(M) Lec 1: Skin Flashcards
1
Q
Largest organ/sensory organ of the body
A
Skin
2
Q
Skin is the largest organ of the body that accounts for what percent of the total body weight?
A
15-20%
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
4
Q
In adults, how large is the surface covered by the skin
A
1.5-2 sq meters
5
Q
Skin is also known as? (2 TO)
A
“Integument” or “Cutaneous layer”
6
Q
In older books, the skin is referred to as the?
A
Integumentary System
7
Q
The skin of composed of ______ and ______
A
Epidermis and dermis
8
Q
What are the 5 functions of the skin?
A
- Protection
- Sensory
- Thermoregulation
- Metabolic
- Sexual Signaling
PST, Me Sex
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
10
Q
Function of the skin: Protection
The skin is against UV light due to the presence of?
A
Melanin
11
Q
Function of the skin: Protection
______, ______, ______ insults
A
Mechanical, Chemical, and Thermal insults
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
13
Q
Skin is the largest sensory organ because of what?
A
Receptors
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
15
Q
Function of the skin: Thermoregulation
What are the 2 insulating components of the skin?
A
- Hair
- Adipose tissues
16
Q
Function of the skin: Thermoregulation
The skin accelerates heat loss during cold temperatures via what mechanisms?
A
- Sweat production
- Dense superficial microvasculature
17
Q
Function of the skin: Thermoregulation
When this evaporates, it gives a cooling effect in the body
A
Sweat/Sweat production
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
19
Q
Function of the skin: Metabolic
What does the skin cells synthesize for calcium metabolism and proper bone formation?
A
Vitamin D3
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)
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)
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
23
Q
Function of the skin: Metabolic
This removes excess electrolytes
A
Sweat
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)
25
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
Sexual Signaling
26
Identify the function of the skin: Sex signaling
What are the 2 visual indicators that is involve in attraction between sexes
Pigment and Hair
27
T or F
In the sex signaling function of the skin, sex pheromones are secreted by holocrine glands
F (Sex pheromones are secreted by APOCRINE GLANDS)
28
T or F
Sex pheromones secreted in apocrine glands are not that developed in humans but more for animals
T
29
This is also called as the "surface epithelium"
Epidermis
30
The epidermis layer is how thick?
0.7 - 0.12 mm thick
31
Which layer of the epidermis has plenty of mitotic figures as it is constantly desquamated
germinal basal layer
32
T or F
rate of mitosis = rate of desquamation
T
33
How many days is the rate of desquamation?
(15-30 days) (25-50 days)
34
T or F
It takes half a month until the old skin cells are completely removed
It takes 1 MONTH (average of the two values) until old skin cells are completely removed
35
In the epidermis layer, specifically during mitosis, what happens?
There is a production of keratin
36
This lowest layer of epidermis is also known as the "Germinal layer"
Stratum Basale
37
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
Stratum Basale
38
What cells does the stratum basale supply?
Keratinocytes
39
Stratum basale has plenty of mitotic figures, this means that?
There is active production of cells
40
What is the specific subtype of the cells in stratum basale?
Simple cuboidal or simple (low) columnar
41
What junction complex is present at stratum basale?
Hemidesmosomes
42
T or F
The stratum basale is separated from the dermis as it is attached to the stratum spinsosum bound by desmosomes
F (The stratum basale is separated from the dermis as it is attached to the BASEMENT MEMBRANE bound by HEMIDESMOSOMES)
43
T or F
The nucleus in stratum basale are large,
while cytoplasm is acidophilic
F (Nucleus is indeed large, but cytoplasm is BASOPHILIC)
44
If the cells in stratum basale are columnar, the nuclei will appear?
Elliptical or ovoid
45
This layer of the epidermis is considered to be the thickest layer
Stratum spinosum
46
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
Stratum Spinosum
47
What is the shape and location of the nuclei in stratum spinosum layer?
Polyhedral cells and centrally located nuclei
48
This layer of epidermis is the site of Keratin and Protein synthesis
Stratum Spinosum
49
T or F
Stratum spinosum is where active site of division stops
F (STILL AN ACTIVE SITE OF DIVISION FOR SOME CELLS)
50
51
Stratum basale + stratum spinosum = ?
Stratum Germinativum
52
These are keratin filaments in the stratum spinnosum that converge at desmosomes and hold the cells together
Tonofibrils
53
Prevously, Stratum Germinativum was only referred to as?
Stratum Basale
54
T or F
Epidermis of thick skin has thicker stratum basale
F (thick skin has thicker STRATUM SPINOSUM)
55
Why is the Stratum Spinosum called "spinosum" ?
because during tissue processing, cells separate and show SPINES
56
Identify what layer of epidermis:
→ 3-5 layers of flattened cells
→ undergoes terminal differentiation of keratinization
→ Cytoplasm is intensely filled with basophilic masses
Stratum granulosum
57
These are basophilic masses found in stratum granulosum
Keratohyaline granules
58
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
Stratum Lucidum
59
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
Stratum Corneum
60
In which layer of the epidermis is the end of keratinization?
Stratum Corneum
61
What is preceded by disruption of desmosomes and internal structure of cells in the stratum corneum?
Desquamation
62
T or F: There is loss of granules as you reach the surface from the base
Ano raw??? Basta False
63
T or F: One of the structural changes in the stratum corneum is the loss of organelles as a result of accumulation of granules
True
64
In terms of layers of the epidermis, what's the difference between thick skin and thin skin?
Thick skin has stratum lucidum
65
Number of epidermal layers in thick skin
5
66
Number of epidermal layers in thin skin
4
67
Location of thick skin
Palm and soles
68
Location of thin skin
Rest of the body (except palms and soles)
69
T or F: Thick skin has hair follicles
False
70
T or F: Thin skin has hair follicles
True
71
T or F: Thick skin has arrector pili muscle
False
72
T or F: Thin skin has arrector pili muscle
True
72
T or F: Thick skin has sebaceous glands
False
73
T or F: Thin skin has sebaceous glands
True
74
T or F: Thick skin has sweat glands
True
75
T or F: Thin skin has sebaceous glands
True
76
Enumerate the cells of the epidermis
Keratinocytes
Melanocytes
Langerhans cells
Merkel cells
77
These are the parenchyma of the epidermis
Keratinocytes
78
These cells synthesize keratin and are the major cells in the epidermis
Keratinocytes
79
These cells synthesizes and releases the brown pigment melanin
Melanocytes
80
Melanocytes are located scattered infrequently where?
| layer
Basal layer and junction of dermis
81
These are round cells with pale-staining cytoplasm
Melanocytes
82
Melanocytes contain which enzyme needed for melanin synthesis
Tyrosinase
83
These cells are dendritic cells and are present in all layers of epidermis especially stratum spinosum
Langerhans cells
84
Langerhan cells are how many percent of the epidermal cells?
2 to 8%
85
These are:
– Intercepts microbial invaders in adaptive immune response
– Antigen-presenting cells, for contact allergic and other cell -mediated response
Langerhans Cells
86
These are epithelial tactile cells and low-threshold mechanoreceptors
Merkel Cells
87
These cells sense gentle touch
Merkel Cells
88
Where are Merkel cells abundant?
Fingertips and bases of hair follicles
89
This supports the epidermis and binds to the hypodermis
Dermis
90
Thickness of dermis
0.3 – 4 mm
91
T or F: Epidermis has blood supply but the dermis doesn't
False (Epi is avascular)
92
Where does the epidermis get its nutrients from?
Dermis
93
T or F: Hypodermis is not part of the skin
True
94
Which part is the thickest dermis?
Upper back (i also dk where this is)
95
The layer most responsible for thermoregulation
Dermis
96
Why is the dermis suited for thermoregulation?
It has plenty of blood supply
97
What are the two zones of the dermis?
Papillary and Reticular
98
This is an important constituent of the dermis and makes the skin supple
Elastin
99
– Long and thick in reticular, and follow course of collagen fibers
– Very fine, scanty, scarcely stained in papillary
Elastin
100
Thinner layer of the dermis
Papillary
101
Papillary layer is made up of which specific subtype of CT?
Loose connective tissue
102
Papillary dermis is made up of which type of collagen?
Types I and III
103
What are the cells found in the papillary dermis?
* Fibroblasts
* Mast cells
* Macrophages
* Leukocytes
104
This zone of dermis is made of very fine interlacing collagen fibers with few elastic fibers
Papillary
105
T or F: Reticular dermis is more cellular than the papillary
False
106
T or F: Papillary dermis has smaller blood vessels than the reticular
True
107
What specific subtype of CT is reticular dermis made up of?
Dense irregular CT
108
Reticular dermis is made up of which type of collagen?
Type I
109
This zone of dermis has coarse, irregular bundles of collagen & elastic fibers and blood vessels are larger and deeper
Reticular dermis
110
Hypodermis is also called as?
Superficial fascia
111
This is where some drugs are injected; called as subcutaneous injection
Hypodermis
112
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
Hypodermis
113
What are the accessories found in the dermis?
Meissner Corpuscles and Pacinian Corpuscles
114
These:
- Respond to light touch or low-frequency stimuli
– Abundant in Fingertips, palms, soles
– Decline as one ages
Meissner Corpuscles
115
These:
> Are found in reticular
dermis and hypodermis
> Can detect
* Coarse touch
* Pressure
* High-frequency vibrations
Pacinian corpuscle
116
These are abundant in walls of the rectum, urinary bladder
Pacinian corpuscle
117
What are the skin appendages in the skin?
Hairs
Sebaceous glands
Sweat glands
Nails
118
These are:
- Highly modified keratinized structures
– Produced by hair follicles
Hairs
119
This is the terminal expansion of the follicle where hair growth takes place
Hair bulb
120
Which smooth muscle is attached to the hair?
Arrector pili muscle
121
Part of the hair which has vascular tissue
Dermal papilla
122
Max of how many sebaceous glands can be associated with a hair follicle?
6
123
T or F: Sebaceous glands can be found regardless of presence of hairs
False
124
What is the oily substance secretion of sebaceous glands?
Sebum
125
Which layer of the skin are sebaceous gland embedded?
Dermis
126
Where is the secretion of sebaceous glands released?
To the hair follicle
127
Morphology of sebaceous glands
Simple branched alveolar glands
128
Type of secretion of sebaceous glands
Mucous
129
Mechanism of release of sebaceous glands
Holocrine
130
Cells responsible to produce sebum in sebaceous glands
Sebocytes
131
T or F: There is a total destruction of sebaceous glands as it releases sebum in hair follicles
True
132
The pilosebaceous unit is composed of?
Hair follicle and sebaceous gland
133
T or F: When the arrector pili relaxes, it helps emptying the sebaceous gland in the hair follicle
False (when it contracts)
134
T or F: When the arrector pili contracts, there is an erection of hair shaft
True
135
Sweat glands are also called?
Sudoriferous glands
136
Morphology of sweat glands
Simple coiled tubular glands
137
These glands react by secreting in stressful situations
Sweat gland
138
The watery fluid that sweat glands secrete contains what?
| clue: components ito
Ammonia, sodium, chloride,
urea, and uric acid
139
T or F: Sweat glands discharge in the epidermis
False (directly into the skin surface)
140
Two parts of sweat gland
Secretory tubulus
Excretory duct
141
Mechanism of secretion of sweat glands
Merocrine
142
Two types of sweat gland
Apocrine and Eccrine
143
Parts of an eccrine sweat gland
1. Secretory portions
2. Excretory ducts
3. Myoepithelial cells
144
Part of eccrine sweat gland:
Single layer of large cuboidal or columnar cells
Secretory portion
145
Part of eccrine sweat gland:
– Two layers of smaller cuboidal cells
– Narrower lumen
Excretory duct
146
Part of eccrine sweat gland:
– Between secretory cells and basement membrane
– Contraction expels sweat into ducts
Myoepithelial cells
147
Type of sweat gland found in the axillae, areola, inguinal, and genital regions
Apocrine Sweat Glands
148
T or F: The eccrine sweat gland when acted upon by bacteria, produces an objectionable odor.
False (Apocrine sweat gland)
149
T or F: Apocrine sweat gland needs a hair follicle because it is where its secretion is discharged
True
150
When does apocrine sweat begin functional activity?
Puberty
151
Apocrine sweat glands are activated by which kind of nerves?
Adrenergic nerves
152
Its secretory portion is composed of:
– Coiled tubular type
– Widely dilated lumen
– Low cuboidal cells
– Eosinophilic cytoplasm
Apocrine sweat gland
153
Dense keratinized plate of nail
Nail plate
154
Nail rests on a stratified squamous epithelium called?
Nail bed
155
Proximal end of the nail
Nail root
156
The underlying nail root; where nail growth occurs
Nail matrix
157
White crescent shape at base of nail
Lunula
158
Skin overlying root of nail
Nail fold
159
Nail's highly keratinized free edge
Eponychium
160
The skin beneath free end of nail
Hyponychium
161
These are:
– Highly modified apocrine sweat glands
– Located anterior to pectoral muscles
Mammary glands
162
Morphology of mammary glands
Compound tubuloacinar gland
163
In which tissue are mammary glands embedded?
Adipose tissue
164
Mammary glands are subdivided by what?
Collagenous septa
165
In each breast, how many glandular units are there?
15 - 25
166
Glandular units are called?
Breast lobes
167
In breast, this is a single large duct draining each lobe
Lactiferous duct
168
This is the skin surrounding the nipple, pigmented, contains sebaceous glands not associated with hair follicles
Areola
169
In breasts, lobes are arranged ________ around the nipple
Radially
