Skin
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- Created by: merlinstudies
- Created on: 02-01-23 15:16
What are the three layers of the skin?
Epidermis—superficial region
Dermis—middle region
Hypodermis (superficial fascia)—deepest region
Dermis—middle region
Hypodermis (superficial fascia)—deepest region
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What are the functions of the skin?
Protection from pathogens
Waterproof
Temperature regulation
Absorption
Waterproof
Temperature regulation
Absorption
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What cells help with immunity function?
Where are these cells found?
Where are these cells found?
Langerhans cells
stratum spinosum
stratum spinosum
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What are the layers of the epidermis?
Stratum corneum
Stratum granulosum
Stratum spinosum
Stratum basale
Stratum granulosum
Stratum spinosum
Stratum basale
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What is the structure of the epidermis?
Keratinized stratified squamous epithelium
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What are the cells of the epidermis and what do they do?
Keratinocytes—produce fibrous protein keratin
Melanocytes
10–25% of cells in lower epidermis
Produce the pigment melanin
Epidermal dendritic (Langerhans) cells—macrophages that help activate immune system
Tactile (Merkel) cells—touch receptors
Melanocytes
10–25% of cells in lower epidermis
Produce the pigment melanin
Epidermal dendritic (Langerhans) cells—macrophages that help activate immune system
Tactile (Merkel) cells—touch receptors
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Describe the structure of the stratum corneum
The outermost layer of the epidermis
Most superficial layer
20-30 layers dead skin cells
Most superficial layer
20-30 layers dead skin cells
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What is the role of keratin?
A protein which gives strength to hir and nails and strengthens the stratus corneum
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What is the role of a corneocyte?
keratinocytes mature into corneocytes in the epidermis
Each corneocyte is surrounded by a protein envelope filled with keratin & layers of lipid bilayers
This barrier prevents physical injury and also helps to hold 3x its weight in water
Each corneocyte is surrounded by a protein envelope filled with keratin & layers of lipid bilayers
This barrier prevents physical injury and also helps to hold 3x its weight in water
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Describe the structure of the Stratum granulosum
Three to five layers of flattened cells
organelles deteriorating; cytoplasm full of
lamellated granules (release lipids) and
keratohyaline granules.
organelles deteriorating; cytoplasm full of
lamellated granules (release lipids) and
keratohyaline granules.
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Describe the structure of the Stratum spinosum
Several layers of keratinocytes connected by
desmosomes.
Cells contain thick bundles of
intermediate filaments made of pre-keratin.
desmosomes.
Cells contain thick bundles of
intermediate filaments made of pre-keratin.
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Describe the structure of the Stratum basale
Deepest epidermal layer
one row of actively
mitotic stem cells
some newly formed cells
become part of the more superficial layers. This takes 25-45 days.
Occasional melanocytes and epidermal
dendritic cells.
one row of actively
mitotic stem cells
some newly formed cells
become part of the more superficial layers. This takes 25-45 days.
Occasional melanocytes and epidermal
dendritic cells.
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What is the role of a desmosome?
They connect together cells that are next to eachother
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Describe insensible perspiration
Water from interstitial fluids penetrates the surface of the stratus corneum and evaporates into the air
500ml a day
severe burns increase rate of insensible perspiration and lead to dangerous loss of excess fluid
500ml a day
severe burns increase rate of insensible perspiration and lead to dangerous loss of excess fluid
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Describe sensible perspiration
This is sweat produced by the sweat glands
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Describe the stratum luceum
A smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum.
This thin layer of cells is found only in the thick skin of the palms, soles, and digits.
This thin layer of cells is found only in the thick skin of the palms, soles, and digits.
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Describe the function of the dermis
Mostly made of collagen – providing strength
Elastin- to give flexibility
Proteoglycans give this layer hydration
Mast cells and macrophages also present
Skin can stretch- pregnancy, obesity, goitre (swelling of thyroid gland)
Elastin- to give flexibility
Proteoglycans give this layer hydration
Mast cells and macrophages also present
Skin can stretch- pregnancy, obesity, goitre (swelling of thyroid gland)
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Describe the structure of the dermis
A strong, flexible connective tissue
Richly supplied with blood vessels and nerves
Thickness varies = 0.6mm to 3mm
Dermal papillae - extensions of the dermis into the epidermis
Richly supplied with blood vessels and nerves
Thickness varies = 0.6mm to 3mm
Dermal papillae - extensions of the dermis into the epidermis
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What receptors live in the skin?
What are their functions?
What are their functions?
Thermo-receptors- Temperature
Meissner's corpuscle- Touch
Nociceptor- Pain
Pacinian corpuscle- Pressure
Meissner's corpuscle- Touch
Nociceptor- Pain
Pacinian corpuscle- Pressure
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Describe the papillary layer of the Dermis
Superficial layer; 20% of dermis
Lots of elastic fibres
Dermal papillae - fingerlike extensions of dermis
Form ridges of the fingerprint
Capillary beds
Touch receptors (Meissner's), free nerve endings sensing pain
Lots of elastic fibres
Dermal papillae - fingerlike extensions of dermis
Form ridges of the fingerprint
Capillary beds
Touch receptors (Meissner's), free nerve endings sensing pain
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Describe the reticular layer of the dermis
Deeper layer; 80% of dermis
Composed of dense irregular connective tissue
Collagen and elastic fibres
Stretching of skin (obesity, pregnancy) can tear collagen fibers and produce striae (stretch marks)
Hair follicles, nerves, oil glands, ducts of sweat g
Composed of dense irregular connective tissue
Collagen and elastic fibres
Stretching of skin (obesity, pregnancy) can tear collagen fibers and produce striae (stretch marks)
Hair follicles, nerves, oil glands, ducts of sweat g
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What is the role of the Sebaceous glands?
Derived from epidermal cells
Oil flows into hair follicles
Androgens (hormones like testosterone.) stimulate sebum
Cells break down to release sebum (Bactericidal)
Oil collects dirt, softens and lubricates hair & skin. It also gives UV protection and mai
Oil flows into hair follicles
Androgens (hormones like testosterone.) stimulate sebum
Cells break down to release sebum (Bactericidal)
Oil collects dirt, softens and lubricates hair & skin. It also gives UV protection and mai
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Describe the roll of Dermcidin
a human antibiotic peptide secreted by sweat glands
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Sodium chloride can be measured in sweat to see is a person has what disease?
Cystic fibrosis
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Describe Eccrine sweat glands?
1. Eccrine (merocrine) sweat glands—abundant on palms, soles, and forehead
Function in thermoregulation
Function in thermoregulation
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What are the componants of sweat?
99% water, NaCl, vitamin C, antibodies, dermcidin, metabolic wastes
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What are the specialized apocrine glands?
Ceruminous glands—in external ear canal; secrete cerumen
Mammary glands
Mammary glands
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Describe the role of the arrector pilli
Smooth muscle attached to hair follicle
Responsible for “goose bumps”
Helps in thermoregulation by trapping air
May have a possible role in hair loss
Responsible for “goose bumps”
Helps in thermoregulation by trapping air
May have a possible role in hair loss
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Describe the structure and function of the hypodermis
Subcutaneous tissue, superficial fascia
Mostly adipose tissue
Binds skin to underlying tissue
Energy reservoir (fat)
Thermal insulation
Mostly adipose tissue
Binds skin to underlying tissue
Energy reservoir (fat)
Thermal insulation
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What can a decrease in ozone lead to?
Malignant melanomas
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What three factors determine skin colour
pigments (melanin, Hb, carotene)
blood circulating through the skin
thickness of stratum corneum
different size and number of melanosomes (organelles which synthesise and store melanin pigment)
blood circulating through the skin
thickness of stratum corneum
different size and number of melanosomes (organelles which synthesise and store melanin pigment)
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What can a lack of the cholesterol sulphatase enzyme cause?
Icthyosis
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Other cards in this set
Card 2
Front
What are the functions of the skin?
Back
Protection from pathogens
Waterproof
Temperature regulation
Absorption
Waterproof
Temperature regulation
Absorption
Card 3
Front
What cells help with immunity function?
Where are these cells found?
Where are these cells found?
Back
Card 4
Front
What are the layers of the epidermis?
Back
Card 5
Front
What is the structure of the epidermis?
Back
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