Skin: Histology Flashcards
1
Q
2 junctions that connect keratinocytes
A
Desmosomes and adherens junctions
2
Q
Cells of the stratum germinativum are connected to the basement membrane by these
A
Hemidesmosomes
3
Q
Cells of this are connected to the basement membrane by hemidesmosomes
A
Stratum germinativum
4
Q
Is the epidermis vascularized?
A
No
5
Q
Is the epidermis keratinized?
A
Yes
6
Q
What is the main cell morphology of the epidermis?
A
Stratified squamous epithelium
7
Q
Name the 5 layers of the epidermis from superficial to deep
A
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
8
Q
Component of the corneocyte layer that is found only in thicker skin
Are densely packed with keratin filaments
A
Stratum lucidum
9
Q
Component of the corneocyte layer where nucleus and cytoplasmic organelles become disrupted and disappear as the cell gradually fills with keratin
A
Stratum lucidum
10
Q
Layer of the epidermis that is made up of anucleate, dead cells that are cornified or filled with keratin in place of the cytoplasm
A
Stratum corneum
11
Q
The most superficial cells of this epidermis layer undergo desquamation (shedding)
A
Stratum corneum
12
Q
Layer of the epidermis where keratinocytes take on more keratin and contain basophilic, keratohyalin granules
A
Stratum granulosum
13
Q
Two proteins contained in keratohyalin granules in the granular epidermis layer
A
Profilaggrin and involucrin
14
Q
Filaggrin plays a role in this function of the skin
A
Barrier function
15
Q
Genetic deficiency of this is characterized by lack of water retention in the skin, dryness, eczema, and reduction of protection to external substances
A
Filaggrin
16
Q
Granules in the epidermis granular layer that contain polysacchardies, glycoproteins, and lipids that extrude into the intercellular space help hold together the stratum corneum cells
A
Lamellar granules
17
Q
Lamellar granules are found in this epidermis layer
A
Stratum granulosum
18
Q
Epidermis layer that receives maturing cells that proliferate from the stratum basale
A
Stratum spinosum
19
Q
Epidermis layer made up of large polyhedral keratinocytes
A
Stratum spinosum
20
Q
Keratinocytes in the stratum spinosum synthesize cytoplasmic intermediate filaments called
A
Cytokeratins
21
Q
Cytoplasmic intermediate filaments synthesized by keratinocytes in the stratum spinosum that form tonofilaments
A
Cytokeratins
22
Q
Keratinocytes in the stratum spinosum synthesize cytoplasmic intermediate filaments called cytokeratins that form these
A
Tonofilaments
23
Q
These condensate and form desmosomes, which form strong contacts between adjacent keratinocytes in the stratum spinosum
A
Tonofilaments
24
Q
In the stratum spinosum, tonofilaments condensate and form these
A
Desmosomes
25
Other name for macula adherens
Desmosome
26
Other name for desmosome
Macula adherens
27
2 members of the cadherin family that provide the linkage between the plasma membrane and adjacent cells in a desmosome
Desmogleins and Desmocollins
28
Deepest layer in the epidermis
Stratum basale
29
Morphology of the stratum basale
Single layer of cuboidal to low columnar epithelial cells
30
Layer of the epidermis that consists of a single layer of cuboidal to low columnar epithelial cells
Stratum basale
31
Keratinocytes in this layer proliferate so mitotic figures would be expected
Stratum basale
32
Keratinocytes are anchored to the dermis via these in the stratum basale
Hemidesmosomes
33
These belong to the integrin class of matrix receptors and occur in epithelia that require strong, stable adhesion to the connective tissue
Hemidesmosomes
34
Two types of cells that are dispersed among the keratinocytes of the stratum basale
Melanocytes and Merkel cells
35
Melanocytes and Merkel cells are dispersed among the keratinocytes of this layer of the epidermis
Stratum basale
36
Skin layer that supports the epidermis and consists of fibrous materials, and neurovascular structures
Dermis
37
Skin layer that consists of adipose tissue and neurovascular structures
Subcutis (aka Hypodermis or Panniculus)
38
Cells that separate and protect organisms from the external environment and make up approximately 85% of the epidermal cells
Keratinocytes
39
Cytokeratins are synthesized in this epidermis layer
Stratum spinosum
40
During keratinization, cytokeratins form tonofilaments and bundle to becomes these that fill the cytoplasm
Tonofibrils
41
Distinctive feature in the stratum granulosum and contain cysteine as well as involucrin
Keratohyalin granules
42
Keratohyalin granules are the distinctive feature of this layer of the epidermis
Stratum granulosum
43
Keratohyalin granules in the stratum granulosum contains this molecule which binds filaments together
Cysteine
44
Cysteine is contained in these and binds filaments together
Keratohyalin granules in the stratum granulosum
45
Keratin synthesis begins in the keratinocytes in this layer of the epidermis
Stratum basale
46
During keratinization, keratinocytes in the stratum spinosum superficially start to synthesize these
Keratohyalin granules
47
Molecule contained in keratohyalin granules that is associated with formation of the cell membrane and protein-lipid envelope
Involucrin
48
2 proteins in keratohylain granules that are affiliated with intermediate filaments and the formation of tonofibrils, which initiates the conversion of granules cells into cornified cells
Trichohyalin and Filaggrin
49
Trichohyalin and filaggrin are intermediate filament associated proteins that are contained in these
Keratohyalin granules
50
Changes from stratum granulosum to stratum corneum occur with these 3 things
Decrease in pH
Breakdown of nucleus and other organelles
Thickening of plasma membrane
51
Desquamation at the cornified surface is regulated by proteolytic degradation of these
Desmosomes
52
Membrane coating granules produced by the stratum spinosum
Lamellar bodies
53
Granules produced by the stratum spinosum that contain pro-barrier lipids and processing enzymes that are secreted by exocytosis into the intracellular spaces and form the epidermal water barrier
Lamellar bodies
54
Type of melanin that is a brownish black pigment
Eumelanin
55
Type of melanin that is a reddish yellow pigment
Pheomelanin
56
Color of eumelanin
Brownish black
57
Color of pheomelanin
Reddish yellow
58
Melanin is produced by oxidation of tyrosine by this
Tyrosinase
59
Melanin is produced by oxidation of this by tyrosinase
Tyrosine
60
This is produced by oxidation of tyrosine by tyrosinase
Melanin
61
This is transferred to neighboring keratinocytes by pigment donation, which involves the phagocytosis of the tips of the melanocyte processes by keratinocytes
Melanin
62
APCs that originate from bone marrow, migrate to the skin via blood, and make up only 2-8% of the cells in the epidermis
Langerhans' cells
63
Langerhans cells are located mostly in this layer of the epidermis
Stratum spinosum
64
Molecules that structurally expressed on Langerhans cell surface and used as a clinical marker
CD1a
65
CD1a molecules are a clinical marker for this
Langerhans cells
66
Cells with an indented nucleus and possess tennis racquet-shaped Birbeck granules
Langerhans cells
67
Morphology of the nucleus of Langerhans cells
Indented nucleus
68
In Langerhans cells, these represent relatively small vesicles, which appear as rods with a bulbous expansion at their end
Birbeck granules
69
Birbeck granules are found in this type of cell
Langerhans cells
70
APCs in the epidermis that have lobulated nuclei and almost clear cytoplasm
Langerhans cells
71
Mechanoreceptors that are also called epithelial tactile cells and are located in the stratum basale
Merkel's cells
72
Merkels cell are located in this layer of the epidermis
Stratum basale
73
Cells that are characterized by dense neurosecretory granules containing peptides
Merkel's cells
74
Cells that are closely related to terminal, unmyelinated bulb of afferent sensory fibers that are penetrating the basal lamina
Merkel's cells
75
Rete ridges are another name for this
Epidermal downgrowths
76
Two types of cell adhesion junctions that contribute to the anchoring of the epidermis basal lamina to the dermal layer
Hemidesmosomes and focal adhesions
77
2 layers of the dermis
Papillary layer
Reticular layer
78
Layer of the dermis:
Loose areolar connective tissue
Papillary layer
79
Layer of the dermis:
Finger-like dermal papillae projecting into the stratum basale
Papillary layer
80
The dermis papillary layer has finger-like dermal papillae projecting into this layer of the epidermis
Stratum basale
81
Layer of the dermis:
Adipocytes, fibroblasts, phagocytes
Papillary layers
82
Layer of the dermis:
Contains less dense collagen fibers (type I and III)
Papillary layer
83
The papillary layer of the dermis contains these fibers
Less dense collagen fibers (type I and III)
84
Layer of the dermis:
Lymphatics, nerve fibers, and touch receptors called Meissner corpuscles
Papillary layer
85
Layer of the dermis:
Thicker layer
Reticular layer
86
Layer of the dermis:
Dense irregular connective tissue (elastin)
Reticular layer
87
Layer of the dermis:
Rich sensory and sympathetic nerve supply
Reticular layer
88
The reticular layer of the dermis contains these fibers
Elastin
Collagen fibers (mostly type I) extend into the papillary layer and the hypodermis
89
Collagen fibers (mostly type I) of the reticular layer of the dermis extend into these
Papillary layer and hypodermis
90
Creams that help restore skin turgor by stimulating blood flow and repair of the dermis
Retin-A cream
91
Langer lines are based on these
The orientation of collagen and elastic fivers in the reticular layer of the dermis
92
These are based on the orientation of collagen and elastic fiber orientation in the reticular layer of the dermis
Langer lines
93
Langer lines are based on the orientation of collagen and elastic fiber orientation in this skin layer
Reticular layer of the dermis
94
Form regular lines of tension in the skin and skin incisions that are made parallel to these lines heal with the least amount of scarring
Langer lines
95
Skin layer that is richly vascularized, which aids to the contribution of nutrients to the skin, as well as plays a role in thermoregulation
Dermis
96
A subpapillary plexus sits just inferior to this skin layer, and branches extend into the dermal papillae
Epidermis
97
This sits just inferior to the epidermis, and branches extend into the dermal papillae
Subpapillary plexus
98
This structure with larger blood vessels and lymphatic vessels is located where the dermis ends and the subcutis begins
Deep plexus
99
Where is the subpapillary plexus located in the skin?
Just inferior to the epidermis
branches extend into the dermal papillae
100
Where is the deep plexus with larger blood vessels and lymphatic vessels located in the skin?
Where the dermis ends and the subcutis begins
101
Skin layer that serves as an energy storage site
Subcutaneous layer (subcutis layer, hypodermis)
102
Skin layer deep to the dermis
Subcutaneous layer (subcutis layer, hypodermis)
103
Skin layer that contains adipose tissue that varies throughout region in the body, as well as fibrous bands (septa) that act as supportive structures
Subcutaneous layer (subcutis layer, hypodermis)
104
The vascular supply in this skin layer allows for efficient drug uptake when drugs are injected
Subcutaneous layer
105
Thin layer of striated muscle that lies deep to the subcutaneous fascia in many animals
In humans, it remains well defined in the skin of the neck, face and scalp
Panniculus carnosus
106
Where is the panniculus carnosus located in the skin layers?
Deep to the subcutaneous fascia
107
Afferent or efferent:
Sensory nerves
Afferent
108
Afferent or efferent:
Motor nerves
Efferent
109
Free nerve endings are the most abundant receptors in the epidermis and terminate largely in this layer
Stratum granulosum
110
These are the most abundant receptors in the epidermis and terminate largely in the stratum granulosum
Can be myelinated or unmyelinated
Detects pain, itch, and changes in temperature
Free nerve endings
111
Elliptical structures that are located mostly in the dermal papillae in hairless regions of skin like that of palms, fingertips, and soles
Meissner corpuscle
112
Meissner corpuscles have this shape
Elliptical
113
Meissner corpuscles are located in this location of skin layers
Dermal papillae
114
Meissner corpuscles are found in these regions of the body
Hairless regions of skin like that of palms, fingertips, and soles
115
Meissner corpuscle have sensitivity to this
Light touch
116
Structures where axons course through lamellae made up of flattened Schwann cells
Meissner corpuscle
117
Structures in the dermal papillae that are sensitive to light touch
Meissner corpuscles
118
Nervous structure of the skin:
Response to torque, stretch and the mechanical displacement of collagen fibers
Ruffini corpuscles
119
These are considered phasic receptors that generate short action potentials at the beginning and end of a stimulus
Ruffini corpuscles
120
Simple and encapsulated bulb structures that contain thin collagenous capsules
These are found in genitalia regions and sense low frequency vibrations
Krause end bulbs
121
Simple and encapsulated bulb structures that contain thin collagenous capsules
Krause end bulbs
122
Nervous structure of the skin that senses low frequency vibrations
Found in genitalia regions
Krause end bulbs
123
Pacinian corpuscles receive this type of nerve fiber
Myelinated
124
Nervous structure of the skin sensitive to deep pressure, course touch, and vibrations
Pacinian corpuscles
125
Encapsulated receptors found in deeper regions of the dermis (reticular) and subcutaneous tissue
Pacinian corpuscles
126
Type of hair that is short, soft and pale
Vellus
127
Type of hair that is long, coarse and dark
Terminal
128
Part of the hair follicle that's located between the sebaceous duct opening and the bulge
Isthmus
129
Upper part of a hair follicle that extends from the skin's surface to the opening of the sebaceous duct
Infundibulum
130
Hair follicles arise from invaginations of this
Epidermis
(protrudes into the dermis or further)
131
Area located within the outer root sheath of the hair follicle, where stem cells reside, positioned at the point where the arrector pili muscle attaches to the follicle
Follicular bulge
132
Is hair keratinized?
Yes
133
During injury of the epidermis, the epidermal stem cells migrate from this part of the hair follicle toward the skin surface and participate in the initial resurfacing of damaged epidermis
Follicular bulge
134
Multilayered cellular covering that surrounds the deep part of the hair
Internal root sheath
135
These differentiate into keratin-producing cells and the internal root sheath of the hair follicle
Matrix cells (germinative)
136
Melanocytes located here transfer melanosomes into the epithelial cells that will later differentiate to form hair
Hair bulb matrix
137
Most superficial layer of the internal root sheath of hair
Henle's layer
138
Deepest layer of the internal root sheath of hair
Internal root sheath cuticle
139
3 layers of the internal root sheath, from superficial to deep
Henle's layer
Huxley's layer
Internal root sheath cuticle
140
Layer of the internal root sheath that is in contact with the external root sheath and is made of cuboidal cells
Henle's layer
141
Layer of the internal root sheath that is a single or double layer of flattened cells
Huxley's layer
142
Layer of the internal root sheath that is composed of squamous cells that are in contact with the hair shaft
Internal root sheath cuticle
143
Multilayered section of the hair follicle that is composed of rapidly reproducing matrix cells and has the composition similar to epidermal cells
External root sheath
144
At the hair bulb, this takes on the composition of the stratum basale
External root sheath
145
At the hair bulb, the external root sheath takes on the composition of this
Stratum basale
146
The external root sheath takes on the composition of the stratum basale at this part of the hair follicle
At the hair bulb
147
A thick basal lamina that separates the external root sheath of the hair follicle from the dermis
Glassy membrane
148
The glassy membrane separates this part of the hair follicle from the dermis
External root sheath
149
The glassy membrane separates the external root sheath of the hair follicle from this
Dermis
150
Part of the hair proper that forms the central portion of the shaft and contains a column of loosely connected keratinized cells containing soft keratin (only present in thick hairs)
Medulla
151
Largest layer of the hair proper
Cortex
152
Structure of the hair proper that is composed of cortical cells filled with hard keratin intermediate filaments
These filaments are cross-linked which contribute to the rigidness of the hair shaft
Cortex
153
What contributes to the rigidness of the hair shaft?
Hard keratin intermediate filaments in the cortical cells of the cortex of the hair proper are cross-linked
154
Outermost layer of the hair shaft
Cuticle of hair shaft
155
Part of the hair shaft that consists of several layers of transparent, keratinized squamous cells
Said to resemble fish scales or roof tiles
Cuticle of hair shaft
156
What is the morphology of the cuticle of hair shaft?
Several layers of transparent, keratinized squamous cells
Said to resemble fish scales or roof tiles
157
The growth of hair is due to rapidly dividing, proliferating, and differentiating cells in this part
Hair matrix
158
Melanocytes in this part of the follicle transfer melanosomes into the epithelial cells that will later differentiate to form hair
Hair bulb matrix
159
Consists of smooth muscle fibers and elevates the hair shaft during contraction (goose bumps), as well as contributes to the expression of sebum from the sebaceous gland
Arrector pili muscle
160
Sebaceous glands release their contents (sebum) via this process
Holocrine secretion
161
Glands composed of lobules of large polyhedral pale-staining cells containing abundant lipids droplets and small dark-staining central nuclei
Sebaceous glands
162
Lobules from these structures are located about two-thirds up from the hair bulb and connect to the hair follicle through short sebaceous ducts
Sebaceous glands
163
Types of cells in eccrine sweat glands that are mainly contractile and help expel sweat into the lumen of an acinus
The duct lacks these cells
Myoepithelial cells
164
Cells that provide the protein component of sweat
Rough ER and secretory glands
Dark cells
165
Cells that produce the water component of sweat
Have abundant glyocgen
Clear cells
166
Structure composed of large, tubular branches, that are less coiled than eccrine sweat glands
Apocrine sweat gland
167
In many mammals, glands similar to this secrete pheromones
Apocrine sweat glands
168
Apocrine sweat glands start to function at this stage in life
Puberty
Are controlled by sex hormones
169
Type of sweat gland that starts to function at puberty and is controlled by sex hormones
Apocrine sweat gland
170
Nails are a modified extension of the epidermis, specifically this layer
Stratum corneum
171
The nail plate contains this morphological cell type
Squamous cells
with hard keratin (corneocytes)
172
The nail bed consists of these 2 skin layers
Stratum germinativum (nail matrix) and dermis
173
The edge of the skin fold covering the root of the nail
Eponychium (cuticle)
174
The skin beneath the free end of the nail
Hyponychium
175
Is this dermal or epidermal repair:
1. Blood clot formation
2. Removal of damaged collagen fibers (macrophages)
3. Formation of granulation tissue (new connective tissue)
4. Reepithelization of exposed surface. Proliferation and migration of fibroblasts (5-8 days)
5. Deposition and remodeling of ECM
Dermal
176
Is this dermal or epidermal repair:
1. Proliferation in stratum basale of surrounding undamaged sites
2. Increase in mitotic activity
3. Wound covered by scab that represents dehydrated blood clot (10-15 days)
4. The overlying scab is eventually shed due to proliferation of keratinocytes and desquamation
Epidermal
177
Does dermal or epidermal repair involve the formation of scab?
Epidermal
178
Does dermal or epidermal repair involve formation of granulation tissue?
Dermal
