integumentary system Flashcards
What is the integumentary system?
The body covering, which includes the skin and its appendages (e.g. hair, nails, oil and sweat glands), as well as blood vessels, lymphatic and nerve endings embedded in the skin + the hypodermis.
What are the primary functions of the skin?
- Protection from environmental insults
- Protection from dehydration
- Insulation
- Temperature regulation
- Sensation
- Production of vitamin D folates
- Layer of fat
What are the three main layers of the skin?
- Epidermis
- Dermis
- Hypodermis
What type of tissue is the epidermis?
Keratinised stratified squamous epithelium
How many layers are typically found in the epidermis?
4 layers in thin skin, 5 layers in thick skin (including stratum lucidum)
What are the four types of cells found in the epidermis?
- Keratinocytes
- Melanocytes
- Dendritic (Langerhans) cells
- Tactile epithelial (Merkel) cells
What is the role of keratinocytes?
Most abundant cells in the epidermis that produce keratin
What is the function of melanocytes?
Produce melanin and transfer it to keratinocytes for skin pigmentation and protection from UV damage
Where are dendritic cells located and what is their function?
Immune cells that form a network in the epidermis
What is the role of tactile epithelial cells?
Act as receptors for sensation at the epidermal-dermal junction
Match the cell type to its function: Dendritic cell
Ingests foreign substances and activates the immune system
Match the cell type to its function: Melanocyte
Produces pigments that determine our skin color
Match the cell type to its function: Keratinocyte
The most abundant cell type in the epidermis
What are the layers of the epidermis from deep to superficial?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum corneum
- Stratum lucidum (only in thick skin)
What characterizes the stratum basale?
Deepest epidermal layer, single layer of keratinocytes/stem cells, includes melanocytes and tactile epithelial cells
What is found in the stratum spinosum?
Several layers of keratinocytes with thick bundles of pre-keratin and dendritic cells
What occurs in the stratum granulosum?
Keratinocytes contain keratohyaline and lamellar granules; cells are starting to disintegrate
What is the significance of the stratum lucidum?
A clear layer found only in thick skin
What is the stratum corneum composed of?
Flattened dead keratinocytes, 20-30 layers thick
What are the two layers of the dermis?
- Papillary dermis
- Reticular dermis
What is the composition of the papillary dermis?
Areolar connective tissue with collagen and elastin, blood vessels, nerve endings, and touch receptors
What characterizes the reticular dermis?
Coarse, dense, irregular connective tissue, making up 80% of the dermis
What are the three major forms of skin cancer?
- Basal cell carcinoma
- Squamous cell carcinoma
- Melanoma
What is the most common form of skin cancer?
Basal cell carcinoma
What is the most dangerous form of skin cancer?
Melanoma
What are the components of skin appendages?
- Hair
- Nails
- Sweat glands
- Sebaceous glands
What is the primary structure that produces hair?
Hair follicles
What are the macroscopic parts of a hair?
- Shaft
- Root
What is the nail matrix responsible for?
Growth of the nail
A nail forms a clear protective covering on the _______ surface of the _______ part of a finger or toe.
[DORSAL] [DISTAL]
A nail is made of _______ keratin.
[HARD]
The nail rests on a bed of epidermis called the nail bed. Over the nail bed is the nail plate, which is effectively the stratum _______ of the epidermis.
[CORNEUM]
The part of the nail responsible for its growth is called the nail matrix, which is a thickened _______ portion of the nail bed.
[PROXIMAL]
A nail is made of (SOFT or HARD) keratin?
HARD keratin
The nail rests on a bed of epidermis called the _______.
nail bed
The nail plate is effectively the stratum _____________ of the epidermis.
corneum
The part of the nail responsible for its growth is called the _______.
nail matrix
The nail matrix is a thickened (PROXIMAL or DISTAL) portion of the nail bed.
PROXIMAL
Nails normally appear pink because _________________
of the underlying blood vessels
The crescent-shaped region that lies over the thick nail matrix is _______.
white
Nails have 3 folds, namely skin folds. One of these folds is the cuticle, which projects (PROXIMALLY or DISTALLY) onto the nail body.
PROXIMALLY
The other two skin folds lie (LATERALLY or MEDIALLY) to the nail body.
LATERALLY
The thickened area beneath the free edge of the nail is called _______.
hyponychium
Endocytosis is a form of _______ transport.
active
Endocytosis is a vesicular transport that moves substances _______ the cells.
into
Name the several types of endocytosis based on the cell type.
- Phagocytosis
- Pinocytosis
- Receptor-endocytosis
- Vesicular trafficking
Exocytosis is also a form of _______ transport.
active
Exocytosis is a vesicular transport that moves substances _______ of the cells.
out
Ceruminous glands and mammary glands are specialized/modified _______ sweat glands.
apocrine
Merocrine glands release secretory products via _______.
exocytosis
Holocrine glands accumulate secretory products in the secretory cells, which then _______.
die
In holocrine glands, the entire cell and its secretory products are released into a _______.
short duct
