Anatomy and Phyisology of the Integument - 2 Flashcards
What is in the integumentary system
Skin w/ adjoining structures, horns, hooves, claws, other modified structures
Skin
Largest organ, continuous covering
Skin functions
Protective barrier, reduces water loss, reduce invasion of microbes, thermoregulation, sensory regulation
Skin characteristics
Thickness varies on species and individual, thickest where exposed, thinner where protected, attachment varies across body
Structure of skin
Epidermis, dermis, hypodermis
Epidermis
Outer most layer, comprised of epithelial tissue, nearly nerve free
Epidermis- histological layer
Outer most - Corneum, lucidum, granulasum, spinosum, basale - inner most
Stratum Corneum
Flatten dead cells
Stratum lucidum
Not present in all locations
Stratum granulasum
Spindle shape cells with “grainy” appearance
Stratum basale
Layer that contours the underlying dermis
Striatum spinosum
“Spiny” appearance due to the abundance of desmosomes
Desmosomes
Fibrous proteins that connect to the cell next to cell
Process of replace in epidermis layer
Cells in S.B. undergo mitosis division, new psh the superficial layers away from blood vessels, cells in S.C. fatten, old cells are sloughed off
Keratin
Fibrous structural protein
What happens when cells are completely full of keratin
The nucleus and organelles disappear
What does keratin do for the surface of the skin
Water-resistance, toughens
What are made if keratin
Outer layer of skin, hair, horns, nails, claws, hooves
What produces the cells the render color
Melanocytes
Where are melanocytes located stratum basal
Melanin
Pigment derived from the amino acid tyrosine
What is the second layer of skin
Dermis/cerium
What does the dermis/curium contain
Arteries, veins, capillaries, lymphatic, nerve fibers
Hyperdermis
Inner most layer, Composed of adipocytes
Hypodermis functions
Fat storage, movement of skin without tearing, heat insulation, absorb shock
Hair types
Guard, wool, tactile
Guard hair
Smooth outer coat
Wool hair
Fine (often curly), undercoat
Tactile hair
Long, stiff hairs utilized as sensory structure
Hair follicle structure
Hair bulb, dermal papilla, hair matrix, internal / external root sheath
Hair bulb
Origin of hair
Dermal papilla
Base of follicle that connects to dermis, blood supply via capillaries
Hair matrix
Collection of epithelial cells and melanocytes giving rise to the hair and color
Internal root sheath
Directly adjacent to the hair
External root sheath
Covers the internal root sheath and give rise to sebaceous (oil) glands
Three layers of hair
Medulla, cortex, cuticle
Medulla
Inner most layer containing air spaces between cells
Cortex
Thickest layer containing keratinized cells that give hair its color
Cuticle
Outer most layer of clear cells that cover cortex
arrector pili muscle
Tiny bundle of smooth muscle that extends from lower portion of follicle at an angle, can contract 90°, increases insulation
Sebaceous gland
Secrets sebum (oil/waxy material) into hair
Sweat glands (sudoriferous glands)
Tubular gland arising from the dermis to the skin
Sudoriferous gland function
Thermoregulation
Livestock are — meaning they have hooves
Ungulate
Two distinctive characteristics of unglates
Well developed hoofs, distal phalanx
Two layer of hooves
Epidermis (non), cerium (vascular)
Periople
Thin waxy layer outside the hoof
Hoof wall
Thick layers of keratin that create hard surface
Coronary band
Region where haired skin becomes hoof
Laminae
Bi-layered, interdigitated region between the hoof and corium
Sole
Hard surface that contact the ground
Bulb
Softer rear portion of the sole
Digital cushion
Interior portion of the sole that absorbs shock, frog
Horns
Formed over corneal process that projects from frontal bone
Interior of the horn
Combined corium and periosteum
Coronal diverticulum
Frontal sinus cavity extends into horn, Rick of external exposure when/if dehorned
Dewclaws
Resemble horn-type structure, little importance, can be removed to avoid injury,
Chestnuts
Horn like growths on the medial sides of horses limbs
Ergot
Small projects if conified epithelium at the rear of the fetlock of horses
