Integument Flashcards
Keratinocytes aka?
Skin cells
Vascular supply for epidermis
Dermis
2 layers of dermis
- Papillary layer
2. Reticular layer
Papillary layer of dermis
Dermal ridges or papillae interdigitate with rete pegs of epidermis
5 layers of epidermis
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
Where do nerve endings in the skin occur?
- Hypodermis
- Dermis
- Epidermis
Thickest layer of dermis
Reticular layer
What cells make up the bulk of the epidermis?
Keratinocyes
2 types of tumors arising from keratinocytes
- Squamous cell carcinoma
2. Basal cell carcinoma
3 types of epidermal cells other than keratinocytes
- Melanocytes
- Langerhan’s cells
- Merkel cells
Melanocytes are?
Pigment cells
Langerhan’s cells are?
Antigen-presenting cells
Merkel cells are derived from ____ and associated with?
Neural crest → associated with nerve endings in epidermis
Langerhan’s cells originates from?
Monocytes → migrate to epidermis
Function of Langerhan’s cells
- Phagocytize antigens
- Migrate to lymph nodes
- Present antigen to lymphocytes
Langerhan’s cells are located in?
Mainly in stratum spinosum but found throughout the epidermis and dermis
Melanocytes originate from?
Neural crest
Melanocytes produce?
Melanin
After melanin is produced by melanocytes, what happens?
Transferred to keratinocytes → shield nucleus
Melanoma is?
Melanocyte tumor
Modified keratinocyte in contact with a nerve ending is called?
Merkel cell
Merkel cells are found?
Basal layer of epidermis
4 types of skin glans
- Sebaceous glands
- Sweat glands
- Special glands (usually scent)
- Mammary glands
Sebaceous glands are associated with?
Hair follicles
2 types of sweat glands
- Apocrine
2. Merocrine
Which type of sweat gland empties into hair follicles?
Apocrine
Merocrine sweat glands can be found on what types of skin?
Hairy or non-hairy → do not empty to hair follicles
3 special skin glands in sheep
- Infraorbital
- Inguinal
- Interdigital
Special skin glands in goat
Glands near horn
2 special skin glands in cat
- Submental organ glands
2. Circumoral glands
Special skin gland found in both dog and cat
Supracaudal glands
Glands of anal region are in what 4 species?
- Dog
- Cat
- Ferret
- Skunk
Glands of anal sac do what type of secretion?
Merocrine
Hepatoid glands do what type of secretion?
Do not secrete
What is microscopic evidence of apocrine secretion?
Bubble-like blebs of cytoplasm at apical cell surface
Follicle is continuous with?
Epidermis of surface of skin
Shaft of hair protrudes from?
Surface of skin
The part of the hair embedded in the follicle is called?
Root of the hair
Parts of shaft of hair
- Cuticle
- Cortex (hard keratin)
- Medulla (in thick hair only)
Parts of root of hair
- Cuticle
- Cortex
- Medulla (+/-)
Expanded end of the root of hair is called?
Bulb
Bulb of the root surrounds?
Dermal papilla
4 layers of follicle
- Hair
- Inner root sheath
- Outer root sheath
- CT sheath
Cuticle is the layer located?
Between hair and inner root sheath
Inner root sheath doesn’t extend superficially beyond?
Opening of sebaceous glands
Outer root sheath is continuous with?
Skin surface
What is between outer root sheath and CT sheath?
Basement membrane
Where do cells division occur during hair growth?
In the bulb, covering surface of dermal papilla
During hair growth, cells at the tip of the papilla forms?
Medulla
During hair growth, cells covering sides of papilla form?
Cortex
During hair growth, cuticle and inner root sheath form from?
Cells at reflection of cells at base of papilla
3 types of hairs
- Guard hairs
- Wool hairs
- Sensory hairs
Principle hairs are also called?
Guard hairs
Secondary hairs are also called?
Wool hairs
Sensory hairs are also called?
Vibrissae
Sensory hairs can be what two types?
Tactile or sinus
Sensory hairs contain?
- Venous sinuses in CT sheath around hair root
2. Nerve endings in CT
The venous sinus in a tactile hair divides which layer of the follicle into 2 layers?
CT sheath
Hoof tissue is composed of?
Tubular and intertubularhorn
How does hoof tissue grow?
Division of cells in stratum basale
Stratum basale in the hoof is immediately adjacent to?
CT
How does hoof tissue receive nutrition?
From underlying CT (dermis/corium)
Dermis in the hoof is called?
Corium
Main part of the hoof
Hoof wall
Coronet
Junction of hoof wal with skin
Periople
Thin, cuticle-like covering over hoof wall
Bottom flat surface of hoof is called?
Sole
White line is?
Junction of hoof wall and sole
Frog of hoof is?
Wedge of tissue in center of ground surface of hof
The term hoof refers to?
Epidermis
Projections of corium
Laminae and papillae
Blood and nerve supply to hoof is located in he?
Corium
Major function of laminae and papillae
Increase surface area for attachment
Dermal laminae function
Primary structure for adherence of hoof wall to foot
Papillae function
Template for hoof wall, sole and frog tissue → cause dividing epidermis to form tubules and intertubular horn
Laminae is found in?
Both hoof and dermis → interdigitate with each other
Laminae are located at what surface of the hoof wall?
Deep surface
2 divisions of laminae
- Primary
2. Secondary
Which type of laminae is grossly visible?
Primary
Secondary laminae is only present in?
Equidae
Primary epidermal laminae is composed o?
Non-pigmented keratinized cells
Primary epidermal laminae is connected to?
Inner surface of stratum medium
Secondary epidermal laminae are attached to?
Primary laminae
Secondary epidermal laminae are composed o?
Stratum basale and stratum spinosum
Each primary lamina contains how many secondary laminae?
100-200
3 layers of hoof wall
- Stratum externum
- Stratum medium
- Stratum internum
Stratum externum is also called?
Stratum tectorium
Periople is composed of what layer of hoof wal?
Stratum externum (tectorium)
Stratum medium is?
Bulk of hoof wall
Stratum medium grows from?
Cell division of epidermis in coronary region
Stratum internum is also called?
Stratum lamellatum
Epidermal laminae form from what hoof wall layer?
Stratum interum
During growth of hoof wall, where does division occur?
In stratum basale where it covers corium of coronary band
Division in the stratum basale at the coronary band forms?
Tubular and intertubular horn
Rate of growth of hoof wall
1/4-1/2 inch per month
Defecs at coronary region require how long to grow out completely (reach ground surface)?
8-12 months
Laminitis is?
Separation of hoof wall from third phalanx
Laminitis is usually due to loss of normal function of?
Laminae
Epikeras refers to?
Bovine horn
Rhino horn
Like horse hoof but grows directly from skin with no bony base
Antlers are?
Bone covered by velvety skin
Do antlers shed?
Annually