Week 13 (exam 4) Flashcards
What is the integumentary system?
Skin and whatever derives from it-
Hair
Nails
What are the accessory structures of the integumentary system?
Hair, nails and various exocrine glands
What are the 2 basic layers of the skin?
1) epidermis
2) dermis
What are cornified cells?
Lost all moisture
On top of epithelium
Dead layer
Has keratin
What is keratin?
Protein in these cells
Makes up hair and fingernails
Where and what is the hypodermis?
Under dermis
CT
What are the functions of the skin?
Protection- sturdy cover
Excretion- salt, water and organic waste removal
Temp maintenance- insulation and evaporation
Synthesis vitamins- D3 and important to calcium metabolism
Touch detection- various senses
What is the epidermis?
Stratified squamous epithelium
Seals water in
What are the cells of the epidermis called?
Keratinocytes
What is the subcutaneous layer or hypodermis or superficial fascia and what cells is it made of?
Innermost layer of the skin
Areolar and adipose tissue
Not part of integument
What are the 2 complex interfaces of the skin?
Dermal papillae
Epidermal ridges
What is dermal papillae?
Squiggly lines project upwards
What is epidermal ridges?
Squiggly lines project downwards to interlock with them
What are the 6 layers of the epidermis?
1) stratum Corneum
2) stratum lucidum
3) stratum granulosum
4) stratum spinosum
5) stratum germinativum
6) basal lamina (basement membrane)
What is the deepest layer of the epithelium?
Stratum germinativum or stratum basale
What are cells of the stratum germinativum or stratum basale attached by and to what?
Hemideamosomes
Basal lamina
Why is basal lamina’s surface area increased?
Because it is folded
Why are the folds of the basal lamina good?
Because it increases the strength of attachment between the epidermis and underlying dermis
The pattern of epidermal ridges is reflected where?
An outer surface of skin
Ex: fingerprints
The stratum germinativum is dominated by what cells?
Basal cells or germinative cells
Merkel cells
Melanocytes
What are basal or germjnative cells?
Stem cells whose division replace cells above them as they are worn away
What are merkel cells?
Only in skin areas with no hair
Sensitive to touch
The daughter cells produced by the basal cells are pushed upwards into what layer?
Stratum spinosum
Stratum spinosum consists have several or few layers?
Several
What do stratum spinosum fella look like and why?
Cells looks like miniature pin cushions
Because the cytoplasm of these cells shrunk while the cytoskeletal elements remain intact
How are the stratum spinosum connected to one another?
Desmosomes
What causes the thickness of the cells?
The continue division of the cells
What layer is above the stratum spinosum?
Stratum granulosum- “grainy layer”
What happens in the stratum granulosum?
Cells engage in a process that will result in their destruction
Will produce non living protective layer of dead cells that lie above
Cells grow thinner and flatter- membrane thickens and become less permeable)
Nuclei and other organelle disintegrate and cells die
What does the stratum granulosum cells produce?
Keratin
Keratohyalin
What is keratin?
A tough fibrous protein
Basic structural component of hair and nails
What is keratohyalin?
Forms dense granules in cytoplasm that promotes dehydration of the cell and cross linking keratin fibers
What is the dead layer called?
Stratum corneum
What happens in the stratum corneum layer?
Cells are keratinized or cornified
Cells remain tightly connected by desmosomes
Why skin sheds in sheets
Water resistant but not water proof
What is insensible perspiration?
Water loving tissue beneath blank the surface and evaporate away
We can lose a pint a day this way
What is sensible perspiration?
Different from sweating which is carried out by specialized sweat glands
What tissues is the dermis layer made of?
Areolar tissue and reticular tissue
What are the 2 layers of the dermis and explain
1) papillary layer- areolar tissue
Layer of skin affected by dermatitis (poison ivy)
2) reticular layer- mesh work of dense irregular tissue
What is skin color a result of?
Epidermal pigmentation
Dermal circulation
What are the 2 pigments?
1) carotene
2) melanin
What is carotene?
Orange yellow (same stuff as as carrots and squash)
Accumulated in epidermal cells and in fatty tissues of dermis
What is melanin?
Yellow brown to black
Manufactured by melanocytes in stratum germinativum
What is the difference of melanocytes in light and dark skin?
Light skin-
melanosomes relatively small and so bit spread further then stratum spinosum
Dark skin-
Larger and can go as high as stratum granulosum
Same number of melanocytes just different because of how active they are
What is dermal circulation?
Determines skin color
Blood vessels located in the Demis but not epidermis
Gives skin a reddish tint most seen in light skin people
Shock can reduce blood flow and light skin person turns white
Cyanosis
Most apparent where skin is thin (lips/ beneath nails)
What is cyanosis?
If oxygen depleted blood turns a dark red
Seen from the surface, skin takes a blackish color
Why does skin resist stretching and is quite elastic?
Collagen in dermis
Elastin in dermis
What happens when there’s a reduction amount of elastin?
Wrinkles and saggy skin
What is caused if skin is overstretches to exceed elastic capabilities and damage to dermis prevents it from recoiling to original size?
Stretch marks
Do collagen and elastin fibers run in the same direction/ parallel bundles?
Yes because this way it resists the forced the skin normally encounters
What is the lines of cleavage?
Resulting pattern of fiber bundles create
An incisions parallel to the lines of cleavage will close naturally
An incision cutting across line of cleavage will pull open as cut elastic fibers recoil
Is there a blood supply in epidermis?
No
What happens when you’re exposed to UV?
The epidermal cells in stratum germinativum ans stratum spinosum produce vitamin D3
What is vitamin D3 needed for?
To synthesize calcitriol which is essential for absorption of calcium but the small intestine
What can happen to Children who have overcast skin and lack of vitamin D3?
Abnormal bone development
Rickets- softening of the bones
Leads to osteomalacia in adults
What is vitamin D3 added to?
Milk as vitamin D
What absorbs UV? Why does this affect different people?
Melanin
Europe people cover up more and need few parts shown to make D3
Tropics lot of skin exposed good on D3 but skin cancer
Disadvantage of having dark skin
Why do some tumors affect pituitary?
Result in over secretion of Melanocytes stimulation hormone (MSH)
What is Addison’s disease?
Also affect pituitary- thistime
Large quality of Adrenocorticotropic hormone is secreted
What is vitiligo?
Melanocytes die off producing a very light skin color
Where does skin cancer arise?
Epidermis
What layer does basal cell carcinoma occur?
In stratum germinativum
Most common skin cancer
What layer does squamous cell carcinoma occur?
Higher layers
What is malignant melanoma?
Melanocytes have become cancerous
Very dangerous- metastasizes
Critical to catch early on
The mnemonic ABCD helps to remark key identification points
What is the mnemonic ABCD stand for?
A) asymmetry- irregular size, if one side does not mirror the other
B) border- is irregular and may be scalloped, jogged, notched or blurred
C) color- more then one color and mottled appearance
D) diameter- larger than a pencils eraser diameter
What is the function of melonin to protect skin from UV in keratinocytes?
Melanosomes concentrate around the nucleus to protect DNA (absorbs the radiation
What is the function of melonin to protect skin from UV in cells of epidermis?
Helps protect the dermis (CT)
UV damages fibroblasts causes wrinkling in people exposed to too much sunlight
When tanning melanocytes produce more or less melanin in response to increased sunlight exposure taking several days?
Additional melanin
Merkel cells are found in what layer?
Stratum germunativum
Meissners corpuscle or tactile corpuscle is found in what layer of the dermis?
Papillary layer
Pacinien corpuscle or lamellated corpuscle is found in what layer do the dermis?
Vibrations in Reticular layer
The accessory structures (hair, nails, various glands) of the integumentary strain originate in the epidermis but are known as what?
Epidermal Denvatives
They project down into dermis
Non living structures of hair is produced in what?
Hair follicles
What is the cuticle?
Dead keratinized cells
What is the cortex?
Cells with hard keratin (gives hair stiffness)
What is medulla?
contains cells with soft keratin
What is the hair shaft?
Part of hair follicle halfway in and sticking out of the epidermis
What is the hair root?
Inside the skin
Extended for bulb
What is the hair bulb?
Place where internal organization of hair is complete about halfway to skin surface
What is hair papilla?
Peg of CT with capillaries and nerves
What is the early embyonic or Lanugo type of hair?
Extremely fine and unpigemented
Most shed before birth
What is bellies or terminal hairs?
Replace early embyonic or lanugo hair
“Peach fuzz”
Heavy and more deeply pigmented
May be curly
Why hair follicles switch hairs produced?
Hormones
Armpits, pubic area and liabi produce vellus hairs with puberty
Sex hormones cause then to produce to terminal hairs
What causes hair color?
Results from melanin produced by melanocytes at the hair papilla
Different forms of melanin which give dark brown, yellow brown or red coloration
Pigment produced decrease with age
White hairs result from lack of pigment and air bubbles in medulla
What is the function of hair on your head, nostrils and ears, and eyelashes?
Protects scalp and insulates it
Act as fillers to help prevent entry of foreign particles
What is the root hair plexus of sensory nerves?
Surround base of each hair follicle
Can feel movement of the shift of every single hair
What is arrector pili?
Smooth muscle fibers
Extend from the papillary layer of dermis to a sheath of CT that surrounds the hair
How do you get goosebumps?
Construction of muscles cause hairs to stand erect
Can react to emotional states or cold
Hair production is a specialized version of the what seen in the epidermis?
Keratinization
What cells does the hair matrix have?
Contains basal cells like stratum germinativum
Divide to produce daughter cells that gradually get pushed toward surface
What is the hair growth cycle?
At the end of the cycle (2-5 for scalp hairs) follicle becomes inactive and becomes a club hair
Connection between matrix and hair itself breaks down
Another cycle begins and a new hair starts to grow
Old hair is pushed out and shed
What are the 2 glands in skin?
1) Sebaceous glands or oil glands
2) sweat glands or sudoriferous
What are sebaceous glands or oil glands?
Sebum- Oily lipid that coats hair shaft and epidermis
Holocene glands
Cells self destruct
Simple branched alveolar structure
Inhibits bacterial growth and conditions keratinized cells at surface and those forms hair shaft
Get dry and brittle when exposed to the environment
What is the apocrine sweat gland?
Use merocrine
Found in armpits, around nipples and groin
Begin to function at puberty
Secret products into hair follicles
Secretion is sticky and may be odorous
- Bactria consumes the secretion and their activity can intensify odor
What is the merocrine or eccrine type of sweat gland?
Far more numerous
Sweat produced equals sensible perspiration
Discharged directly to the surface
Cools skins surface thru evaporation (primary function)
Excretes water and electrolytes
Protection
- flushes skin
- low pH impedes bacterial growth
- contains dermicidin (antibiotic)
- lysozyme
What is the mammary gland?
Related to apocrine sweat glands
What is a ceruminous gland?
Modified sweat glands in ear canal
Secretions combined with those of sebaceous glands to produce ear wax (cerumen)
Helps traps foreign objects and keeps them away from ear drum
What underlying the nail gives nail pink color?
Blood vessels
What leaves the pale crescent of the nail?
Lunula
