Skin AR Flashcards
What are the functions of the skin?
Protection, thermoregulation, sensation, secretion of protective lipids
Which cells in the skin produce keratin?
Keratinocytes (mostly cuboidal/polyhedral)
Give the 4 layers of the epidermis
Stratum basale = basal layer Stratum spinosum = prickle cell layer Stratum granulosum = granular layer Stratum corneum = keratin layer
Give the 4 layers of the epidermis
Stratum basale = basal layer Stratum spinosum = prickle cell layer Stratum granulosum = granular layer Stratum corneum = keratin layer
Where do blisters/abrasions commonly occur?
At the dermal/epidermal interface
What is the role of Merkel cells?
Merkel cells form synapses with nerve fibers in the dermis to convey information about fine touch
In which layer of the epidermis would you find mitotic cells?
Basal layer
Describe dermal papillae?
Dermal papillae are made at the wavy boundary between the dermis and epidermis
People with darker skin have the same number of melanocytes but they just produce more melanin. True/false?
True
Where are fibroblasts found?
The dermis but not the epidermis
Where would you find Meissner’s corpuscles?
Mainly around the dermal papillae
What does a Pacinian corpuscle detect?
Pressure and vibration
Where would you find a pacinian corpuscle?
In the deep dermis/subcutaneous fat
Where are melanocytes derived from?
Neural crest cells
Where is melanin transferred to?
keratinocytes of basal and prickle cell layers
Which cell is being described? Pale cytoplasm with an irregular shaped nucleus. They recognise antigens.
Langerhan’s cells
Where are sebaceous glands particularly abundant?
Face, scalp, ears, nostrils, vulva and around the anus
Where are sebaceous glands absent?
Soles & palms
What can be found at the dermis?
Hair roots, poleaxe of blood vessels, sensory transducers and nerve endings
What ducts occur in the breast?
Lactiferous ducts (stratified cuboidal epithelium)
Which hormones cause the breast to enter a proliferative phase in the first trimester?
Oestrogen, growth hormone and cortisol
How many opening are there arranged around the nipple and what epithelium surrounds them?
12-20 rings lined by keratinised, stratified, squamous epithelium. (Plugged by keratin in a non-lactating breast)
Describe the changes to the breast in pregnancy
The ducts divide and secretory alveoli develop (columnar surrounded by myoepithelial cells) Alveoli cells mature & secretory material builds up. Storm becomes depleted of adipose tissue
Describe the changes to the breast in pregnancy
The ducts divide and secretory alveoli develop (columnar surrounded by myoepithelial cells) Alveoli cells mature & secretory material builds up. Storm becomes depleted of adipose tissue
What percentage of the epidermis is made up of keratinocytes
90-95%
How are cells of the stratum basale layer attached to the basement membrane
Hemidesmosomes
Where does the dermis develop?
Mesoderm
Describe the papillary dermis
Loose meshwork of thin, poorly organised type 3 collagen, some type 1 and a delicate network of elastic fibres.
What do fibroblasts in the dermis produce?
collagen, elastic tissue and ground substance
Where are apocrine glands found
They accompany hair follicles (simple coiled tubular glands)
Where has this been taken?
Non-hairy skin eg finger
What are the small arrows pointing to?
Dermal papillae
- Caused by the irregular (wavy) basal layer of the epidermis.
- Give rise to finger prints
What is the arrow pointing to?
granular layer of cells that contain keratohyaline granules (precursors of keratin).
- This is the most superficial of the living layers of the epidermis.
What are the green arrows pointing to?
Dividing cells (mitotic division) in the basal layer of the epidermis.
These cells are recognized by the pale staining of their cytoplasm and the very compact nature of their nuclear chromatin.
What is inplace to prevent the skin breaking when stretched?
Desmosomes between the cells of the spinous layer
Makes them look spiny
What is this?
Sebaceous glands
Oil glnads - sebum = lubricant & kills bacteria
Not found on the palms/soles
Ducts usually empty into a hair follicle
