sebaceous gland, no sweat glands, no arrector pili
Compound of hair follicles
Cluster of hair follicles
Compound follicles usually have
1 1ry hair follicle
Several 2ry hair follicles
Arrector pili muscle is
Smooth muscle attached to follicle of 1ry hairs
Sebaceous glands produce
SEBUM (mixture of lipid and disintegrated cells)
Sebaceous glands are a type of what gland
Holocrine
Other sebaceous glands (7) and what animal are they in
Supracaudal in dog Mental glands in cat Horn glands in Buck goat Circumanal gland in Ruminants Preputial gland in Smegma of horse Tarsal (meibomian) glands in Eyelid Uropygial gland in birds
Apocrine glands are secrete by
Apical budding/pinches
Function of apocrine sweat glands
Mainly communication
Apocrine sweat glands examples (4)
Mammal glands
Glands of Moll (eyelid)
Anal sac
Ceruminous glands (ear wax)
Merocrine glands excrete via what
Exocytosis
Merocrine glands are mainly for
Thermoregulation
Secrete fluid into skin when temperature rises
T or F
Dogs produce sweat for thermoregulation
FALSE
Merocrine glands in dogs functions (2)
Seal outer layer of epidermis
Secrete pheromones that give dogs a distinctive body color
What is the hoof
Highly modified, specialized skin derivative that protects and encloses the ends of digits of an ungulate mammal
Main layers of the hoof
Outer epidermis Underlying dermis (Corium)
Epidermal layers of hoof
Stratum tectorium/externum
Stratum medium
Stratum lamellatum/internum
What is the main supportive layer of the hoof
Stratum medium
What is the lamellar horn
Stratum lamellatum
What is the dermis of the hoof called
Laminar corium
