Skin Histology and Pathology Flashcards
What are the extentions of dermis that lie between the rete ridges called?
Dermal papilla
Who has more melanocytes, black people or caucasians?
They have the same number, however black people produce more melanin
Are Meissner or Merkel sensory receptors located in the epidermis?
Merkel
How long it take for a keratinocyte to replicate and eventually be sloughed off the epidermis?
60 days
What is the major difference between healing by primary intention and healing by secondary intention?
In primary intention, the edges of the epidermis are opposed easing the healing process
What are the three phases of healing in healing by primary intention?
Inflammation
Proliferation
Maturation
What are keloid scars due to?
Excessive collagen formation
Is there pain in full thickness burns?
No, due to loss of pain receptors
What is characteristic of the stratum spinosum?
Intercellular bridges
How long does it take for the mature scar to form in healing by primary intention?
6-8 weeks
Where the vascular plexi of the skin located?
The papillary plexus is located in the dermis at the border of the epidermis
The cutaneous plexus is located in the hyperdermis, at its border with the dermis
Where in the skin are sweat follicle located?
In the dermis
Where in the skin are hair follicles located?
Base of dermis or subcutaneous tissue
What are tonal fibrils?
Cytokeratin in the cytoplasm of stratun spinosum cells that insert into dermosomal junctions
Where is melanin located within keratinocytes?
External to the nucleus to protect if from UV radiation
How do you identify cells of the stratum granulosum?
By the presence of purple granules within their cytoplasm
What are the two layers of the dermis and how do they differ from each other?
Papillary layer with fine collagen bundles and lots of elastin (more superficial)
Reticular layer with deeper, thicker and more course collagen bundles. Immune cells are highly prevalent
What is the function of Merkel cells?
These are neuroendocrine cells that secrete humours that function in a paracrine manner. They are involved in the sensation
What tissue are adnexal tumours derived from?
Sweat glands
Hair follicles
Sebaceous glands
What are the layers of the epidermis, from deep to superficial?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum corneum
Describe the appearance of sebaceous gland cells
Foamy due to their high lipid content
How do the hair follicles of the scalp differ from the rest of the body?
They are deeper
Where are apocrine sweat gland located?
Groin
Axilla
