Skin (MTM) Flashcards
What are the five layers of the skin, from the most superficial layer to the deepest?
Stratum:
Corneum Lucidium Granulosum Spinosum Basale
In which layer of the skin are the proliferating cells found?
Stratum Basale
What is the nail plate composed of?
Several layers of keratin.
What is the nail bed?
- The skin beneath the nail plate.
- Composed of the deeper dermis and the epidermis.
What is a sebaceous gland?
A gland in the skin which secretes sebum onto the hair follicles to lubricate the skin.
What is an apocrine sweat gland?
- Usually associated with hair follicles.
- Continuously secrete fatty sweat into the gland tubules.
- Tubule wall can contract to expel the fatty sweat onto the hair follicle.
- Inactive before puberty.
How does an eccrine gland differ from an apocrine gland?
- Excrete sweat directly onto the surface of the skin.
- Smaller than apocrine sweat glands.
- Secretes less sweat than apocrine sweat glands.
What is a malignant melanoma? Which population is most at risk and why?
- A cancer that develops from melanocytes.
- People with lighter skin are more at risk as they have less melanin to absorb UV light, so their nuclei are more exposed.
What is the name of the cells in all layers except for the stratum basale?
Keratinocytes.
What is the function of keratinocytes?
To store and produce keratin.
What is between the epidermis and dermis?
The basal lamina.
What are dermal papillae?
Projections of the dermis into the epidermis that increase the strength of their connection.
What are the names of the cells found in the stratum basale?
Basal cells
Merkel Cells
Melanocytes
What are basal cells and what is their function?
Basal cells are stem cells and precursors to keratinocytes.
What are Merkel cells and what is their function?
Merkel cells are sensory organs that are responsible for perception of touch.
What are melanocytes and what is their function?
- Melanocytes produce the pigment melanin.
- Melanin protects cells of the epidermis from UV radiation.
- Melanin gives skin and hair its colour.
What gives the stratum spinosum its spiny appearance?
The protruding cell processes that join the cells via desmosomes.
What is the function of desmosomes? How do they differ form hemidesmosomes?
- Desmosomes are a form of adhering junction that do not form a continuous band.
- Their function is to rivet cells together.
- Hemidesmosomes attach cells to the extracellular matrix, whereas desmosomes attach cells to cells.
Which cell is found among the keratinocytes in the stratum spinosum?
Langerhans cells
What is the function of Langerhans cells?
- Langerhans cells are macrophages.
- Engulf bacteria, foreign particles and damaged cells.
Where does keratin synthesis begin?
In the stratum spinosum.
What causes keratinocytes to be pushed upwards in the epiderims?
The production of more keratinocytes in the stratum basale.
What gives the stratum granulosum its granular appearance?
- Production of keratohyalin by keratinocytes.
- Keratohyalin accumulates as granules within keratinocytes.
What are the differences in the keratinocytes between the stratum granulosum and the stratum spinosum?
Keratinocytes in the stratum granulosum compared to those in the strautm spinosum:
- Are flatter
- Have thicker cell membranes
- Generate more keratin and keratohyalin.
