Exam 2 Integument Flashcards
9 Functions of the skin
- protection
- prevents water loss
- temp. regulation
- Sensation
- Elasticity to permit movement
- Immune function
- Excretion
- Calcium homeostasis
- Energy storage
What are the 5 functions of hair?
- Insulation
- Camouflage
- Social Display
- Sense/protection
- Sex Recognition
What are the 3 layers of the skin?
- Epidermis
- Dermis
- Hypodermis
What are the 2 layers of the dermis?
- Papillary layer
2. Reticular layer
Where does the epidermis originate from?
The Ectoderm
T/F the Epidermis is Avascular
T
Where does the dermis originate from?
Mesoderm
What is the hypodermis?
loose CT layer below dermis
What is the diff. between thick and thin skin?
Thick- Hairless, merocrine sweat glands, digital pads, muzzle
Thin- Hair follicles with arrector pili muscle, sebaceous and sweat glands
What are Epidermal pegs
Downward projections of the epidermis into the underlying dermis
What are Dermal papillae
Upward projections of the superficial dermis
What are the functions of the dermal papillae
Inc. SA between epidermis and dermis
Bring blood vessels near the epithellium
What are the two layers of the dermis?
- Papillary Layer
2. Reticular Layer
Which type of collagen can be found in the papillary layer of the dermis?
Type 1 and 3
What is found in the papillary layer of the dermis?
Mast cells, Macrophages, Vessels, Nerves
What type of connective tissue is the Papillary layer of the dermis composed of?
Loose CT
What type of connective tissue is the Reticular layer of the dermis composed of?
Dense irregular CT
Which type of collagen can be found in the reticular layer of the dermis?
Type 1
What is found in the reticular layer of the dermis?
Blood vessels, Nerves, elastic fibers
How is the skin elastic?
Network of elastic fibers in reticular layer of the dermis
What are the two cell types of the epidermis
- Keratinocytes
2. Non- Keratinocytes
What is the most common cell type of the epidermis
Keratinocytes
What are 4 types of non- Keratinocytes found in the epidermis
- Langerhans cells
- Merkel’s Cells
- Melanocytes
- Intraepithelial lymphocytes
Attach basal cells to the basal lamina
Hemidesmosomes
What is the basic plan of the epidermal layers?
- Constant supply of cells
- Adhere cells
- Replace cytoplasm with keratin
What are the 5 layers of the epidermis?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
Where is the stratum basale located?
Epidermal-Dermal junction
Rests on basal lamina
What shaped cells are in stratum basale?
cuboidal to columnar
What shaped cells are present in stratum spinosum?
cuboidal or slightly flattened
What gives cells of the stratum spinosum their spiny appearance?
increased number of tonofilaments
can cells of the stratum spinosum divide?
yes sometimes if needed, but not much division
What gives stratum granulosum its color?
Keratohyalin granules
Does the stratum granulosum stain basophilic or eosinophilic?
Basophilic
Secreated by cells in the stratum granulosum, to form waterproof lipid sheets
Lamellar granules
Is the stratum granulosum living or non living?
Last LIVING layer
Is the Stratum lucidium present in thick or thin skin?
Thick
Are cells of the stratum lucidium living or non living?
non living
In the cytoplasm of the stratum lucidium, a protein chemically related to keratin.
Eleidin
What is the function of keratin in the stratum corneum?
Water resistant protection
What is another name for the cells of the stratum corneum?
Horny cells
The Stratum ______ is the last living cells with keratohyalin granules
Granulosum
Stratum lucidum cells have _______ nuclei
Pyknotic
Process by which keratinocytes differentiate.
Keratinization
how long does keratinization take in dogs?
21 days
Production of stratum corneum by terminal epidermal differentiation.
Cornification
What is the function of langerhans cells?
immune system
What is the function of Merkel’s cells?
sensory cells
What is the function of Melanocytes
Protective function
Where are langerhan’s cells found?
Stratum basale and stratum spinosum
Where are langerhan’s cells derived from?
bone marrow, (intra-epidermal macrophages)
what is the immunological role of langerhan’s cells
Antigen presenting cells
Where are merkel’s cells found?
Stratum basale of thick skin
What is the function of Merkel’s cells?
May be sensory mechanoreceptors for cutaneous sensationor diffuse neuroendocrine system
Where are Melanocytes found?
Stratum basale
Where do melanocytes originate?
Neural crest
Which pigment do melalnocytes produce?
melanin
What is the function of Melanin?
Protect cells from UV radiation
Which enzyme must be present for Melanin production?
Tyrosinase
What happens if Tyrosinase is not present?
No melanin production, Albino animals
What is the most common form of melanin? (brown/black pigment?
Eumelanin
A red-brown polymer largely responsible for red hair and freckles
Pheomelanin
What are the 2 layers of a hair follicle?
- Dermal papilla
2. Root sheath
What is the function of the Dermal papilla of a hair follicle?
Carries blood supply to cells of hair
What are the 4 layers of the root sheath of a hair follicle?
- External glassy membrane
- External root sheath
- Internal root sheath
- Cuticle
What are the 2 types of hair follicles?
- Primary/Guard Hair
large diameter, rooted deepin dermis - Secondary/Under Hair
smaller diameter, rooted near surface
What type of glands are present in Primary hair follicles?
sebaceous glands and sweat glands
What type of glands are present in secondary hair follicles?
sebaceous gland, no sweat glands
Clusters of several hair follicles, usually consist of one primary follicle and numerous secondary follicles
compound hair follicle
Whiskers are an example of what type of hair?
Sinus Hair
What is produced by sebaceous glands?
sebum- a mixture of lipid and disintegrated cells
What type of gland is sebaceous glands?
Holocrine gland
what is the function of sebaceous glands?
produce sebum- antibacterial and waterproofing agent
Examples of sebaceous glands:
- Supracaudal glands
- Mekntal glands
- Horn glands
- Circumanal glands
- Preputial glands
- Tarsal glands
- Uropygial gland
Examples of apocrine glands?
- Sweat glands
- mammary glands
- Glands of moll
- Glands of Anal sac
- ceruminous glands
Type of gland that excretes via exocytosis
Merocrine
What is the function of merocrine glands?
thermoregulation, electrolyte balance,
Hooves and claws arise from which stratum of the dermis?
Stratum corneum
Which stratum(s) of the dermis are hooves and claws lacking?
granulosum and lucidum
What are the 2 main layers of the hoof?
- outer epidermis
2. underlying dermis (corium)
Which part of the hoof contains nerves and blood vessels?
laminar corium
What are the 3 epidermal layers of the hoof wall?
- Stratum Tectorium
- Stratum Medium
- stratum lamellatum/internum
Which part of the hoof is known as the insensitive lamellae?
Stratum lamellatum
Which part of the hoof is known as the sensitive lamimnae?
Laminar corium