Integumentary System A&P Flashcards

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1
Q

What is the term for skin?

A

subcutaneous membrane

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2
Q

What are the appendages of the skin?

A

Sweat glands
Sebaceous/oil glands
Hairs and hair follicles
Nails

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3
Q

What is the largest organ?

A

skin

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4
Q

Skin forms how much of the total body mass?

A

8%

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5
Q

What skin covers most part of the body?

A

thin, hairy (hirsute) skin

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6
Q

What skin covers the palm, sole, flexor aspect of digits?

A

thick, hairless (glabrous) skin

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7
Q

What are the 3 major regions (layers) of the skin?

A

epidermis
dermis
hypodermis/subcutis/paniculus (superficial fascia)

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8
Q

What are the 2 main layers of the skin?

A

epidermis and dermis

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9
Q

What is the hypodermis mostly made up of?

A

adipose tissue

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10
Q

What layer of the skin is the subcutaneous layer part of?

A

hypodermis

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11
Q

Is the subcutaneous layer technically considered part of the skin?

A

no

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12
Q

Explain epidermis

A

continuously self-renewing, keratinized stratified squamous epithelium

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13
Q

What are the cells of the epidermis?

A

keratinocytes
melanocytes
epidermal dendritic (langerhans) cells
tactile (merkel) cells

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14
Q

Explain keratinocytes

A

make up majority of the cells (about 90%)
produce fibrous protein keratin

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15
Q

Explain Melanocytes

A

10-25% of cells in the basal layer
produce pigment melanin

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16
Q

what does pigment melanin do?

A

gives color to our skin

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17
Q

What cell is important to the basal layer?

A

melanocytes

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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)

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19
Q

Who is most at risk for infection and cancer?

A

person with defective langerhans cells

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20
Q

Explain tactile (merkel) cells

A

touch receptors
mostly found in thick skin

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21
Q

How many layers does the epidermis contain?

A

5

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22
Q

What are the layers of the epidermis? from superficial to deep

A

stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
stratum basale

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23
Q

Stratum corneum

A

cornified layer

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24
Q

stratum lucidum

A

clear layer found in thick skin - palms and soles

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25
Q

stratum granulosum

A

granular layer

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26
Q

stratum spinosum

A

spinous or prickle layer

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27
Q

stratum basale

A

basal layer

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28
Q

What layer of the epidermis is the deepest and firmly attached to the dermis?

A

stratum basale

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29
Q

What is another name for stratum basale?

A

stratum germinativum

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30
Q

Define the stratum germinativum

A

source of epidermal stem cells that undergo rapid division

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31
Q

How long is the journey from basal layer to surface?

A

25-45 days

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32
Q

What is the arrangement of stratum basale?

A

single row of stem cells

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33
Q

Where do the cells within the layers of the epidermis derive from?

A

stratum basale

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34
Q

Does stratum granulosum have a nucleus?

A

no

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35
Q

What layer of the epidermis is thin and has 3-5 cell layers?

A

stratum granulosum

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36
Q

Explain what happens in the stratum granulosum

A

cells flatten, lose their nuclei and cytoplasmic organelles

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37
Q

What do the granules of stratum granulosum contain?

A

lipid rich secretion which acts as a water sealant and filaggrin

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38
Q

Define filaggrin

A

protein that retains water within keratinocytes

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39
Q

In what layer of the epidermis do cells keratohyaline and lamellated granules accumulate?

A

stratum granulosum

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40
Q

Which layer of the epidermis is found in thick skin (palms and soles)?

A

Stratum lucidum

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41
Q

Explain stratum lucidum

A

thin, transparent band superficial to the stratum granulosum

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42
Q

What is the arrangement of stratum lucidum?

A

a few flat rows of dead keratinocytes

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43
Q

What layer of the epidermis contains 20-30 rows of dead, flat, keratinized membranous sacs?

A

stratum corneum

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44
Q

What layer of the epidermis makes ip 3/4 of the epidermal thickness?

A

stratum corneum

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45
Q

Explain what happens in the stratum corneum

A

the squames on the surface flakes off (makes the main content of household dust)

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46
Q

What are the functions of stratum corneum?

A

protects from abrasion and penetration
waterproofs
acts as a mechanical barrier against biological, chemical, and physical assaults

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47
Q

Are the cells of stratum corneum regenerative?

A

yes

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48
Q

What layer of the epidermis can be thought of as a wall of bricks and mortar?

A

stratum corneum

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49
Q

What are the bricks of stratum corneum?

A

flattened keratinocytes filled with keratin and filaggrin

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50
Q

what are the mortar of stratum corneum?

A

liquid mixture, which surrounds the keratinocytes and provides the water barrier

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51
Q

What diseases are related to the epidermis?

A

bullous pemphigoid
pemphigus vulgaris
psoriasis
atopic dermatitis
melanocytic nevi
melanoma
basal cell cancer

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52
Q

What is Bullous pemphigoid?

A

An autoimmune blistering disease, typically affects older pts
antibodies form to antigens directly beneath the basal layer of the epidermis at the dermoepidermal junction

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53
Q

How does bullous pemphigoid clinically present?

A

tense bullae on an erythemous base on the skin

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54
Q

What is Pemphigus Vulgaris?

A

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

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55
Q

What is psoriasis?

A

the rate of epidermal turnover is increased
the accelerated rate doesn’t allow adequate time for differentiation which is recognized as a scale

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56
Q

What is atopic dermatitis?

A

caused by mutations in filaggrin
may be associated with other atopic diseases (asthma)

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57
Q

What is Melanocytic Nevi?

A

aka moles
benign collections of melanocytes
effects epidermis

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58
Q

What is melanoma?

A

malignancy of melanocytes

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59
Q

What is basal cell cancer?

A

composed of cells that resemble basal layer keratinocytes
effects stratum basale

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60
Q

How does basal cell cancer present?

A

pearly, erythematous papules or plaques with rolled borders and telangectatisias in sun exposed areas

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61
Q

What is the dermis composed of?

A

strong, flexible connective tissue
contains blood and lymphatic vessels and nerves which supply the skin, sweat glands, and hair follicles

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62
Q

What are the 2 layers of the dermis?

A

papillary and reticular

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63
Q

What does the papillary layer of the dermis do?

A

provides mechanical anchorage and metabolic support

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64
Q

What does the papillary layer of the dermis consist of?

A

areolar connective tissue with collagen and elastic fibers and blood vessels

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65
Q

What does the papillary layer of the dermis form?

A

numerous papillae which bulge into the epidermis
these are what form your fingerprints

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66
Q

What do the dermal papillae of the papillary layer of the dermis contain?

A

capillary loops
pacinian corpuscle
Meissner’s corpuscles
Free nerve endings

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67
Q

What parts of the dermal papillae are receptors?

A

Pacinian corpuscles
Meissner’s corpuscles
Free nerve endings

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68
Q

What are the pacinian corpuscles responsible for?

A

pressure and vibration

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69
Q

What are the Meissener’s corpuscles responsible for?

A

light touch receptors

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70
Q

What are the free nerve endings responsible for?

A

pain and heat receptors

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71
Q

How much of the dermis is made up of the reticular layer?

A

80% of the thickness

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72
Q

What is the reticular layer of the dermis?

A

thick collagen fibers provide strength and resiliency (granular tissues)
elastic fibers provide stretch-recoil properties

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73
Q

Which layer of the dermis is more superficial?

A

papillary

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74
Q

Which layer of the dermis is more deep?

A

reticular

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75
Q

What are the cells of the dermis?

A

Fibroblasts
macrophages
occasionally mast cells and WBC

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76
Q

What do fibroblasts look like?

A

flat and irregular in outline, with extended processes appearing to be fusiform or spindle shaped

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77
Q

What do fibroblasts do?

A

synthesize most of the extracellular matrix of connective tissue
usually adherent to the fibers of the matrix they lay down

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78
Q

When are fibroblasts active and for what reason?

A

active during wound repair and activity is influenced by various factors such as steroids, dietary content, and mechanical stress

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79
Q

What happened to fibroblasts with those with vitamin C deficiency?

A

there is an impairment of collagen formation, it is slowed down

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80
Q

What are keloids?

A

abnormal scars

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81
Q

How do keloids occur?

A

uncontrolled synthesis and excessive deposition of collagen at sites of prior dermal injury and wound repair - fibroblasts play a role!

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82
Q

What is the result of a keloid?

A

prominent scar that extends beyond the wound

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83
Q

Explain the clinical correlation of fibroblasts and keloids

A

fibroblasts are hyperactive, the overactivity of them results in the scar to keep growing

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84
Q

Are keloids hereditary?

A

you are genetically predisposed to keloids

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85
Q

What is a hypertrophied scar?

A

prominent raised scar that is localized to the wound

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86
Q

Explain the correlation of fibroblasts and hypertrophied scars

A

hyperactivity of fibroblasts results in a raised scar

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87
Q

What dermatologic conditions have a correlation to fibroblasts?

A

keloid and hypertophied scars

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88
Q

What is the difference between a keloid and a hypertrophied scar?

A

hypertrophied scars are localized to the wound (could turn into a keloid) keloids are continuously growing and spreading, not localized to the wound

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89
Q

What are mast cells?

A

defensive cells

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90
Q

Where are mast cells most numerous?

A

around blood vessels

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91
Q

What do mast cells look like?

A

round or oval, with many filopodia extending from the cell surfaces

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92
Q

In mast cells, what is the nucleus surrounded by?

A

vesicles containing granule (such as proteoglycan heparin, HISTAMINE, tryptase) responsible for inflammation

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93
Q

Why might mast cells be disrupted?

A

to release some or all of their granules, either by direct mechanical or chemical trauma, or after contact with particular antigens

94
Q

What are the consequences of granule release?

A

inflammation

95
Q

What to the disrupted release of mast cells result in?

A

localized response such as urticaria or generalized response (anaphylactic shock)

96
Q

What is the clinical correlation for mast cells?

A

urticaria

97
Q

How do mast cells effect urticaria?

A

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
Q

How are friction ridges formed?

A

epidermal ridges lie atop deeper dermal papillary ridges to form friction ridges of fingerprints

99
Q

How are sweat ducts used in friction ridges?

A

apertures of sweat ducts open at regular intervals along the summit of each ridge

100
Q

What and where are friction ridges?

A

palm and sole
stable throughout life
unique to individual
significant as a means of identification

101
Q

What forms cleavage lines?

A

collagen fibers arranged in bundles

102
Q

How are incisions and cleavage lines related?

A

incisions made parallel to cleavage lines heal more readily - minimize scarring

103
Q

What three pigments contribute to skin color?

A

melanin
carotene
hemoglobin

104
Q

Where is melanin produced?

A

melanocytes
migrates to keratinocytes where it forms pigment shields for nuclei

105
Q

What is melanin

A

yellow to reddish-brown to black, responsible for dark skin colors

106
Q

What are examples of local accumulations of melanin?

A

freckles and pigmented moles

107
Q

What is carotene?

A

yellow to orange, most obvious in the palms and soles

108
Q

How does hemoglobin contribute to skin color?

A

responsible for the pinkish hue of skin

109
Q

What are other factors to consider for skin color?

A

distribution of hair
skin glands
changes associated with maturation, aging, metabolism, hydration (turgor), pregnancy

110
Q

What is the hypodermis layer?

A

layer of loose connective tissue that merges with the deep aspect of the dermis

111
Q

What is another term for hypodermis?

A

superficial fascia

112
Q

Explain the adipose component of the hypodermis

A

adipose component contributes to thermal insulation, acts as a shock absorber and constitutes a sore of metabolic energy

113
Q

What is the hypodermis rich in?

A

fatty tissue

114
Q

the hypodermis contributes to the production of which vitamin?

A

vitamin D

115
Q

What are lipomas?

A

benign tumors of fat (hypodermis) that are the most common soft tissue tumors of adulthood.

116
Q

What are characteristics of lipomas?

A

mobile, slowly enlarging, painless masses, mostly solitary lesions

117
Q

What are multiple lipomas suggestive of?

A

presence of rare autosomal dominant syndromes

118
Q

What is curative of lipomas?

A

complete excision

119
Q

What disease affects the hypodermis?

A

erythema nodosum

120
Q

What is erythema nodosum?

A

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
Q

what are the appendages of the skin?

A

derivatives of the epidermis
-sweat glands
-sebaceous/oil glands
-hairs and hair follicles
-nails

122
Q

What are the 2 main types sweat glands?

A

eccrine
apocrine

123
Q

What are the eccrine (merocrine) sweat glands?

A

sweat
ducts connect to pores
function in thermoregulation (its absence will lead to hyperthermia)

124
Q

What is sweat?

A

99% water, NaCl, potassium, urea, ammonia, lactic acid, vitamin C and antibodies
loss of hypotonic fluid

125
Q

Where are eccrine sweat glands most abundant?

A

palms, soles, and forehead

126
Q

What are apocrine sweat glands?

A

large glands of the dermis or hypodermis that are functional from puberty onward

127
Q

Where are apocrine sweat glands most present?

A

axilla, perianal region, areolae, periumbilical skin

128
Q

What is the function of apocrine sweat glands?

A

secretion is initially sterile but it undergoes bacterial decomposition to generate potent odor

129
Q

What are the specialized apocrine sweat glands?

A

ceruminous glands and mammary glands

130
Q

What are ceruminous glands?

A

found in the external ear canal, secrete cerumen, produce want to protect ears

131
Q

What characteristic can help to differentiate between eccrine and apocrine in a picture?

A

eccrine is smaller and more concentrated in the dermis while apocrine are larger

132
Q

What are sebaceous glands?

A

widely distributed
most develop in hair follicles
become active at puberty
contain sebum

133
Q

What is sebum?

A

oily holocrine secretion
bactericidal
softens hair and skin

134
Q

What does bactericidal mean?

A

kills bacteria

135
Q

How can you describe sebaceous glands in a picture?

A

closely associated to the hair follicle, open into hair follicle

136
Q

What are the functions of hair?

A

alerting the body to presence of insects on the skin
guarding the scalp against physical trauma, heat loss, and sunlight

137
Q

What is the distribution of hair?

A

entire body surface except palms, soles, lips, nipples, and portions of external genitalia

138
Q

What are the parts of the hair?

A

shaft
root
bulb
follicle

139
Q

What is the hair shaft?

A

filiamentous cornified structures

140
Q

What is the hair shaft made up of?

A

columns of dead keratinized cells

141
Q

What are the concentric zones?

A

In fully developed hair, there are 3 concentric zones - cuticle, cortex, and medulla

142
Q

List the 3 concentric zones from most outwards in?

A

cuticle, cortex, medulla

143
Q

What are the hair pigments in the hair shaft?

A

melanin (yellow, rust brown, black)

144
Q

Explain gray/white hair?

A

decreased melanin production, increased air bubbles in shaft

145
Q

What is the hair follicle?

A

two-layered wall - outer connective tissue root sheath, inner epithelial root sheath - that extends from the epidermal surface into the dermis

146
Q

What are the hair follicle receptors (hair root plexus?

A

sensory nerve endings around each hair bulb stimulated by bending a hair

147
Q

What is the hair bulb?

A

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
Q

How do we know new hair will grow?

A

as long as dermal papilla is present new hair will grow

149
Q

What is arrector pili?

A

smooth muscle attached to hair follicle that is responsible for “goose bumps”

150
Q

Where is arrector pili absent from?

A

facial
eyelashes
eyebrows
nostrils
ear
axillary
pubic hairs

151
Q

Explain smooth muscle and the correlation to arrector pili

A

supplied by sympathetic nervous system
involuntary, no control how muscle reacts

152
Q

What is the cycle of hair growth?

A

anagen
catagen
telogen
exogen

153
Q

What is the anagen phase of the hair growth cycle?

A

the growing phase
hair is actively growing

154
Q

What is the catagen phase of the hair growth cycle?

A

involuting phase
hair growth ceases and follicle shrinks

155
Q

what is the telogen phase of the hair growth cycle?

A

resting phase
the inferior segment of the follicle is absent

156
Q

what is the exogen phase of the hair growth cycle?

A

shedding phase
hair sheds off

157
Q

Why is it normal for us to lose some hair regularly?

A

because of the hair growth cycle

158
Q

What is a disorder of the pilosebaceous unit?

A

acne vulgaris

159
Q

What are the 4 factors causing acne vulgaris?

A

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
Q

Why is acne vulgaris more present during puberty?

A

presence of hormones (androgens)

161
Q

What is the structure of a nail?

A

scalelike modification of the epidermis on the distal, dorsal surface of fingers and toes

162
Q

What are the parts of a nail?

A

nail plate/body
nail bed
eponychium (cuticle)
lunule
nail matrix

163
Q

What is the nail plate/body?

A

strong plate of hard keratin

164
Q

What is the nail bed?

A

specialized form of skin, and has the same four layers of the epidermis

165
Q

What is the eponychium (cuticle)?

A

thickened layer of skin surrounding fingernails

166
Q

What is the lunule?

A

white crescent at the proximal end

167
Q

why is the lunule white?

A

because the underlying epithelium is thicker here and the color of the dermis does not show through from underneath

168
Q

What is the nail matrix?

A

formed by proliferating cells in the nail root

169
Q

How is the nail matrix effected by an ingrown nail?

A

it is destroyed

170
Q

What are the 3 main sources that the skin receives its blood supply from?

A

direct cutaneous system
musculocutaneous system
fasciocutaneous system

171
Q

What two main factors are involved in skin aging?

A

chronological (physiological change we don’t have control of)
environmental

171
Q

What is the skin innervated by?

A

both somatic and autonomic nervous system, thus making skin a major sensory surface and thermoregulatory oran respectively

172
Q

Explain chronological changes

A

physiological or intrinsic in origin

173
Q

What is a major environmental factor?

A

chronic exposure to the sun - referred to as photoaging

174
Q

What are the 4 functions of skin?

A

protection
body temperature regulation
cutaneous sensations
metabolic functions
blood reservoir
excretion
social communication

175
Q

What are the 3 types of protection barriers (functions of the skin)?

A

chemical barriers
physical/mechanical barriers
biological barriers

176
Q

What are chemical barriers?

A

produces enzymes
low pH secretions (acid mantle) and densins retard bacterial activity
thermoregulation
vasoconstriction
production of nutrients (vitamin D)

177
Q

What are physical/mechanical barriers?

A

keratin and glycolipids block most water and water soluble substances
melanin protects against ultraviolet radiation

178
Q

What are the biological barriers?

A

dendritic cells
macrophages

179
Q

Explain body temperature regulation as a function of skin

A

~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
Q

Explain cutaneous sensations as a function of the skin

A

temperature, touch, and pain
dysfunction leads to pruritis, dysethesia, and insensitivity to injury

181
Q

Explain metabolic functions as a function of the skin

A

synthesis of vitamin D precursor and collagenase

182
Q

Explain blood reservoir as a function of the skin

A

up to 5% of body’s blood volume

183
Q

Explain excretion as a function of the skin

A

nitrogenous wastes and salt in sweat

184
Q

explain social communication as a function of the skin

A

facial skin can signal emotional states by means of muscular and vascular responses

185
Q

What are common skin lesions?

A

cyst
fissure
macule
papule
pustule
ulcer
can reflect local or systemic cause

186
Q

What are signs of systemic disease reflected into the skin?

A

anemia
icterus (liver issuses, skin appears yellow)
cyanosis
dehydration
shock
vitamin deficiency

187
Q

What is inflammation?

A

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
Q

What are cardinal signs of inflammation?

A

rubor
calor
tumor
dolar
functio laesa

189
Q

Rubor

A

area becomes red

190
Q

calor

A

hot

191
Q

tumor

A

larger

192
Q

dolor

A

pain

193
Q

What is acute inflammation?

A

immediate response to injury
short duration

194
Q

What are the main components of acute inflammation?

A

hemodynamic changes
neutrophils (main type of WBC)
chemical mediators

195
Q

What are hemodynamic changes?

A

1st step
2nd step
3rd step
4th step

196
Q

What is the 1st step of hemodynamic changes?

A

initial transient vasoconstriction (close down)

197
Q

What is the 2nd step of hemodynamic changes?

A

massive vasodilation mediated by histamine, bradykin, and prostaglandins

198
Q

what is the 3rd step of hemodynamic changes?

A

increased vascular permeability
increased blood supply to area

199
Q

What is the 4th step of hemodynamic changes?

A

blood flow slows due to increased viscosity, allows neutrophils to marginate

200
Q

What is the function of neutrophils in acute inflammation?

A

margination and adhesion
emigration
chemotaxis
phagocytosis and degranulation
intracellular killing

201
Q

What/where are the neutrophils in the skin?

A

neutrophils stick to walls of capillary
will move out and attach to site of inflammation/injury

202
Q

Diapedesis

A

neutrophils flatten and squeeze out of capillaries

203
Q

leukocytosis

A

neutrophils enter blood from bone marrow

204
Q

chemotaxis

A

neutrophils follow chemical trail

205
Q

What are the 6 chemical mediators?

A

vasoactive amines
products of kinin system
arachidonic acid products
products of lipoxygenase pathway
completment system
cytokines

206
Q

What are the 2 vasoactive amines?

A

histamine
serotonin

207
Q

What is histamine?

A

produced by basophils, platelets, and mast cells
causes vasodilation and increased vascular permeability

208
Q

What is serotonin?

A

produced by platelets
causes vasodilation and increased vascular permeability

209
Q

What is the product of the kinin system?

A

bradykinin

210
Q

What is bradykinin?

A

increases vascular permeability
causes pain
vasodilation
bronchoconstriction

211
Q

What are the arachidonic acid products?

A

thromboxane A2
prostacyclin (PG12)
prostaglandin E2

212
Q

What is thromboxane A2?

A

produced by platelets
causes vasoconstriction and platelet aggregation

213
Q

What is prostacyclin (PG12)?

A

produced by vascular endothelium
causes vasodilation and inhibits platelet aggregation

214
Q

What is prostaglandin E2?

A

causes pain and vasodilation

215
Q

What are products of lipoxygenase pathway?

A

leukotriene (B4, C4, D4, E4)
causes neutrophil chemotaxis, vasodilation, and increased vascular permeability

216
Q

What is complement system?

A

helps phagocytosis

217
Q

What are cytokines?

A

interleukins and tumor necrosis factor
causes fever, enhances adhesions of molecules

218
Q

What are the 4 outcomes of acute inflammation?

A

complete resolution with regeneration
complete resolution with scarring
abscess formation
transition to chronic inflammation

219
Q

What is chronic inflammation?

A

inflammation of prolonged duration (weeks to years)

220
Q

What is chronic inflammation characterized by?

A

infiltrations with mononuclear cells (macrophages, LYMPHOCYTES, and plasma cells)
tissue destruction, largely induced by inflammatory products
repair, involving new vessel proliferation and fibrosis

221
Q

What are the steps of the inflammatory response? Hint: 5 R’s

A

recognition of the injurious agent
recruitment of leukocytes (neutrophils = acute, lymphocytes = chronic)
removal of the agent
regulation (control) of the response
resolution (repair)

222
Q

When does wound healing begin?

A

as soon as the inflammatory process begins

223
Q

What are the 2 separate processes involved in wound healing?

A

regeneration of the damaged tissue by cells of the same type
tissue repair by connective tissue (in wound is too big)

224
Q

What are the regenerative capacities of labile cells?

A

regenerate throughout life (unless stratum basale is gone)
ex: surface epithelial cells, hematopoietic cells, stem cells

225
Q

What are the regenerative capacities of stable cells?

A

replicate at a low level throughout life
ex: hepatocytes (liver cells), endothelium

226
Q

What are the regenerative capacities of permanent cells?

A

cannot replicate
ex: neurons and cardiac muscle
replaced by fibrous tissue (scar tissue)

227
Q

What are the 2 types of tissue repair?

A

primary union and secondary union

228
Q

What is primary union tissue repair?

A

healing by first intention
occurs with clean wounds
ex: surgical incision

229
Q

What is secondary union tissue repair?

A

healing by secondary intention
occurs in wounds that have large tissue defects
often results in larger residual scars