Epidermis Flashcards
What are the two main layers of the skin?
Epidermis and dermis
The epidermis is the superficial layer, while the dermis lies deep to it.
What type of tissue makes up the epidermis?
Stratified epithelium tissue
The epidermis is specifically composed of stratified squamous epithelium.
What is the deepest layer of the skin called?
Subcutaneous layer
This layer consists of loose connective tissue and adipose tissue.
List the layers of the epidermis.
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
These layers are arranged in strata.
What anchors the epidermis to the dermis?
Basement membrane
This membrane provides structural support between the two layers.
Do the epidermis contain blood vessels?
No
The cells of the stratum basale are nourished by blood vessels in the dermis.
What is the most superficial layer of the epidermis?
Stratum corneum
It consists of hardened cells filled with keratin.
What is keratin and where is it secreted?
A protein secreted by keratinocytes
Keratinocytes are located in the deep layers of the epidermis.
Where is the stratum lucidum found?
Only in the palms of the hands and soles of the feet
This layer provides added thickness.
What happens to the cells in the stratum granulosum?
They lose their nuclei
These cells remain active and secrete keratin.
What are prickle cells and where are they found?
Cells in the stratum spinosum with small radiating processes
These processes connect with other cells.
What is the role of the stratum basale?
Contains epidermal stem cells that divide
This layer is where basal cell cancer can develop.
What is psoriasis?
An abnormality of keratinocytes
It involves rapid division and migration of keratinocytes, leading to flaky, silvery scales.
Fill in the blank: The stratum basale is the _______ layer of the epidermis.
Deepest
It is also where new cells are generated.
What are keratinocytes?
Cells located in the epidermis responsible for producing keratin
Keratin is a protein that helps protect the skin.
What is psoriasis?
An abnormality of keratinocytes characterized by rapid division and migration
This condition leads to flaky, silvery scales on the skin.
Which areas of the body are commonly affected by psoriasis?
Knees, elbows, and scalp
These areas often show the characteristic flaky scales.
What are corns and calluses?
Thickened areas of skin formed in response to friction
They are protective responses of the epidermis.
What is the function of melanocytes?
To produce the pigment melanin that gives skin its color
Melanocytes are located in the deepest portion of the epidermis.
Where are melanocytes located?
In the deepest layer of the epidermis and superficial dermis
They are crucial for skin pigmentation.
What triggers melanocytes to produce more melanin?
Ultraviolet radiation
This leads to a darker skin color.
What type of UV radiation do melanocytes respond to?
UVB radiation (approximately 320 nm wavelength)
This type of radiation stimulates melanin production.
What is malignant melanoma?
A condition that can develop in melanocytes
It is a serious form of skin cancer.
What is vitamin D also known as?
Cholecalciferol
It is synthesized in the skin when exposed to UV radiation.
How is vitamin D synthesized in the body?
A precursor molecule absorbs ultraviolet radiation, then travels to the liver and kidney for conversion
This process leads to the active form of vitamin D.
What is the primary function of vitamin D?
To help the body absorb calcium
It also aids in calcium transport in the intestines.
List the layers of the epidermis.
- Stratum corneum
- Stratum lucidum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
These layers have distinct functions and characteristics.
What are lamellar granules?
Structures found in the stratum granulosum of the epidermis
They play a role in water retention and skin barrier function.
What type of cells are found in the stratum basale?
- Keratinocytes
- Merkel cells
Merkel cells are involved in the sensation of touch.
