Histology of Skin Flashcards
The skin is made up of two main layers, the _ and _
The skin is made up of two main layers, the epidermis and dermis
Most of the cells in the epidermis are _ ; they are produced in the basal layer and then go through various stages of differentiation until they shed off the surface of the skin at the stratum corneum
Most of the cells in the epidermis are keratinocytes ; they are produced in the basal layer and then go through various stages of differentiation until they shed off the surface of the skin at the stratum corneum
Name the layers of the epidermis, superficial to deep
“Come Let’s Get Sun Burned”
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
The _ layer serves as the main functional barrier of the skin
The stratum corneum layer serves as the main functional barrier of the skin
The stratum corneum is mostly composed of _
The stratum corneum is mostly composed of 10-30 layers of dead keratinocytes which lack nuclei and contain abundant keratin filaments
The _ layer is only found in the thick layer of the palms and soles
The stratum lucidum layer is only found in the thick layer of the palms and soles
The stratum lucidum consists of 3-5 layers of _
The stratum lucidum consists of 3-5 layers of dead keratinocytes
The dead keratinocytes in the stratum lucidum layer contain a protein called _ that later gets converted into keratin in the stratum corneum
The dead keratinocytes in the stratum lucidum layer contain a protein called eleiden that later gets converted into keratin in the stratum corneum
The stratum granulosum is a relatively thin layer in the epidermis that is also known as the _ layer
The stratum granulosum is a relatively thin layer in the epidermis that is also known as the granular layer
The stratum granulosum layer features _ and _
The stratum granulosum layer features keratohyalin granules and (secrete) lamellar bodies
The keratohyalin granules in the stratum granulosum are filled with proteins that lead to _
The keratohyalin granules in the stratum granulosum are filled with proteins that lead to aggregation and cross-linking of keratin filaments
The lamellar bodies that are secreted by the stratum granulosum are composed of lipids and proteins that help to form the _
The lamellar bodies that are secreted by the stratum granulosum are composed of lipids and proteins that help to form the water-tight hydrophobic barrier of the skin
How do we characterize the stratum spinosum?
The stratum spinosum consists of several layers of cells with large nuclei
* These cells have begun keratinization (process of producing keratin and creating epidermal barrier)
The stratum basale is the deepest layer of the epidermis; therefore we find a single layer of cells with many _
The stratum basale is the deepest layer of the epidermis; therefore we find a single layer of cells with many keratinocyte stem cells –> these will divide and migrate to form the stratum spinosum
Besides keratinocyte stem cells, what else do we find in the stratum basale layer?
Stratum basale:
1. keratinocyte stem cells
2. melanocytes
3. merkel cells
Melanocytes produce _ ; which is stored in organelles called _ and can be transported to keratinocytes in close proximity
Melanocytes produce melanin ; which is stored in organelles called melanosomes and can be transported to keratinocytes in close proximity
Merkel cells are _
Merkel cells are sensory cells/ fine-touch receptors
* Found in high quantities in finger tips
Langerhan cells are special _ cells found in _
Langerhan cells are special dendritic cells found in all layers of the epidermis
* They are the primary antigen-presenting cells of the skin
We find birbeck granules in _ cells
We find birbeck granules in langerhans cells
* Classic tennis-raquet shape
* Very small, only seen on electron microscopy
What is vitiligo?
Vitiligo is a skin condition in which you lose pigmentation over time; it is autoimmune; destruction of melanocytes
When we are talking about thin skin, we are talking about skin that has _ layers
When we are talking about thin skin, we are talking about skin that has 4 layers
* Lacking the stratum lucidum
Where is thick skin found and what does it lack?
Thick skin lacks hair, sebacceous glands, apocrine sweat glands
* Found in the soles of the feet and palms of the hand
* Able to withstand high shear and frictional stress
The two primary layers of the dermis are _ and _
The two primary layers of the dermis are papillary dermis and reticular dermis
The _ layer is the layer of the dermis that lies directly below the epidermis
The papillary dermis is the layer of the dermis that lies directly below the epidermis
The papillary layer is named for its finger-like projections (papillae) that extend to form an interdigitating interface with the underside of the epidermis; these projections contain _ and _
The papillary layer is named for its finger-like projections (papillae) that extend to form an interdigitating interface with the underside of the epidermis; these projections contain capillaries andMeissner corpuscles (quick changes to light touch)
The reticular dermis is composed of _ and is characterized by its strength and elasticity
The reticular dermis is composed of dense irregular connective tissue and is characterized by its strength and elasticity
* Thicker than the papillary dermis
* Collagen, elastic, reticular fibers
* Contains hair follicles, sweat glands, sebaceous glands, Pacinian, Ruffini
_ are sensory receptors that respond to quick changes in pressure and vibration
Pacinian corpuscles are sensory receptors that respond to quick changes in pressure and vibration (high frequency)
* They are in thin and thick skin
_ are slowly adapting sensory receptors that respond to skin stretch and sustained pressure
Ruffini endings are slowly adapting sensory receptors that respond to skin stretch and sustained pressure
_ are sensory receptors that adapt quickly to light touch and low-frequency vibration
Meissner corpuscles are sensory receptors that adapt quickly to light touch and low-frequency vibration
Merkel discs respond slowly to _
Merkel discs respond slowly to light touch and pressure
A pilosebaceous unit or apparatus includes _, _, and _
A pilosebaceous unit or apparatus includes hair follicle, associated arrector pili muscle, and sebaceous gland
The _ is responsible for causing hair to stand up when the muscle contracts, which is part of feeling goosebumps
The arrector pili muscle is responsible for causing hair to stand up when the muscle contracts, which is part of feeling goosebumps
Sebaceous glands produce _ which serves to _
Sebaceous glands produce sebum (an oily, waxy substance) which serves to lubricate skin and hair
* They are usually found in pilosebaceous units but can also be found independent from hair follicles at some sites
* For example, they might be found independently at the buccal mucosa of the lip, areolae on women, labia minora, gland penis, eyelids
Sebaceous glands typically have _ structures with numerous crops of gland tissue extending out of a central duct
Sebaceous glands typically have acinar structures with numerous crops of gland tissue extending out of a central duct
_ sweat glands produce watery sweat, that covers nearly all of the skin and is responsible for thermoregulation
Eccrine sweat glands produce watery sweat, that covers nearly all of the skin and is responsible for thermoregulation
The coiled up secretary tubule (eccrine duct) is found in the _
The coiled up secretary tubule (eccrine duct) is found in the deep dermis or hypodermis
* The duct ascends into the epidermis before emptying into a sweat pore on the skin surface
* The coil straightens up as it gets closer to the skin surface
_ sweat glands produce an oily sweat that contains pheromones
Apocrine sweat glands produce an oily sweat that contains pheromones
Apocrine sweat glands are found in the _
Apocrine sweat glands are found in the axillae and genital areas
_ glands produce an odorless substance that gets broken down by bacteria and eventually produces a characteristic odor
Apocrine glands produce an odorless substance that gets broken down by bacteria and eventually produces a characteristic odor
* Armpits and genitals
The apocrine secretory tubules are found at the _ level
The glomerulus of apocrine secretory tubules are found at the transition of the dermis to the hypodermis
(Apocrine/ Eccrine) sweat glands are the largest in size
Apocrine sweat glands are the largest in size
(Apocrine/ Eccrine) sweat glands are deeper in the skin
Eccrine sweat glands are deeper in the skin
* Eccrine are found in the hypdermis or deep into the dermis layer
* Apocrine are in the transition of dermis to hypodermis
_ glands remain inactive until stimulated by the hormonal changes that occur at puberty
Apocrine glands remain inactive until stimulated by the hormonal changes that occur at puberty
The (epidermis/ dermis) contains Merkel cells for fine-touch sensation
The epidermis contains Merkel cells for fine-touch sensation
The (epidermis/ dermis) contains Meissner corpuscles
The dermis contains Meissner corpuscles for low frequency vibration and light touch
* Located in the papillary dermis
The (dermis/ epidermis) contains Pacinian corpuscles
The dermis contains Pacinian corpuscles for fine touch, pressure, and vibration
* In the deep reticular dermis
