Histology Integument Flashcards
What type of epithelium can be found in the epidermis?
stratified squamous epithelium
What are the 2 layer of the dermis?
- papillary layer
- reticular layer
What are the components of the papillary layer of the dermis?
small blood vessels, lymph & nerves
fine collagen and elastic fibers
What are the components of the reticular layer of the skin?
vasular plexus
lymph, nerves
compact collagen fibers and thick elastic fibers
List the layers of the epidermis from bottom to top?
S. basale (germinal)
S. spinosum (desmosomes)
S. granulosum (keratohyaline granules)
Stratum lucidium
S. corneum (squames)
What are the distinct cell types found in the epidermis?
1) Keratinocyte,
2) Melanocyte,
3) Langerhans cell,
4) Merkel cell
Label the special cells in the image.
What type of cells are in the stratum basale? (cuboidal, squamous, or columnar?
cuboidal cells
Which layer of the epidermis contains basophilic cells that synthesize keratin?
stratum basale
What layer of the epidermis are melanocytes and Merkel cells contained?
stratum basale
What are the 2 main functions of keratinocytes?
to produce keratin and contain melanin
as a water barrier
How often do keratinocytes renew themselves?
every 15-30s
What are desmosomes? Where are they located in the layers of the epidermis?
Desmosomes are a junction complex for cell anchorage
Stratum spinosum
What does the term “spinosum” in stratum spinosum come from?
Because of the many FALSE cytoplasmic extensions (hence “spinosum”)
Where are Langerhans cells found in the epidermis?
In the stratum spinosum
The “prickle cell layer” of the epidermis?
stratum spinosum
What is the purpose of keratin filaments?
crucial for maintaining structural integrity stability, and continuity of the epithelium
What are the keratin filaments of the keratinocytes cross linked bye?
filaggrin (keratohyalin granules)
Keratin filaments form large aggregates within the keratinocyte called what?
tonofilaments
What substance are the keratohyaline granules (filaggrin) rich in?
sulfated amino acids (cysteine)
What are keratosomes? What layer of the epidermis are they in?
Membranous lamellar bodies/vesicles/ granules
Found in the S. granulosum
Are keratohyalin granules eosinophilic or basophilic?
basophilic
Another name for keratosomes?
Olland bodies?
What is the purpose of keratosomes?
Act as a waterproofing cement
What does the stratum granulosum consist of?
glycophospholipids
What areas of the body is the stratum lucidum more prominent in?
thick skin only (palms and soles only)
The cells of the S. lucidum are described as flattened cells with desmosomes. Do these flattened cells contain a nucleus?
They are non-nucleated.
T/F. The stratum corneum contains layers of living cells?
False; dead and dying cells
About how many layers thick is the stratum corneum in thick skin? Thin skin?
15-20 layers thick
3-5 layers in thin skin
Understand this slide.
Understand slide
What are hemidesmosomes? What do they do?
stud-like structures found in keratinocytes that
act in the signal transduction process via a integrin and regulate cellular activities such as gene expression and cell proliferation and differentiation
Difference between orthokeratinization and parakeratinization?
Orthokeratinization process by which cells in S. corneum are flat and lose nuclei and cytoplasmic organelles
In parakeratinization the cells keep nuclei, considered incomplete keratinization
What are some conditions parakeratinization may be observed in?
- actinic keratosis
- psoriasis
What layer of the epidermis are Langerhan’s cells located?
in stratum spinosum
What is the embryonic origin of Merkel’s cells?
the neural crest
Describe the color of the melanocyte cells?
Pale cells with brown granules in them.