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Questions and Answers
Which of the following layers of the epidermis is responsible for producing melanin?
Which of the following layers of the epidermis is responsible for producing melanin?
What is the primary function of the subcutaneous layer?
What is the primary function of the subcutaneous layer?
Which type of skin cancer originates in the stratum spinosum?
Which type of skin cancer originates in the stratum spinosum?
Which of the following is NOT a characteristic of thick skin?
Which of the following is NOT a characteristic of thick skin?
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What is the function of the sebaceous glands associated with hair follicles?
What is the function of the sebaceous glands associated with hair follicles?
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Which of these epidermal cells is responsible for protecting the body from UV radiation?
Which of these epidermal cells is responsible for protecting the body from UV radiation?
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What is the main function of keratinocytes?
What is the main function of keratinocytes?
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Where in the epidermis do keratinocytes undergo mitosis?
Where in the epidermis do keratinocytes undergo mitosis?
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What is the primary role of Langerhans cells in the epidermis?
What is the primary role of Langerhans cells in the epidermis?
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Which of the following statements accurately describes the role of melanin in the skin?
Which of the following statements accurately describes the role of melanin in the skin?
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What is the primary function of the lamellar granules found in the stratum granulosum?
What is the primary function of the lamellar granules found in the stratum granulosum?
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Which layer of the epidermis is responsible for the majority of cell division and proliferation of keratinocytes?
Which layer of the epidermis is responsible for the majority of cell division and proliferation of keratinocytes?
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Which layer of the epidermis contains cells that are responsible for pigmentation?
Which layer of the epidermis contains cells that are responsible for pigmentation?
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Which of the following is NOT a characteristic of the stratum corneum?
Which of the following is NOT a characteristic of the stratum corneum?
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Which layer of the epidermis is characterized by the presence of desmosomes?
Which layer of the epidermis is characterized by the presence of desmosomes?
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Which type of cell is responsible for stimulating a sensory nerve cell in the epidermis?
Which type of cell is responsible for stimulating a sensory nerve cell in the epidermis?
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Which of the following cell types is responsible for immune responses in the epidermis?
Which of the following cell types is responsible for immune responses in the epidermis?
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Which of the following statements accurately describes the stratum lucidum?
Which of the following statements accurately describes the stratum lucidum?
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Which of the following is NOT a function of apocrine glands?
Which of the following is NOT a function of apocrine glands?
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What is the primary function of fibroblasts during the granulation phase of wound healing?
What is the primary function of fibroblasts during the granulation phase of wound healing?
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Which of the following events is NOT a characteristic of the inflammatory phase of wound healing?
Which of the following events is NOT a characteristic of the inflammatory phase of wound healing?
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What is the role of macrophages in wound healing?
What is the role of macrophages in wound healing?
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Which of the following statements accurately describes the process of wound closure?
Which of the following statements accurately describes the process of wound closure?
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What is the main outcome of the granulation phase of wound healing?
What is the main outcome of the granulation phase of wound healing?
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Which of the following is NOT a characteristic of the inflammatory phase of wound healing?
Which of the following is NOT a characteristic of the inflammatory phase of wound healing?
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Which of these statements accurately describes the role of epithelial cells in wound healing?
Which of these statements accurately describes the role of epithelial cells in wound healing?
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What is the main difference between the inflammatory phase and the granulation phase of wound healing?
What is the main difference between the inflammatory phase and the granulation phase of wound healing?
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Study Notes
Integumentary System
- The integument, or skin, is a barrier between the internal and external environments.
- It contains accessory structures.
- Major functions:
- Barrier to environmental microbes
- Prevents water loss
- Thermoregulation
- Detecting sensations
- Vitamin D synthesis
- Excretion
Learning Objectives
- List major functions of the skin.
- Identify tissue types of the epidermis, papillary layer, reticular layer of the dermis, and subcutaneous tissues.
- List five layers of the epidermis and describe their structural and functional differences.
- Explain thick skin and its differences from thin skin.
- Describe functions of each type of cell in the epidermis.
- Describe factors contributing to skin color and alterations.
- Explain the anatomical basis for fingerprints.
- Describe structural and functional differences of two dermis layers.
- Describe secondary structures of the skin (sensory structures, exocrine glands, hair, and nails).
- Explain short-term and long-term burn dangers and degree determination.
- Explain the significance of the Rule of Nines.
- Relate three types of skin cancer to the epithelial layers.
- Describe tissue repair process for superficial wounds.
Layers of the Skin
-
Epidermis:
- Keratinized stratified squamous epithelium
-
Dermis:
- Papillary layer (20%)
- Areolar loose connective tissue
- Reticular layer (80%)
- Dense irregular connective tissue
- Papillary layer (20%)
-
Subcutaneous Layer (Hypodermis):
- Adipose loose connective tissue
Epidermis
- The outermost layer of skin.
- Keratinocytes in strata (layers):
- Stratum corneum (top layer)
- Stratum lucidum (middle layer in thick skin)
- Stratum granulosum (middle layer)
- Stratum spinosum (middle layer)
- Stratum basale (bottom - germ layer)
- Cells:
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
Strata of the Epidermis
-
Stratum basale:
- Deepest layer
- Closest to capillaries
- Keratinocyte mitosis
- Melanocytes producing melanin
- Merkel cells (sensory nerve cells)
-
Stratum spinosum:
- Spiny cell junctions (desmosomes)
- Langerhans cells
- Melanin granules
Stratum Granulosum
- Lamellar granules (dark spots)
- Prevent water loss
- Keratinization begins
Stratum Corneum
- Outermost layer of dead cells
- Keratinization for abrasion and microbe protection
- Constant shedding and replacement
Stratum Lucidum
- Clear layer
- Only in thick skin
- Between stratum corneum and granulosum
Cells of the Epidermis
-
Keratinocytes:
- Most abundant
- Replenish epithelium
- Produce keratin
- Mitosis in stratum basale
- Dead in outer layers
-
Langerhans cells:
- Immune system of epidermis
- Phagocytize foreign substances
- Migrate to epidermis from red bone marrow
-
Melanocytes:
- Melanin-producing cells
- Provide skin pigmentation
-
Merkel cells:
- Rare; specialized sensory receptors
- Detect touch and proprioception
Skin Pigments
-
Melanin: Reddish-yellow/brownish-black pigment from melanocytes
- Exposure to UV stimulates melanocyte activity
-
Carotene: Yellow/orange pigment from plants
- Accumulates in stratum corneum
- Hemoglobin: Leads to red/pink color from red blood cells in dermis
Alterations to Skin Color
- Erythema: Redness due to increased blood flow
- Pallor: Paleness due to decreased blood flow
- Bruising: Changing color due to pooling blood
- Jaundice: Yellowing due to liver malfunction
- Cyanosis: Blueness due to low oxygenated blood
- Albinism: Lack of melanin production
- Vitiligo: Loss of melanin in certain areas
- Addison's Disease: Bronze patches due to adrenal gland malfunction
The Dermis
- Thickest layer
- Papillary layer (superficial)
- Loose areolar connective tissue
- Reticular layer (deep)
- Dense irregular connective tissue
- Contains blood vessels, nerves, lymphatic vessels
The Papillary Layer
- Ridges with collagen fibers and nervous structures
- Determine fingerprint pattern (friction ridges)
The Reticular Layer
- Dense irregular connective tissue
- Collagen fiber orientations (cleavage lines)
- Locations of cleavage lines
Secondary Structures
- Sensory receptors (detect different kinds of information)
- Location can predict information they collect
- Free nerve endings (pain, temperature)
- Merkel's discs (touch)
- Meissner's corpuscles (touch)
- Hair follicle receptors (touch)
- Pacinian corpuscles (vibration and pressure)
- Ruffini's endings (stretch)
- Exocrine glands
- Eccrine (watery sweat, thermoregulation)
- Apocrine (protein- and lipid-rich sweat, body odor, reproductive signaling)
- Sebaceous (sebum, lubricates and waterproofs hair and skin)
Sebaceous Gland Malfunctions
- Whiteheads/blackheads: Blocked sebaceous glands
- Pimples, Cysts: Infected sebaceous glands
Anatomy of Hair
- Composed of dead keratinized cells
- Grows out of hair follicles
- Functions:
- Detecting sensations
- Protection against heat loss and sunlight
- Eye protection (eyelashes)
- Terminal hairs (coarse)
- Vellus hairs (fine)
Fingernails
- Extension of epidermis
- Harder keratin proteins than keratinocytes
- Grow from nail matrix
- Blood capillaries under nail bed lead to pink color
Skin Cancer
- Types:
- Basal cell carcinoma (most common, least dangerous)
- Squamous cell carcinoma (may spread)
- Malignant melanoma (most deadly)
- Risk factor: UV exposure
The ABCDEs of Detecting Melanoma
- Asymmetry (uneven shape)
- Border (irregular or uneven edges)
- Color (various shades or uneven coloration)
- Diameter (larger than 1/4 inch)
- Evolving (changes over time)
Burns
- Damage to skin by heat, electricity, chemicals, or radiation
- Protein denaturation and cell death occur
- Protective layer compromised (water loss, electrolyte/protein loss, septicemia, bacterial infection)
Degrees of Burns
- First-degree: Epidermis only damaged (redness, swelling, pain)
- Second-degree: Epidermis and upper layers of the dermis damaged (blisters appear)
- Third-degree: All layers of the skin are damaged (full thickness)
Treating Burns
- Critical situation for 2nd-degree burns (> 30%) or 3rd-degree burns (> 20%)
- Initial concern: Fluid and protein replacement
- Next: Infection and sepsis prevention
- Finally: Skin grafts create barrier (necessary for 3rd-degree burns)
The Rule of Nines
- Estimation of burned skin surface area
- Each body area approximately 9% plus genital region (1%)
Stages of Tissue Repair
- Inflammation: Blood flow increases and blood clots form.
- Granulation (scar tissue): Granulation replaces clots, fibroblasts produce collagen, epithelium regenerates, and macrophages clean up debris.
- Wound Closure: Fibrosis pulls the area closed, epithelium thickens, and scabs detach; underlying scar tissue may remain.
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Description
This quiz covers the major functions and structures of the integumentary system, focusing on the skin and its accessory structures. You'll explore the layers of the skin, their roles, and factors influencing skin color. Additionally, learn about sensory structures and exocrine glands associated with the skin.
