10/2 Class Lecture Chapter 5 Flashcards
skin functions
protection body temperature regulation cutaneous sensation metabolic fucntions blood/water resevoir excretion
cutaneous sensations
pain, pressure, temperature
example of metabolic functions for skin
we make vitamin D in our skin
examples of secretion for skin
nitrogen waste mixed with our skin
another word for skin
integument
what is the largest body organ
skin
what are the two regions of the skin
dermis and epidermis
where is the epidermis
the superficial region, on top of the dermis
what tissue makes up the epidermis
epithelial tissue
where is the dermis
underlies epidermis
what tissue makes up demis
mostly fibrous connective tissue
what is the hypodermis also called
superficial fascia
what is the hypodermis
connective tissue below the dermis
subcutaneous layer deep to the skin
mostly adipose tissue that absorbs shock and insulates
anchors skin to the underlying structure- mostly muscles
is the hypodermis apart of the skin
no, but it shares some functions
who has more hair follicles male or females
both have same number
what is keratin
protein that kills cells and makes them waterproof
what makes up the epidermis
keratinized stratified squamous epithelium
what are the layers of the epidermis from bottom to top
Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (only in thick skin) Stratum corneum
what are the cell types of the epidermis
keratinocytes
melanocytes
dendritic (Langerhans) cells
tactile (merkel) cell
what do melanocytes contain
the pigment melanin
what are the structures for dendritic cells
root like structures
what do tactile (merkel) cells deal with
our immune system and fighting off bacteria
what type of fibers do keratinocytes produce
fibrous protein keratin
what cells make up most of the epidermis
keratinocytes
what are keratinocytes connected by
desmosomes
what cells makeup 10-25% of the deepest epidermis
melanocytes
what do melanocytes produce and how are they packaged
produce pigment melanin packages into melanosomes
what do melanocytes protect
Protect the apical surface of keratinocyte nucleus from UV damage
what are dendric (Langerhan) cells
Macrophages – key activators of the immune system
what are tactile (Merkel) cells
sensory touch receptors
what is the deepest epidermal layer
stratum basal
what is the stratum basal also called
stratum germinativum
what is the stratum basal attached to
firmly attached to the epidermis
how many rows and what kind of cells do the stratum basal have
a single row of stem cells
what are stem cells
the generic type of cell, not specialized
What type of activity occurs in the stratum basal layer
actively mitotic
produces 2 daughter cells
how long does it take for cell to get to the basal surface
25-25 days
what happens as the cells move towards the surface during mitosis in the stratum basal
dies as it moves towards the surface (keratin kills the cell)
what does one cell do at the end of mitosis in the stratum basal
remains in the stratum basal as a stem cell
what 3 pigments contribute to skin color
melanin
carotene
hemoglobin
cyanosis
Other symptoms: fatigue, fainting
erythema
(redness) (person overheated, high blood pressure, inflammation, etc)
Fever, hypertension, inflammation, allergy
pallor
(blanching) opposite of erythema
Anemia, low blood pressure, fear, anger
jaundice
(yellow cast) seen in skin and in whites of the eyes
Liver disorder
Bile (yellow pigment produced in the liver)
bronzing
Inadequate steroid hormones in Addison’s disease
bruises
Clotted blood beneath skin
derivatives of the epidermis
Hairs and hair follicles
Nails
Sweat glands
Sebaceous (oil) glands
what does every hair have
Every hair has its own oil gland, lubrication system and it has its own muscle
what causes goosebumps
When the muscle contracts the hair stands up and produces goosebumps
what has heavy deposits of keratin
hair and nails
what is the purpose of finger nails
scratch and they give a backing with some support so we have dexterity to use our fingers to pick things up
what type of product are nails
extracellular product
what is the prickly layer of the epidermis
stratum spinosum
how many cell layers make up the stratum spinosum
several layers thick
what do stratum spinosum cells contain
Cells contain a web-like system of intermediate prekeratin filaments (will become keratin, keratin wannabe cells) attached to desmosomes
what type of cells do stratum spinosum contain
Abundant melanosomes and dendritic cells (defense cells) protect with color
how many cell layers does the stratum granulosum
thin-4-6 cell layers
what happens to cell appearance as they move up in the stratum granulosum layer
as they work their way up they become squamous (Cells flatten, Nuclei and organelles disintegrate, Keratinization begins, Cell accumulate lamellar granules)
what happens to cells above the stratum granulosum layer
they die bc they are too far from dermal capillaries (too far away from their nutrition and oxygen)
what is the clear layer
stratum lucidum
where is the stratum lucidum found in
only in thick skin examples: palms of hands, soles of feet
where is stratum lucidum located
Thin, translucent band superficial to the stratum granulosum
how many layers of cells are in the stratum lucidum
A few rows of flat, dead keratinocytes
what is the horny layer
stratum corneum
how many layers of cells are in the stratum corneum
20–30 rows of dead, flat, anucleate (no nucleus) keratinized membranous sacs
how thick is the stratum corneum
3 quarters of epidermal thickness
what are the functions of cells in the stratum corneum
Protect deeper cells from the environment and water loss
Protect from abrasion and penetration
Barrier against biological, chemical, and physical assaults
how do cells change in the epidermis
change as they grow
apoptosis
Controlled cellular suicide
Nucleus and organelles break down
Plasma membrane thickens
Allows cells to slough off as dandruff and dander
how many cells of the epidermis are shed every minute
50,000
what cells make up the dermis
fibroblasts, macrophages, occasionally mast cells and white blood cells
what are fibroblasts
fiber making cells
what do the fibers in the dermis do
fibers in matrix bind bodies together
example of connective tissues
“hide” used to make leather
what does the dermis contain
nerve fibers, blood, and lymphatic vessels, epidermal hair follicles, oil and sweat glands
what are the layers of the dermis
papillary, reticular
papillary layer
Areolar connective tissue with collagen and elastic fibers and blood vessels
what type of tissue is in the dermis
loose tissue
what is in the loose tissue in the dermis
phagocytes can patrol for microorganisms
what are dermal papillae
bump-like, superficial peg-like projections, Most contain capillary loops some contain Meissner’s corpuscles, Some contain free nerve endings, In thick skin lie atop dermal ridges (fingerprints) that cause epidermal ridges
what are meissners corpuscles
touch receptors (pain, pressure, temp)
what are ridges collectively called in the dermis
friction ridges
what do friction ridges do
Enhance gripping ability
Contribute to the sense of touch
Pattern is fingerprints
what percent of dermal thickness does the reticular layer make up
80%
what tissue makes up the reticular layer
dense fibrous connective tissue
what allows for stretch in the reticular layer
Elastic fibers provide stretch-recoil properties elasticity to our skin
are collagen fibers weak or strong
strong
what do the collagen fibers in the reticular layer allow for
Provide strength and resiliency
Bind water
what do collagen fibers have in the reticular layer
cleavage lines
what are cleavage lines
Externally invisible
Important to surgeons
Incisions parallel to cleavage lines gapless and heal more readily patterns and different ways to cut
what are flecture lines
slide easily for joint movement causing deep creases Dermal folds at or near joints, where our skin bends
Dermis tightly secured to deeper structures at those spots, allowing some places to move
Skin cannot move unless in certain places
Visible on hands, wrists, fingers, soles, toes
what are striae
Silvery-white scars from dermal markings
“Stretch marks”
Extreme stretching causes dermal tears usually it’s just a folding
what is a blister
Fluid-filled pocket that separtes epidermal and dermal layers
From acute, short-term trauma eventually goes back to being it self
Fluid-filled pocket that separate
what are examples of skin markings
flecture lines, stria, blister
what is melanin designed as
protection
how many forms of melanin are there
2
what are the forms of melanin
reddish-yellow to brownish-black
what is color difference of melanin due to
amount and form
where is melanin produced
melanocytes
how much melanin and melanocytes are in people
the same number of melanocytes different amount of melanin
what does the melanin do
Migrates to keratinocytes to form “pigment shields” for nuclei
what are examples of local accumulation of melanin
Freckles and pigmented moles
what stimulates melanin production
sun exposure
what is another name for sunspots
tinea versicolor
what causes sunspots
fungal infection
are sunspots related to melanin
no
carotene
all humans have a certain amount, some groups have a higher amount
what color is carotene
yellow-orange pigment
where is carotene located
palms and soles
where is carotene accumulated
in stratum corneum and hypodermis
what can carotene be converted to
to vitamin A for vision and epidermal health
what group has a yellow tinge and what contributes to it
some aisans have a yellow tinge from carotene and melanin variations
hemoglobin
pinkish hue of fair skin
what is hair
Dead keratinized cells of hard keratin
More durable than soft keratin of skin hair covers most of our skin, but some areas have no hair
what areas do not have hair
palms, soles, lips, nipples, portions of external genitalia
functions of hair
Warn of insects on skin
Physical trauma
Heat loss
Sunlight
hair pigments
Melanins (yellow, rust, brown, black); trichosiderin in red hair
Gray/white hair: decreased melanin production, increased air bubbles in shaft
are hair follicles living
hair is dead the follicle is alive
where do hair follicles extend from
Extend from epidermal surface to dermis
how many layers are apart of hair follicles
Two-layered wall - part dermis, part epidermis
what is the hair bulb
expanded deep end
sensory nerve endings
hair follicle receptor
hair matrix
hair follicle receptor
root hair plexus
sensory nerve endings
touch receptors
hair matrix
Actively dividing area hair grows from the roots on up
Arrector Pili
Smooth muscle attached to follicle involuntary
Responsible for “goosebumps”
hair papilla
Dermal tissue - blood supply
