Histo, Higi Skin Flashcards
What is the integument system?
Skin :) that gives us a window into disease processes such as jaundice, cyanosis, measles and chicken poxes and accounts for 16% of total body weight
What is the function of our integumentary system?
protection sensory receptor role in excretion vit D metabolism regulation of blood pressure and body temperature
What is the general organization of our skin?
epidermis-> dermis->hypodermis
What is the largest sensory organ in our body?
skin
What does the skin excrete?
ammonium
Is the hypodermis part of the skin? what does it have within it?
NO
blood vessels [hence why we use hypodermic needles ;) ]
Tell me what the epidermis is derived from?
ectoderm-> stratified squamos epithelium
How often is the epidermis regenerated?
every 30 days
When do keratinocytes divide?
at night
The epidermis overlies projections of the dermis (dermal papillae) forming a series of (blank)
epidermal ridges (fingerprints)!!!!!!!
How may layers are there within the epidermis?
5 layers
What make up most of the epidermis and undergo continuous turnover?
keratinocytes
WHat is the process of turnover of keratinocytes?
cell renewal (mitosis)
differentiation (keratinization)
cell death
exfoliation
Do we only have epidermal ridges on our fingertips?
nope, we have epidermal ridges in swirls on our fingertips and we have epidermal ridges in diamonds on our back and eyelids
What are the 5 layers of the epidermis from outside in?
stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale Basement membrane :)
What do you find underneath the epidermis?
elastic and collagen fibers with capillaries and free nerve endings
What is another name for the statum basale?
germinativum
What does the stratum basale rest on?
the basement membrane (basal=basement)
What do we find in the stratum basale that undergoes continual mitosis?
keritinocytes
What do the keritinocytes of the startum basal possess?
desmosomes, hemidesmosomes, cytokeratin
Keritonocytes of the stratum basal possess cytokeratin, what is interesting about these cytokeratin?
they increase in numbers as they approach the surface
What all do you find in the stratum basale of the epidermis?
keratinocytes, desmosomes, hemidesmosomes, cytokeratin, melanocytes, Merkel’s cells
What is several layers thick and is filled with tonofibrils and desomosomes and has prickle cells with intercellular bridges, with keratinocytes in deep layers that are mitotically active and has melanocytes and langerhans cells?
startum spinosum of the epidermis
What are tonofibrils?
bundles of cytokeratin
what does this equal:
tonofibrils + desmosomes
spiny processes of the stratum spinosum
Where do we find prickle cells with intercelllular bridges?
stratum spinosum
Where do we find langerhan cells?
stratum spinosum
What are the stratum basal and stratum spinosum known as?
the malpighian layer (mitotically active layers)
What do we find within the stratum granulosum?
lamellar bodies, membrane-less keratohyalin granules, and bundles of tonofilaments (cytokeratin).
What does the stratum granulosum contain, that fuses with the PM and releases GAGs and phospholipids into the intercellular spaces.
lamellar bodies (granules)
What is the importance of lamellar bodies?
allows for sealing deep layers and water proofing.
Keratohyalin granules contain (blank) and (blank) rich proteins which bind the tonofilaments together to form keratin in the stratum granulosum
histidine, cystine
what is the first step in keratinization?
conversion of granular cells to cornified cells
What am I describing:
loss of organelles
thickened plasma membrane
bundle of tonofilaments
Keratinized cells
What is only seen in thick skin (palmar and plantar), has acidophilic cells and contains immature keratin called eleidin?
stratum lucidum
What is immature keratin called?
eleidin
What is the most superificial layer of the epiderm that is dead and platelike with enucleated keratinocytes containing mature keratin?
stratum corneum
What does the stratum corneum have within it?
keratin birefringent scleroprotein of at least 6 polypeptides and tonofilaments
and keratin
What is this:
accelerated keratinocyte mitosis in stratum basale and spinosum turnover (one week instead of 4 weeks); leads to thickening of epidermis
Psoriasis
What is the mneumonic so you can remember the layers of epidermis from superifical to deep
Cut Lab Get Some Good Beer
Corneum, lucidum, granulosum, spinosum, germanitivum, basement membrane
What are the 2 nonkeratinocytes in the epidermis?
langerhan’s cells and Merkel’s cells
Where do langerhan cells originate from?
originate in the bone marrow and are part of the MNP system
What do langerhan cells contain?
Birbeck’s granules rodlike or racket shaped
What are the antigen presenting cells of the epidermis?
langerhan cells
Since langerhan cells are APC wat do they have on their surface?
have cell surface antibody and complimnt receptors
Where do we mostly find langerhan cells in the epidermis?
mostly in the stratum spinosum
What kind of epithelium do we find langerhan cells in?
find in the oral, esophaeal, rectal and vaginal epithelium and thymus
What is thought to initiate allergic contact dermatitis reaction?
those pesky langerhan cells
Where do we find merkel cells and where are they derived from?
in the stratum basale
derived from neural crest (merkel sounds like urkle, and urkle was the nerdy guy on family matter, therefore merkel cells are nerdy “from Neural crest” hehehe)
What do merkel cells possses and where do we find them in the skin?
desmosomes, tonofilaments, sensory mechanoreceptors
Thick skin
When do merkel cells appear in development?
8-12 weeks of gestation on palmar and plantar epidermis
Merkel cells are associated with the (blank)
basal lamina
Describe a merkel cell
they sit on basal lamina and have a nerve plate with a short unmyelinated axon that pierces through basal lamina and then a long myelinated axon penetrating the dermis
the (blank) is a peripheral dendritic cell of the immune system and presents antigens to T cells in the dermis to initiate responses against foreign antigens.
langerhan cells
(blank) contribute to skin, eye, hair color and freckles.
melanins
What are patches of epidermal melanin?
freckles
What synthesizes melanins?
melanocytes
What are melanocytes derived from and where are they found and do they have desmosomes?
Neural crest (cuz nerdy people eat melons)
in stratum basale (10-25%)
no desmosomes
What is the site of melanin granule synthesis?
melanosomes
What is tyrosinase and where do we find it?
It is a UV sensitive enzyme involved in melanin synthesis
found in melanocytes
When do melanocytes develope?
8th embryonic week
Is there a difference in the number of melannocytes per unit are in dark and light skinned races? Why are there different colored people then?
NO
cuz there is different in rate of melanin synthesis, accumulation and degredation
What are the first cells to arrive in the epidermis?
melanoctyes
Where is the cell body of the melanocyte located and where does the cytoplasmic process extend?
located in stratum basale
extends to meet 36 keratinocytes forming an epidermal melanin unit
What does a melanocyte and 36 keratinocytes create?
an epidermal melanin unit
What is the fate of mature melanin granules?
mature granules move from golgi into tips of melanocytes
What do mature melanocytes do?
they inject melanin granules into keratinocytes of basale and spinosum by cytocrine secretion
Where do we find most of our melanin?
in keratinocytes rather than melanocytes cuz they injected all their melanin into keratinocytes
(blank) accumulate over the nuclei of dividing keratinocytes, protecting the DNA from damaging effects of the sun’s rays.
melanin granules
How do melanin pigments die?
they are eventually attacked and degraded by lysosomes of the keratinocyts (over a period of several days)
What is melanin function?
pigment absorbs sun rays and free radicals
What is this:
- vascular CT (collagen and elastic fibers)
- derived from mesoderm
- ateriovenous shunts for temperature regulation
Dermis
What is the superficial layer of the dermis?
papillary layer
What are the two layers of the dermis?
papillary layer and reticular layer
how to remember: dermatologists use a lot of PR
WHat do dermal papillae do and where are they found?
they interdigitate with the epidermal ridges and are found in the papillary (superifical) layer of the dermis
What all does the papillary layer of the dermis contain?
contains dermal papillae meissner's corpuscles type III collagen elastic fibers type VII anchoring fibers
What do the type VII anchoring fibers of the papillary layer do?
binds epidermis to dermis
What part of the dermis has follicles, sweat and sebacous glands?
reticular layer
What kind of connective tissue does the reticular layer have?
dense irregular CT
What kind of fibers are found within the reticular layer of the dermis?
elastic fibers and bundles of collagen fibers (mostly type I)
What kind of corpuscles are found within the reticular layer?
pacinian corpuscles (pressure receptors) and Ruffini corpuscles (temp and press receptors)
What is this:
not part of the skin, thickness varies with nutrition, activity and gender. Made up of loose CT and adipose, AKA subcutaneous fascia and has panniculus adiposus
hypodermis
WHat kind of CT does hypodermis have?
loose w/ thick panniculus adiposus
Where does the epidermis come from? where does the dermis come from?
ectoderm
mesoderm
How is the thickness of the skin determined?
by thickness of epidermis, not overall thickness
Tell me about the epidermis of thick skin: location? stratum corneum? stratum lucidum? stratum granulosum? stratum basale? dermatoglyphics?
palms and soles thicker present a few layers more merkel's cells present (fingerprints)
Tell me about the epidermis of thin skin: location? stratum corneum? stratum lucidum? stratum granulosum? stratum basale?
rest of body thinner usually absent single often discontinuous layer few merkel cells
Tell me about the dermis of thick skin: hair follicles? sebacous glands? eccriine sweat glands? meissners corpuscles? elastic fibers?
absent fewer more more fewer
Tell me about the dermis of thin skin: hair follicles? sebacous glands? eccriine sweat glands? meissners corpuscles? elastic fibers?
present (excep in glans penis, labia minor, clitoris and lips) more (ass. w/ hairs) fewer fewer more
(blan) is hairy, oily and stretchy
Thin skin
(blank) is smooth, sweaty, touchy (meisners corpscles)
thick skin
(blank) are formed by the epidermis and dermis together.
hair follicles
(blank) is comprised of a hair shaft and a hair bulb
hair follicle
Are hair follicles formed after birth?
NOOOOOO
but hair growth is cyclic
What is this:
smooth muscle
- elevates the hair and causes goose bumps depressions of the skin where the muscle attaches to the dermis
arrector pili muscles
So since hair has vascular component as well as a hair component what can we say about the origin of hair?
mesodermal (vascular component) and ectoderm (hair component)
What causes goose bumps?
arrector pili muscles
What are the three components of hair?
medulla, cortex,cuticle
Are sebacous glands always associated with hair follicles?
no just sometimes
The sebacous gland has a (blank) secretory mechnism and once the cell is released this is called sebum.
holocrine secretory mechanism
How are eccrine sweat glands arranged?
into long tubes
Where do sebacous glands empty into?
the neck of a hair follicle
(blank) are embedded in dermis over entire body other than palms and soles
sebacous glands
Where are sebacous glands most abundant?
face, forehead, and scalp
What makes hair shine, skin supple and ACNE?
holocrine gland secretion
Mature sebacous glands are present on the face by (blank) months in utero
6
(blank) is a greasy deposit covering the skin of a baby at birth
vernix caseosa
At birth, what glands become inactive and when do they reactivate?
sebacous glands
puberty
It is thought that the increase in (blank) in both females and males at puberty leads to abundant quantities of sebum which becomes infected leading to acne.
androgens
(blank) cells divide by mitosis and accumulate lipids as they move into the central part of the acinus.
basal
(blank) is the oily secretion of sebacous cells. It is released by a holocrine mechanism resulting in the destruction of the entire cell which become part of the secretion
sebum
(blank) regenerate sebum-producing cells lost during the holocrine secretory process.
basal cells
Sebum secreting cells on top of the basal cells begin to store the oily secretion within (blank)
cytoplasmic droplets
In proximity to the acinar duct, the nuclei of the sebum-secreting cells shrink and degenerated, and coalescing droplets of sebum are released into the (Blank) since the acini lack a proper lumen
short ducts
(blank) are appendages of the hair folicles. Their short ducts (lined by stratified squamos epithelium continuous with the external root sheath of the hair) open into the hair canal.
sebacous glands
Where do you find hair independent sebacous glands?
lips, areolae of the nipples, labia minora, inner surface of the prepuce
What are these;
simple coiled tubular gland with stratifed cuboidal epithelium lined ducts that respond to heat and stress
Eccrine sweat glands
What are the ducts of the eccrine sweat glands lined with?
stratified cuboidal epithelium
What do the ducts of the eccrine sweat glands do?
they modify sweat by absorbing electrolytes,excretion ions, urea and lactic acid
What is the mechanism of eccrine sweat gland secretion?
merocrine secretion with an unlimited distribution
What do eccrine sweat glands respond to?
heat and nervous stress
What is the purpose of eccrine sweat glands?
cooling/ thermoregulatory
excretion (urea, ammonia)
When do we sweat?
thermoregulation
emotional sweating
What is this:
excessive sweating
hyperhidrosis
What is the treatment of hyperhydrosis?
antiperspirants, lontophoresis, drugs, surgery for axillary glands
What do the dark cells (apical cells) of eccrine sweat glands secrete?
glycoproteins by exocytosis
What do the basal clear cells of the eccrine sweat glands secrete?
water and electrolytes into intercellular canaliculi
What are the three kinds of cells we find in the eccrine sweat glands?
apical dark cells
clear basal cells
myoepithelial cells
Where are apocrine sweat glands found?
axilla, circumanal region, and in the mons pubis
The coiled region of apocrine glands is (blank) than that of the eccrine sweat gland.
larger
Where are apocrine sweat glands located?
in dermis
Where doe the excretory ducts of the apocrine sweat glands open into?
the canal of the hair follicles
The secretory cells of the apocrine sweat gland are cuboid and associated with (blank) at their basal surface.
myoeptihelial cells
When does the secretory activity of apocrine sweat glands begin?
at puberty
What is the apocrine sweat gland secretion like?
its smelly cuz of bacteria
How do apocrine sweat glands secrete their fluid?
merocrine secretions
What is this:
include large specialized sweat glands in axilla, areola of the nipple, glands of Moll in eyelids and ceruminous (wax) glands of the ear.
Apocrine sweat gland
What are vestigial scent glands?
a type of apocrine sweat gland
What do apocrine sweat glands respond to?
hormonal influences and emotion and sensory stimuli but NOT to heat
What is the ONLY benefit of sunlight?
vit D
The effects of sun exposure are …. ?
cumulative
Cumulative average percentage of lifetime sun exposure 1-18 ? 19-40? 41- 59? 60-78?
23%
47%
74%
100%
(blank) is a sign of pathological damage to the skin
tanning
(blank) lose alignment, flatten, obtain nuclear inclusion with sun burns/tans.
keratinocytes
tans occur because of (blank) nuclear capping trying to protect DNA from UV radiation
melanosomal
During a tan/ sun burn, what do melanocytes do?
enlarge, increase in number and migrate to higher levels of epidermis
How does sunburns affect the immune system of your skin?
it decreases lengerhan’s cells capabilites and activated T suppressor networks :(
What are the dermal changes that sun burn/tans induce?
change up elastic tissue and collagen fibers, leaky vasculature, increased mast cells
What are these:
leathery texture, wrinkling, sagging, blotchy discoloration, and actinic changes
components of photo aging
What is this:
premalignant condition of thick, scaly or crusty patches of skin.
actininc keratosis
What is this:
- more common in fair-skinned people and it is associated with frequent exposed to the sun.
- some progress to squamous cell carcinoma,
- range in size from as small as a pinhead to over an inch across. They may be flat or raised on appearance.
- light or dark, tan, pink, red, a combination of these, or the same color as ones skin
actinic keratosis
How do most keratosis go away?
on their own if sun avoidance
(blank) is the most common form of cancer in the United States. Each year there are more new cases of this cancer than the combined incidence of cancers of the breast, prostate, lung and colon
Skin cancer
(blank) is the most common pre-cancer for squamos cell carcinoma
actinic keratosis
Between 40 and 50 percent of americans who live to age 65 will have either (blank) or (blank) at least once
basal cell carcinoma or squamos cell carcinoma at least once
What is the most common form of skin cancer and where does it come from and is it treatable?
basal cell carcinoma (75% of all skin cancers)
arises from stratum basale
slow growing with high cure rate w/ early DX
(blank) have signif risk of metastatic spread especially lesions larger than 1-2 cm
squamos cell carcinomas
What is this: - 20% of all skin cancers - arises from stratum spinosum - usually appears in elderly - can grow rapidly and ulcerate - high cure rate with early Dx - best documentation for risk with sun exposure
squamous cell carcinomas
What is this:
- 5% of all skin cancers
- most dangerous of three
- usually appears as dark brown or black mole like lesions
- any changes in mole appearance should be checked out
- most common sites: upper back in men and legs in women
- grows rapidly, metastasizes quickly
melanoma
One person dies of melanoma every (blank) minutes
62
(blank) is the most common form of cancer for young adults 25-29 years old and the second most for young people 15-29 years old.
melanoma
The survival rate for patients whose melanoma is detected early, before the tumor has penetrated the skin, is about (blank) percent. The survival rate falls to (blank) percent for those with advanced disease.
99
15
Melanoma accounts for less than (blank) percent of skin cancer cases, but it causes more than (blank) percent of skin cancer deaths.
five
75
One or more blistering sunburns in childhoor od adolescene more than doubles a person’s chances of developing (blank). Also your chance doubles if you’ve had more than (blank) sunburns at any age.
melanoma
5
What are the ABCDs of melanoma diagnosis?
A; assymetry
B: border irregularity
C: color-black or much darker than other moles w/ red, white or blue areas
D: diameter > 6 millimeters
What is the single most reliable indicator of the risk of metastasis for melanoma?
depth!
