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Questions and Answers
What primary component distinguishes hair density among individuals?
What primary component distinguishes hair density among individuals?
Which structure provides nourishment to the hair follicle?
Which structure provides nourishment to the hair follicle?
Which part of the hair contains the actively growing cells?
Which part of the hair contains the actively growing cells?
What aspect does the hair bulb primarily contain?
What aspect does the hair bulb primarily contain?
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What is the visible part of the hair called?
What is the visible part of the hair called?
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Which structure of the nail is formed by the combination of the free edge, nail body, and nail root?
Which structure of the nail is formed by the combination of the free edge, nail body, and nail root?
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What condition is characterized by vertical splitting and increased breakage of nails?
What condition is characterized by vertical splitting and increased breakage of nails?
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Which nail disorder is associated with a fungal infection that causes yellowish discoloration and thickening?
Which nail disorder is associated with a fungal infection that causes yellowish discoloration and thickening?
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What nail condition indicates potential iron deficiency by presenting as concave nails?
What nail condition indicates potential iron deficiency by presenting as concave nails?
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Which of the following nail disorders typically shows horizontal lines across the nail due to temporary interruption of growth?
Which of the following nail disorders typically shows horizontal lines across the nail due to temporary interruption of growth?
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What is primarily the function of merocrine sweat glands?
What is primarily the function of merocrine sweat glands?
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Which statement about apocrine sweat glands is accurate?
Which statement about apocrine sweat glands is accurate?
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What distinguishes sebaceous glands from sweat glands?
What distinguishes sebaceous glands from sweat glands?
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Where are apocrine sweat glands predominantly located?
Where are apocrine sweat glands predominantly located?
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What role do myoepithelial cells play in sweat and sebaceous glands?
What role do myoepithelial cells play in sweat and sebaceous glands?
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Which of the following is NOT a characteristic of merocrine sweat glands?
Which of the following is NOT a characteristic of merocrine sweat glands?
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Where are sebaceous glands not found?
Where are sebaceous glands not found?
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Which statement correctly compares merocrine and apocrine sweat glands?
Which statement correctly compares merocrine and apocrine sweat glands?
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What is the primary cause of threat to life in burn victims?
What is the primary cause of threat to life in burn victims?
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Which of the following best describes a second-degree burn?
Which of the following best describes a second-degree burn?
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How does the location of a burn influence its severity?
How does the location of a burn influence its severity?
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What is a key characteristic of third-degree burns?
What is a key characteristic of third-degree burns?
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Which treatment is essential for managing burn injuries?
Which treatment is essential for managing burn injuries?
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What occurs during the anagen phase of hair growth?
What occurs during the anagen phase of hair growth?
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How is hair color primarily determined?
How is hair color primarily determined?
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Which statement accurately describes the structure of the hair?
Which statement accurately describes the structure of the hair?
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Which of the following is NOT a function of hair on the human body?
Which of the following is NOT a function of hair on the human body?
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What is true about the catagen phase of hair growth?
What is true about the catagen phase of hair growth?
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How does gray hair develop according to the discussed mechanisms?
How does gray hair develop according to the discussed mechanisms?
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What characterizes regeneration in the integumentary system?
What characterizes regeneration in the integumentary system?
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What is the role of macrophages during the wound healing process?
What is the role of macrophages during the wound healing process?
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In which stage of wound healing does granulation tissue formation primarily occur?
In which stage of wound healing does granulation tissue formation primarily occur?
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Which process is involved when functional restoration is not fully achieved after tissue repair?
Which process is involved when functional restoration is not fully achieved after tissue repair?
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What triggers the thickening of the epidermis in response to mechanical stress?
What triggers the thickening of the epidermis in response to mechanical stress?
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Psoriasis primarily results from an abnormal response of which type of immune cell?
Psoriasis primarily results from an abnormal response of which type of immune cell?
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What is the primary function of ceruminous glands in the integumentary system?
What is the primary function of ceruminous glands in the integumentary system?
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Which statement best describes fibrosis in the context of tissue repair?
Which statement best describes fibrosis in the context of tissue repair?
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Which factor does NOT contribute to the inflammatory response after blood vessel injury in wound healing?
Which factor does NOT contribute to the inflammatory response after blood vessel injury in wound healing?
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Which of the following conditions is characterized by patches of scaly skin resulting from an autoimmune response?
Which of the following conditions is characterized by patches of scaly skin resulting from an autoimmune response?
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What is the primary function of merocrine sweat glands?
What is the primary function of merocrine sweat glands?
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Which type of gland is characterized as a holocrine gland?
Which type of gland is characterized as a holocrine gland?
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What distinguishes apocrine sweat glands from merocrine sweat glands?
What distinguishes apocrine sweat glands from merocrine sweat glands?
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What are comedones in relation to acne?
What are comedones in relation to acne?
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Which statement about sebaceous gland secretion is true?
Which statement about sebaceous gland secretion is true?
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What is a characteristic of a pustule in terms of acne lesions?
What is a characteristic of a pustule in terms of acne lesions?
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How does benzoyl peroxide function in acne treatment?
How does benzoyl peroxide function in acne treatment?
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Which type of acne lesion is characterized by a large, fluid-filled sac?
Which type of acne lesion is characterized by a large, fluid-filled sac?
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What is the main component of merocrine sweat secretions?
What is the main component of merocrine sweat secretions?
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Which statement about ceruminous glands is accurate?
Which statement about ceruminous glands is accurate?
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Study Notes
Nails
- Nails are formed from the stratum corneum layer of the epidermis, located on the dorsal edges of fingers and toes
- Free edge: Distal & light-colored
- Nail body: Visible part
- Nail root: Proximal & embedded
- Nail plate: Free edge, nail body, and nail root
- Nail bed: Layer of epidermis under the nail plate
- Nails protect the tips of fingers and toes and assist in grasping objects
Nail Disorders
- Brittle nails: Vertical splitting and breaking, often due to environmental factors like water and chemicals
- Ingrown nails: Nail edges digging into the skin, caused by improper trimming or tight shoes
- Nail pitting: Tiny depressions or holes in the nail body, possibly a sign of psoriasis, alopecia areata, dermatitis, or connective tissue disorders
- Nail clubbing: Enlarged fingertip and curved nail, often linked to hypoxia
- Onychomycosis: Fungal infection causing yellowish discoloration, thickening, and brittle/cracked nail edges
- Yellow nail syndrome: Slowed nail growth and yellowing, sometimes associated with respiratory diseases
- Spoon nails (koilonychia): Concave nails, often linked to iron deficiency
- Beau's lines: Horizontal lines across the nail, caused by temporary growth interruption due to injury or illness
- Vertical ridging: Commonly found in older individuals, typically not a serious medical issue
Hair
- Found almost everywhere on the body except palms, soles, lips, and parts of the external genitalia
- Shaft: Visible part of the hair
- Root: Embedded portion
- Hair bulb: Base of the follicle containing the hair matrix
- Hair papilla: Connective tissue projection providing follicle nourishment
- Medulla: Innermost hair shaft layer
- Cortex: Middle layer
- Matrix: Actively growing part in the hair bulb
- Hair follicle: Tube-like structure surrounding the root
- Arrector pili muscle: Smooth muscle attached to the hair follicle
Sensory Reception and Visual Identification
- Hair follicles have tactile receptors (root hair plexuses) that detect light touch
- Hair characteristics are important in determining age and identifying individuals
Hair Color
- Determined by melanin produced in the matrix adjacent to the hair papilla
- Variations in melanin structure influence hair color
- Environmental and hormonal factors affect hair color
- Gray hair results from reduced melanin production; white hair occurs with complete stoppage of melanin production
Hair Growth and Replacement
- Anagen: Active growth phase. Cells in the hair bulb grow, divide, and transform into hair
- Catagen: Brief regression period. Cell division stops, and the follicle shrinks
- Telogen: Resting phase. Hair is shed. Cells in the hair bulb begin to regrow, and the follicle re-enters the anagen phase
Hair Structure and Follicles
- Bulb: Swelling at the base where hair originates in the dermis; contains living cells and a hair papilla
- Root: Zone extending from the bulb to the skin's surface
- Shaft: Portion extending beyond the skin's surface; consists of dead epithelial cells
- Medulla: Soft core (not in all hair types)
- Cortex: Relatively hard layers
- Cuticle: Single cell layer coating the cortex
- Outer connective tissue root sheath: From the dermis
- Inner epithelial tissue root sheath: From the epidermis
- The arrector pili muscle connects the hair follicle to the dermal papillae in the dermis.
Functions of Hair
- Protection: Protects the scalp from sunburn and injury
- Heat Retention: Prevents heat loss from the scalp
- Sensory Reception: Detects light touch
- Visual Identification: Identifies individuals
Hair Loss
- Temporary hair loss can be caused by drugs, diet, radiation, fever, and stress
- Baldness (alopecia) can be an autoimmune disorder (alopecia areata)
- Male pattern baldness often results from genetic and hormonal influences related to testosterone levels
Sweat Glands
- Exocrine glands located in the dermis' reticular layer
- Ducts transport secretions to the epidermis' surface (merocrine sweat glands) or into hair follicles (apocrine sweat glands)
Merocrine (Eccrine) Sweat Glands
- Found throughout the body
- Secrete sweat onto the skin's surface
- Contain myoepithelial cells
Apocrine Sweat Glands
- Located in the armpits, groin, and around the nipples
- Secrete thicker, milky sweat into hair follicles
- Contain myoepithelial cells
Sebaceous Glands
- Exocrine glands that secrete sebum (oil) into hair follicles
- Found almost everywhere except the palms and soles
Merocrine Sweat Glands
- Structure: Simple, coiled, tubular glands that discharge secretions directly onto the skin's surface
- Composition: 99% water and 1% other chemicals
- Function: Thermoregulation (regulating body temperature), helps eliminate waste products and drugs, provides some protection from environmental hazards
Apocrine Sweat Glands
- Structure: Coiled, tubular glands that release secretions into hair follicles
- Secretion Process: Initially thought to secrete via an apocrine mechanism; recent research shows both apocrine and merocrine glands produce secretions
- Location: Axillae, nipples, pubic region, and anal region
Sebaceous Glands
- Structure: Holocrine glands; secretions are discharged into hair follicles
- Secretion: Sebum – oily, waxy substance to keep skin and hair from drying out
- Function: Keeps skin and hair lubricated; stimulated by hormones
Other Integumentary Glands
- Ceruminous glands: Modified apocrine sweat glands located in the ear canal; produce cerumen
- Mammary glands: Modified apocrine sweat glands that produce breast milk during pregnancy and lactation
Acne and Acne Treatments
- Plugged ducts of sebaceous glands
- Cause: Increased sebaceous gland secretions
- Lesion Types:
- Comedo: Open comedo (blackhead) and closed comedo (whitehead)
- Papule: Fluid-filled, red elevations
- Pustule: Dome-shaped lesion filled with pus
- Nodule: Deeper lesion, often rupturing the hair follicle wall
- Cyst: Large, fluid-filled, severely inflamed nodule
- Treatments: Benzoyl peroxide, salicylic acid, topical/oral antibiotics, topical vitamin A-k compounds (retinoids), systemic retinoids, light chemical peels, comedo extraction
Integumentary System Repair and Regeneration
- Regeneration: Replacement of damaged cells with the same cell type, restoring tissue function
- Fibrosis: Deposition of scar tissue to fill gaps where regeneration cannot occur
Wound Healing
- Blood vessel injury: Blood vessels are cut, releasing blood, clotting proteins, white blood cells, and antibodies
- Blood clot formation: A clot forms, creating a barrier to pathogens; macrophages and neutrophils remove cellular debris
- Granulation tissue formation: Blood vessels regenerate, forming granulation tissue; macrophages remove clots, and fibroblasts produce collagen
- Epithelial regeneration: Epithelial cells divide and migrate over the wound
- Fibrosis: Connective tissue replaces the clot
Psoriasis
- Chronic autoimmune disease causing rapid skin cell overgrowth
- T-lymphocytes mistakenly attack keratinocytes, causing scaly, whitish skin (plaques)
- May cause itching, pain, cracking, and bleeding
- Common areas include the scalp, limbs, and buttocks
- Nail pitting can be a symptom
Burns
- Caused by heat, radiation, chemicals, sunlight, or electrical shock
- Threat to life due to fluid loss, infection, and tissue damage
- Categorized by depth:
- First-degree burns (superficial): Affect the epidermis, characterized by redness, pain, and swelling
- Second-degree burns: Involve the epidermis and part of the dermis; skin blisters and is painful
- Third-degree burns (full-thickness): Destroy the epidermis, dermis, and subcutaneous layers; often require hospitalization and skin grafting
Severity of Burn Injury
- Degree of the burn
- Size of the burn (measured using the rule of nines):
- The rule of nines divides the body surface area into areas representing 9% or multiples of 9% of the total body surface area
- Location of the burn
- Age of the patient
Treatments for Burn Injuries
- Managing fluid loss, pain, removing dead tissue (debridement), and controlling infection
- Escharotomy (incision in the skin to relieve constriction) might be necessary
- Increased caloric intake is needed during healing
Development of the Integument and Its Derivatives
- By week 7, the ectoderm forms a layer of squamous epithelium which becomes the periderm and a deeper layer
- The periderm sheds off during the fetal period
- The dermis is formed from mesoderm which develops into mesenchymal cells, forming the components of the dermis
- Fingernails and toenails start to form at 10 weeks
- Hair follicles appear at 9-12 weeks as pockets of cells invading the dermis
- Sweat and sebaceous glands develop from the stratum basale at 20 weeks
Aging of the Integument
- Skin changes become apparent during middle age
- Skin repair takes longer due to fewer active stem cells
- Thinner skin is less protective against abrasion
- Collagen and elastic fibers decrease, resulting in wrinkles
- Facial expressions contribute to wrinkles and sagging
Skin Cancer
- Basal cell carcinoma: Least dangerous; originates in the stratum basale
- Squamous cell carcinoma: Arises from keratinocytes of the stratum spinosum; can metastasize
- Malignant melanoma: Most deadly; arises from melanocytes
ABCDE Rule for Melanoma Detection
-
Asymmetry
-
Border
-
Color
-
Diameter
-
Evolving
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UV Exposure: Chronic exposure to UV rays damages DNA in epidermal cells, accelerating aging and increasing the risk of skin cancer
-
Risk Factors: Age, fair skin, a history of severe sunburns
Chapter Summary
- The integumentary system consists of the skin and its derivatives
- The epidermis is the superficial layer composed of keratinized stratified squamous epithelium
- The deeper layer is the dermis composed of areolar and dense irregular connective tissue
- The subcutaneous layer helps adhere the integument to underlying structures
Cell Types in the Epidermis
- Keratinocytes: Most abundant cell type
- Melanocytes: Produce melanin
- Epidermal dendritic cells: Immune response
- Tactile cells: Touch
Epidermis
- Layers: Stratum basale, spinosum, granulosum, lucidum (thick skin only), and corneum
- Stratum basale: Deepest layer, actively dividing keratinocytes
- Keratinization: Process where keratinocytes fill with keratin, resulting in cell death, begins in stratum granulosum
- Stratum corneum: Composed of many layers of dead keratinocytes
- Thick skin: Found on palms and soles, has five epidermal strata
- Thin skin: Found on the rest of the body, has four epidermal strata
- Skin color: Determined by hemoglobin, melanin, and carotene pigments
Dermis
- Layers: Papillary and reticular layer
- Papillary layer: Superficial layer, composed of areolar connective tissue, contains dermal papillae that interlock with epidermal ridges
- Reticular layer: Deep layer, composed of dense irregular connective tissue, contains hair follicles, glands, and nerve endings
Subcutaneous Layer
- Functions: Provides padding and protection, acts as an energy reservoir, and provides thermal insulation
Functions of the Integument
- Protection: From the external environment
- Water Regulation: Prevents water loss and gain
- Vitamin D Synthesis: Produces vitamin D upon exposure to sunlight
- Secretion: Secretes sweat, sebum, and other substances
- Absorption: Absorbs certain substances
- Temperature Regulation: Regulates body temperature through sweating and blood flow
- Immune Function: Plays a role in immune responses
- Sensory Reception: Contains sensory receptors for touch, pressure, temperature, and pain
Nails
- Formation: From the stratum corneum of the epidermis
- Functions: Protect digits and aid in grasping
Hair
- Components: Bulb (origin in dermis), root (deep to skin), shaft (beyond skin)
- Arrector pili muscles: Contract to elevate hair, providing protection, heat retention, sensory reception, and visual identification
Exocrine Glands of the Skin
- Merocrine Sweat Glands: Produce watery sweat
- Apocrine Sweat Glands: Produce viscous secretion, often with odor
- Sebaceous Glands: Secrete sebum onto hair follicles through holocrine secretion
- Ceruminous Glands: Modified apocrine glands, produce cerumen (earwax)
- Mammary Glands: Modified apocrine glands, produce breast milk
Repair and Regeneration of the Integumentary System
- Regeneration: Replacement of damaged/dead cells with the same cell type
- Fibrosis: Replacement of damaged tissue with scar tissue
- Repair time: Varies depending on the extent of the surface affected
Development and Aging of the Integumentary System
- Development: Forms during weeks 3-9 of development
- Nail Development: Appears during week 20
- Hair Follicles: Appear between 9 and 12 weeks
- Aging: Stem cell activity decreases, skin becomes thinner, wrinkles appear, and skin cancers become more likely
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Description
Explore the anatomy of nails, including their structure and function. This quiz also covers common nail disorders such as brittle nails, ingrown nails, and nail clubbing, helping you understand their causes and implications for health.
