Structure and function of the skin
What locations can we find apocrine sweat glands?
axillas, anogenital region, areolas, ear canal eyelids
What is another name for nails?
unguis
What is the most superficial and thinnest part of the skin?
epidermis
What is keratino-melanocyte unit?
1 melanocyte + 36 keratinocytes
What kind of cells can we find in stratum granulosum?
1-3 layers of granular cells(keratinocytes migrating from stratum spinosum)
How much surface does the skin cover of the human body?
2m^2
What is the weight of the skin?
4-5 kg
Where can we find stratum spinosum?
Above stratum basale
Where can we find eccrine sweat glands?
Almost all over the surface of skin
Wnat are the three main layers of the skin?
Epidermis, dermis, subcutaneous tissue
What function does Langerhans cells have?
Immunologic function(antigen-presenting immune cells)
What cells produce desmosomes?
Keratinocytes
What does the dermis contain?
Mechanoreceptors, hair follicles, sweat glands, sebaceous glands, blood and lymphatic vessels
What can we find inside a hair follicle?
Pappila (mainly of connective tissue and a capillary loop) Matrix (around pappila) Medulla Cortex
What are the two main parts of dermis?
Pars papillaris (thin collagen fibres) Pars reticullaris (thick collagen fibers)
Apocrine sweat glands produce smell due to
Typical smell by bacterial decomposition
Where can we find hair?
all over the body except for the palm and soles
What is function of sebum?
antimicrobial, lubricate the skin
Keratin monomers
assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal connections
Is the epidermis vascular or avascular?
avascular(no blood vessels)
What fibers are present in dermis?
collagen, elastic, reticular
What is dermis made up of?
connective tissue
Dermis is also known as?
corium
What main cells can we find in the stratum corneum?
corneocytes
What is the middle part of the skin?
dermis
What is the function of degradation enzymes?
destroy nucleus and others cytoplasmatic organels
When is the apocrine sweat glands activated?
during puberty
Where does the epidermis develop from?
embryonic neuroectodermal cells
In what locations can we find sebaceous glands?
face, capilicium, partly chest
What is tela subcutanea made up of mostly?
fat tissue
What cells are present in dermis?
fibroblasts, histiocytes, macrophages, mastocytes
What does the sebaceous gland consist of?
hair follicle and gland = pilosebaceous unit
What does keratinocytes produce?
keratin
What does the keratinocytes produce?
keratin
What substance are corneocytes filled with?
keratin
Corneocytes are a type of
keratinocyte without nucleus or other cytoplasmatic organels
What is the predominant cell type of epidermis?
keratinocytes
Which cells makes up many layers of the epidermis?
keratinocytes
What types of cells are the most of in the epidermis?
keratinocytes(90-95%)
What cells can we find in stratum basale?
keratinocytes(basal keratinocytes), melanocytes, merkel cells
What cells can we find in straum spinosum?
keratinocytes, langerhans cells
What types of cells can we find in epidermis?
keratinocytes, melanocytes, langerhans cells, merkel cells
What does granules contain?
keratohyalin
What does the lamellar bodies contain?
lipids and proteins
What kind of cells are Langerhans cells identical to?
macrophages
What are the parts of the nail?
matrix, nail plate, nail bed, eponychium, perinychium, hyponychium
What cells produce the pigment melanin?
melanocytes, they are dendritic cells
Where can we mostly find eccrine sweat glands?
mostly palms and soves
Is keratin soluble in water and in organic solvents?
no, it is extremely insoluble
How does epidermis get blood supply?
oxygen supply provided from blood vessels by difusion
What are melanosomes?
pigment granules responsible for synthesis, storage and transport of melanin
What is the function of keratohyalin?
promotes dehydration of the cell as well as aggregation and cross-linking of the keratin fibers
What is the purpose of melanin?
protection against UV radiation
What is the function of tela subcutanea?
protection against low temperature, protection against trauma, storage of energy, metabolic activity
What is the function of keratin?
protects epithelial cells from damage or stress
What is the function of extracellular matrix in dermis?
provides connection between cells and fibers
What is the function of lamellar bodies?
results into the formation of the hydrophobic lipid envelope responsible for the skin's barrier properties
What location are merkel cells most commonly found on the body?
skin of palms and soles
What is the function of sebaceous glands?
secretion of sebum
What is "desquamation"?
shedding of the outermoust layer(stratum corneum) also known as skin peeling
What is the stratum basale?
single layer of cells
What is the largest organ of the human body?
skin
Where can we find merkel cells?
stratum basale, hair follicles
What are the 5 layers of the epidermis?
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
What is the outermoust part of the epidermis?
stratum corneum
Where can we find degradation enzymes, which layer?
stratum granulosum
Where can we find the lamellar bodies?
stratum granulosum
In which layer of epidermis do we find the stem cells of epidermis?
straum basale
What part of the nervous system are the apocrine sweat glands innervated by?
sympathetic nervous system
What part of the nervous system innervates eccrine sweat glands?
sympathetic nervous system
What is the most inner layer of the skin?
tela subcutanea
Corneocytes are...
terminally differentiated keratinocytes
What is the function of eccrine sweat glands?
thermoregulatory function (secretion of sweat = water, electrolytes, urea, lactate, ammonia)
What does the apocrine sweat glands produce?
viscous secretion rich in lipids, proteins, carbohydrates, ammonia