Skin & Oral Mucosa Flashcards
(89 cards)
1
Q
What are the skin layers
A
Epidermis (5 layers) & dermis (2 layers)
2
Q
What areas have thick skin
A
palms & soles
3
Q
What areas have thin skin
A
majority of the body
4
Q
Is the hypodermis (subcutaneous fat) part of the skin?
A
It is closely associated with, but not part of the skin
5
Q
What kind of epithelium does the Epidermis have?
A
Stratified squamous epithelium
6
Q
What populates and regenerates the epidermis
A
keratinocytes
7
Q
What are the layers of the epidermis
A
Stratum Corneum –> Lucidum (thick skin only) –> granulosum –> Spinosum –> Basale
8
Q
What is the cell turnover from basal to superficial layers of the epidermis
A
renewed every 15-30 days
9
Q
What produces sweat glands and hair follices
A
invaginations of the epidermis
10
Q
Does the epidermis contain free nerve endings (sensory receptors)?
A
Yes
11
Q
Is the epidermis avasculature?
A
yes, the cells have to receive nutrients from the dermis
12
Q
What is coated with extracellular layer of lipids for water barrier
A
The stratum corneum
13
Q
What is cornification?
A
Occurs in the stratum corneum: When the keratinocytes are pushed to the surface and become flatted dead cells = squames
14
Q
Does the stratum corneum have nuclei or organelles present?
A
No, and the keratin filaments replace the cytoplasm
15
Q
What is desquamation?
A
The surface cells are shed and replaced continuously to maintain thickness
16
Q
Is stratum corneum thick?
A
The layer varies in thickness, thick skin (15-20 layers)
17
Q
What is found only thick skin and absent in thin skin?
A
Stratum Lucidum
18
Q
What layer has thin, transparent layer of flattened keratinocytes?
A
Stratum Lucidum
19
Q
What is considered a subdivision of the stratum corneum?
A
Stratum Lucidum
20
Q
What layer has refractile appearance and stains poorly?
A
Stratum Lucidum
21
Q
What layer has no nuclei nor organelles present due to degeneration?
A
Stratum Lucidum
22
Q
Is nuclei and organelles present in the stratum granulosum?
A
Yes, but soon cells degenerate and flatten
23
Q
What granules are present in the stratum granulosum?
A
Keratohyalin granules (basophilic): accumulated and adhere keratin filaments together and initiate cornification process
24
Q
Does the stratum granulosum undergo keratinization
A
yes, the cells fill with keratin and move to the surface to be sloughed off
25
Does the stratum granulosum have thick or thin skin?
Both, it can have thin or interrupted in thin skin (3-4 cells in thick skin)
26
What is typically the thickest layer of the epidermis?
Stratum Spinosum & they have the largest keratinocytes
27
What are keratinocytes attached by in the stratum spinosum?
Desmosomes (junctional complexes): gives off spiny/ prickly appearance
28
What layer has cells that exhibit mitotic activity (cell division) and is actively synthesizing keratins?
Stratum spinosum
29
What layer of the epidermis has a round and euchromatic nuclei?
Stratum spinosum
30
What epidermis layer is the deepest?
Stratum Basale, and its adjacent to the dermis
31
What kind of cell shape does the stratum basale have?
single layer of cuboidal or columnar cells
32
What kind of cells reside in the stratum basale layer?
Contains progenitor cells from which new keratinocytes arise by active mitotic division (cell division)/cell proliferation & will be pushed upward, with round euchromatic nuclei
33
What layer rests on the basal lamina of the basement membrane
Stratum basale
34
What layer contains melanocytes
Stratum basale
35
What are the characteristics of thick skin?
palms of the hands & soles of the feet
subject to most abrasion
(0.8 mm to 1.5 mm thick)
hairless, hairless thus no sebaceous glands
thick epidermis
Contains sweat glands
36
What are the characteristics of thin skin?
found on majority of the body
(0.5 mm on the eyelid, 5 mm on the back)
Hairy
thin epidermis, dermis can vary in thickness
contains hair follicles with sebaceous glands
Contains sweat glands
37
What is the difference in thickness within the epidermis layers
Corneum
thick > thin
Lucidum
Absent in thin
Granulosum
thick > thin
Spinosum
thick > thin
Basale
thick = thin
38
What are the cells of the epidermis and what are their functions?
1. Keratinocytes
Highly specialized epithelial cells
2. Langerhans cells
Antigen-presenting cells involved in signaling in the immune system
3. Melanocytes
Pigment-producing cells
4. Merkel cells
Mechanoreceptor cells associated with sensory nerve endings
39
What cell participates in the formation of the epidermal water barrier
keratinocytes
40
Where does the keratinocytes originate from?
stratum basale
41
How do keratinocytes renew themselves
exfoliated cells are constantly being replaced by a steady flow of terminally differentiated cells
42
What cells make up 2%-5% of the epidermis
Langerhans cells
43
What layer is the langerhans cells commonly seen in?
Spinosum layer
44
What cell provides immunosurveillance? What is immunosurveillance?
Langerhans cells; immunosurveillance: sensing the outer environment through dendritic processes
45
How does langerhans cells stain?
stains very poorly with routine histological stain
46
Where are melanocytes predominantly located
Stratum basale
47
What cells synthesize melanin granules which are transferred to keratinocytes?
Melanocytes
48
Octopus like processes
melanocytes
49
What cell appear clear in an H&E-stained section
melanocytes
50
True or false: The number of melanocytes is approximately the same irrespective of race
True!
51
What is the epidermal-dermal junction and what is its function
Scalloped margin consisting of epidermal pegs and dermal papillae
Strengthens attachment of epidermis to the underlying dermis
52
What is situated deep the epidermis and overlies the hypodermis
Dermis
53
What are the 2 layers of the dermis
arranged in 2 layers:
papillary layer = loose CT
reticular layer = dense irregular CT
54
What does the dermis contain?
collagen, elastic fibers (stretch)
blood & lymphatic vessels (richly vascularized for temperature & blood pressure regulation)
nerves/nerve endings & encapsulated receptors
hair follicles with sebaceous glands, & sweat glands
55
What are the characteristics of the papillary layer
composed of loose CT
houses the dermal papillae
loops of small blood vessels, capillaries, nerve endings
56
What are the characteristics of the reticular layer
composed of dense irregular CT
forms the bulk of the dermis
houses blood vessels, lymphatics, & nerves/nerve endings
57
What are the characteristics of the hypodermis
aka superficial fascia/subcutaneous tissue
Deep to dermis but NOT part of the skin
composed of loose CT with adipose tissue
Serves as major energy storage
Provides insulation & cushioning
hair follicles with sebaceous glands
Contains individual smooth muscle cells (arrector pili) “goose bumps”
sweat glands
encapsulated sensory receptors
58
Associated structures
Derived from down growths of epidermal epithelium during development
Includes: hair follicles, sebaceous glands, sweat glands (Apocrine & Eccrine), nails, tactical receptors
59
Hair follicles
Thin skin only with sebaceous glands
similar development to teeth
60
Sebaceous glands
Simple, branched acinar glands
Sebum (lipid-rich/ oily secretion)
61
Sweat glands
Simple coiled tubular glands, associated with BOTH thick & thin skin, secretory portion located deep in the dermis or hypodermis, duct continues to the surface of the skin
62
Apocrine
secretes thick, odorous fluid into hair follicles
63
Eccrine
discharges watery fluid onto skin surface
64
Tactile receptors
located either superficial or deep in the dermis (or hypodermis)
respond to touch, pressure, & vibration
65
Functions of the oral mucosa
protection, taste, secretion, sensation, regeneration, absorption
66
What does the oral cavity extend?
Extends from the lips to the junction of mouth and pharynx
67
What are the subdivision oral cavity
vestibule and oral cavity proper
Vestibule - external junction between teeth & gingivae
Oral Cavity Proper - internal space between dental arches
68
What is the oral cavity bounded by
Bounded by:
Roof – hard & soft palate
Posterior – oropharynx
Floor – tongue & mylohyoid mm
69
What are the oral junctions
mucocutaneous (vermillion boarder)
mucogingival
70
What are the main layers of the oral epithelium
Oral Epithelium (3 types & 3-4 layers)
Lamina Propria (2 layers)
71
What is the lining mucosa
Oral Epithelium (3 types & 3-4 layers)
Lamina Propria (2 layers)
72
What is the masticatory mucosa
Oral Epithelium (3 types & 3-4 layers)
Lamina Propria (2 layers)
73
What is the specialized mucosa
Lines dorsal surface of tongue;
mechanical functions & taste
74
What are some characteristics of the lining mucosa for the oral mucosa?
Only 3 distinct layers
Not keratinized
No lucidum or granulosum
75
What are characteristics of the masticatory mucosa for the oral mucosa?
Only 3 distinct layers
Not fully keratinize – pyknotic nuclei
No lucidum or granulosum
76
What are characteristics of the specialized mucosa for the oral mucosa?
4 distinct layers
fully keratinize – squames
No lucidum, but granulosum present
77
What are components of the submucosa
Loose ct, Fat cells, Blood vessels, Nerves, Salivary glands
78
Submucosa mucosa
lining: present
Specialized: present
Masticatory: only in lateral hard palate (fatty and glandular zone)
79
what is the general characteristics of the lining mucosa
Function - protection & stretch
Location - Lines majority of the oral cavity & vestibule: cheeks, lips, soft palate, uvula, alveolar, sublingual
Epithelium - Non-keratinized
Lamina Propria Papillae - Few shallow
Submucosa - present
80
what is the general characteristics of the masticatory mucosa
Function - Protect against forces of mastication
Location - Gingiva & hard palate
Epithelium - Parakeratinized or Orthokeratinized
Lamina Propria Papillae - Tall
Submucosa - ONLY in lateral hard palate: fatty zone & glandular zone
81
what is the general characteristics of the specialized mucosa
Function - taste
Location - Dorsal surface of tongue
Epithelium - Parakeratinized or Orthokeratinized
Lamina Propria Papillae - Lots of thick
Submucosa - present
82
What are characteristics of the filiform
Filiform
anterior 2/3 dorsal tongue
Most numerous type of papillae
Tough, abrasive surface
No tastebuds
83
What are characteristics of the fungiform
anterior 2/3 dorsal tongue
Less numerous than filiform papillae
Mushroom shaped
Taste buds on surface
84
What are characteristics of the circumvallate
8-10 Near sulcus terminalis
non-keratinized epithelium on lateral walls
Surrounded by a moat
Taste buds on lateral wall
Von Ebner glands: clustered around
85
what epithelium covering a CT core
Papillae
86
What does the cutaneous membrane contain (skin)?
Epidermis
Dermis
Hypodermis
Sweat glands
Hair follicles
87
What does vermillion zone contain
Epithelium
lamina propria
88
Mucosa Membrane (lining mucosa) contains:
Epithelium
Lamina propria
Submucosa
Minor salivary gland
89
Where is the mucogingival junction
Between adjacent gingiva & alveolar regions, transitioning from lining to masticatory mucosa.
