1
Q
What is the integumentary system?
A
The skin (cutaneous membrane) and its accessory structures
2
Q
What is the largest organ system?
A
The integumentary system
3
Q
Primary function of the integument?
A
Protection and homeostasis
4
Q
What type of tissue is the epidermis?
A
Keratinized stratified squamous epithelium
5
Q
Is the epidermis vascular?
A
No – it is avascular
6
Q
Primary cell type of the epidermis?
A
Keratinocytes
7
Q
What protein makes skin waterproof?
A
Keratin
8
Q
List the epidermal strata (deep to superficial)
A
Basale → Spinosum → Granulosum → Lucidum → Corneum
9
Q
Which epidermal layer undergoes mitosis?
A
Stratum basale
10
Q
Which layer is only found in thick skin?
A
Stratum lucidum
11
Q
Which layer contains dead keratinized cells?
A
Stratum corneum
12
Q
Is the dermis vascular?
A
Yes
13
Q
Name the two dermal layers of the dermis and their relative positions
A
- Papillary - superficial
- Reticular - deep
14
Q
Which dermal layer contains capillaries?
A
Papillary layer
15
Q
Which dermal layer provides strength?
A
Reticular layer
16
Q
What tissue type is the hypodermis?
A
Areolar and adipose connective tissue
17
Q
Is the hypodermis part of the skin?
A
No – it is subcutaneous
18
Q
Function of hypodermis
A
Insulation, energy storage, cushioning, and anchoring.
19
Q
Which germ layer forms the epidermis?
A
Ectoderm
20
Q
Which germ layer forms the dermis?
A
Mesoderm
21
Q
Which cells provide immune defense in epidermis?
A
Langerhans cells
22
Q
Which cells produce pigment?
A
Melanocytes
23
Q
What structure causes goosebumps?
A
Arrector pili muscle
24
Q
A patient has a mutation that reduces keratin production. Which skin function is most directly impaired?
A
Prevention of water loss and physical protection
25
Why does the epidermis heal slower than the dermis?
Because the epidermis is avascular and relies on diffusion from the dermis
26
A drug applied topically must cross which skin layer to reach blood vessels?
The epidermis to reach the dermal blood vessels.
- especially the stratus corneum -
27
Why are first-degree burns painful but heal well?
They damage the epidermis but spare the dermis
28
Why does thick skin resist friction better than thin skin?
It has a thicker stratum corneum and stratum lucidum
29
Loss of dermal collagen would most directly reduce which property of skin?
Tensile strength
30
Why are sweat glands ineffective in hypothermia?
Vasoconstriction limits heat loss but reduces sweating.
31
If epidermal mitosis stops which layer is affected first?
The **stratum basale** is first affected, as it’s where epidermal mitosis occurs, producing new skin cells.
32
Why is edema more likely in hypodermal damage?
Because loose connective tissue allows fluid accumulation
33
Why does dehydration increase skin wrinkling?
Reduced water content affects **keratin** and **dermal elasticity**.
34
Vitiligo affects which epidermal cell type?
Melanocytes
35
Psoriasis is characterized by excessive proliferation of which layer?
Stratum basale
36
Why does psoriasis cause scaling?
Rapid keratinocyte turnover prevents normal keratinization
37
Why do third-degree burns require grafts?
They destroy epidermis and dermis
38
Which skin cancer originates from keratinocytes?
- Basal cell carcinoma (BCC)
- Squamous cell carcinoma (SCC)
39
Which skin cancer is most dangerous and why?
Melanoma, because it metastasizes rapidly and spreads early via blood and lymph.
40
Why are burns involving the dermis life-threatening?
Loss of fluid balance
41
Diabetes impairs wound healing by affecting which skin layer?
Dermis due to reduced blood supply
42
Why does aging skin tear more easily?
Loss of collagen and elastin in the dermis
43
Why are injections often given subcutaneously?
Hypodermis is less vascular, allowing slow, steady absorption of medication into bloodstream.
44
What germ layer gives rise to the epidermis?
Ectoderm
45
What germ layer gives rise to the dermis (corium)?
Mesoderm (mesenchyme)
46
What is another name for the stratum basale?
Stratum germinativum
47
Which epidermal layer is mitotically active?
Stratum basale
48
Which epidermal layer anchors the epidermis to the basement membrane?
Stratum basale
49
Which epidermal layer contains abundant desmosomes?
Stratum spinosum
50
Why is the stratum spinosum called "spiny"?
Desmosomes give cells a spiny appearance
51
Where does keratinization begin?
Stratum granulosum
52
What cellular change occurs in the stratum granulosum?
Cells flatten and lose nuclei
53
Which epidermal layer is present only in thick skin?
Stratum lucidum
54
Where is thick skin found?
Palms of hands and soles of feet
55
Which epidermal layer forms the primary protective barrier?
Stratum corneum
56
Are cells in the stratum corneum alive?
No – they are dead
57
Does thick skin contain hair follicles?
No
58
Does thin skin contain sebaceous glands?
Yes
59
Where are melanocytes located?
Stratum basale
60
What amino acid is used to synthesize melanin?
Tyrosine
61
How is melanin transferred to keratinocytes?
Via melanosomes
62
What is the primary function of melanin?
Protection of nuclear DNA from UV radiation
63
What two germ layers contribute to the integumentary system?
Ectoderm and mesoderm
64
What germ layer gives rise to the epidermis?
Ectoderm
65
What germ layer gives rise to the dermis (corium)?
Mesoderm (mesenchyme)
66
What is another name for the stratum basale?
Stratum germinativum
67
Which epidermal layer is mitotically active?
Stratum basale
68
Which epidermal layer anchors the epidermis to the basement membrane?
Stratum basale
69
Which epidermal layer contains abundant desmosomes?
Stratum spinosum
70
Why is the stratum spinosum called "spiny"?
Desmosomes give cells a spiny appearance
71
Where does keratinization begin?
Stratum granulosum
72
What cellular change occurs in the stratum granulosum?
Cells flatten and lose nuclei
73
Which epidermal layer is present only in thick skin?
Stratum lucidum
74
Where is thick skin found?
Palms of hands and soles of feet
75
Which epidermal layer forms the primary protective barrier?
Stratum corneum
76
Are cells in the stratum corneum alive?
No – they are dead
77
Does thick skin contain hair follicles?
No
78
Does thin skin contain sebaceous glands?
Yes
79
Where are melanocytes located?
Stratum basale
80
What amino acid is used to synthesize melanin?
Tyrosine
81
How is melanin transferred to keratinocytes?
Via melanosomes
82
What is the primary function of melanin?
Protection of nuclear DNA from UV radiation
83
What two germ layers contribute to the integumentary system?
Ectoderm and mesoderm
84
What type of connective tissue makes up most of the reticular layer of the dermis?
Dense irregular connective tissue
85
Why is dense irregular connective tissue ideal for the dermis?
Collagen fibers run in multiple directions allowing resistance to stress from many angles
86
What connective tissue predominates in the papillary layer of the dermis?
Loose (areolar) connective tissue
87
Which dermal fiber provides tensile strength vs elasticity?
- Collagen provides tensile strength
- Elastic fibers provide stretch and recoil
88
What structure interlocks with epidermal ridges?
Dermal papillae
89
Why do surgeons cut parallel to Langer (tension) lines?
- less tension
- faster healing
- better cosmetic outcomes
- less separation of wound edges
- smaller scars
90
What factors determine the orientation of Langer lines?
Collagen fiber orientation
91
Is the hypodermis part of the dermis?
No; it is subcutaneous tissue composed mainly of adipose and areolar connective tissue
92
What are the main functions of the hypodermis?
Insulation
93
Why is areolar connective tissue well suited for diffusion and immune activity?
Loose fibers, abundant ground substance, rich blood supply, and immune cells allow diffusion and surveillance.
94
What mesodermal structure contributes to dermis formation?
Somites
95
Which part of the somite forms the dermis?
Dermatome
96
What are somites?
Body segments of mesoderm
97
Why is mesoderm segmentation important for skin?
It establishes patterned regions that align with
- spinal nerves
- muscles
- bones
98
Which tissues develop in a coordinated segmental pattern?
- Skin (Dermatome)
- Skeletal Muscle (Myotome)
- Bone (Sclerotome)
99
Which somite derivative forms skeletal muscle?
Myotome
100
Which somite derivative forms bone and cartilage?
Sclerotome
101
Is the epidermis segmented like the dermis?
No epidermis is not segmented
102
Clinical relevance: Why does pain follow dermatomal patterns?
Skin sensory regions align with spinal nerve segments
103
What is the rate-limiting step for transdermal (topical) drug absorption?
Stratum corneum — the primary barrier of the epidermis
104
Why is the stratum corneum the rate-limiting step for transdermal drug absorption?
It is keratinized lipid-rich tightly packed and composed of dead cells which impede diffusion
BIOLOGY II
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