What are the functions of skin?
Protection
Thermoregulation
Fat store
Sensation
Produce vitamin C
Produce vitamin D
What is the most superficial layer of skin?
Dermis
Epidermis
Subcutis
How many layers make up the epidermis?
5 in normal skin, 4 in thick skin
4 in normal skin, 5 in thick skin
What is the deepest layer of the epidermis?
Stratum corneum
Stratum lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
What is the most superficial layer of the epidermis?
Stratum Corneum
Stratum Lucidum
Which layer of the epidermis is only found in thick skin?
Stratum granulosum
Stratum spinosum
Stratum basale
Where on the body would you find thick skin?
Soles of the feet
Knees
Fingertips
Palms of the hands
Lips
Between which layers of the epidermis is the stratum lucidum found?
Between the stratum corneum and the stratum granulosum
Between the stratum granulosum and the stratum spinosum
Between the stratum spinosum and the stratum basale
What is the function of the stratum basale?
Endure the normal wear and tear of everyday life
Produce keratin and hydrophobic substances which keep the skin waterproof
Allow keratinocytes to mature and play a role in immune function
Constantly produce keratinocytes
What is the function of the stratum granulosum?
Endure the normal everyday wear and tear
Produce keratin and hydrophobic substances that keep skin waterproof
Allow keratinocytes to mature and have a role in immunity
What is the function of the stratum corneum?
Endure the everyday wear and tear of everyday life
Produce keratin and hydrophobic substances that help to keep skin waterproof
Allow keratinocytes to mature and has a role in immune function
What is the function of the stratum spinosum?
Endures the normal everyday wear and tear
Produces keratin and hydrophobic substances that help to keep skin waterproof
Allow keratinocytes to mature and has a role in immunity
Constantly produces keratinocytes
How many days, on average, does it take for cells produced in the stratum basale to reach the stratum corneum?
2 days
5 days
10 days
20 days
50 days
In what dermatological disease is the turnover of keratinocytes increased?
Atopic eczema
Psoriasis
Impetigo
Tinea
Which of the following are non-keratinising cells that can be found in the epidermis?
Merkel cells
Beta cells
Langerhan cells
Melanocytes
Kpuffer cells
Keratinocytes
What are Langerhan cells
Phagocytes
Antigen Presenting Cells
Pigment Producing Cells
What are Merkel Cells thought to do?
Act as sensory receptors
Produce the pigment that gives skin its colour
Produce collagen
What keeps the dermis and the epidermis separate?
A layer of fat
A layer of type II collagen
A basement membrane
What is the name of the upper layer of the dermis?
Papillary dermis
Reticular dermis
What is the name of the lower layer of the dermis?
Which of the following is not found within the dermis?
Fibroblasts, fibrocytes and their extracellular products
Collagen and elastin
Glycosaminoglycans
Blood vessels and nerves
Some immune cells
Where is the deep vascular plexus?
Stratum basale of the epidermis
Reticular dermis only
Reticular dermis, with small branches entering the papillary dermis
Where is the superficial vascular plexus?
Reticular dermis, with branches running into the papillary dermis
Why does blood flow within the skin need to be variable?
To allow sensation
To allow blood to be directed to other areas of the body when they functioning more than usual
For thermoregulation
What nervous system allows the blood flow to the skin to be changed by constricting some of the anastamoses?
Sympathetic nervous system
Parasympathetic nervous system
What are the four different types of nerve endings found in the dermis?
Free nerve endings
Fixed nerve endings
Pacinian corpuscles
Meissner's corpuscles
Merkel cellls
What is the subcutis predominantly made up of?
Type II collagen
Type I collagen
Adipose tissue
What are the functions of the subcutis?
Heat insulator
Act as a food store
Produce melanin
Produce type II collagen
Act as a shock absorber
Which of the following are associated with hair follicles?
Apocrine sweat glands
Eccrine sweat glands
Sebaceous glands
Arrector pili muscles
What do sebaceous glands produce?
Watery substances
Sebum
Kertain for hair formation
What is the function of sebum?
It has antibiotic functions and protects us from bacteria
It moisturizes skin and hair
It allows us to lose heat when we are too hot
Hair and nails are made out of the same substance: keratin. True or false?
What does soft keratin contain that hard keratin does not?
Granular layer
What are the two types of sweat gland found in skin?
Sebaceous
Apocrine
Eccrine
Which of these sweat glands produces smelly sweat?
What is the mechanism of secretion for eccrine sweat glands?
Holocrine
Apotosis
Merocrine
How are eccrine sweat glands innervated?
Sympathetic cholenergic control
Sympathetic adrenergic control
Parasympathetic cholenergic control
Where on the body are apocrine sweat glands found?
Hands and feet
Armpits
Genitalia and groin
Everywhere that there is thick hair on the body
What is the innervation of apocrine sweat glands?
What is the function of vitamin D?
Regulates calcium and phosphate metabolism
Regulates sodium and calcium metabolism
Regulates sodium and potassium metabolism
How much vitamin D is produced by our skin?
25%
55%
70%
90%
Lack of vitamin D in adults can cause what disease?
Osteomalacia
Osteoarthritis
Rickets
Osteoporosis
Where in the body is vitamin D activated?
Blood vessels
Kidneys
Spleen
In what layer of the epidermis are melanocytes found?
What is the histological appearance of melanocytes?
Dark, flat cells resting on the basement membrane
Cells with many dendrites which mostly penetrate the basale layer
Round cells with visible granules inside
What does melanin do?
Gives skin its colour
Protects the skin from harmful UV radiation
All of the above
What are the two types of melanin?
Eumelanin
Pheomelanin
Fibromelanin
Neomelanin
How do these two types of melanin cause the wide range of skin colours seen in humans?
They are mixed in different ratios
Darker skinned people have more melanin than lighter skinned people
Lighter skinned people only have one type of melanin
