Integumentary System A&P Flashcards
1
Q
What is the term for skin?
A
subcutaneous membrane
2
Q
What are the appendages of the skin?
A
Sweat glands
Sebaceous/oil glands
Hairs and hair follicles
Nails
3
Q
What is the largest organ?
A
skin
4
Q
Skin forms how much of the total body mass?
A
8%
5
Q
What skin covers most part of the body?
A
thin, hairy (hirsute) skin
6
Q
What skin covers the palm, sole, flexor aspect of digits?
A
thick, hairless (glabrous) skin
7
Q
What are the 3 major regions (layers) of the skin?
A
epidermis
dermis
hypodermis/subcutis/paniculus (superficial fascia)
8
Q
What are the 2 main layers of the skin?
A
epidermis and dermis
9
Q
What is the hypodermis mostly made up of?
A
adipose tissue
10
Q
What layer of the skin is the subcutaneous layer part of?
A
hypodermis
11
Q
Is the subcutaneous layer technically considered part of the skin?
A
no
12
Q
Explain epidermis
A
continuously self-renewing, keratinized stratified squamous epithelium
13
Q
What are the cells of the epidermis?
A
keratinocytes
melanocytes
epidermal dendritic (langerhans) cells
tactile (merkel) cells
14
Q
Explain keratinocytes
A
make up majority of the cells (about 90%)
produce fibrous protein keratin
15
Q
Explain Melanocytes
A
10-25% of cells in the basal layer
produce pigment melanin
16
Q
what does pigment melanin do?
A
gives color to our skin
17
Q
What cell is important to the basal layer?
A
melanocytes
18
Q
Explain Epidermal dendritic (Langerhans) cells
A
macrophages that help activate immune system (prevents skin infection)
play a role in facilitating skin allergic reactions (contact dermatitis)
19
Q
Who is most at risk for infection and cancer?
A
person with defective langerhans cells
20
Q
Explain tactile (merkel) cells
A
touch receptors
mostly found in thick skin
21
Q
How many layers does the epidermis contain?
A
5
22
Q
What are the layers of the epidermis? from superficial to deep
A
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale
23
Q
Stratum corneum
A
cornified layer
24
Q
stratum lucidum
A
clear layer found in thick skin - palms and soles
25
stratum granulosum
granular layer
26
stratum spinosum
spinous or prickle layer
27
stratum basale
basal layer
28
What layer of the epidermis is the deepest and firmly attached to the dermis?
stratum basale
29
What is another name for stratum basale?
stratum germinativum
30
Define the stratum germinativum
source of epidermal stem cells that undergo rapid division
31
How long is the journey from basal layer to surface?
25-45 days
32
What is the arrangement of stratum basale?
single row of stem cells
33
Where do the cells within the layers of the epidermis derive from?
stratum basale
34
Does stratum granulosum have a nucleus?
no
35
What layer of the epidermis is thin and has 3-5 cell layers?
stratum granulosum
36
Explain what happens in the stratum granulosum
cells flatten, lose their nuclei and cytoplasmic organelles
37
What do the granules of stratum granulosum contain?
lipid rich secretion which acts as a water sealant and filaggrin
38
Define filaggrin
protein that retains water within keratinocytes
39
In what layer of the epidermis do cells keratohyaline and lamellated granules accumulate?
stratum granulosum
40
Which layer of the epidermis is found in thick skin (palms and soles)?
Stratum lucidum
41
Explain stratum lucidum
thin, transparent band superficial to the stratum granulosum
42
What is the arrangement of stratum lucidum?
a few flat rows of dead keratinocytes
43
What layer of the epidermis contains 20-30 rows of dead, flat, keratinized membranous sacs?
stratum corneum
44
What layer of the epidermis makes ip 3/4 of the epidermal thickness?
stratum corneum
45
Explain what happens in the stratum corneum
the squames on the surface flakes off (makes the main content of household dust)
46
What are the functions of stratum corneum?
protects from abrasion and penetration
waterproofs
acts as a mechanical barrier against biological, chemical, and physical assaults
47
Are the cells of stratum corneum regenerative?
yes
48
What layer of the epidermis can be thought of as a wall of bricks and mortar?
stratum corneum
49
What are the bricks of stratum corneum?
flattened keratinocytes filled with keratin and filaggrin
50
what are the mortar of stratum corneum?
liquid mixture, which surrounds the keratinocytes and provides the water barrier
51
What diseases are related to the epidermis?
bullous pemphigoid
pemphigus vulgaris
psoriasis
atopic dermatitis
melanocytic nevi
melanoma
basal cell cancer
52
What is Bullous pemphigoid?
An autoimmune blistering disease, typically affects older pts
antibodies form to antigens directly beneath the basal layer of the epidermis at the dermoepidermal junction
53
How does bullous pemphigoid clinically present?
tense bullae on an erythemous base on the skin
54
What is Pemphigus Vulgaris?
autoimmune disease typically seen in young adults
autoantibodies are formed against antigens that lie in the intercellular spaces leading to decrease adhesions of the cells and thus skin breaks off
55
What is psoriasis?
the rate of epidermal turnover is increased
the accelerated rate doesn't allow adequate time for differentiation which is recognized as a scale
56
What is atopic dermatitis?
caused by mutations in filaggrin
may be associated with other atopic diseases (asthma)
57
What is Melanocytic Nevi?
aka moles
benign collections of melanocytes
effects epidermis
58
What is melanoma?
malignancy of melanocytes
59
What is basal cell cancer?
composed of cells that resemble basal layer keratinocytes
effects stratum basale
60
How does basal cell cancer present?
pearly, erythematous papules or plaques with rolled borders and telangectatisias in sun exposed areas
61
What is the dermis composed of?
strong, flexible connective tissue
contains blood and lymphatic vessels and nerves which supply the skin, sweat glands, and hair follicles
62
What are the 2 layers of the dermis?
papillary and reticular
63
What does the papillary layer of the dermis do?
provides mechanical anchorage and metabolic support
64
What does the papillary layer of the dermis consist of?
areolar connective tissue with collagen and elastic fibers and blood vessels
65
What does the papillary layer of the dermis form?
numerous papillae which bulge into the epidermis
these are what form your fingerprints
66
What do the dermal papillae of the papillary layer of the dermis contain?
capillary loops
pacinian corpuscle
Meissner's corpuscles
Free nerve endings
67
What parts of the dermal papillae are receptors?
Pacinian corpuscles
Meissner's corpuscles
Free nerve endings
68
What are the pacinian corpuscles responsible for?
pressure and vibration
69
What are the Meissener's corpuscles responsible for?
light touch receptors
70
What are the free nerve endings responsible for?
pain and heat receptors
71
How much of the dermis is made up of the reticular layer?
80% of the thickness
72
What is the reticular layer of the dermis?
thick collagen fibers provide strength and resiliency (granular tissues)
elastic fibers provide stretch-recoil properties
73
Which layer of the dermis is more superficial?
papillary
74
Which layer of the dermis is more deep?
reticular
75
What are the cells of the dermis?
Fibroblasts
macrophages
occasionally mast cells and WBC
76
What do fibroblasts look like?
flat and irregular in outline, with extended processes appearing to be fusiform or spindle shaped
77
What do fibroblasts do?
synthesize most of the extracellular matrix of connective tissue
usually adherent to the fibers of the matrix they lay down
78
When are fibroblasts active and for what reason?
active during wound repair and activity is influenced by various factors such as steroids, dietary content, and mechanical stress
79
What happened to fibroblasts with those with vitamin C deficiency?
there is an impairment of collagen formation, it is slowed down
80
What are keloids?
abnormal scars
81
How do keloids occur?
uncontrolled synthesis and excessive deposition of collagen at sites of prior dermal injury and wound repair - fibroblasts play a role!
82
What is the result of a keloid?
prominent scar that extends beyond the wound
83
Explain the clinical correlation of fibroblasts and keloids
fibroblasts are hyperactive, the overactivity of them results in the scar to keep growing
84
Are keloids hereditary?
you are genetically predisposed to keloids
85
What is a hypertrophied scar?
prominent raised scar that is localized to the wound
86
Explain the correlation of fibroblasts and hypertrophied scars
hyperactivity of fibroblasts results in a raised scar
87
What dermatologic conditions have a correlation to fibroblasts?
keloid and hypertophied scars
88
What is the difference between a keloid and a hypertrophied scar?
hypertrophied scars are localized to the wound (could turn into a keloid) keloids are continuously growing and spreading, not localized to the wound
89
What are mast cells?
defensive cells
90
Where are mast cells most numerous?
around blood vessels
91
What do mast cells look like?
round or oval, with many filopodia extending from the cell surfaces
92
In mast cells, what is the nucleus surrounded by?
vesicles containing granule (such as proteoglycan heparin, HISTAMINE, tryptase) responsible for inflammation
93
Why might mast cells be disrupted?
to release some or all of their granules, either by direct mechanical or chemical trauma, or after contact with particular antigens
94
What are the consequences of granule release?
inflammation
95
What to the disrupted release of mast cells result in?
localized response such as urticaria or generalized response (anaphylactic shock)
96
What is the clinical correlation for mast cells?
urticaria
97
How do mast cells effect urticaria?
mast cell is the major effector cell
characterized by a vascular reaction of the skin with the development of wheals and a red halo or flare
98
How are friction ridges formed?
epidermal ridges lie atop deeper dermal papillary ridges to form friction ridges of fingerprints
99
How are sweat ducts used in friction ridges?
apertures of sweat ducts open at regular intervals along the summit of each ridge
100
What and where are friction ridges?
palm and sole
stable throughout life
unique to individual
significant as a means of identification
101
What forms cleavage lines?
collagen fibers arranged in bundles
102
How are incisions and cleavage lines related?
incisions made parallel to cleavage lines heal more readily - minimize scarring
103
What three pigments contribute to skin color?
melanin
carotene
hemoglobin
104
Where is melanin produced?
melanocytes
migrates to keratinocytes where it forms pigment shields for nuclei
105
What is melanin
yellow to reddish-brown to black, responsible for dark skin colors
106
What are examples of local accumulations of melanin?
freckles and pigmented moles
107
What is carotene?
yellow to orange, most obvious in the palms and soles
108
How does hemoglobin contribute to skin color?
responsible for the pinkish hue of skin
109
What are other factors to consider for skin color?
distribution of hair
skin glands
changes associated with maturation, aging, metabolism, hydration (turgor), pregnancy
110
What is the hypodermis layer?
layer of loose connective tissue that merges with the deep aspect of the dermis
111
What is another term for hypodermis?
superficial fascia
112
Explain the adipose component of the hypodermis
adipose component contributes to thermal insulation, acts as a shock absorber and constitutes a sore of metabolic energy
113
What is the hypodermis rich in?
fatty tissue
114
the hypodermis contributes to the production of which vitamin?
vitamin D
115
What are lipomas?
benign tumors of fat (hypodermis) that are the most common soft tissue tumors of adulthood.
116
What are characteristics of lipomas?
mobile, slowly enlarging, painless masses, mostly solitary lesions
117
What are multiple lipomas suggestive of?
presence of rare autosomal dominant syndromes
118
What is curative of lipomas?
complete excision
119
What disease affects the hypodermis?
erythema nodosum
120
What is erythema nodosum?
inflammation of the hypodermis on the shin
may be idiopathic or a reaction to infections, medication or an underlying autoimmune disease (ex. crohns disease)
121
what are the appendages of the skin?
derivatives of the epidermis
-sweat glands
-sebaceous/oil glands
-hairs and hair follicles
-nails
122
What are the 2 main types sweat glands?
eccrine
apocrine
123
What are the eccrine (merocrine) sweat glands?
sweat
ducts connect to pores
function in thermoregulation (its absence will lead to hyperthermia)
124
What is sweat?
99% water, NaCl, potassium, urea, ammonia, lactic acid, vitamin C and antibodies
loss of hypotonic fluid
125
Where are eccrine sweat glands most abundant?
palms, soles, and forehead
126
What are apocrine sweat glands?
large glands of the dermis or hypodermis that are functional from puberty onward
127
Where are apocrine sweat glands most present?
axilla, perianal region, areolae, periumbilical skin
128
What is the function of apocrine sweat glands?
secretion is initially sterile but it undergoes bacterial decomposition to generate potent odor
129
What are the specialized apocrine sweat glands?
ceruminous glands and mammary glands
130
What are ceruminous glands?
found in the external ear canal, secrete cerumen, produce want to protect ears
131
What characteristic can help to differentiate between eccrine and apocrine in a picture?
eccrine is smaller and more concentrated in the dermis while apocrine are larger
132
What are sebaceous glands?
widely distributed
most develop in hair follicles
become active at puberty
contain sebum
133
What is sebum?
oily holocrine secretion
bactericidal
softens hair and skin
134
What does bactericidal mean?
kills bacteria
135
How can you describe sebaceous glands in a picture?
closely associated to the hair follicle, open into hair follicle
136
What are the functions of hair?
alerting the body to presence of insects on the skin
guarding the scalp against physical trauma, heat loss, and sunlight
137
What is the distribution of hair?
entire body surface except palms, soles, lips, nipples, and portions of external genitalia
138
What are the parts of the hair?
shaft
root
bulb
follicle
139
What is the hair shaft?
filiamentous cornified structures
140
What is the hair shaft made up of?
columns of dead keratinized cells
141
What are the concentric zones?
In fully developed hair, there are 3 concentric zones - cuticle, cortex, and medulla
142
List the 3 concentric zones from most outwards in?
cuticle, cortex, medulla
143
What are the hair pigments in the hair shaft?
melanin (yellow, rust brown, black)
144
Explain gray/white hair?
decreased melanin production, increased air bubbles in shaft
145
What is the hair follicle?
two-layered wall - outer connective tissue root sheath, inner epithelial root sheath - that extends from the epidermal surface into the dermis
146
What are the hair follicle receptors (hair root plexus?
sensory nerve endings around each hair bulb stimulated by bending a hair
147
What is the hair bulb?
encloses the dermal papilla, which is an imp cluster of inductive mesenchymal cells (needed for hair growth)
forms the lowermost part of the follicle
148
How do we know new hair will grow?
as long as dermal papilla is present new hair will grow
149
What is arrector pili?
smooth muscle attached to hair follicle that is responsible for "goose bumps"
150
Where is arrector pili absent from?
facial
eyelashes
eyebrows
nostrils
ear
axillary
pubic hairs
151
Explain smooth muscle and the correlation to arrector pili
supplied by sympathetic nervous system
involuntary, no control how muscle reacts
152
What is the cycle of hair growth?
anagen
catagen
telogen
exogen
153
What is the anagen phase of the hair growth cycle?
the growing phase
hair is actively growing
154
What is the catagen phase of the hair growth cycle?
involuting phase
hair growth ceases and follicle shrinks
155
what is the telogen phase of the hair growth cycle?
resting phase
the inferior segment of the follicle is absent
156
what is the exogen phase of the hair growth cycle?
shedding phase
hair sheds off
157
Why is it normal for us to lose some hair regularly?
because of the hair growth cycle
158
What is a disorder of the pilosebaceous unit?
acne vulgaris
159
What are the 4 factors causing acne vulgaris?
plugging of the hair follicle as a result of abnormal keratinization of the upper portion (gives rise to comedones)
propionibacterium acnes in the hair follicle (lives on the oil and breaks it down to free fatty acids which cause inflammation)
presence of hormones (adrogens)
sebaceous gland activity (increased in presence of androgens)
160
Why is acne vulgaris more present during puberty?
presence of hormones (androgens)
161
What is the structure of a nail?
scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes
162
What are the parts of a nail?
nail plate/body
nail bed
eponychium (cuticle)
lunule
nail matrix
163
What is the nail plate/body?
strong plate of hard keratin
164
What is the nail bed?
specialized form of skin, and has the same four layers of the epidermis
165
What is the eponychium (cuticle)?
thickened layer of skin surrounding fingernails
166
What is the lunule?
white crescent at the proximal end
167
why is the lunule white?
because the underlying epithelium is thicker here and the color of the dermis does not show through from underneath
168
What is the nail matrix?
formed by proliferating cells in the nail root
169
How is the nail matrix effected by an ingrown nail?
it is destroyed
170
What are the 3 main sources that the skin receives its blood supply from?
direct cutaneous system
musculocutaneous system
fasciocutaneous system
171
What two main factors are involved in skin aging?
chronological (physiological change we don't have control of)
environmental
171
What is the skin innervated by?
both somatic and autonomic nervous system, thus making skin a major sensory surface and thermoregulatory oran respectively
172
Explain chronological changes
physiological or intrinsic in origin
173
What is a major environmental factor?
chronic exposure to the sun - referred to as photoaging
174
What are the 4 functions of skin?
protection
body temperature regulation
cutaneous sensations
metabolic functions
blood reservoir
excretion
social communication
175
What are the 3 types of protection barriers (functions of the skin)?
chemical barriers
physical/mechanical barriers
biological barriers
176
What are chemical barriers?
produces enzymes
low pH secretions (acid mantle) and densins retard bacterial activity
thermoregulation
vasoconstriction
production of nutrients (vitamin D)
177
What are physical/mechanical barriers?
keratin and glycolipids block most water and water soluble substances
melanin protects against ultraviolet radiation
178
What are the biological barriers?
dendritic cells
macrophages
179
Explain body temperature regulation as a function of skin
~500 ml/day of routine insensible perspiration (at normal body temperature)
at elevated temperature, dilation of dermal vessels and increased sweat gland activity (sensible perspirations) cool the body
at cooler temperature, dermal blood vessels constrict
180
Explain cutaneous sensations as a function of the skin
temperature, touch, and pain
dysfunction leads to pruritis, dysethesia, and insensitivity to injury
181
Explain metabolic functions as a function of the skin
synthesis of vitamin D precursor and collagenase
182
Explain blood reservoir as a function of the skin
up to 5% of body's blood volume
183
Explain excretion as a function of the skin
nitrogenous wastes and salt in sweat
184
explain social communication as a function of the skin
facial skin can signal emotional states by means of muscular and vascular responses
185
What are common skin lesions?
cyst
fissure
macule
papule
pustule
ulcer
can reflect local or systemic cause
186
What are signs of systemic disease reflected into the skin?
anemia
icterus (liver issuses, skin appears yellow)
cyanosis
dehydration
shock
vitamin deficiency
187
What is inflammation?
It is a protective response intended to eliminate the cause of cell injury
this is first line of defense we are all born with
can be acute or chronic
188
What are cardinal signs of inflammation?
rubor
calor
tumor
dolar
functio laesa
189
Rubor
area becomes red
190
calor
hot
191
tumor
larger
192
dolor
pain
193
What is acute inflammation?
immediate response to injury
short duration
194
What are the main components of acute inflammation?
hemodynamic changes
neutrophils (main type of WBC)
chemical mediators
195
What are hemodynamic changes?
1st step
2nd step
3rd step
4th step
196
What is the 1st step of hemodynamic changes?
initial transient vasoconstriction (close down)
197
What is the 2nd step of hemodynamic changes?
massive vasodilation mediated by histamine, bradykin, and prostaglandins
198
what is the 3rd step of hemodynamic changes?
increased vascular permeability
increased blood supply to area
199
What is the 4th step of hemodynamic changes?
blood flow slows due to increased viscosity, allows neutrophils to marginate
200
What is the function of neutrophils in acute inflammation?
margination and adhesion
emigration
chemotaxis
phagocytosis and degranulation
intracellular killing
201
What/where are the neutrophils in the skin?
neutrophils stick to walls of capillary
will move out and attach to site of inflammation/injury
202
Diapedesis
neutrophils flatten and squeeze out of capillaries
203
leukocytosis
neutrophils enter blood from bone marrow
204
chemotaxis
neutrophils follow chemical trail
205
What are the 6 chemical mediators?
vasoactive amines
products of kinin system
arachidonic acid products
products of lipoxygenase pathway
completment system
cytokines
206
What are the 2 vasoactive amines?
histamine
serotonin
207
What is histamine?
produced by basophils, platelets, and mast cells
causes vasodilation and increased vascular permeability
208
What is serotonin?
produced by platelets
causes vasodilation and increased vascular permeability
209
What is the product of the kinin system?
bradykinin
210
What is bradykinin?
increases vascular permeability
causes pain
vasodilation
bronchoconstriction
211
What are the arachidonic acid products?
thromboxane A2
prostacyclin (PG12)
prostaglandin E2
212
What is thromboxane A2?
produced by platelets
causes vasoconstriction and platelet aggregation
213
What is prostacyclin (PG12)?
produced by vascular endothelium
causes vasodilation and inhibits platelet aggregation
214
What is prostaglandin E2?
causes pain and vasodilation
215
What are products of lipoxygenase pathway?
leukotriene (B4, C4, D4, E4)
causes neutrophil chemotaxis, vasodilation, and increased vascular permeability
216
What is complement system?
helps phagocytosis
217
What are cytokines?
interleukins and tumor necrosis factor
causes fever, enhances adhesions of molecules
218
What are the 4 outcomes of acute inflammation?
complete resolution with regeneration
complete resolution with scarring
abscess formation
transition to chronic inflammation
219
What is chronic inflammation?
inflammation of prolonged duration (weeks to years)
220
What is chronic inflammation characterized by?
infiltrations with mononuclear cells (macrophages, LYMPHOCYTES, and plasma cells)
tissue destruction, largely induced by inflammatory products
repair, involving new vessel proliferation and fibrosis
221
What are the steps of the inflammatory response? Hint: 5 R's
recognition of the injurious agent
recruitment of leukocytes (neutrophils = acute, lymphocytes = chronic)
removal of the agent
regulation (control) of the response
resolution (repair)
222
When does wound healing begin?
as soon as the inflammatory process begins
223
What are the 2 separate processes involved in wound healing?
regeneration of the damaged tissue by cells of the same type
tissue repair by connective tissue (in wound is too big)
224
What are the regenerative capacities of labile cells?
regenerate throughout life (unless stratum basale is gone)
ex: surface epithelial cells, hematopoietic cells, stem cells
225
What are the regenerative capacities of stable cells?
replicate at a low level throughout life
ex: hepatocytes (liver cells), endothelium
226
What are the regenerative capacities of permanent cells?
cannot replicate
ex: neurons and cardiac muscle
replaced by fibrous tissue (scar tissue)
227
What are the 2 types of tissue repair?
primary union and secondary union
228
What is primary union tissue repair?
healing by first intention
occurs with clean wounds
ex: surgical incision
229
What is secondary union tissue repair?
healing by secondary intention
occurs in wounds that have large tissue defects
often results in larger residual scars
