Integumentary system Flashcards
What components are included in the integumentary system?
skin + accessory structures (sweat and oil glands, hair and nails)
What are the 3 layers of skin?
- epidermis
- dermis
- hypodermis (superficial fascia)
What is the epidermis made of and explain keratinization?
superficial epithelial region: layered - thick keratinized stratified squamous epithelium
Keratinization: keratin in epithelium cells which died and provide a tough surface for protection
What is the dermis made of and what is the purpose of vascularization?
dense connective tissue
- blood vessels for blood regulation and nutrition
What is the hypodermis made of and what is its purpose?
adipose tissue and not considered a part of the skin, hence considered subcutaneous
- anchors skin
What are the 4 types of epidermal cells?
- keratinocytes
- melanocytes
- dendritic (Langerhans) cells
- tactile (Merkel) cells
What is the main function and lifespan of keratinocytes?
- produces keratin (protein for strength, flexibility and waterproof)
- 30 days
Where is the stem cell that produces keratinocytes and what is the growth factor?
- in the basal layer
- stimulate growth of keratinocytes and other skin cells
What is the function of melanocytes and where are they located?
- produce melanin which is packed into melanosomes
- deepest layer of epidermis which branches into adjacent cells
Why is melanin important and how does it contribute to different colour skins and tanning?
absorbs and disperses UV rays and protects cells from damage
- to produce melanin which gives colour
Where is the dendritic cells located and how does macrophages contribute to the body?
epidermal dendritic cells (star-shaped); migrates from bone marrow to epidermis
- contains macrophages that activate immune system (capture antigens for T cells)
Where are tactile (Merkel) cells located and what is their role?
the junction between the epidermis and dermis
- sensory nerve endings for touch sensation (texture and shape)
What is the different between thick and thin skin when it comes to layers of the epidermis?
Thick - all 5 layers
Thin - 4 layers
What are the 5 layers of the epidermis?
- Stratum corneum
- Stratum lucidum (only in thick skin)
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What are the cells and fibers that are included in the dermis?
- fibroblasts (production of CT)
- macrophages (immune)
- Mast cells
- WBC
- collagen, elastin, and reticular
What type of innervation and accessories are in the dermis?
nerves, blood vessels, and lymphatic vessels, epidermal hair follicles, oil glands, and sweat glands
What are the layers of the dermis?
- Papillary layers
- dermal papillae - Reticular layers
What makes up the papillary layer and the subcategory?
areolar CT fibers with blood vessels
- Dermal papillae: superficial region of dermis that indents the overlying epidermis
What makes up the dermal papillae?
- capillary loops
- free nerve endings
- touch receptors (Meissner’s corpuscles - sensitivity to light touch)
What important functions do the dermis provides?
- increased SA for O2, nutrition and waste product exchange
- are finger prints
Where are friction ridges located and what are their functions?
on palms and fingers, soles of feet, dermal papillae lie on top of dermal ridges
- enhances gripping ability (friction)
- contributes to sense of touch (SA fir sensory nerves)
- sweat pores in ridges leave unique fingerprints
How are friction ridges unique?
- developed fully before birth
- permanent
- unique pattern
What is the reticular layer of the dermis made of, what is it a source of and when functions does it provide?
thick dense irregular CT (thick collagen fibers in different directions)
- langer’s lines
- strength and resiliency and maintain skin hydration; elastic fibers provide stretch-recoil
What is the hypodermis made of and what functions does it provide?
areolar CT + blood vessels (more supply than in the dermis) and adipose tissue
- anchors skin to underlying structure
- shock absorbers and insulation
- stores fat
What are the 3 pigments that contribute to skin colour?
- melanin
- carotene
- hemoglobin
What is melanin derived from and what what is the color range it provides?
- tyrosine
- reddish yellow to brownish black
How does the sun damage the skin and how does melanin help?
- damages the DNA in skin cells
- creates more melanin
What is the role of melanocytes?
to create melanin
What is carotene?
yellow to orange pigment found in plant products (ex., carrots)
- deposits in keratinocytes and hypodermis
What is hemoglobin when it comes to skin pigmentation and what is cyanosis?
found in capillary circulation and gives skin a pinkish hue
- bluish discoloration of skin signaling poor oxygenation of blood
What is hair made of and where is it not found?
dead, keratinized cells
- palms, soles, lips, nipples, and parts of external genitalia
What are the layers of the hair shaft made of and what are their functions?
Medulla: large cells separated by air spaces (not in fine hair)
Cortex: several layers of flattened keratinocytes (pigment here)
Cuticle: single layer of overlapping cells
What causes split ends and hair to turn gray?
- protective cuticle at ends is stripped away
- melanocytes stop producing melanin
What determines the shape of the hair shaft?
the shape of the hair follicle
What is the follicle made of?
follicle wall
- peripheral CT sheath
- glassy membrane
- epithelial root shaft (external and internal)
Hair structure - explain the function of the shaft, root and bulb?
S - part that projects from skin (3 parts)
R - part embedded in skin (contains hair follicle)
B - expanded deep end of follicle - has dermal papilla and root hair plexus
Hair structure - explain the function of the follicle, arrector pili muscle and sebaceous gland.
F - outer CT root sheath and inner epithelial root sheath - extending into dermis
APM - 1/ follicle; contract to pull hair up and dimple skin
SG - holocrine gland that secrete sebum (oil)
What is the hair papilla?
dermal tissue containing a knot of capillaries that supplies nutrients to growing hair
What is the hair matrix and how does it move?
actively dividing area of bulb that produces hair cells
- new cells push old ones upwards
- this is where keratinization happens
What is the arrector pili and what is it responsible for?
small band of smooth muscle attached to follicle
- goose bumps
What is the difference between vellus hair and terminal hair?
VH - fine, short, light (peach fuzz)
TH - thick, long, pigmented (face, scalp, public region)
What is hirsutism and what is it caused by?
- unwanted male pattern hair growth in women
- endocrine disfunction
What is alopecia and what is it caused by?
- a level of hair thinning with age in both males and females
- disturbed autoimmune function
What is male pattern baldness and what is it caused by?
altered response of hair follicle to androgen that shortens growth cycle
- genetically-determined, gender-influenced
What are the 3 parts of the nails?
free edge, body (epidermis under keratinized nail plate), nail folds - 2 lateral and 1 proximal
What are the 2 sections of the nail folds?
Eponychium: nail fold that projects onto surface of nail body AKA cuticle
Hyponychium: area under free edge of plate that accumulates dirt
What is the nail matrix and what is the lunule?
thickened portion of bed responsible for nail growth - becomes the nail plate
- lunule: thicked nail matrix, appears white
What are the 2 kinds of sweat glands?
- Eccrine (merocrine)
- Apocrine (merocrine)
What is the eccrine (merocrine) made of and what is its function?
simple coiled tubular glands with pore at surface that release sweat
- thermoregulation and secrete sweat
What is the composition of sweat?
99% water + salt, Vit C, antibodies, dermcidin, metabolic waste (urea, uric acid, ammonia)
Where do apocrine glands secrete, what does its sweat contain that is different and what is its function?
- into hair follicles
- same as sweat + fatty substances and proteins (odorless until bacteria breaks it down)
- sexual scent gland
What are the 3 modified sweat glands and explain?
- sebaceous gland (holocrine)
- secretes sebum (oil)
- leads to pimples and blackheads - ceruminous
- secretes wax in external ear cannel (contains antibodies) - mammary
- secretes milk in females
- pregnancy and postpartum
What are the 6 functions of the skin and explain?
- protection
- thermoregulation - sweating
- cutaneous sensation - sensory information
- metabolic - Vit D synthesis
- excretion - NaCl and H20 loss via sweat
- blood reservoir - holds 5% of total blood volume
What are the 3 types of protects?
Chemical - acidic skin secretion stops bacteria reproductions - protects against UV - contains antibacterial agents
Biological - Langerhans cells of epidermis and macrophages of dermis
Physical - barrier to trauma and bacterial invasion; also waterproof
What layers to the different kinds of burns affect?
First: epidermis
Second: epidermis and upper dermis
Third: entire thickness of skin (epidermis and dermis)
What are the medical concerns for burn victims?
- depth of medical care
- prevention of infection
- fluid loss
- hypothermia
- scarring and loss of mobility
What is the rule of 9?
estimates water loss in burn victims
