Exam 2 - Integument Flashcards
1
Q
functions of integument (5)
A
- protection
- thermoregulation
- sensory organ
- metabolism (vit D synthesis, energy storage)
- excretion (excess water, salt, nitrogenous metabolic wastes through sweat)
2
Q
where is thick skin found?
A
palms of hand and soles of feet
3
Q
what is special about thick skin?
A
no hair follicles
4
Q
where is thin skin found?
A
skin other than palms and soles
5
Q
epidermis
A
keratinized stratified squamous epithelium that contains keratinocytes
6
Q
what is the pattern of keratin accumulation in epidermal cells?
A
accumulate more keratin as they migrate from basal layer
7
Q
maturation time for epidermal cell maturation/desquamation?
A
25-50 days
8
Q
layers of epidermis
A
- stratum basale/germinativum
- stratum spinosum
- stratum granulosum
- stratum lucidum
- stratum corneum
9
Q
stratum basale/germinativum
A
single layer of columnar to cuboidal cells that has many mitotic figures and contains intermediate filaments, desmosomes, and hemidesmosomes
10
Q
what type of intermediate filaments are found in stratum basale?
A
10 nm tonofilaments
11
Q
where are desmosomes found in stratum basale?
A
lateral and upper surface of cells
12
Q
where are hemidesmosomes found in stratum basale?
A
bind cells to basal lamina
13
Q
stratum spinosum
A
cuboidal, polygonal to slightly flattened cells with processes filled with intermediate filaments that terminate with desmosomes and has mitotic figures
14
Q
what do stratum spinosum cells accumulate?
A
fibrillar protein cytokeratin that aggregates to form tonofibrils
15
Q
stratum granulosum
A
3-5 layers of flattened polygonal cells with basophilic keratohyaline granules and oval/rod-like lamellar granules in cytoplasm
16
Q
lamellar granules/keratinosomes
A
granules formed by lipid bilayers which that fuse with cell membrane and exocytose contents into intercellular spaces of stratum granulosum
17
Q
function of lamellar granules?
A
penetration barrier to foreign materials and maintain hydration of body
18
Q
product of lamellar granules?
A
glycolipid - acylglucoceramide
19
Q
stratum lucidum
A
thin layer of eosinophilic, newly keratinized cells w/ no organelles or nuclei
20
Q
where is stratum lucidum found?
A
only in thick skin, but not in all thick skin
21
Q
what is eleidin?
A
transformation product of keratohyalin
22
Q
where is eleidin found?
A
stratum lucidum cells
23
Q
stratum corneum
A
15-20 layers of flattened, non-nucleated cells filled w/ keratin
24
Q
squames
A
dead flattened cells
25
how does skin heal if epidermis injured?
surrounding basal cells migrate and divide to cover wound - retinol/vitamin A needed for keratinocyte differentiation
26
retinol
vitamin A
27
how far do first degree burns extend?
statum lucidum
28
how far do second degree burns extend?
stratum basale
29
how far do third degree burns extend?
dermis
30
where does keratinocyte differentiation occur?
from basal layer to spinosum or granulosum
31
what happens w/ keratinocytes in granulosum?
glycolipids secreted to form multilayered lipid layer on outside of cell membrane
32
what happens w/ keratinocytes in corneum?
protein complex of involucrin-small Pro-rich-loricrin and keratin-filagrin aggregates link to inside of cell membrane
33
melanocytes
pigment producing cells of stratum basale
34
what are melanocytes derived from?
neural crest cells
35
location of melanocytes
rest on basal lamina and send processes into spinosum
36
function of melanocytes
distribute melanin to other cells/hair by exocytosis (cytocrine secretion)
37
how do keratinocytes obtain pigment granules?
endocytosis
38
where does melanin formation occur?
within melanosomes - organelles derived from golgi
39
how is melanin produced?
oxidation of tyrosine to 3,4-DOPA by tyrosinase and transformation of DOPA into melanin
40
how does number of melanocytes differ b/w people of varying skin colors?
same number of melanocytes in everyone - difference is in melanin production
41
addison's disease
lack of cortisol from adrenal cortex which causes overproduction of ACTH -> increases skin pigmentation
42
albinism
melanocytes do not make melanin
43
what causes vision problems in albinism?
abnormal retina development and abnormal nerve connections b/w eye and brain
44
vitiligo
loss of melanocytes - depigmentation; patchy areas on skin that lose pigment
45
what causes vitiligo?
unknown - possibly autoimmune or from sunburn
46
langerhans cells
star shaped cells mainly in spinosum but occasionally in dermis near blood vessels that contain Fc and complement C3 receptors
47
what are langerhans cells derived from?
bone marrow - macrophage lineage
48
function of langerhans cells
can migrate out of epidermis to lymph nodes and present antigens to T cells and/or differentiate into activated dendritic cells
49
what type of attachments do langerhans cells NOT form?
desmosomal attachments with other cells
50
what type of granules do langerhans cells contain?
Birbeck/vermiform granules
51
Birbeck/vermiform granules
membrane-bound, rod-like to racquet shaped granules that contain proteins (langerin) necessary for antigen uptake
52
merkel's cells
tactile epithelium cells associated w/ sensory nerve endings that participate in 2-pt discrimination
53
location of merkel's cells
primarily in thick skin of palms/soles
54
what does merkel cell cytoplasm contain?
small dense granules that are catecholamine-like neurosecretory granules
55
what is base of merkel cell in contact with?
peripheral neuron terminal
56
dermis composition
CT divided into papillary layer and reticular layer containing follicles, sweat glands, sebaceous glands, nerves, extensive capillary network
57
dermis function
supports epidermis and binds it to subQ (hypodermis)
58
dermal papillae
capillary network for thermoregulation and provides blood supply to epidermis by diffusion
59
dermal papillae counterpart in epidermis
epidermal ridges or rete ridges
60
what binds dermis to epidermis?
collagenous anchoring fibrils extending from basal lamina into anchoring plaques
61
papillary layer composition
loose CT w/ fibroblasts, mast cells, macrophages
62
reticular layer composition
dense irregular CT that is thicker than papillary layer
63
hypodermis
deeper continuation of dermis made of loose CT and adipose tissue
64
location of pacinian corpuscles
hypodermis near dermis-hypodermis jxn
65
pacinian corpuscles
pressure/vibration sensors (look like onions)
66
hair follicle
invagination of epidermis that terminates in hair bulb
67
dermal papilla
projects into hair bulb
68
what forms hair root?
epidermal cells covering hair bulb form hair root that produces and is continuous w/ hair shaft
69
hair medulla
cells at apex of dermal papilla that produce large, vacuolated, moderately keratinized cells
70
hair cortex
other cells around the papilla that differentiate into fusiform, heavily keratinized cells
71
hair cuticle
produced by cells more peripheral in the hair root
72
internal and external root sheath
produced by most peripheral root cells of hair
73
glassy membrane
thickened basal lamina that separates hair follicle from dermis
74
arrector pili muscles
smooth muscle bundles extending from dermis papillary layer to hair follicle CT sheath
75
hair follicle and wound healing
clonogenic keratinocyte stem cells migrate up the hair follicles to heal wound
76
sebaceous glands
holocrine glands that secrete oil
77
sebaceous gland distribution
100 glands/cm2 of skin, but face, forehead, scalp have 400-600 glands/cm2 - none on palms and soles
78
sebum
dead sebaceous gland cells + cell contents
79
holocrine gland secretion
as cells proliferate and differentiate, gland acini fills with cells containing fat droplets -> nuclei become pyknotic -> cells burst and release contents
80
acini
basal layer of undifferentiated flattened epithelial cells on basal lamina
81
sudiferous glands
eccrine (merocrine) sweat glands that open onto skin surface
82
what is the shape of sudiferous glands?
simple coiled tubuler gland
83
what nerve fibers do sudiferous glands receive?
cholinergic nerve fibers
84
where is secretory portion of sudiferous glands?
deep in dermis
85
cell types in sudiferous glands?
myoepithelial cells (contractile), dark cells, clear cells
86
secretion from sudiferous glands?
non-viscous secretion w/ little protein, but contains water, NaCl, urea, ammonia, uric acid (ultra filtrate of plasma)
87
dark cells of sweat glands
mucoid, pyramidal cells that secrete glycoproteins
88
clear cells of sweat glands
no secretory granules, but abundant glycogen - secrete water and electrolytes into intercellular canaliculi
89
apocrine sweat glands
sweat glands containing only one kind of secretory cell whose ducts open into hair follicles
90
apocrine sweat gland location
axillary, areolar, anal regions
91
apocrine sweat gland secretion
viscous, protein-containing secretion
92
what nerve fibers do apocrine sweat glands receive?
adrenergic nerve fibers
93
mechanism of secretion for apocrine sweat glands
merocrine mechanism of secretion
94
nails
plates of keratinized epithelial cells
95
where is nail root?
embedded in fold of skin
96
eponychium
cuticle - s. corneum of epithelium over nail root
97
nail plate
from nail matrix, lies on nail bed
98
nail bed
only s. basale and s. spinosum
99
nail matrix
extends from nail root to lunula
100
lunula
white crescent at base of nail
101
liver spots
big freckles on skin of older folks (lentigos) due to sun exposure - NOT related to liver
102
actinic keratosis
precancerous condition that presents w/ thick, scaly patches of skin
103
removal of actinic keratosis?
with liquid N
104
what cancer makes up 90% of skin cancers?
basal cell carcinoma - slow growing and treatable if found early
105
what cancer often develops from sun damaged areas?
squamous cell carcinoma - actinic keratosis due to sun damage
106
malignant melanoma
cancer derived from melanocytes that is hard to treat once metastasized
107
psoriasis
immune-mediated, genetic disease that presents w/ red, scaly patches of skin due to inflammation and hyperplasia -
108
what other clinical manifestations is psoriasis often seen with?
joint problems
