Integumentary system Flashcards
What is the difference between thin and thick skin?
Thin skin has four layers while thick skin has five
What is left as the nuclei and organelles disintegrate as the keratinocytes die in the stratum granulosum?
Keratin and the cell membranes that will form the stratum lucidum, stratum corneum, and accessory structures of hair and nails
What do sebaceous glands excrete?
Sebum
Name the layer deep to the dermal papillary layer
Reticular layer
Name the functions of the stratum corneum
Dry, dead layer helps:
- prevent the penetration of microbes
- prevent the dehydration of underlying tissues
- provides mechanical protection against abrasion for the more delicate underlying layers
What cells/structures are found in the dermal papillary layer? There are seven possible answers
- Fibroblasts
- A small number of adipocytes
- An abundance of small blood vessels
- Lymphatic capillaries
- Nerve fibres
- Touch receptors
- Immune cells
Of the epidermis, dermis, and superficial fascia, which is considered the ‘core’ of the integumentary system?
Dermis
What are sudoiferous glands in lay terms?
Sweat glands
Which layer of the epidermis is exposed to the external environment?
Stratum corneum
Are there blood vessels in the epidermis?
No, the epidermis is avascular
The greater the folding of the superficial portion of the dermis, the ____ the connections between epidermis and dermis
Stronger
What is the name for a finger-like projection/fold in the superficial portion of the dermis?
Dermal papilla
Are the superficial layers of the epidermis comprised of squamous, cuboidal, or columnar cells?
Squamous keratinised
What type of tissue comprises the reticular layer of the dermis?
Dense, irregular connective tissue
What type of cells produce the interconnected mesh of elastin and collagenous fibres in the dermis?
Fibroblasts
What layer is deep to the dermis?
Superficial fascia
What is provided by the collagenous fibres in the reticular layer of the dermis?
Structure and tensile strength
Describe what changes occur in the keratinocytes as they are pushed from the stratum spinosum and through the stratum granulosum
The cells become flatter, their membranes thicken, and they generate large amounts of the fibrous protein keratin. The nuclei and other organelles disintegrate as the cells die
Name the pigments that influence the colour of skin
Melanin, carotene, and haemoglobin
What comprises the superficial fascia?
Mainly loose connective and fatty tissues
What forms during foetal development where the cells of the stratum basale meet the dermal papillary layer?
The ridges on the fingers known as fingerprints
What comprises the dermis?
Dense irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures
How many layers of connective tissue comprise the dermis?
Two
Do the cells of the stratum corneum remain attached?
No, the cells are shed periodically
Cells in the stratum basale binding to the dermis via intertwining collagen fibres is known as what?
Basement membrane
What type of cell produces melanin?
Melanocytes
Describe the components of the superficial fascia
Well vascularised loose areolar connective tissue and adipose tissue
Describe the appearance of the dermal reticular layer
Reticulated (net-like) due to a tight meshwork of fibres
Name the two main layers of the skin
Epidermis and dermis
Melanocytes transfer the melanin pigment to the ____ (cell type) to protect the cell nucleus from UV-associated DNA damage
Keratinocytes
Give two other names for the superficial fascia
Hypodermis, subcutaneous layer
What is the stratum lucidum?
The second layer of epithelium in the epidermis (thick skin only)
What is the stratum spinosum?
The third deepest layer of epithelium in the epidermis
Is the deeper layer of skin vascular?
Yes, the deeper layer of skin is well vascularised
What does the stratum basale attach the epidermis to?
The basal lamina which is between the epidermis and dermis
What is a keratinocyte?
A cell that manufactures and stores the protein keratin
Name a type of cell aside from the basal cells that is found in the stratum basale
Melanocyte
Name the second/third (thin/thick) deepest layer of epithelium in the epidermis
Stratum granulosum
What is the purpose of the superficial fascia?
Connects the skin to the underlying fascia of the muscles and bones
What is produced by melanocytes?
Melanin, a pigment that protects living cells of the epidermis from UV radiation damage as well as giving hair and skin their colour
What is the stratum basale (AKA stratum germinativum)?
The fourth deepest layer of epithelium in the epidermis
The cells in the stratum basale bond to the dermis via what structures?
Intertwining collagen fibres
An interconnected mesh of elastin and collagenous fibres are composed by two layers of connective tissue that form the ____
Dermis
Where is the superficial fascia?
Deep to the dermis
Name the third deepest layer of epithelium in the epidermis
Stratum spinosum
What comprises the epidermis?
Closely packed keratinised, stratified squamous epithelium
The deeper layer of skin has what kinds of nerve fibres?
Sensory, autonomic, and sympathetic
Where does the keratin and the cell membranes that form the stratum lucidum, stratum corneum, and accessory structures of hair and nails come from?
Disintegration of the nuclei and organelles of the keratinocytes in the stratum granulosum
The collagen and elastin fibres of the dermal papillary layer form a ____ mesh
Loose
The cells in every layer of the epidermis except the ____ ____ are called keratinocytes
Stratum basale
How long does it take for new cells to completely replace those of the stratum corneum?
Approximately four weeks
How do keratinocytes move away from the stratum basale?
Existing cells are pushed superficially away as new cells are formed
What is composed of the two layers of connective tissue in the dermis and produced by fibroblasts?
An interconnected mesh of elastin and collagenous fibres
Is the stratum basale a single or multi- layer of basal cells?
Single layer
Describe the keratinocytes in the stratum lucidum
Flattened and dead
What is a visual characteristic of the stratum granulosum?
It has a grainy appearance due to changes in the keratinocytes as they are pushed from the stratum spinosum
What is the function of the keratinocytes of the stratum spinosum?
They begin the synthesis of keratin and release a water-repelling glycolipid
Where do the strands of collagen from the dermal reticular layer extend?
Superficially into the papillary layer and deep into the superficial fascia
The basal layer of the epidermis is composed of cuboidal cells, while the superior layers are keratinised squamous cells. How is the whole epithelium usually described?
Keratinised stratified squamous epithelium
What is provided by the elastin fibres in the reticular layer of the dermis?
Elasticity to the skin
How does the stratum basale constantly produce new cells?
Constantly going through mitosis
Name the second layer of epithelium in the epidermis (thick skin only)
Stratum lucidum
What is a dermal papilla?
A finger-like projection/fold in the superficial portion of the dermis
What is the stratum granulosom?
The second/third (thin/thick) deepest layer of epithelium in the epidermis
What is the stratum corneum?
The most superficial layer of epithelium in the epidermis
Is the superficial fascia a layer of skin?
It is not a true layer of skin, but the border between the superficial fascia and the dermis can be difficult to distinguish
Name the accessory structures of the skin. There are four possible answers
- Hair
- Nails
- Sudoriferous (sweat) glands
- Sebaceous glands
What is keratin?
An intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties
The collagen and elastin fibres of the dermal papillary layer form a loose ____
Mesh
Is most skin ‘thin skin’ or ‘thick skin’?
Thin skin (four layers of epithelium)
What is the purpose of the water-repelling glycolipid from the keratinocytes in the stratum spinosum?
Helps prevent water loss from the body, making the skin relatively waterproof (and preventing us semi-dissolving in water)
The cells in every layer of the epidermis except the stratum basale are called ____
Keratinocytes
What is generated in large amounts by keratinocytes as they are pushed through the stratum granulosum
Keratin, a fibrous protein
What type of tissue comprises the papillary layer of the dermis?
Loose areolar connective tissue
What layer of epithelium does thick skin have that thin skin does not?
Stratum lucidum, located between the stratum corneum and stratum granulosum
Where can ‘thick skin’ be found on the body?
Palms of the hands, soles of the feet, digits
How many layers of cells are in the epidermis?
Four or five, depending on location
How many layers are in the stratum granulosum?
Three to five layers deep
What happens to the most superficial keratinocytes in the stratum spinosum as more are produced by the stratum basale?
The most superficial keratinocytes are pushed into the stratum granulosum
Describe the appearance of the stratum lucidum
Smooth, seemingly translucent layer of the epidermis located superficial to the stratum granulosum and deep to the stratum corneum
Describe the structure of the stratum spinosum
Eight to ten layers of keratinocytes formed by cell division in the stratum basale
What is the general term for skin that has four layers of cells?
Thin skin
Why is the statum basale constantly going through mitosis?
Continuous production of keratinocytes
What are produced by the basal cells of the stratum basale?
Keratinocytes
What is between the epidermis and dermis?
Basal lamina
What is the function of dermal papillae?
Increase the strength of the connection between the epidermis and dermis
How many layers are usually in the stratum corneum?
15 to 30
Is the basal layer of the epidermis comprised of squamous, cuboidal, or columnar cells?
Cuboidal
What is the proper anatomical term for sweat glands?
Sudoriferous glands
The stratum basale is also known as the stratum ____
Germinativum
Are the cells in the stratum corneum alive or dead?
Dead
Which is thicker, the papillary or reticular layer of the dermis?
Reticular layer
Name the fourth deepest layer of epithelium in the epidermis
Stratum basale (AKA stratum germinativum)
What shape are sudoiferous glands?
Coiled
Do people with darker skin have more melanocytes, or do their melanocytes produce more melanin?
Their melanocytes produce more melanin
Name a difference between thin and thick skin that’s visible to the eye
Thick skin is hairless
Name the most superficial layer of epithelium in the epidermis
Stratum corneum
