Nail Structure and Disorders

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Questions and Answers

What primary component distinguishes hair density among individuals?

The shape of the hair follicle

The thickness of the hair shaft

Differences in hair texture and pigmentation (correct)

The number of hair follicles on the scalp

Which structure provides nourishment to the hair follicle?

Hair Matrix

Hair Papilla (correct)

Hair Bulb

Cortex

Which part of the hair contains the actively growing cells?

Hair Matrix (correct)

Medulla

Hair Shaft

Cortex

What aspect does the hair bulb primarily contain?

Hair Matrix Signup and view all the answers

What is the visible part of the hair called?

Shaft Signup and view all the answers

Which structure of the nail is formed by the combination of the free edge, nail body, and nail root?

Nail plate Signup and view all the answers

What condition is characterized by vertical splitting and increased breakage of nails?

Brittle nails Signup and view all the answers

Which nail disorder is associated with a fungal infection that causes yellowish discoloration and thickening?

Onychomycosis Signup and view all the answers

What nail condition indicates potential iron deficiency by presenting as concave nails?

Spoon nails (koilonychia) Signup and view all the answers

Which of the following nail disorders typically shows horizontal lines across the nail due to temporary interruption of growth?

Beau's lines Signup and view all the answers

What is primarily the function of merocrine sweat glands?

Transport secretions exclusively to the epidermis' surface Signup and view all the answers

Which statement about apocrine sweat glands is accurate?

They primarily produce a thicker, milky secretion Signup and view all the answers

What distinguishes sebaceous glands from sweat glands?

They produce sebum instead of sweat Signup and view all the answers

Where are apocrine sweat glands predominantly located?

In the armpits and groin Signup and view all the answers

What role do myoepithelial cells play in sweat and sebaceous glands?

They contract to facilitate secretion release Signup and view all the answers

Which of the following is NOT a characteristic of merocrine sweat glands?

They secrete a thicker milky substance Signup and view all the answers

Where are sebaceous glands not found?

Palms of the hands Signup and view all the answers

Which statement correctly compares merocrine and apocrine sweat glands?

Merocrine glands are prevalent throughout the body while apocrine glands are located in specific areas Signup and view all the answers

What is the primary cause of threat to life in burn victims?

Infection Signup and view all the answers

Which of the following best describes a second-degree burn?

Involves epidermis and part of the dermis, causing blisters Signup and view all the answers

How does the location of a burn influence its severity?

Burns on the face may necessitate more extensive treatment Signup and view all the answers

What is a key characteristic of third-degree burns?

Involve all skin layers and require hospitalization Signup and view all the answers

Which treatment is essential for managing burn injuries?

Controlling infection and fluid loss Signup and view all the answers

What occurs during the anagen phase of hair growth?

Living cells in the hair bulb rapidly grow and divide. Signup and view all the answers

How is hair color primarily determined?

By melanin synthesized in the matrix adjacent to the hair papillae. Signup and view all the answers

Which statement accurately describes the structure of the hair?

The hair consists of the bulb, root, and shaft, with the shaft being composed of dead cells. Signup and view all the answers

Which of the following is NOT a function of hair on the human body?

Providing a barrier against bacterial infection. Signup and view all the answers

What is true about the catagen phase of hair growth?

It is a brief regression period lasting 3–4 weeks. Signup and view all the answers

How does gray hair develop according to the discussed mechanisms?

From a reduction in melanin production during the growing cycle. Signup and view all the answers

What characterizes regeneration in the integumentary system?

Damaged cells are replaced with the same cell type. Signup and view all the answers

What is the role of macrophages during the wound healing process?

To remove cellular debris and pathogens. Signup and view all the answers

In which stage of wound healing does granulation tissue formation primarily occur?

Granulation tissue formation. Signup and view all the answers

Which process is involved when functional restoration is not fully achieved after tissue repair?

Fibrosis. Signup and view all the answers

What triggers the thickening of the epidermis in response to mechanical stress?

Increased cell division in the basal layer. Signup and view all the answers

Psoriasis primarily results from an abnormal response of which type of immune cell?

T-lymphocytes. Signup and view all the answers

What is the primary function of ceruminous glands in the integumentary system?

To trap foreign particles with earwax. Signup and view all the answers

Which statement best describes fibrosis in the context of tissue repair?

It is characterized by collagen fiber deposition. Signup and view all the answers

Which factor does NOT contribute to the inflammatory response after blood vessel injury in wound healing?

Epithelial cell migration. Signup and view all the answers

Which of the following conditions is characterized by patches of scaly skin resulting from an autoimmune response?

Psoriasis. Signup and view all the answers

What is the primary function of merocrine sweat glands?

Thermoregulation through evaporation Signup and view all the answers

Which type of gland is characterized as a holocrine gland?

Sebaceous glands Signup and view all the answers

What distinguishes apocrine sweat glands from merocrine sweat glands?

Location in hair follicles instead of directly on the skin Signup and view all the answers

What are comedones in relation to acne?

Lesions resulting from excessive sebum blockage Signup and view all the answers

Which statement about sebaceous gland secretion is true?

Sebaceous secretion increases during puberty Signup and view all the answers

What is a characteristic of a pustule in terms of acne lesions?

Contains dead skin cells and bacteria Signup and view all the answers

How does benzoyl peroxide function in acne treatment?

Reduces inflammation and kills acne-causing bacteria Signup and view all the answers

Which type of acne lesion is characterized by a large, fluid-filled sac?

Cyst Signup and view all the answers

What is the main component of merocrine sweat secretions?

Water and salts Signup and view all the answers

Which statement about ceruminous glands is accurate?

They produce a waxy substance found in the ear canal. Signup and view all the answers

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
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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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.