(M) Lec 1: Skin Flashcards

1
Q

Largest organ/sensory organ of the body

A

Skin

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2
Q

Skin is the largest organ of the body that accounts for what percent of the total body weight?

A

15-20%

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3
Q

T or F

Skin is the largest organ of the body that accounts for 5-10% of the total body weight

A

F (15-20%) IJUSTASKED

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4
Q

In adults, how large is the surface covered by the skin

A

1.5-2 sq meters

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5
Q

Skin is also known as? (2 TO)

A

“Integument” or “Cutaneous layer”

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6
Q

In older books, the skin is referred to as the?

A

Integumentary System

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7
Q

The skin of composed of ______ and ______

A

Epidermis and dermis

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8
Q

What are the 5 functions of the skin?

A
  1. Protection
  2. Sensory
  3. Thermoregulation
  4. Metabolic
  5. Sexual Signaling

PST, Me Sex

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9
Q

Identify the function of the skin:

→ The skin is against UV light because of the presence of melanin

→ Mechanical, chemical, and thermal insults

→ Prevents dehydration

→ A physical barrier

A

Protection

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10
Q

Function of the skin: Protection

The skin is against UV light due to the presence of?

A

Melanin

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11
Q

Function of the skin: Protection

______, ______, ______ insults

A

Mechanical, Chemical, and Thermal insults

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12
Q

Identify the function of the skin:

→ largest sensory organ because of receptors

→ Helps in regulation of the body’s interaction with physical objects

A

Sensory

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13
Q

Skin is the largest sensory organ because of what?

A

Receptors

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14
Q

Identify the function of the skin:

→ Maintains constant body temperature

→ A major organ of thermoregulation

→ Hair and adipose tissues are its insulating components

→ Accelerates heat loss during cold temperatures

A

Thermoregulation

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15
Q

Function of the skin: Thermoregulation

What are the 2 insulating components of the skin?

A
  1. Hair
  2. Adipose tissues
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16
Q

Function of the skin: Thermoregulation

The skin accelerates heat loss during cold temperatures via what mechanisms?

A
  1. Sweat production
  2. Dense superficial microvasculature
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17
Q

Function of the skin: Thermoregulation

When this evaporates, it gives a cooling effect in the body

A

Sweat/Sweat production

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18
Q

Identify the function of the skin:

→ Skin cells synthesize Vitamin D for calcium metabolism and proper bone formation

→ Sweat removes excess electrolytes

→ Subcutaneous tissues store energy as fat

A

Metabolic

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19
Q

Function of the skin: Metabolic

What does the skin cells synthesize for calcium metabolism and proper bone formation?

A

Vitamin D3

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20
Q

T or F

Vitamin D3 is synthesized by the skin cells for the repair and moisturization our skin barrier

A

F (Vitamin D3 is synthesize by the skin cells for CALCIUM METABOLISM AND PROPER BONE FORMATION)

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21
Q

T or F

Wide action of UV light on the Vitamin’s precursor performs the action of Vitamin D3 synthesis

A

F (LOCAL action of UV light)

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22
Q

Function of the skin: Metabolic

How many secs/mins/hours is the recommended sun exposure and how many times?

A

10-15 minutes, 2 times a week for vitamin synthesis

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23
Q

Function of the skin: Metabolic

This removes excess electrolytes

A

Sweat

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24
Q

T or F

In the metabolic function of the skin, the cutaneous tissues store energy as proteins

A

F (SUBCUTANEOUS TISSUES store energy as FATS)

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25
Q

Identify the function of the skin:

→ Visual indicators such as pigment and hair that is involved in attraction between sexes

→ Sex pheromones are secreted by apocrine glands

A

Sexual Signaling

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26
Q

Identify the function of the skin: Sex signaling

What are the 2 visual indicators that is involve in attraction between sexes

A

Pigment and Hair

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27
Q

T or F

In the sex signaling function of the skin, sex pheromones are secreted by holocrine glands

A

F (Sex pheromones are secreted by APOCRINE GLANDS)

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28
Q

T or F

Sex pheromones secreted in apocrine glands are not that developed in humans but more for animals

A

T

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29
Q

This is also called as the “surface epithelium”

A

Epidermis

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30
Q

The epidermis layer is how thick?

A

0.7 - 0.12 mm thick

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31
Q

Which layer of the epidermis has plenty of mitotic figures as it is constantly desquamated

A

germinal basal layer

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32
Q

T or F

rate of mitosis = rate of desquamation

A

T

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33
Q

How many days is the rate of desquamation?

A

(15-30 days) (25-50 days)

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34
Q

T or F

It takes half a month until the old skin cells are completely removed

A

It takes 1 MONTH (average of the two values) until old skin cells are completely removed

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35
Q

In the epidermis layer, specifically during mitosis, what happens?

A

There is a production of keratin

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36
Q

This lowest layer of epidermis is also known as the “Germinal layer”

A

Stratum Basale

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37
Q

Identify what layer of epidermis:

→ Provides constant supply of new skin cells

→ The cells here are single layer, simple cuboidal or simple (low) columnar

→ Has plenty of mitotic figures

→ Separated from dermis through membrane bound by hemidesmosomes attached to basement membrane

→ Nucleus is large and cytoplasm is basophilic

A

Stratum Basale

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38
Q

What cells does the stratum basale supply?

A

Keratinocytes

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39
Q

Stratum basale has plenty of mitotic figures, this means that?

A

There is active production of cells

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40
Q

What is the specific subtype of the cells in stratum basale?

A

Simple cuboidal or simple (low) columnar

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41
Q

What junction complex is present at stratum basale?

A

Hemidesmosomes

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42
Q

T or F

The stratum basale is separated from the dermis as it is attached to the stratum spinsosum bound by desmosomes

A

F (The stratum basale is separated from the dermis as it is attached to the BASEMENT MEMBRANE bound by HEMIDESMOSOMES)

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43
Q

T or F

The nucleus in stratum basale are large,

while cytoplasm is acidophilic

A

F (Nucleus is indeed large, but cytoplasm is BASOPHILIC)

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44
Q

If the cells in stratum basale are columnar, the nuclei will appear?

A

Elliptical or ovoid

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45
Q

This layer of the epidermis is considered to be the thickest layer

A

Stratum spinosum

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46
Q

Identify what layer of epidermis:

→ Has polyhedral cells with centrally located nuclei

→ site of keratin and protein synthesis

→ Still an active site of division for some cells

→ Presence of tonofibrils

→ Name derived from its process of separation of cells and showing spines

A

Stratum Spinosum

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47
Q

What is the shape and location of the nuclei in stratum spinosum layer?

A

Polyhedral cells and centrally located nuclei

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48
Q

This layer of epidermis is the site of Keratin and Protein synthesis

A

Stratum Spinosum

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49
Q

T or F

Stratum spinosum is where active site of division stops

A

F (STILL AN ACTIVE SITE OF DIVISION FOR SOME CELLS)

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50
Q
A
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51
Q

Stratum basale + stratum spinosum = ?

A

Stratum Germinativum

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52
Q

These are keratin filaments in the stratum spinnosum that converge at desmosomes and hold the cells together

A

Tonofibrils

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53
Q

Prevously, Stratum Germinativum was only referred to as?

A

Stratum Basale

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54
Q

T or F

Epidermis of thick skin has thicker stratum basale

A

F (thick skin has thicker STRATUM SPINOSUM)

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55
Q

Why is the Stratum Spinosum called “spinosum” ?

A

because during tissue processing, cells separate and show SPINES

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56
Q

Identify what layer of epidermis:

→ 3-5 layers of flattened cells

→ undergoes terminal differentiation of keratinization

→ Cytoplasm is intensely filled with basophilic masses

A

Stratum granulosum

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57
Q

These are basophilic masses found in stratum granulosum

A

Keratohyaline granules

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58
Q

Identify layer of epidermis:

→ Found only in thick skin

→ A thin translucent layer of flattened eosinophilic keratinocytes

→ Held together by desmosomes

→ Does not contain any organelles and nuclei anymroe

→ Cytoplasm contains packed keratin filaments in an electron-dense matrix

A

Stratum Lucidum

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59
Q

Identify layer of epidermis:

→About 15-20 layers of squamous keratinized cells

→ Contains birefringement filamentous keratins

→ Marks of the end of keratinzation

→ Most superficial layer slough off

A

Stratum Corneum

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60
Q

In which layer of the epidermis is the end of keratinization?

A

Stratum Corneum

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61
Q

What is preceded by disruption of desmosomes and internal structure of cells in the stratum corneum?

A

Desquamation

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62
Q

T or F: There is loss of granules as you reach the surface from the base

A

Ano raw??? Basta False

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63
Q

T or F: One of the structural changes in the stratum corneum is the loss of organelles as a result of accumulation of granules

A

True

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64
Q

In terms of layers of the epidermis, what’s the difference between thick skin and thin skin?

A

Thick skin has stratum lucidum

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65
Q

Number of epidermal layers in thick skin

A

5

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66
Q

Number of epidermal layers in thin skin

A

4

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67
Q

Location of thick skin

A

Palm and soles

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68
Q

Location of thin skin

A

Rest of the body (except palms and soles)

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69
Q

T or F: Thick skin has hair follicles

A

False

70
Q

T or F: Thin skin has hair follicles

A

True

71
Q

T or F: Thick skin has arrector pili muscle

A

False

72
Q

T or F: Thin skin has arrector pili muscle

A

True

72
Q

T or F: Thick skin has sebaceous glands

A

False

73
Q

T or F: Thin skin has sebaceous glands

A

True

74
Q

T or F: Thick skin has sweat glands

A

True

75
Q

T or F: Thin skin has sebaceous glands

A

True

76
Q

Enumerate the cells of the epidermis

A

Keratinocytes
Melanocytes
Langerhans cells
Merkel cells

77
Q

These are the parenchyma of the epidermis

A

Keratinocytes

78
Q

These cells synthesize keratin and are the major cells in the epidermis

A

Keratinocytes

79
Q

These cells synthesizes and releases the brown pigment melanin

A

Melanocytes

80
Q

Melanocytes are located scattered infrequently where?

layer

A

Basal layer and junction of dermis

81
Q

These are round cells with pale-staining cytoplasm

A

Melanocytes

82
Q

Melanocytes contain which enzyme needed for melanin synthesis

A

Tyrosinase

83
Q

These cells are dendritic cells and are present in all layers of epidermis especially stratum spinosum

A

Langerhans cells

84
Q

Langerhan cells are how many percent of the epidermal cells?

A

2 to 8%

85
Q

These are:

– Intercepts microbial invaders in adaptive immune response
– Antigen-presenting cells, for contact allergic and other cell -mediated response

A

Langerhans Cells

86
Q

These are epithelial tactile cells and low-threshold mechanoreceptors

A

Merkel Cells

87
Q

These cells sense gentle touch

A

Merkel Cells

88
Q

Where are Merkel cells abundant?

A

Fingertips and bases of hair follicles

89
Q

This supports the epidermis and binds to the hypodermis

A

Dermis

90
Q

Thickness of dermis

A

0.3 – 4 mm

91
Q

T or F: Epidermis has blood supply but the dermis doesn’t

A

False (Epi is avascular)

92
Q

Where does the epidermis get its nutrients from?

A

Dermis

93
Q

T or F: Hypodermis is not part of the skin

A

True

94
Q

Which part is the thickest dermis?

A

Upper back (i also dk where this is)

95
Q

The layer most responsible for thermoregulation

A

Dermis

96
Q

Why is the dermis suited for thermoregulation?

A

It has plenty of blood supply

97
Q

What are the two zones of the dermis?

A

Papillary and Reticular

98
Q

This is an important constituent of the dermis and makes the skin supple

A

Elastin

99
Q

– Long and thick in reticular, and follow course of collagen fibers
– Very fine, scanty, scarcely stained in papillary

A

Elastin

100
Q

Thinner layer of the dermis

A

Papillary

101
Q

Papillary layer is made up of which specific subtype of CT?

A

Loose connective tissue

102
Q

Papillary dermis is made up of which type of collagen?

A

Types I and III

103
Q

What are the cells found in the papillary dermis?

A
  • Fibroblasts
  • Mast cells
  • Macrophages
  • Leukocytes
104
Q

This zone of dermis is made of very fine interlacing collagen fibers with few elastic fibers

A

Papillary

105
Q

T or F: Reticular dermis is more cellular than the papillary

A

False

106
Q

T or F: Papillary dermis has smaller blood vessels than the reticular

A

True

107
Q

What specific subtype of CT is reticular dermis made up of?

A

Dense irregular CT

108
Q

Reticular dermis is made up of which type of collagen?

A

Type I

109
Q

This zone of dermis has coarse, irregular bundles of collagen & elastic fibers and blood vessels are larger and deeper

A

Reticular dermis

110
Q

Hypodermis is also called as?

A

Superficial fascia

111
Q

This is where some drugs are injected; called as subcutaneous injection

A

Hypodermis

112
Q

This layer:

– Loose CT beneath the dermis
–”superficial fascia”
– Binds skin loosely to subjacent organs
– Mainly adipose tissue
– BV’s promote uptake of injected drugs

A

Hypodermis

113
Q

What are the accessories found in the dermis?

A

Meissner Corpuscles and Pacinian Corpuscles

114
Q

These:

  • Respond to light touch or low-frequency stimuli
    – Abundant in Fingertips, palms, soles
    – Decline as one ages
A

Meissner Corpuscles

115
Q

These:

> Are found in reticular
dermis and hypodermis
Can detect
* Coarse touch
* Pressure
* High-frequency vibrations

A

Pacinian corpuscle

116
Q

These are abundant in walls of the rectum, urinary bladder

A

Pacinian corpuscle

117
Q

What are the skin appendages in the skin?

A

Hairs
Sebaceous glands
Sweat glands
Nails

118
Q

These are:

  • Highly modified keratinized structures
    – Produced by hair follicles
A

Hairs

119
Q

This is the terminal expansion of the follicle where hair growth takes place

A

Hair bulb

120
Q

Which smooth muscle is attached to the hair?

A

Arrector pili muscle

121
Q

Part of the hair which has vascular tissue

A

Dermal papilla

122
Q

Max of how many sebaceous glands can be associated with a hair follicle?

A

6

123
Q

T or F: Sebaceous glands can be found regardless of presence of hairs

A

False

124
Q

What is the oily substance secretion of sebaceous glands?

A

Sebum

125
Q

Which layer of the skin are sebaceous gland embedded?

A

Dermis

126
Q

Where is the secretion of sebaceous glands released?

A

To the hair follicle

127
Q

Morphology of sebaceous glands

A

Simple branched alveolar glands

128
Q

Type of secretion of sebaceous glands

A

Mucous

129
Q

Mechanism of release of sebaceous glands

A

Holocrine

130
Q

Cells responsible to produce sebum in sebaceous glands

A

Sebocytes

131
Q

T or F: There is a total destruction of sebaceous glands as it releases sebum in hair follicles

A

True

132
Q

The pilosebaceous unit is composed of?

A

Hair follicle and sebaceous gland

133
Q

T or F: When the arrector pili relaxes, it helps emptying the sebaceous gland in the hair follicle

A

False (when it contracts)

134
Q

T or F: When the arrector pili contracts, there is an erection of hair shaft

A

True

135
Q

Sweat glands are also called?

A

Sudoriferous glands

136
Q

Morphology of sweat glands

A

Simple coiled tubular glands

137
Q

These glands react by secreting in stressful situations

A

Sweat gland

138
Q

The watery fluid that sweat glands secrete contains what?

clue: components ito

A

Ammonia, sodium, chloride,
urea, and uric acid

139
Q

T or F: Sweat glands discharge in the epidermis

A

False (directly into the skin surface)

140
Q

Two parts of sweat gland

A

Secretory tubulus
Excretory duct

141
Q

Mechanism of secretion of sweat glands

A

Merocrine

142
Q

Two types of sweat gland

A

Apocrine and Eccrine

143
Q

Parts of an eccrine sweat gland

A
  1. Secretory portions
  2. Excretory ducts
  3. Myoepithelial cells
144
Q

Part of eccrine sweat gland:

Single layer of large cuboidal or columnar cells

A

Secretory portion

145
Q

Part of eccrine sweat gland:

– Two layers of smaller cuboidal cells
– Narrower lumen

A

Excretory duct

146
Q

Part of eccrine sweat gland:

– Between secretory cells and basement membrane
– Contraction expels sweat into ducts

A

Myoepithelial cells

147
Q

Type of sweat gland found in the axillae, areola, inguinal, and genital regions

A

Apocrine Sweat Glands

148
Q

T or F: The eccrine sweat gland when acted upon by bacteria, produces an objectionable odor.

A

False (Apocrine sweat gland)

149
Q

T or F: Apocrine sweat gland needs a hair follicle because it is where its secretion is discharged

A

True

150
Q

When does apocrine sweat begin functional activity?

A

Puberty

151
Q

Apocrine sweat glands are activated by which kind of nerves?

A

Adrenergic nerves

152
Q

Its secretory portion is composed of:

– Coiled tubular type
– Widely dilated lumen
– Low cuboidal cells
– Eosinophilic cytoplasm

A

Apocrine sweat gland

153
Q

Dense keratinized plate of nail

A

Nail plate

154
Q

Nail rests on a stratified squamous epithelium called?

A

Nail bed

155
Q

Proximal end of the nail

A

Nail root

156
Q

The underlying nail root; where nail growth occurs

A

Nail matrix

157
Q

White crescent shape at base of nail

A

Lunula

158
Q

Skin overlying root of nail

A

Nail fold

159
Q

Nail’s highly keratinized free edge

A

Eponychium

160
Q

The skin beneath free end of nail

A

Hyponychium

161
Q

These are:
– Highly modified apocrine sweat glands
– Located anterior to pectoral muscles

A

Mammary glands

162
Q

Morphology of mammary glands

A

Compound tubuloacinar gland

163
Q

In which tissue are mammary glands embedded?

A

Adipose tissue

164
Q

Mammary glands are subdivided by what?

A

Collagenous septa

165
Q

In each breast, how many glandular units are there?

A

15 - 25

166
Q

Glandular units are called?

A

Breast lobes

167
Q

In breast, this is a single large duct draining each lobe

A

Lactiferous duct

168
Q

This is the skin surrounding the nipple, pigmented, contains sebaceous glands not associated with hair follicles

A

Areola

169
Q

In breasts, lobes are arranged ________ around the nipple

A

Radially