Integument Flashcards
What are the 5 layers on skin?
Stratum corneum Stratum Lucidum Stratum granulosum Stratum spinosum Stratum basale
Where does cell division of skin cells happen?
Stratum basale
What are the 2 layers of the dermis?
Papillary layer
Reticular layer
Characteristics of the papillary layer of the dermis
Dermal ridges interdigitate with rete pegs of the epidermis
Which layer is the thickest layer of the dermis?
Reticular
What is the most common cell of the epidermis?
Keratinocytes
What 2 cancers generally arise from keratinocytes?
Basal cell carcinoma
Squamous cell carcinoma
What are Langerhans cells?
Antigen-presenting cell found in Stratum spinosum
Where do melanocyte originate from?
Neural crest
What cells accept melanin from melanocytes?
Keratinocytes
What is a Merkel cell?
Modified keratinocyte in contact with nerve ending
Is the hair follicle continuous with the epidermis of the skin?
Yes
What are the sections of the hair?
Cuticle
Cortex
Medulla (thick hair)
What is the difference between the root and the shaft of hair?
Root is embedded in follicle
Shaft protrudes from surface
What does the bulb of the hair surround in the dermis?
Dermal papilla
Where is the cuticle located?
Between hair & inner root sheath
Where is the ‘glassy’ basement membrane of the hair follicle located?
Between outer root sheath & connective tissue
Where are dividing cells located?
Bulb
Where are the cells that form the medulla located?
Tip of dermal papilla
Where are the cells that form the side of the hair located?
Cortex
Where do the cells for the cuticle and inner root sheath form?
Base of papilla
What are the 3 hair types?
Guard
Wool
Sensory
Where are the nerve endings located in tactile hairs?
Connective tissue
What is the main difference between tactile and normal hair?
Tactile hair has venous sinus
The venus sinus in tactile hair divides which layer of the follicle in to 2 layers?
Connective tissue sheath
What 2 types of tissue is the hoof made of?
Tubular horn
Intertubular horn
What is the purpose of intertubular horn?
Holds tubular horn together
What layer produces cells for hoof growth?
Stratum basale
Similar to the epidermis, the hoof receives blood supply from the underlying connective tissue (dermis). What is this called in the horse?
Corium
What is the coronet?
Junction of hoof wall & skin
What is the periople?
Cuticle-like covering of hoof that makes it shiny
What are the components of the hoof wall?
coronet
Periople
What is the white line of the hoof?
Junction of hoof wall and sole
What is the frog?
Tissue located in ground surface
What are the projections of the corium called?
Laminae
Pappillae
What are the primary adherence structures of the hoof wall?
Laminae
What acts as the template for hoof wall, sole and frog tissue?
Papillae
How does the papillae act as the template for hoof growth?
Cause epidermis to form tubules and intertubular horn
How does laminae act as the main adherence structure?
Increases surface area for hoof wall adhesion
Are laminae present in both epidermis (hoof) and dermis (corium)?
Yes
What are the 2 divisions of laminae?
Primary
Secondary
What is the difference between primary and secondary laminae?
Primary is visible
Secondary is microscopic
Where do primary epidermal laminae connect?
Inner surface of stratum medium
Where do secondary laminae attach?
To primary laminae
What type of dermal layers are secondary laminae composed of?
Stratum basale
Stratum spinosum
What function does the stratum externum (periople) provide?
Waterproofing
What is the stratum medium?
Makes majority of hoof wall
What is the stratum internum?
Forms epidermal laminae
What is the weak area of the hoof wall?
White line
Where does cell division occur for hoof wall?
Stratum basale in corium of coronary band
How much do hooves grow per month?
1/4 - 1/2”
If a defect occurs at the coronary region, how long does it take to grow out completely?
8-12 months
What is the coffin bone of the horse?
3rd phalanx
Separation of the hoof wall from the 3rd phalanx (laminitis) is due to loss of normal function of what?
Laminae
What is the difference in cell division of tubules and intertubular horn?
Tubules: cells divide on papillae
Intertubular horn: cells divide between papillae
What is the main difference between claws/nails & hooves?
Claws/nails do not have secondary laminae
What is the main difference between bovine and equine hooves?
Bovine hooves don’t have laminae
Are there any large difference between the way antler/horns grow and hooves?
Not much
Antlers are shed every year
Antlers are covered in skin
