Skin Flashcards
(272 cards)
1
Q
What basis of study would crime scene investigators use to capture the large and unique dermal ridges of the suspect?
A
dermatoglyphics
2
Q
What three processes occur during the acute to subacute phase change in first intention healing?
A
neovascularization
fibroplasia
re-epithelialization
3
Q
How are antlers different than horns?
A
antlers have a bony core; horns come from keratin from a horn bud
4
Q
What are the 3 layers of the skin, superficial to deep?
A
epidermis
papillary layer of dermis
reticular layer of dermis
hypodermis
5
Q
Thick skin has a thick ___ layer.
A
cornified
6
Q
In inflammation more intense in first intention wound or second intention wound healing? Why?
A
second intention; because there is more necrotic debris, exudate, and fibrin to be removed
7
Q
Which layer of the dermis is thicker and less cellular?
A
deep reticular layer
8
Q
What type of melanin is present in individuals with dark or brown hair?
A
eumelanin
9
Q
Which glands are alveolar, holocrine glands consisting of branches acini?
A
sebaceous glands
10
Q
Which glands develop at puberty?
A
apocrine glands
11
Q
As epithelial cells mature, they fill with ___ and die.
A
keratin
12
Q
What are the sphincters called in arterioles?
A
glomus bodies
13
Q
Birds and reptiles produce ___ keratins and are found in things like feathers, claws, scales, and beaks.
A
beta
14
Q
What determines the overall length of hair on the body?
A
the ratio of growth between the active growth and resting phases
15
Q
Where would you find the most Meissner’s corpuscles?
A
in the hands, feet, lips, and genitalia
16
Q
What coating on the surface of skin cells forms a mature waterproof layer?
A
glycolipid coating exocytosed from keratinized cells
17
Q
What is the dermis composed of?
A
dense irregular collagenous connective tissue (Type I collagen) with elastic fibers
18
Q
What represents the interaction between keratohyaline granules and tonofibrils?
A
process of keratinization
19
Q
What is the most common form of hair loss?
A
androgenic alopecia
20
Q
What happens if the neonate does not ingest the colostrum?
A
increased chance of death due to infection due to decreased maternal antibodies
21
Q
The ____ is lined by actively dividing epithelial cells (like the stratum basale).
A
root bulb
22
Q
Which types of skin cancers are derived from epithelial cells?
A
squamous cell carcinoma
basal cell carcinoma
23
Q
In the animal kingdom, what are apocrine glands used for?
A
sexual attractant pheromones
24
Q
Which type of laceration would heal with less scarring?
A
skin incisions or lacerations parallel to Langer’s lines
25
Where would you find the subcutaneous plexus?
deep within the hypodermis
26
Under what hormone control is melanin synthesis under?
pituitary hormone (melanocyte stimulating hormone)
27
What does the deep reticular layer of the dermis interdigitate with?
the subcutis (underlying hypodermis)
28
Besides pigmentation, where else is melanin important?
it is necessary for normal neural development
29
What is the deepest layer of the epidermis?
stratum basale (stratum germinativum)
30
Where do melanocytes originate from?
neuroectoderm (neural crest origin) dendritic cells present in epidermis
31
Mammary glands are highly modified ____.
apocrine glands
32
Straight hair is more ____ in cross-section; wavy hair is more ____ in cross-section; curly hair is more ____ in cross-section.
round; oval; flattened
33
Where does adrenergic sweating begin on the body?
palms and soles of feet
34
What sensory receptor is the most numerous in the skin?
free nerve endings
35
Where would you find Langer's lines?
in the reticular layer of the epidermis
36
What is it called when cells mature from the stratum basale to the stratum corneum in wound repair?
keratinization
37
____ healing occurs when wound edges are not able to be approximated and may contain extensive loss of tissue.
Second intention
38
What is the superficial portion of a hair follicle called?
infundibulum
39
What is the developing hair surrounded by?
internal and external root sheath
40
In people with albinism, ____ form but do not mature.
premelanosomes
41
What are the phases of hair growth?
anagen
catagen
telogen
exogen
42
____-skinned individuals produce less pigment or digest pigment faster.
Lighter
43
What type of nerve fibers do Meissner's and Pacinian corpuscles possess?
afferent nerve fibers (surrounded by modified Schwann cells - more modified in PC)
44
Under what influence do mammary glands in females develop?
pituitary and ovarian hormones
45
What is an example of modified apocrine glands in the ear?
ceruminous wax glands (secrete cerumen)
46
Where would you find vellus hair?
fine body hair of women and children
47
Why do we make melanin?
because DNA is subject to damage by UV and melanin functions as a shield to prevent mutagenesis
48
What are the layers of the epidermis, from superficial to deep?
```
stratum corneum
stratum lucidum (thick skin)
stratum granulosum
stratum spinosum
stratum basale
```
49
Where does melanin go?
it is taken up by surrounding epidermal cells
50
Why are Demodex mites helpful?
they keep hair follicles clear which prevents sebum buildup and potential acne
51
What layer of the epidermis is continuously exfoliated or desquamated?
stratum corneum
52
What initiates keratinization?
the rupture of lysosomes and release of lysosomal enzymes; rupture of keratohyaline granules + polymerization of contents
53
Are the collagen bundles in he dermis randomly oriented?
NO - follow lines of tension
54
__ are used in thermoregulation, especially in the periphery of the body.
Vascular plexi
55
Hair, nails, sebaceous glands, sweat glands, and horns are all considered ___.
skin appendages
56
____-skinned individuals produce more pigment and retain more pigment longer.
Darker
57
Where do mammary ridges or milk lines extend from?
from axillae to groin
58
Why do tattoos "blur" and fade?
because macrophages come along to digest the ink but cannot, so they die and another macrophage comes along. These macrophages do not remain in the same position so the lines of tattoo ink become slightly blurred as macrophages get replaced.
59
The ___ is the darkly pigmented, ridged region around the nipple and contains numerous glands (merocrine, sebaceous).
areola
60
How many sebaceous glands are associated with a hair follicle?
one or more (develop as outgrowths of external root sheath)
61
Where is hair absent from?
thick skin of palms and soles of feet
62
What is the nail lunula covered by?
the cuticle or eponychium
63
What exfoliated layer of the skin makes up the bulk of house dust and dandruff?
stratum corneum dead cells
64
What type of sensory receptors look like melanocytes and are located in stratum basale?
Merkel cells
65
What is first intention healing from?
a clean, surgical incision
66
What enzyme do people affected with albinism possess?
tyrosinase
67
After birth, what is the secretory product of the mammary glands for the first few days?
colostrum
68
Which cell layer is characterized by keratohyaline granules?
stratum granulosum
69
What is gray hair the result of?
decreased melanin production or even air bubbles
70
These glands contain proteins, carbohydrates, ammonia, lipids and organic products.
apocrine glands
71
What is the nail bed called?
hyponichium
72
These unbranched, tubular glands have 1-2 layers of cuboidal or columnar epithelium with excretory ducts.
merocrine/eccrine glands
73
What burn involves only the epidermis?
1st degree burn
74
How can you distinguish an amelanotic melanoma from a squamous cell carcinoma or basal cell carcinoma?
by using a stain for tyrosinase
(+) = melanocytes
(-) = not melanocytes
75
How is tyrosinase useful in tumor identification?
tyrosinase can be used as a marker in tumor cells to differentiate between melanocytes and keratinocytes containing phagocytosed melanin
76
Which keratins are more delicate?
alpha
77
These glands have coiled, tubular glands with large dilated lumina.
apocrine glands
78
Demodex mites feed on ___ secretions.
sebaceous gland
79
What is one of the most common causes of acne?
hypertrophy
80
Where would you find free nerve endings in the skin?
in the epidermis and papillary dermis
81
Which layer of the epidermis has spiny, prickly-looking cells?
stratum spinosum
82
What does a pilosebaceous unit consist of?
a hair follicle, associated arrector pili muscle, and sebaceous gland
83
Wound repair if often referred to as what?
re-epithelialization
84
What is hair made of?
dead keratin
85
What are mammary glands drained by?
drained into the terminal ducts >> lactiferous ducts >> lactiferous sinus (in nipple)
86
In first intention healing, when do neutrophils infiltrate the clot?
within 3-24 hours (acute phase)
87
What layer of the dermis contains hair follicles, sweat glands and sebaceous glands?
deep reticular layer
88
Where is the nail matrix?
underneath the lunula (white crescent) at the base of the nail
89
What prevents shear and mechanical abrasion of the skin?
the corrugations in the attachment area between the epidermis and papillary layer
90
How does the sebaceous gland release its contents?
by secreting the entire cells in its duct
91
The two layers of the dermis are ___ and ___.
superficial papillary layer; deep reticular layer
92
What is the inactive resting phase of hair growth called?
telogen
93
What are "goosebumps" caused by sympathetic stimulation due to cold, fear, or aggression?
piloerection
94
The internal root sheath corresponds to the ___ of the skin.
stratum corneum
95
During ___, fibroblasts produce collagen that migrate into the wound.
fibroplasia
96
What are the flattened, enucleate, dead cell remnants of skin cells?
squames
97
At the base of the bulb is a ____, which is an invagination of dermis containing blood vessels.
vascular core (dermal papilla)
98
___ are derived from the neural crest and are pressure-sensitive mechanoreceptors.
Merkel cells
99
What causes thick "caterpillar" eyebrows in older men?
the missed telogen (rest) phase of the hair growth cycle
100
What does the proximal end of the nail, the "nail root," attach to?
the periosteum of distal phalanx
101
How does your body retain heat in cold temperatures?
by bypassing heat-releasing capillary beds with AV shunts
102
Where does hair growth occus?
deep within the terminal expansion of the follicle "root bulb"
103
What is indicative of a change in phagocytic cells?
the transition from acute to subacute phase
104
____ is an alkaline, yellowish secretion with high protein and salt content, low lipid and carbohydrate content and many antibodies.
Colostrum
105
Where and how is sweat secreted?
onto the skin surface; via a sweat pore
106
Which sensory receptor lacks connective tissue capsule and associated Schwann cells?
free nerve endings
107
Where do new keratinocytes come from?
from the deep germinal layer (matured in 25-50 days)
108
What hair is certain vellus hair replaced with at puberty?
terminal hair
109
Why do we suture wounds?
to attempt to turn a second intention wound healing process into a first intention wound healing process
110
These glands only secrete product.
merocrine/eccrine
111
What forces the shunting of blood around the capillaries?
thickened regions of smooth muscle (sphincters) in the walls of arterioles called glomus bodies - when they contract they force blood into AV shunts
112
How long does it take to replace a fingernail? A toenail?
3 months; 9 months
113
Where does the oxidation of a tyrosine precursor to DOPA occur?
premelanosomes
114
____ forms tonofilaments which aggregate into larger tonofibrils and anchor to desmosomes.
Cytokeratin
115
Why would a surgeon choose to make an incision along a tension line?
so it will heal with less scarring
116
What happens to collagen in an individual with a vitamin C deficiency?
collagen breaks down; old scars can re-open and bleed
117
Is sweating a form of excretion? Why or why not?
YES - because sweat contains urea and uric acid
118
What sensory receptors does the skin contain?
touch, pressure, pain and temperature
119
Why is waxing not permanent?
it removes the hair follicle but does not remove the germinal layer that exhibits growth
120
What are the 4 main functions of skin?
protection
sensation
thermoregulation
metabolic functions
121
A raised, thickened scar from excess fibroplasia during healing is called a what?
keloid
122
An infarct, ulcer or abscess would heal through ____ healing.
second intention
123
What layers of skin do hair follicles originate in?
dermis (and sometimes hypodermis)
124
During first intention healing when is the incision filled with granulation tissue?
day 5
125
What phase of hair growth signals the end of active growth?
catagen
126
In individuals with androgenic alopecia, what enzyme do they have high levels of?
5-a-reductase (causes follicular atrophy)
127
What do Pacinian corpuscles detect?
mechanical and vibratory pressure
128
What contributes to the itching experienced during wound healing?
presence of inflammatory cells and their products
129
What raises the hair follicles by attaching to the sheath and epidermal ridges?
arrector pili muscles
130
What kind of lamellar structures contain glycolipids and provide waterproofing coat for skin cells?
keratinosomes (Odland bodies)
131
Is the dermis vascular?
highly (many sensory receptors)
132
Why do we "tan?"
because exposure to UV light stimulates melanin synthesis (via MSH)
133
Where is the hair growth phase long but the resting phase short?
scalp
134
These glands have a secretory, cuboidal epithelium that is 2-3 cell layers thick and surrounds a large lumen.
apocrine glands
135
What is the purpose of sebum?
waterproofing and moisturizing skin and hair
136
Where would you not find merocrine glands?
the lips and genitalia
137
When does epithelial reapproximation by new stratum basale cells begin during first intention healing?
within 24-48 hours
138
____ sense heat and cold, touch, pain, an movement.
Free nerve endings
139
Does the epidermis have blood vessels?
NO
140
What are the organelles melanin is released from?
melanosomes
141
What are the two kinds of sweating?
thermoregulatory - cholinergic
| emotional - adrenergic
142
Can you find sebum in non-haired skin?
YES - sebum secreted directly onto skin
143
What are the metabolic functions of the skin?
energy stored in subcutaneous fat as triglycerides; Vitamin D synthesized in skin; maintains homeostasis; sweating; immune defense
144
What accounts for our fingerprints (dermatoglyphs)?
large dermal ridges in thick skin
145
Where would you find the subpapillary plexus?
at the junction of papillary and reticular layers
146
What augments re-epithelialization in haired skin in second intention wound healing?
the migration of cells from the external root sheath of hair follicles
147
What slowly restores the multi-layered stratified epidermis during second intention wound healing?
the simultaneous proliferation and maturation of keratinocytes behind the migrating front
148
How is the epidermis supplies and nourished?
by blood vessels in underlying or subjacent dermis
149
Can the epidermis be thick or thin?
yes (1 mm to more than 5 mm)
150
What is the thickest layer of epidermis in thick skin?
stratum corneum
151
What is the largest organ in the body?
skin
152
How does skin protect the body?
blocks UV, mechanical, chemical and thermal damage; prevents dehydration; provides physical barrier to keep microorganisms out
153
What is the involuting phase of hair growth called?
catagen
154
What does 5-a-reductase convert its product to?
testosterone to dihydroxytestosterone
155
What layer of the epidermis is only present in thick skin?
stratum lucidum
156
What happens when keratinocytes mature?
they die and lose nuclei and other organelles
157
What does the nail rest on?
the nail plate rests on a bed of stratified squamous epithelium
158
What are the two types of melanin?
eumelanin and pheomelanin
159
___ is an autoimmune disease characterized by the destruction of melanocytes, leading to depigmentation.
Vitiligo
160
What do sebaceous glands secrete? How?
oily sebum via a pilosebaceous canal
161
This layer is located below the dermis and is composed of loose irregular connective tissue and adipose tissue.
hypodermis
162
The protein fraction is secreted by ____ glands; the lipid fraction is secreted by ____ glands.
merocrine; apocrine
163
What forms the nail plate?
keratin filaments embedded in amorphous matrix
164
Where is the hair growth phase short and resting phase long?
arm hair, eyebrows, body hair
165
Melanocytes are a type of ____ cell.
neuroectodermal
166
How is the stratum basale secured to the basal layer?
by numerous hemidesmosomes, via anchoring filaments and microfibrils
167
What cells contain distinctive Birbeck granules?
Langerhans cells
168
What forms the matrix for tonofibrils of cytokeratin and leads to a mass of mature keratin?
the release and polymerization of lysosomal enzymes
169
What is the thickest layer of epidermis in the skin?
stratum spinosum
170
Where would you find the most Pacinian corpuscles?
in the fingertips and around joints
171
Fingernails grow at ___ the rate of toenails.
3X
172
In first intention healing, when are neutrophils replaced by macrophages?
day 3-7 (transition from acute to subacute phase)
173
What compounds are not formed in those who have albinism?
DOPA; melanin
174
What are structural pigments?
cells are lined up and layered in sheets which cause the reflection and refraction of light (iridescence)
175
What kind of sweating is adrenergic (sympathetic)?
emotional sweating
176
The ___ layer is composed of soft keratin and acts as a hydrophobic barrier.
stratum corneum (squames)
177
The ___ plexus is located at the junction of the reticular layer and hypodermis.
cutaneous
178
In the fingers, toes, and ears, vascular plexi are associated with AV shunts called ___.
glomus bodies
179
____ is genetic and androgen-dependent hair loss.
Androgenic alopecia
180
Which glands secrete their product along with some of the cytoplasm?
apocrine sweat glands
181
During what time period of first intention healing is connective scar tissue covered in intact epithelium?
month 2
182
What happens when the epithelial cells lining hair bulbs mature?
they fill with hard keratin filaments arranged in parallel bundles (which meld together to form hair)
183
The cells of the epidermis are called ___.
keratinocytes
184
How are mammary glands arranged inside the body?
as tubulo-acinar glands organized into secretory lobules
185
Which layer of the epidermis consists of keratinized, stratified squamous epithelium?
epidermis
186
What causes the acrid odor of sweat?
bacterial breakdown
187
How much melanin do melanocytes contain?
not much actually because they release melanin to get taken up by surrounding epithelial cells
188
Thick skin that lacks hair is ___ skin.
glabrous
189
Why do our fingers and toes get cold in freezing tempertures?
because the capillary beds are bypassed and blood is rerouted from arterial to venous circulation to maintain body temperature
190
Where are Langerhans cells generally located?
deep within the stratum spinosum
191
What attributes to psoriasis plaques?
expedited keratinocyte maturation (leads to absence of a granular layer and abnormal keratohyaline and tonofibrils)
192
What are the 3 main layers of the skin?
epidermis
dermis
hypodermis
193
Is hair growth continuous?
NO - happens in phases
194
What burn involves both the epidermis and the dermis?
2nd degree burn
195
Where does nail proliferation and differentiation occur?
in the germinal zone in the nail matrix
196
What is the most superficial layer of the epidermis?
stratum corneum
197
What are inactive mammary glands composed of?
dense irregular collagenous connective tissue, interspersed with adipose tissue and smooth muscle
198
What kind of sweating is cholinergic (parasympathetic)?
thermoregulatory sweating
199
Humans produce 54 different types of keratin, which are all ___ keratins.
alpha
200
Which parts of the body have a thick keratinized layer?
palms and soles of feet
201
How long is the process from keratinization to desquamation and lifting of the scab to reveal new cells?
3 weeks
202
Does hard keratin or soft keratin contain more disulfide bonds to allow cross-linking?
hard keratin
203
What happens due to progressive damage to elastic fibers?
loss of skin tone
204
What constituents is the sebum high in?
lipids and cell debris
205
Coarse hair on scalp, axillae and pubis are known as ___ hair.
terminal
206
What is the growth phase of hair growth called?
anagen
207
The ____ sheath actually lines the hair follicle.
external root
208
Milk production is both ___ and ___.
merocrine; apocrine
209
What are the mechanoreceptors or touch receptors in the dermal ridges of the papillary layer?
Meissner's corpuscles
210
Mammary glands are ___ in males and females until ___.
identical; puberty
211
To produce ____, a tyrosine precursor is oxidized to DOPA by tyrosinase and then eventually to its final product.
melanin
212
Release of lysosomes can also lead to the ___ of the cell.
death
213
What does the high number of antibodies in colostrum equate to?
passive immunity for offspring
214
What is the prominent cellular product of the stratum spinosum?
cytokeratin
215
What are Ruffini corpuscles?
small dermal mechanoreceptors, common in the soles of the feet
216
____ glands are simple, coiled, tubular glands surrounded by myoepithelial cells and assist in secretion.
Sweat
217
What varies in melanin for different indivduals?
variable rates of melanin production and degradation by lysosomal enzymes
218
Which type of sweat gland discharges thick and viscous secretions into the hair follicle?
apocrine glands
219
Which vascular plexus in the skin is the largest of the 3?
subcutaneous plexus
220
Where does thermoregulatory sweating first occur on the body? What about the last place to occur?
axillae, forehead and scalp; last on hands and feet
221
When would skin grafting be necessary?
in full-thickness abrasion or 3rd degree burns or if the wound is very large
222
The ____ is a modified basement membrane that separates hair bulb from surrounding dermis.
glassy membrane
223
What is the shedding of the old hair shaft called?
exogen
224
What burn involves all three layers of the skin?
3rd degree burn
225
Why does the phenomena of raised hair in puffed up cats or raised hackles in dogs not translate to humans?
we have such a reduced hair code the changes can't be seen
226
What are the epidermal projections into the dermis called?
epidermal ridges (rete ridges)
227
Is adrenergic sweating from sympathetic or parasympathetic stimulation?
sympathetic
228
What type of melanin is present in individuals with blonde or red hair?
pheomelanin
229
What forms the lines of tension, Langer's lines?
thick collagen bundles and elastin fibers
230
Where is melanin released from?
melanocytes in organelles called melanosomes
231
How does the skin facilitate thermoregulation?
insulation via hair and subcutaneous fat; heat loss by sweat glands and dermal capillary network
232
These are mechanoreceptors located in the dermis and hypodermis and are large ovoid structures.
Pacinian corpuscles
233
____ contain abundant cytoplasmic extensions and do not stain well on HE.
Langerhans cells
234
What are the three anastomosing vascular plexi of the skin?
superficial subpapillary plexus
deep cutaneous plexus
deeper subcutaneous plexus
235
What is the layer of the epidermis superficial to the stratum basale?
stratum spinosum
236
These granules are non-membrane bound, electron dense granules.
keratohyaline granules
237
Why are white cats with light eyes usually deaf? Why do those with albinism often have neurologic deficits? Why do Dalmatians need to be bred to have a certain number of spots?
because normal pigmentation is important for normal neural development
238
Which types of skin cancer are derived from melanocytes?
melanoma
239
What exfoliated cells in females are collected for a Pap smear?
cervical cells
240
What is the hair shaft produced by?
hair follicles (cylindrical downgrowths of epithelium covered by collagen sheaths)
241
Melanosomes containing eumelanin are ___; those containing pheomelanin are ___.
elongate; ovoid
242
What 3 processes together lead to the production of granulation tissue?
neovascularization
fibroplasia
re-epithelialization
243
Is cholinergic sweating sympathetic or parasympathetic?
parasympathetic
244
What type of cells does the stratum basale consist of?
cuboidal germinal cells that rest on the basement membrane
245
What are unique to primates?
flattened nails
246
During what time period of first intention healing is granulation tissue matured, inflammation is decreasing, and inflammatory cell products cause itching?
week 2
247
The ___ can also be referred to as the subcutis, superficial fascia or panniculus adiposus.
hypodermis
248
What are Langerhans cells associated with regarding allergies?
involved in contact allergic dermatitis
249
What skin layer cells migrate to the edges of the wound in second intention healing?
stratum basale
250
What cells facilitate wound contraction?
myofibroblasts
251
What is the homogenous epidermal layer of enucleate cells between the stratum granulosum and stratum corneum?
stratum lucidum
252
What is sweat composed of?
hypertonic solution of salts and ammonia, urea, and uric acid
253
Sweat is important for ___ cooling.
evaporative
254
What stimulation causes goosebumps?
sympathetic
255
____ are fixed tissue macrophages and antigen presenting cells.
Langerhans cells
256
What is the excessive secretion of sebum called?
seborrhea
257
Do skin cell cancers have the tendency to metastasize?
yes - all are aggressive with tendency to metastasize
258
Where do mammary glands develop along?
paired epidermal ridges (mammary ridges/milk lines)
259
What does hair aid in?
protection and thermoregulation
260
What are the dermal projections into the epidermis called?
dermal ridges (dermal papillae)
261
What is the purpose of keratin plates?
to prevent matting
262
What is the structure of a hair shaft?
outer cortex and inner medulla covered by a thin cuticle of keratin plates
263
____ are in the stratum spinosum and ____ are in the stratum basale, but they look the same!
Langerhans cells; melanocytes
264
What produces hair color?
the incorporation of the absorbed melanin from neighboring melanocytes into the cortex of hair
265
In apocrine glands, what stimulates secretion?
sympathetics (adrenergic)
266
In the dermis, the ___ layer is thin and interdigitates with the epidermis.
papillary layer
267
This cell layer has polyhedral cells with prominent intercellular bridges (desmosomes), numerous cytoplasmic processes, and folding of the cell membrane.
stratum spinosum
268
Are apocrine gland secretions odorless when secreted?
YES
269
What are melanocytes responsible for?
production of melanin, or skin pigment
270
Do all individuals have the same number of melanocytes?
YES
271
What are the two types of sweat glands?
merocrine/eccrine and apocrine
272
Where are melanocytes largely restricted to? Where can they extend into?
basal cell layer (processes may extend into stratum spinosum)
