1
Q
adip/o
A
fat
2
Q
lip/o
A
fat
3
Q
derm/o
A
skin
4
Q
cutane/o
A
skin
5
Q
diaphor/o
A
profuse sweating
6
Q
erythr/o
A
red
7
Q
hidr/o
A
sweat
7
Q
hist/o
A
tissue
8
Q
kerat/o
A
hard
9
Q
melan/o
A
black
10
Q
onych/o
A
nail
11
Q
plas/o
A
formation
12
Q
purpur/o
A
purple
13
Q
seb/o
A
sebum (oil)
14
Q
squam/o
A
scale
15
Q
trich/o
A
hair
16
Q
xer/o
A
dry
17
Q
six functions of the skin
A
1) thermoregulation
2) protection
3) cutaneous sensations
4) excretion and absorption
5) synthesis of vitamin D
6) immunity
18
Q
rickets and osteomalacia are disorders of _____ _____ deficiency
A
vitamin D
19
Q
stratified, keratinized epithelium with lipids provides a ____ and ______ barrier
A
mechanical, water-proof
20
Q
oily sebum controls _____ growth
A
bacteria
21
Q
melanin protects from ___ ____
A
UV rays
22
Q
thermoregulation occurs via ____ feedback
A
negative
23
Q
two major parts of skin
A
1) epidermis
2) dermis
24
subcutaneous layer is part of the skin true or false?
false
not part of the skin
25
subcutaneous layer is also known as ____ and ____ _____
hypodermis, superficial fascia
26
subcutaneous layer is anchored to the dermis via _____ tissue
areolar
27
subcutaneous layer contains:
- adipocytes
- blood vessels that supply the skin
- pressure receptors
28
What is the epidermis?
avascular, keratinized, stratified, squamous epithelial tissue
29
What are the types of cells of the spidermis
1) keratinocytes
2) melanocytes
3) langerhans cells
4) merkel cells
30
keratonocytes
- 90% of epidermis cell
- produce and fills up with keratin
- produces lamellar granules
- keratinocytes held together by desmosomes and adherens junctions
- anchored by hemidesmosomes to basement membrane
- tight junction prevent leakage between cells
31
Melanocytes
- 8% of epidermis
- produce melanin
- melanin granules transferred to keratinocytes via long slender projections
- protects nucleus from UV, umbrella!
32
Langerhans cells
- arise in bone marrow and migrate to epidermis
- function in immunity to microbes that invade the skin
- easily damaged by UV light
33
merkel cells
- found in deepest layer of epidermis, attached to keratinocytes by desmosomes
- connect to Merkel (tactile) discs (nerve endings) and may function in touch
34
Five layers of epidermis
1) stratum basale (stratum germinativum)
2) stratum spinosum
3) stratum granulosum
4) stratum lucidum
5) stratum corenum
35
stratum basale
- deepest layer
- single layer of columnar or cuboidal keratinocyte stem cells, large nuclei with lots of ribosomes and mitochondria
- tonofilaments, precursor to keratin, is produced here
- stem cells divide to produce new keratinocytes, which then are pushed up and away
- also contains melanocytes and merkel cells
36
stratum spinosum
- 8 - 10 rows of closely packed spiny, polyhedral keratinocyte cells
- shape due to cell shrinkage during slide preparation and the tonofilaments anchoring desmosomes at cell junctions give it a spiny appearance
-provides strength and flexibility
-long projections of melanocytes extended among the keratinocytes
Langerhan’s cells are also located here
37
strtum granolusum
- 3 - 5 rows of flattened keratinocyte cells that develop darkly staining granules (of
keratohyalin)
- substance is involved in arrangement of tonofilaments into thicker bundles of keratin
- contain lamellar granules for secretion of lipids for water-proofing between cells
- cell begin to undergo apoptosis – genetically pre-programmed cell death involving lysosomes
38
stratum lucidum
- found only in the skin of the palms of the hands and the soles of the feet
- 3-5 layers of clear, flat, dead keratinocytes
- contains densely packed intermediate filaments and thickened cell membranes
39
stratum corneum
- most dense and most superficial layer
- 25-30 rows of flat dead keratinocytes completely filled with the tough protein keratin
and surrounded by lipids from lamellar granules
- cells are continually shed and replaced by cells from deeper layers
- effective microbial, mechanical and water-repellent barrier
- callus is an abnormal thickening of the stratum corneum due to constant friction
40
types of skin
1) thin:
hair + sebaceous glands, no stratum lucidum, thinner stratum spinosum and corneum
2) thick:
no hair or sebaceous glands, soles and palms, stratum lucidum present and thicker stratum spinosum and corneum, more sensory receptors
41
keratinization
process that produces a layer of cells that resist abrasion and provide protection
- takes around 4 weeks
- cells form in the basal layer, rise to the surface, become keratinized, die (apoptosis) and are
eventually sloughed off
42
what is psoriasis?
autoimmune skin condition where keratinization is greatly accelerated
43
The dermis consists of:
- connective tissue containing fibers (collagen and elastic)
- cells (fibroblasts, macrophages and adipocytes)
- blood vessels, nerves, sensory structures, glands, hair follicles
- two regions with no distinct demarcation between the two
44
Layers of the dermis
1) papillary region
2) reticular region
45
papillary region is the most _____ region of the dermis
superficial
46
the papillary region consists of ____ connective tissue with fine ____ fibers
areolar, elastic
47
the reticular region of the ___ region of the dermis
deeper
48
what percentage of the dermis does the reticular region take up?
4/5
49
reticular region of the dermis consists of:
- dense, irregular connective tissue with bundles of collagen and coarse elastic fibers
- hair follicles, nerves, sebaceous glands and sweat glands
50
what are striae
stretch marks
tears that occur in the dermis
51
fibrosis is the formation of ____ tissue
scar
52
collagen fibres in scars are ___
denser
53
what are hypertrophic scars?
scars that are slightly raised above the original wound
54
what are keloid scars?
abnormal healing causes the scar to extend well beyond the boundaries of the original
wound
55
What are the three things that make up skin colour?
1) Melanin
2) Carotene
3) Hemoglobin
56
Melanin
- produced by melanocytes
- genetic variations affect the quantity of melanin produced (enzyme production)
- freckles and liver spots are accumulations melanin
- UV light increases the enzymatic activity necessary for the production of melanin
-melanin granules protect the nuclei of keratinocytes in the stratum basale from the
mutagenic effects of UV light
57
albinism is a ____ disorder where one does not synthesize _____
recessive, thyrosinase
58
vitiligo is a ______ disorder caused by the ____ of melanocytes
autoimmune, loss
59
carotene
- yellowish-orange pigment
- precursor to vitamin A needed for vision
- carotene + melanin = yellowish tint to skin
-found in stratum corneum and fatty areas of hypodermis
60
Hemoglobin
- color depends upon the amount and quality of blood moving through capillaries in
the dermis
- vasoconstriction of arteriole blood vessels results in blue skin – cyanotic
- reduced oxygen – pale color due to shock, anemia
61
epidermal ridges
- develop during 3rd - 4th fetal month
- epidermis conforms to underlying nipple-like projections of the dermal papillae
- ridges act to increase the grip of the hand or the foot by acting like little suction cups
62
what are the accessory structures of the integumentary system?
- hair
- exocrine skin glands
- nails
63
functions of hair
- protection, prevents sweat, dust and microbes from getting into eyes, nose, ears (eyebrows, nasal
hairs, eyelashes...)
- protecting the scalp from UV light and acting as insulation
- sensory role, at the base of hairs are touch receptors (hair root plexuses) which are activated when the hair is moved
64
hair is ___
dead💀
65
What are the 3 layers of epithelial cells of shaft and root of hair?
1) medulla
2) cortex - pigment granules in dark hair, gone in white hair
3) outer cuticle - simple squamous cells, keratinized for protection
66
hair follicles are composed of:
1) external root sheath; downward continuation of the epidermis
2) internal root sheath; produced by the matrix
3) dermal root sheath; dense connective tissue of the dermis
67
bulb pf the hair follicle consist of:
1) papilla of the hair; blood vessels provide nutrients for the growing hair
2) matrix of the bulb; ring of cells forming the germinal layer where the hair grows by mitosis
68
______ glands produce the oil in your hair
sebaceous
69
what are arrector pili muscles?
- bands of smooth muscle that attach the hair follicle to the superficial dermis
-contract to pull the hair to a vertical position causing goose bumps when cold/frightened/angry
70
hair root plexuses
nerve endings at the base of each hair,, sensitie to hair movement/touch
71
eumelanin
true melanin, makes brown or black hair
72
pheomelnanin
produces yellow/blond and red hair
73
decline of tyrosinae
this is the enzyme that produces melanin, therefore decline results in greying hair
74
lack of pigment cells of the medulla of hair
causes white hair
75
What are the four exocrine glands of the skin?
1) sebaceous
2) sudoriferous
3) ceruminous
4) mammary
76
sudoriferous glands
- sweat glands
- millions of coiled, tubular glands which open onto the skin surface
Two types:
a) eccrine sweat glands:
b) apocrine sweat glands
77
eccrine sweat glands
- most common
- watery sweat
- found almost all over the body and function throughout life
- numerous on the palms and soles
- secreting portion found in the dermis
- evaporative cooling for temperature regulation
78
apocrine sweat glands
- viscous sweat containing lipids and proteins along with the other watery components
- secreting portion found in the dermis
- duct opens into hair follicles of armpits and pubic region, and areolar region around nipples
- function from puberty on
- “cold sweat” as opposed to the watery sweat we produce when we are
overheating
79
ceruminous glands
- ceru= wax
- found in the ear canal or external auditory meatus (external ear canal)
- open into ducts of sebaceous glands in the ear canal
- cerumen (mixture of the two gland products) provides a sticky substance to prevent the invasion of foreign bodies
80
nails are composed of tightly packed ____ cells
keratinized
81
nail body is ____ and nail root is _____ in skin
visible, buried
82
hyponychium of nail
thickened stratum corneum that secures the free edge of the nail at the
fingertip
83
eponychium of nail
cuticle; composed of stratum corneum and is found on the margins and proximal edge of the nail
84
lunula of nail
white crescent at base of nail
85
what happens to integumentary system as you age?
decrease in:
- number of collagen fibers
- elasticity in elastic fibers
- number of fibroblasts
- number of Langerhans cells (decreased immunity)
- functional melanocyte number
- rate of nail and hair growth
- sweat production
- size thickness of dermis (thinner skin)
- rate of wound healing
increase in:
- stiffness in collagen fibers
- proliferation of some melanocytes - liver spots
86
disorders of integumentary system
- boils
- burns
- dermatitis and eczema
- fungal infections (mycoses)
- herpes simplex virus
- hives
- impetigo
- mols
- open wounds and sores
- psoriasis
- scar tissue
- skin cancer
- ulcers
- warts
