integument Flashcards
this is the largest organ in the body
skin
skin functions:
_____: barrier against the invasion of physical , chemical , and biological agents
-prevents loss of ___ and __
- ___ regulation-arterio-venous anastomosis , hair elevation and sweating assists in this function.
-sensation
-__ permits movement
-immune function
-___ -sweating helps maintain ion and water balance
-___ homeostasis-UV light absorbed thrugh skin has a role in production of vit D
-___ storage_lipids in adipose tissue within subcutaneous CT
Protection water and electrolytes temperature regulation elasticity excretion calcium homeostasis energy storage
skin regions
epidermis and dermis
-Stratified squamous epithelium , AVAScular, THICK barrier, contains the cells: keratinocytes (most common), non-keratinocytes: langerhans cells, merkel’s cells, melanocytes, and variable numbers of intraepithelial lymphocytes
EPIDERMIS
this part of the skin has a papillary and reticular layer , MESODERMAL origin, CT(principal component) , VAScular and nervous supply, and supports the epidermis,
DERMIS
dermis has 2 layers: this layer is where loose CT is found , type I and III collagen, and found in mast cells, macrophages, vessels and nerves
papillary layer of dermis
dermis has 2 layers: this layer is where dense IRREGULAR CT is, Type I collagen , network of elastic fibers and found in blood vessels and nerves
reticular layer of dermis
what is the order of formation of the strata of the epidermis of the skin
stratum basale stratum spinosum stratum granulosum stratum lucidum stratum corneum
This portion has an
- epidermal dermal junction ,
- single layer of cuboidal to columnar cells,
- rests on the basal lamina,
- is the area of mitotic activity,
- and may have the presence of melanocytes
stratum basale
This layer is
- cuboidal or slightly flattened
- desmosomes and increased number of tonofilaments give SPINY appearance
- cells are cohesive and they resist abrasion
- cells in this layer retain capacity for division if needed
stratum spinosum
This layer is
- 3-5 layers cells start to flatten
- keratohyalin granules present (bind w/keratin filaments)
- stains basophilic
- lamellar granules (secreted to from waterproof lipid sheets)
- NO MITOTIC ACTIVITY
- LAST LIVING LAYER
stratum granulosum
This layer is -translucent
- many keratin filaments, desmosomes present
- cellular organelles are gone now- fully keratinized
- cytoplasm contains eleidin (protein related to keratin)
stratum lucidum
This is the most superficial layer
- 15-20 layers thick
- cells consist of keratin
- known as HORNY cells surrounded by a thicker plasma membrane coated by a thicker plasma membrane
- cells continuously shed here
stratum corneum
-production of stratum corneum by terminal epidermal differentiation is known as
cornification
what produces melanin?these cells also are present in the stratum basale, have neural crest origin, are stable cells and -live for years .
-Absorbs harmful UV radiation by transforming energy into harmless amts of heat
protects cells from effects of UV radiation
-must have tyrosine for proper function
melanocytes
this is the most common form of melanin, brown/black pigment
eumelanin
red brown polymer largely responsible for red hair and freckles
pheomelanin
if there is no tyrosine this means there is no melanin therefore this results in an ______
albino animal
langerhans cells have a function in the ___ __
immune system
this is an epidermal invagination has a glassy membrane - a thick BM.
hair follicle
These parts compose a?
- medulla- loose cuboidal cells, air filled areas
- cortex- dense compact keratinized cells parallel to hair shaft
- cutilce- single layer of flat keratinzed cells
hair
layers of a hair follicle
-dermal papilla-carries blood supply to cells of hair
-root sheath :
external glassy membrane
external root sheath
internal root sheath
cuticle
types of hair follicles
primary and secondary
this type of hair follicle is large diameter , rooted deep in dermis, sebaceous gland, arrector pili muscle, sweat glands
primary hair follicle
this type of hair follicle is smaller diameter, rooted near the surface, +/- sebaceous gland , no sweat glands
secondary hair follicle
clusters of several hair follicles , follicles merge at the level of the sebaceous gland and emerge through one external orifice
compound hair follicle
compound hair follicles usualy have ___ primary follicle and __secondary follicles
one, and several
what are examples of modifications of the skin
hoof, claws, nails
- variations of the stratum corneum
- underlain by highly vascular dermis
- lack stratum granulosum and stratum lucidum
hooves and claws
This is a highly modified specialized skin derivative that protects and encloses the end if the digits of an ungulate animal
-equivalent to nail or claw
hoof
There are 2 main layers of a hoof
outer epidermis and underlying dermis.corium(contains nerves and massive network of blood vessels)
HOof wall:this is the thin layer , external layer is known as “glaze” ab=nd is a continuation of the perioplic epidermis
stratum tectorium
Hoof wall: main supportive layer
-tubular and intertubular horn produced by the stratum basale and stratum spinosum of the epidermis of the coronary groove
stratum medium
hoof wall: lamellar horn = INSENSITIVE LAMELLAE
stratum lamellatum/internum
hoof wall: SENSITIVE LAMIMNAE
laminar corium/ dermis
these granules bind with keratin filaments
keratohyalin granules
these bodies are secreted by cells to form water proof lipid sheets
lamellar bodies
ear wax=
cerumen
oil production
sebum
a type of secretion where the membrane pinches together to release product
apocrine
this is where the gland is the product
holocrine
arrector pili muscle?
and merocrine gland?
refer to PPT
these cells are present in thick skin near stratum basale, may be sensory mechanoreceptors for cutaneous sensation
merkel’s cells
these are upward projections of the superficial dermis
dermal papillae
contractile cells that wrap around a gland to help with secretion
myoepothelial cells
