Term
| What does the structural integrity of the skin depend on? |
|
Definition
| keratin cytoskeleton, desmosomes, hemidesmosomes, and the structures and proteins that make up the basement zone. |
|
|
Term
| What can be found in the epidermis> (3) |
|
Definition
| keratinocytes, melanocytes, Langerhans cells |
|
|
Term
| WHat does the dermis contain? (4) |
|
Definition
| eccrine glands, apocrine glands and sebaceous glands and hair follicels |
|
|
Term
| what is the three stage growth cycle for hair? |
|
Definition
1. anagen
2. catagen
3. telogen |
|
|
Term
|
Definition
most superficial layer of skin providing the first physical barrier and immunological protection from invasion of foreign substances into the body
- no blood supply |
|
|
Term
|
Definition
| provides support and elasticity of the skin, contains immune cells involved in defense against foreign invaders |
|
|
Term
|
Definition
| subcutaneous connective tissue, stores adipose and recognized as superficial fascia; cushion and protection |
|
|
Term
| what is the structure and function of skin? (4) |
|
Definition
1. structure and basic physiology
2. physical and mechanical barrier
3. wound healing
4. immunological barrier |
|
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Term
| What are the 4 layers of the epidermis starting from the bottom to the surface? |
|
Definition
1. stratum basale
2. spinulosum
3. granulosum
4. corneum |
|
|
Term
| Where is the epidermis the thickest? thinnest? |
|
Definition
1. hands and soles of feets
2. genital areas and face |
|
|
Term
1. which cells make up 90% of the epidermis?
2. how long is the cycle of cell recycling in the epidermis?
3. what other cells are found in the epidermis? |
|
Definition
1. keratinocytes
2. 28 days
3. melanocytes and Langerhan's cells |
|
|
Term
keratinocytes contains ______ called ____ which aggregate into _____ to form the cytoskeleton of the cell
- keratin types __ and __ are normal for basal keratinocytes and types ___ and ___ for suprabasal keratinocytes |
|
Definition
keratin intermediate filaments
tonofilaments
tonofibrils
- 5 and 14
- 1 and 10 |
|
|
Term
| which layer(s) of the epidermis is mitotically active? |
|
Definition
|
|
Term
| what kind of cells are found in the stratum basale? how are they attached to the basement membrane? hwo are they attached to each other? |
|
Definition
- columnar cells
- hemidesmosomes
- desmosomes |
|
|
Term
| In the stratum spinosum, the desmosomes consists of 2 plaques...what are they composed of? |
|
Definition
1. desmoplakin
2. plakoglobin |
|
|
Term
|
Definition
attached to one end of the attachment plaques of the desmosome with the other end in the cytoplasm near the nucleaus
- keratin filaments that aggregate into tonofibrils |
|
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Term
| The glycocalyx between plaques in the stratum spinosum contain glycoproteins for ____ and adhesion complexes called _____, which include ___ and _____ |
|
Definition
calcium binding
cadherins
desmogleins
desmocollins |
|
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Term
| Describe the keratinocytes found in the stratum spinosum. |
|
Definition
1. polygonal cells
2. central nucleus
3. lots of eosinophilic cytoplasm
4. cytoplasm has keratin filament bundles |
|
|
Term
| What characterizes the maturation of a keratinocyte? |
|
Definition
| accumulation of keratin - keratinization |
|
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Term
| Describe the keratinocytes in the stratum granulosum |
|
Definition
flattened with keratohyaline granules
- 1-3 cell layers thick but thicker in soles and palms |
|
|
Term
keratohyaline granules
- describe
- functions |
|
Definition
NOT membrane bound, contain profillagrin (multiple linked fillagrins)
- contain proteins and lipids
- form a waterproof barrier to prevent fluid loss from the body |
|
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Term
| What do keratohyaline granules form in the stratum corneum? |
|
Definition
1. interfibrillary matrix of fillagrin to cement the keratin filaments together
2. inner lining of the horny or cornified cells = marginal band |
|
|
Term
| granular cells (stratum granulosum) |
|
Definition
| contain lysosomal enzy,es to break up the nucleus and organelles for keratinization |
|
|
Term
| lamellar granules/Odland bodies |
|
Definition
membrane coating granules that are lipid rich and released into the intercellular spaces in the upper granular layer
- important for water barrier and stratum corneum cohesion |
|
|
Term
stratum corneum
- describe
- function |
|
Definition
- dead and dying cells with mature keratin, anucleate cells in vertical stacks
- wavy
Function: protection as a vapor layer, decrease diffusion of water into the environment |
|
|
Term
| as the cells ascend in the stratum corneum what is lost? |
|
Definition
| - the plasma membrane and desmosomes and cells desquamate - filled with keratin |
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Term
| What are the four zones of the basement membrane zone? (from top to bottom near the dermis) |
|
Definition
1. plasma membrane of basal keratinocytes
2. lamina lucida
3. lamina densa with type IV collagen
4. sub basal lamina (fibrous) |
|
|
Term
hemidesmosomes
- attachment plaque composed of ____ |
|
Definition
in basement membrane zone (BMZ) - from epidermis to dermis with a single attachment plaque
- plaque made of bullous pemphigoid antigen 1 (BP1 or BP230) in an integrin based attachment mechanism |
|
|
Term
| what are the three forms of epidermolysis bullosa> |
|
Definition
1. simplex - split through the basal cells
2. junctional - split through the basement membrane zone
3. dystrophic - split through upper dermis (die early) |
|
|
Term
| What is the function of the dermis? |
|
Definition
1. thermoregulation
2. supports vascular network to supplly avascular epidermis with nutrients |
|
|
Term
| What are the three phases of the hair cycle? |
|
Definition
1. anagen - growth phase
2. catagen - growth arresting phase
3. telogen - resting phase
**Order = ACT |
|
|
Term
| What is the correct order of how keratinocytes mature through the skin before sloughing off? |
|
Definition
1. st. basalis
2. st. spinosum
3. st. granulosum
4. st. corneum |
|
|
Term
Select the true statment.
1. desmosomes attach to the basement membrane
2. hemidesmosomes attach keratinocytes to one another
3. keratohyalin granules are membrane bound
4. keratinocytes contain keratin intermediate filaments called tonofilaments |
|
Definition
|
|
Term
What arises from the matrix of the nails?;
what is the most distal part of the matrix that determines the shape of the free edge of the nail plate? |
|
Definition
|
|
Term
| What constitutes the dermis? (5) |
|
Definition
1. fibroblasts - secrete the ECM
2. ECM with collagen, elastin, ground substance - acid mucopolysacc;s for support and elasticity
(75% collagen)
3. vascular and neural elements
4. adnexal structures (glands, hair, etc)
5. immune cells for defense |
|
|
Term
| what percentage of the dry weight of skin is made of collagen? what is its purpose? |
|
Definition
75%
- physical support and elasticity |
|
|
Term
| What are the two zones of the dermis? |
|
Definition
1. papillary dermis
2. reticular dermis |
|
|
Term
| What does the papillary dermis contain? (4) |
|
Definition
1. loose CT
2. type III collagen
3. free sensory nerve endings and structures called Meissner's corpuscles
4. vascular networks |
|
|
Term
| Cold causes the papillary dermis to ____ and heat causes it to ___ |
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Definition
|
|
Term
What are the two functions of the vascular networks in the papillary dermis?
- the vasculature interdigitates into areas called _____
- the anastomoses are controlled by the _____ nervous system and shunts blood to the ______ to cause heat loss byt ____ and _____ |
|
Definition
Functions:
1. support avascular epidermis with nutrients
2. provide thermoregulation
- dermal papillae
- sympathetic, superficial venous plexus, convection, radiation |
|
|
Term
| Where is the superficial vascular plexus? |
|
Definition
| at the boundary between the papillary and reticular dermis with loops that extend into the papillae |
|
|
Term
| Where is the deep vascular plexus? |
|
Definition
| between the reticular dermis and the subQ fat |
|
|
Term
| describe components of the reticular dermis. |
|
Definition
1. dense irregular CT
2. type I collagen
3. gives skin strength and elasticity
4. glands, hair follicles |
|
|
Term
| What physiological functions does the neural network of the dermis provide? (6) |
|
Definition
1. cell growth
2. immunity
3. inflammation
4. pruritus (itching)
5. wound healing
6. homeostasis |
|
|
Term
Autonomic nerves of the dermis supply what? (4) which glands do they not supply?
where are special nerve end organs found? |
|
Definition
1. blood vessels
2. arrector pili muscles
3. eccrine glands
4. apocrine glands
- does not supply sebaceous glands
- palsm, and soles and mucocutaneous junctions |
|
|
Term
Where are mucocutaneous end organs and meissner corpuscles found?
- what are their functions? |
|
Definition
dermal papillae
function - mediates touch |
|
|
Term
| Where are the Vater-Pacini corpuscles found and what do they do> |
|
Definition
| large nerve end organs in the subcutis that mediates the sense of pressure |
|
|
Term
| Lidocaine only works on which nerve end organs in the dermis? |
|
Definition
| meissner corpuscles (this is why we can feel pressure) |
|
|
Term
anagen
- average length of time
eyebrow v. scalp
what percent of scalp hair is in this phase at any tiem? |
|
Definition
active growth phase; (think anabolic steroids and proliferation)
- lasts 3 years but depends on location
eyebrow = 4 months and scalp = 3-7 years
80-90% of scalp hairs are in anagen |
|
|
Term
catagen:
- how long does it last?
how many hairs are in catagen at one time? |
|
Definition
catabolic or growth arresting stage (Hair begins to die)
- 3 weeks
mitotic activity ends and bulb shrinks away from follicular papilla
- less than 1% of hairs |
|
|
Term
telogen
- how long does it last?
how many scalp hairs are in telogen at any point?
- what is another name for this phase? |
|
Definition
last 3 months - resting phase
10-20%
- shedding phase - hairs with short club root; 50-100 scalp hairs shed daily |
|
|
Term
|
Definition
| main part of hair fiber; keratinized spindle shaped cells |
|
|
Term
|
Definition
found on scalp
- have a central core (medulla) with cells containing air spaces |
|
|
Term
|
Definition
| covers the cortex of hair, a thin layer of cells overlaping like tiles on a roof with free margins towards the tip of the hair |
|
|
Term
What are Langerhans cells?
- where are they found
- functions
- What does UV light do to the number of these cells? |
|
Definition
bone marrow-derived dendritic cells found in the suprabasilar epidermis and dermis
- APC's with a crucial role in contact sensitization and immunosurveillance
- UV light decreases numbers (immunosuppressant - skin cancer) |
|
|
Term
| What are the functions of nails? |
|
Definition
| protective covering of the end of digit and assists in grasping small objects |
|
|
Term
| where does the pink color of nails come from> |
|
Definition
| extensive vascular network through the transparency of the nail plate |
|
|
Term
| What causes the color of the lunula? |
|
Definition
| effect of light scattered by the nucleated cells of the matrix and in part to the thick layer of epithelial cells making up the matrix |
|
|
Term
| lateral and proximal nail folds |
|
Definition
| skin that enveloped the nail plate as it emerges from the matrix |
|
|
Term
|
Definition
| skin underlying the free end of the nail; contiguous with the skin on the tip of the finger |
|
|
Term
| T/F: nails of individual fingers of the same hand grow at different rates. |
|
Definition
|
|
Term
| When is nail growth increased? decreased |
|
Definition
summer
- winter/cold climates |
|
|
Term
| When is there a decrease in the rate of nail growth or thinning and grooving of the plate? |
|
Definition
systemic disorders
acute viral infections such as mumps and measles
starvation
some types of anemia
-see a few weeks after they occur |
|
|
Term
| when do we see an increase in the nail growth rate? |
|
Definition
pregnancy
nail biting
trauma
regrowth after avulsion |
|
|
Term
| what type of cells make up the nails? |
|
Definition
|
|
Term
| What are melanocytes? what is their major function? |
|
Definition
dendritic cells of neural crest origin (1 in 7 cells of basal layer)
function - produce melanin to protcct from UV light |
|
|
Term
|
Definition
melanin pigmentary system of functional units - contains:
1. melanocyte - supplies melanin
2. group of 36 keratinocytes |
|
|
Term
|
Definition
|
|
Term
| WHat is the enzyme that converts tyrosine to melanin in the melanosomes? |
|
Definition
|
|
Term
| what determines pigmentation? |
|
Definition
| amount of melanin transferred to the keratinocytes and the distribution of melanosomes |
|
|
Term
| When does the number of melanocytes differ? |
|
Definition
at various body sites (more on face and genital)
NOTHING TO DO WITH ETHNICITY |
|
|
Term
| What determines white v. black skin? |
|
Definition
white: aggregated melanosomes within membrane bound complexes - show degredation
black - larger melanocytes and more dendritic; singly dispered melanosomes |
|
|
Term
|
Definition
| changing of melanocytes in the melanosomes |
|
|
Term
Light skin:
1. melanization
2. melanosome size
3. number per cell of melanosomes
4. distribution of melanosomes
5. degredation |
|
Definition
1. stage I, II
2. smaller
3. less than 20
4. grouped
5. fast |
|
|
Term
Dark Skin:
1. melanization
2. melanosome size
3. number per cell of melanosomes
4. distribution of melanosomes
5. degredation |
|
Definition
1. stage IV
2. larger
3. greater than 200
4. single
5. slow |
|
|
Term
Where are sebaceous glands found? what are they called in the eyelid?
what type of glands are they? |
|
Definition
1. everywhere on skin but Palms and soles
2. glands of zeis and meibomian glands
3. holocrine (entire cell secreted); associated with hair folliceles |
|
|
Term
| what is the secretion of a sebaceous gland called? What kind of control is it under? |
|
Definition
1. sebum (lipids)
2. endocrine |
|
|
Term
Where are apocrine glands found? What are they called in the external auditory meatus? eyelid?
What is their function? |
|
Definition
1. axillae and genitals, external auditory meatus, areola, eyelid
2. ceruminous glands
3. Moll's gland
4. unknown (scent glands in mammals) |
|
|
Term
Where is the apocrine glandular unit found?
What kind of secreton is it?
Under what control are apocrine glands? |
|
Definition
1. in lower reticular dermis or subcutis and a duct emptying into a sebaceous duct in a hair follicle
2. decapitiation secretion - odorless until broken down by backteria
3. adrenergic sympathetic (fight or flight) |
|
|
Term
Where are eccrine glands found?
function?
where is their secretory portion? |
|
Definition
1. epidermis
2. heat regulation (1.8 liters of sweat per hour)
3. empties onto epidermis; secretory portion found in lower dermis or upper adipose |
|
|
Term
| What 2 cell types are found in eccrine glands? They are surrounded by what cells? What controls them> |
|
Definition
1. clear cells - secrete aqueous material and glycogen and
dark cells - secrete sialomucin
2. myoepithelial cells
3. contract in response to cholinergic stimuli - under some muscle control |
|
|
Term
|
Definition
| hair follicle and associated sebaceous glands |
|
|
Term
| Where does hair grow out of> Where is no hair found? |
|
Definition
- tubular invaginations of the epidermis known as follicles
- palsm and soles |
|
|
Term
|
Definition
small bundle of smooth muscle fibers; extends from beneath the epidermis and is attached to the side of the follicle at an angle
- supplied by adrenergic nerves for erection during cold or emotional stress |
|
|
Term
| Where does the hair protein grow? |
|
Definition
| dermal papillae of the dermis |
|
|
Term
| Where is the sebaceous gland attached? |
|
Definition
| to the follicable above the attachment of the arrector pili |
|
|
Term
| What cells produce hair pigment? |
|
Definition
| melanocytes; become keratinized as they ascend the hair follicle |
|
|
Term
| How does cross-sectional shape of hair varies? |
|
Definition
african ahir - oval
white - circular
pubic, beard and eyelash - oval |
|
|
Term
| What is the average rate of growth of the human scalp hair? |
|
Definition
| 0.037 mm per day or 1 cm/month |
|
|
Term
| Hair and nails keratinize without ______. Tonofilaments harden with incorporation of _____; does not desquamate and needs cutting |
|
Definition
1. keratohyalin granules
2. disulfide bonds |
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