Chapter 5 Stratum of Epidermis & Dermis + Functions Flashcards
Skin
Integument
Integument consists of two distinct regions. What are they?
Epidermis
Dermis
What is the epidermis?
Superficial region (epithelial tissue)
What is the dermis?
Underlies the epidermis (mostly fibrous connective tissue)
Deep to the epidermis and dermis is the …?
Hypodermis (superficial fascia)
Hypodermis is the ____ layer deep to the skin.
subcutaneous
True or false: The hypodermis is part of the skin.
False.
The hypodermis is NOT part of the skin but shares some functions.
What is the hypodermis made of?
Mostly adipose tissue that absorbs shock and insulates
What is the function of the hypodermis?
Anchors skin to underlying structures - mostly muscles
What are the two structures related to the follicles which controls and lubricates the hair?
Arrector pili muscles
Sebaceous glands associated with hair follicles
The epidermis is made up of …
keratinized stratified squamous epithelium
What are the 4 or 5 distinct layers of the epidermis?
Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (only in thick skin) Stratum corneum
What are the four cell types of the epidermis?
Keratinocytes
Malanocytes
Dendritic cells
Tactile cells
What is the specific name for Dendritic cells?
Langerhans cells
What is the specific name for Tactile cells?
Merkel cells
What is the deepest epidermal layer?
Stratum basale
What is the second-deepest epidermal layer?
Stratum spinosum
What is the third epidermal layer from the bottom?
Stratum granulosum
What is the most superficial epidermal layer?
Stratum corneum
List the epidermal layers in order from most superficial to deepest.
Stratum corneum Stratum lucidum (only in thick skin) Stratum granulosum Stratum spinosum Stratum basale
What are the cells of the epidermis?
Keratinocytes
Melanocytes
Dendritic (langerhans) cells
Tactile (merkel) cells
Cell of the epidermis which produce fibrous keratin, makes up most cells of the epidermis, and is tightly connected by desmosomes
Keratinocytes
Keratinocytes produce fibrous ____, makes up most cells of the ____, and is tightly connected by ____.
keratin, epidermis, desmosomes
Cell of the epidermis which is 10-25% of cells in deepest epidermis, produces the pigment melanin – packaged into melanosomes.
Melanocytes
What do melanosomes do?
Protect apical surface of keratinocyte nucleus from UV damage.
Melanocytes are 10-25% of cells in ___ epidermis and produces the pigment ___ – packaged into ___.
deepest, melanin, melanosomes
Cell of the epidermis which are macrophages - key activators of immune system.
Dendritic (langerhans) cells
Dendritic (langerhans) cells which are ____ - key activators of the immune system.
macrophages
Cell of the epidermis which acts as the sensory touch receptors.
Tactile (merkel) cells
Tactile (merkel) cells act as the ___ ___ ___.
Sensory touch receptors
What are the 4 or 5 distinct layers of the epidermis?
Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (only in thick skin) Stratum corneum
What is the deepest epidermal layer?
Stratum basale (basal layer)
What is another name for stratum basale?
Stratum germinativum
The stratum basale is firmly attached to the ___.
dermis
The stratum basale has a single row of __ __.
stem cells.
The stem cells in the stratum basale are actively ___ and produces two __ __.
Mitotic, daughter cells
One of the two daughter cells journeys from basal layer to surface which takes - days and __ as it moves toward surface.
25-45, dies
The other cell remains in the __ __ of the stem cell.
Stratum basale
Melanocytes compose __ -__ % of the stratum basale.
10-25 %
What is the only layer that is vascularized?
The dermis
How does the epidermis receive nourishment?
Nutrients diffuse through the tissue fluid from blood vessels to dermis.
What is the layer just beneath the stratum corneum which is only found in thick skin?
Stratum lucidum
What epidermal layer is the deepest, with one row of actively mitotic stem cells; some newly formed cells become part of the more superficial layers.
Stratum basale
The stratum basale is the deepest epidermal layer, with one row of actively __ __ __; some newly formed cells become part of the more superficial layers.
mitotic stem cells
Which epidermal layer has several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin.
Stratum spinosum
What is a nickname for stratum spinosum?
Prickly layer
The stratum spinosum has several layers of ___ unified by ___. Cells contain thick bundles of ___ ___ made of pre-keratin.
keratinocytes, desmosomes, intermediate filaments
The stratum spinosum is abundant in ____ and __ __.
melanosomes, dendritic cells
Which epidermal layer is thin, (consisting of four to six layers), and is the layer in which keratinocyte appearances change drastically, and the process of keratinization begins.
Stratum granulosum
What is keratinization?
When cells fill with the protein keratin
How do the keratinocyte cells’ appearance change?
- Cells flatten
- Nuclei and organelles disintegrate
- Keratinization begins
- Cells accumulate lamellar granules
During keratinization, cells accumulate ____ ___, which help form keratin in the upper layers.
Keratohyaline granules
After keratinization, cells accumulate __ __.
Lamellar granules
Lamellar granules’ water resistant glycolipid slows __ __.
Water loss
Above the stratum granulosum, the epidermal cells are too far from __ __ and the glycolipids coating their external surfaces cut them off from nutrients, so they die.
dermal capillaries
Which layer of the epidermis that is typically five layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules (releases lipids) and keratohyaline granules.
Stratum granulosum
The stratum granulosum is typically five layers of __ __, organelles ___; cytoplam full of __ __ (releases lipids) and keratohyaline granules.
flattened cells, deteriorating, lamellar granules
In the stratum granulosum, after cells flatten, and thier nuclei and organelles begin to disintegrate, what two types of granules do keratinocyte cells accumulate?
keratohyaline granules
lamellar granules
What do keratohyaline granules do?
Help to form keratin in the upper layers.
What do lamellar granules do?
Help to toughen up the outer strata by creating an epidermal water barrier through the spewing of glycolipids into the extracellular space which thickens the cell membrane.
What epidermal layer is found only in thick skin, is a thin, translucent band superficial to the stratum granulosum, and is a few rows of flat, dead keratinocytes called tonofiliments.
Stratum lucidum
Which epidermal layer is made up of 20-30 rows of dead, flat, anucleate keratinized membranous sacs?
Stratum corneum
The stratum corneum is made up of 20-30 rows of __, __, anucleate keratinized __ __.
dead, flat, membranous sacs.
The stratum corneum makes up __ __ of epidermal thickness.
Three quarters
Though the stratum corneum layer is dead, its cells have several functions. What are they?
- Protect deeper cells from environment and water loss
- Protect from abrasion and penetration
- Barrier against biological, chemical, and physical assaults
Which layer of the epidermis is the most superficial layer and is 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin. Glycolipids in extracellular space.
Stratum corneum
The stratum corneum is the most superficial layer; how many layers of dead cell layers is it made of?
20-30 layers
The dead skin layers of the stratum corneum are essentially __ __ __ filled with __.
flat membranous sacs, keratin
Most epidermal cells are …?
Keratinocytes
Tightly connected together by desmosomes, keratinocytes arise from what cell layer?
The deepest - stratum basale
What are the spider shaped cells that synthesize pigment, and what layer are they found?
melanocytes, stratum basale
As melanin is made, it accumulates in membrane-bound granules called ____ that motor proteins move along actin filaments to the ends of melanocytes spidery arms.
Melanosomes
After being transferred to nearby keratinocytes, the ___ ___ accumulate on the superficial side of the keratinoctye nucleus, forming a pigment shield that protects the nucleus from the damaging uv.
melanin granules
What is the second major skin region?
Dermis
What tissue type is the dermis made up of?
Strong, flexible connective tissue
What cells are found in the dermis?
Fibroblasts
Macrophages
and occasionally mast cells and WBC
Fibers in matrix bind the body together, much like a ___ in making leather.
“hide”
The dermis has a rich supply of ___, ___, and ___.
Nerve fibers
Blood vessels
Lymphatic vessels
Epidermal hair follicles, oil and sweat glands reside in the ___.
Dermis
What are the two layers of the dermis?
Papillary
Reticular
Which is the most superficial layer of the dermis?
Papillary
Dermis layer which is made up of areolar connective tissue with collagen and elastic fibers and blood vessels.
Papillary layer
The papillary layer is made up of what type of connective tissue?
Areolar
Within the papillary areolar connective tissue, there are __ and __, and __. This loose tissue allows ___ to patrol for microorganisms.
Collagen and elastic fibers
Blood vessels
phagocytes
What are dermal papillae?
Superficial peglike projections which indent the underside of the overlying epidermis.
Most dermal papillae contain ___ ___, but only some contain ___ or ___.
Capillary loops
Meissner’s corpuscles
Free nerve endings
What are meissner’s corpuscles?
Touch receptors
What are free nerve endings?
Pain receptors
In thick skin, where do dermal papillae lie?
They lie atop atop dermal ridges.
Dermal ridges cause the overlying epidermis to form
Epidermal ridges
Collectively, these ridges are called …?
Friction ridges
What do friction ridges do?
- Enhance gripping ability
- Contribute to sense of touch
- Pattern is fingerprints
Which dermal layer is deeper?
Reticular layer
The reticular layer makes up what percentage of dermal thickness?
80% thickness
The elastic fibers in the reticular layer provide __-__ properties.
stretch-recoil
The reticular layer has thick bundles of ___ in its extrecellular matrix.
Collagen
What are the collagen fibers’ function within the reticular layer?
- Provide strength and resiliency
- Bind water
- Cleavage lines
Why do cleavage lines form?
Because most collagen fibers are parallel to skin surface, thus becoming externally visible
Why are cleavage lines important?
- Important to surgeons
- Incisions parallel to cleavage lines gape less and heal more readily
What is the difference between cleavage lines and flexure lines?
Cleavage lines are all over the body.
Flexure lines are at or near joints only
What are flexure lines?
Dermal folds at or near joints
Why do flexure lines form?
Because the dermis is tightly secure to deeper structure, skin cannot slide easily for joint movement causing deep creases.
Where are flexure lines visible?
On hands, wrists, fingers, soles, toes
What are striae?
- silvery-white scars from extreme stretching causing dermal tears.
- a.k.a stretch marks
What are blisters?
Fluid-filled pocket that separate epidermal and dermal layers from acute, short-term trauma
What substance is produced in melanocytes, and migrates to keratinocytes to from “pigment sheilds”?
Melanin
True or false: The same relative number of melanin is found in all races of people
True. Color differences due only to amount and form.
Sunspots are not related to melanin but are instead a
Fungal infection
Term for sunspot
Tinea versicolor
Aside from melanin, what other two pigments contribute to skin color?
Carotene
Hemoglobin
Which pigment is the only pigment made in the skin?
Melanin
Which pigment is most obvious in palms and soles?
Carotene
Which pigment accumulates in the stratum corneum and hypodermis?
Carotene
Which pigment can be converted to vitamin A for vision and epidermal health?
Carotene
Which pigment is related to the pinkish hue of fair skin?
Hemoglobin
The yellowish tinge of some asians involve which pigments?
Carotene and melanin
Blue skin color - low oxygenation of hemoglobin
Cyanosis
Fever, hypertension, imflammation, allergy
Erythemia (redness)
Anemia, low blood pressure, fear, anger
Pallor (blanching)
Liver disorder
Jaundice (yellow cast)
Inadequate steroid hormones in Addison’s disease
Bronzing
Clotted blood beneath the skin
Bruises
Appendages/Derivatives of the epidermis are:
- Hair and hair follicles
- Nails (this will be on the test)
- Sweat glands
- Sebaceous (oil) glands
What is the smooth muscle attached to hair follicles that are responsible for “goose bumps”?
Arrector pili muscle
What is pale, fine body hair of children and adult females?
Vellus hair
What is the course, long hair of eyebrows, scalp, and at puberty, appear in the axillary and pubic regions, and on the face and neck of males?
Terminal hair
What is the term meaning hair thinning in both sexes after age of 40?
Alopecia
Scalelike modifications of the epidermis?
Nails
