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Questions and Answers
What is the name given to the condition characterized by a blue skin color due to low oxygenation of hemoglobin?
What is the name given to the condition characterized by a blue skin color due to low oxygenation of hemoglobin?
Which of the following skin conditions can be a sign of elevated blood glucose levels?
Which of the following skin conditions can be a sign of elevated blood glucose levels?
What is the primary component of hair?
What is the primary component of hair?
Which layer of the hair shaft is composed of overlapping layers of single cells?
Which layer of the hair shaft is composed of overlapping layers of single cells?
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Which of the following is NOT a function of hair?
Which of the following is NOT a function of hair?
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Which type of keratin is found in hair?
Which type of keratin is found in hair?
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What is the name given to the area within the scalp where keratinization of hair cells is still ongoing?
What is the name given to the area within the scalp where keratinization of hair cells is still ongoing?
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Which of the following areas IS covered in hair?
Which of the following areas IS covered in hair?
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What is the primary function of sensible perspiration?
What is the primary function of sensible perspiration?
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What happens to dermal blood vessels in a cold external environment?
What happens to dermal blood vessels in a cold external environment?
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Which of the following is an example of a cutaneous exteroreceptor?
Which of the following is an example of a cutaneous exteroreceptor?
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What is the daily volume of insensible perspiration?
What is the daily volume of insensible perspiration?
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What is the primary function of melanin in the skin?
What is the primary function of melanin in the skin?
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What are striae?
What are striae?
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Which of the following can be a consequence of prolonged exposure to heavy metals?
Which of the following can be a consequence of prolonged exposure to heavy metals?
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What is the relationship between melanin and UV exposure?
What is the relationship between melanin and UV exposure?
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Which of the following is a potential negative effect of excessive sun exposure?
Which of the following is a potential negative effect of excessive sun exposure?
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What is the role of carotene in skin color?
What is the role of carotene in skin color?
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How does hemoglobin contribute to skin color?
How does hemoglobin contribute to skin color?
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What are blisters?
What are blisters?
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Which of the following substances is necessary for DNA synthesis and is destroyed by UV light?
Which of the following substances is necessary for DNA synthesis and is destroyed by UV light?
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What is the most dangerous type of skin cancer and why?
What is the most dangerous type of skin cancer and why?
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What is the ABCD rule used for?
What is the ABCD rule used for?
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Which of the following is NOT a characteristic of a first-degree burn?
Which of the following is NOT a characteristic of a first-degree burn?
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What is the main reason why the Rule of Nines is used for burns?
What is the main reason why the Rule of Nines is used for burns?
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Which of the following is a key characteristic of a third-degree burn?
Which of the following is a key characteristic of a third-degree burn?
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What type of cancer is melanoma?
What type of cancer is melanoma?
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What does the term 'metastatic' mean when referring to cancer?
What does the term 'metastatic' mean when referring to cancer?
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What is the most common treatment for melanoma?
What is the most common treatment for melanoma?
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Which of the following contributes to the decreased risk of skin cancer in individuals with younger skin?
Which of the following contributes to the decreased risk of skin cancer in individuals with younger skin?
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What protective substance is secreted by the sebaceous glands during fetal development?
What protective substance is secreted by the sebaceous glands during fetal development?
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What is the main reason for the increased susceptibility to skin infections and damage in aging individuals?
What is the main reason for the increased susceptibility to skin infections and damage in aging individuals?
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Which of the following is NOT a characteristic of aging skin?
Which of the following is NOT a characteristic of aging skin?
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Why does the skin accumulate more subcutaneous fat during infancy and early adulthood?
Why does the skin accumulate more subcutaneous fat during infancy and early adulthood?
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What is the primary function of the stratum lucidum?
What is the primary function of the stratum lucidum?
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Which layer of the epidermis is characterized by cells accumulating lamellar granules?
Which layer of the epidermis is characterized by cells accumulating lamellar granules?
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How does the process of keratinization begin in the epidermis?
How does the process of keratinization begin in the epidermis?
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What is the primary function of cells in the stratum corneum?
What is the primary function of cells in the stratum corneum?
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What is the correct order of the epidermal layers from the innermost to the outermost layer?
What is the correct order of the epidermal layers from the innermost to the outermost layer?
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Which of these layers is responsible for the continuous replacement of skin cells?
Which of these layers is responsible for the continuous replacement of skin cells?
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What causes the cells in the stratum granulosum to die?
What causes the cells in the stratum granulosum to die?
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Why is the stratum corneum so important for skin function?
Why is the stratum corneum so important for skin function?
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Flashcards
Stratum granulosum
Stratum granulosum
A thin layer of the epidermis composed of flattened cells undergoing keratinization.
Keratinization
Keratinization
The process where skin cells accumulate keratin and other substances to form a protective barrier.
Keratohyaline granules
Keratohyaline granules
Granules that accumulate in cells during keratinization, aiding in keratin fiber formation.
Lamellar granules
Lamellar granules
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Stratum lucidum
Stratum lucidum
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Stratum corneum
Stratum corneum
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Apoptosis
Apoptosis
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Cell shedding
Cell shedding
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Striae
Striae
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Blisters
Blisters
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Melanin
Melanin
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Tyrosinase
Tyrosinase
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Carotene
Carotene
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Hemoglobin
Hemoglobin
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Photosensitivity
Photosensitivity
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UV Light Effects
UV Light Effects
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Cyanosis
Cyanosis
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Pallor
Pallor
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Erythema
Erythema
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Jaundice
Jaundice
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Bruises
Bruises
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Hair composition
Hair composition
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Parts of hair shaft
Parts of hair shaft
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Hair follicle function
Hair follicle function
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Homeostatic Imbalance
Homeostatic Imbalance
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Insensible Perspiration
Insensible Perspiration
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Sensible Perspiration
Sensible Perspiration
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Exteroreceptors
Exteroreceptors
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Free Nerve Endings
Free Nerve Endings
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Melanoma
Melanoma
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ABCD Rule
ABCD Rule
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Asymmetry (A)
Asymmetry (A)
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Border Irregularity (B)
Border Irregularity (B)
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Color Variation (C)
Color Variation (C)
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Diameter (D)
Diameter (D)
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Rule of Nines
Rule of Nines
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Burn Severity Classes
Burn Severity Classes
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Lanugo coat
Lanugo coat
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Vernix caseosa
Vernix caseosa
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Aging skin
Aging skin
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Sebaceous gland activity
Sebaceous gland activity
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Delaying aging
Delaying aging
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Study Notes
Chapter 05: The Integumentary System
- The integumentary system comprises skin, hair, nails, sweat glands, and sebaceous glands.
- Understanding the system is crucial for evaluating and treating skin injuries like burns.
Why This Matters
- Knowledge of the integumentary system aids in assessing and managing skin injuries, such as burns.
Integumentary System
- The integumentary system encompasses the skin, hair, nails, sweat glands, and oil glands.
5.1 Structure of Skin
- Skin consists of two principal regions: the epidermis (outer layer) and dermis (underlying layer).
- Beneath the dermis lies the hypodermis (not part of skin), primarily composed of adipose tissue. It anchors the skin to underlying structures. The hypodermis aids in cushioning and insulation.
- The epidermis is avascular, meaning it lacks blood vessels.
- The dermis is vascular and primarily composed of fibrous connective tissue.
5.2 Epidermis
- The epidermis is primarily composed of keratinized stratified squamous epithelium.
- Four cell types reside within the epidermis:
- Keratinocytes: Major cells; produce keratin for protective function. Millions of cells constantly slough off.
- Melanocytes: Produce melanin, a pigment that shields the nucleus from UV damage.
- Dendritic cells (Langerhans cells): Star-shaped macrophages, crucial components of the immune system, patrol deep epidermis.
- Tactile cells (Merkel cells): Sensory receptors responsible for tactile sensation.
- The epidermis is composed of four (thin skin) or five (thick skin) distinct strata (layers):
- Stratum basale (basal layer)
- Stratum spinosum (prickly layer)
- Stratum granulosum (granular layer)
- Stratum lucidum (clear layer, only in thick skin)
- Stratum corneum (horny layer)
Layers of the Epidermis
- Stratum basale (basal layer): Deepest layer adhering to the dermis, a single layer of stem cells actively dividing (mitotic).
- Daughter cells migrate toward the surface, undergoing keratinization over 25-45 days.
- 10-25% of this layer is composed of melanocytes.
- Stratum spinosum (prickly layer): Multiple layers of keratinocytes connected by desmosomes, exhibiting an irregular appearance. Cells resist tension and pulling.
- Stratum granulosum (granular layer): Four to six cell layers where cells flatten, nuclei and organelles disintegrate. Keratohyaline granules aid keratin fiber formation. Lamellar granules secrete a hydrophobic substance that retards water loss. Cells stop dividing and die.
- Stratum lucidum (clear layer): Only present in thick skin and possesses several rows of clear, flat, and dead keratinocytes.
- Stratum corneum (horny layer): 20-30 layers of dead keratinized cells. This is the outermost and most superficial layer. Although dead, cells provide protection.
5.3 Dermis
- The dermis is a strong and flexible connective tissue.
- It comprises fibroblasts, macrophages, and occasionally mast cells and white blood cells.
- It forms the "hide" used to create leather.
- Houses nerves, blood vessels, and lymphatic vessels, as well as hair follicles, sebaceous glands, and sweat glands.
- It is structured into two layers:
- Papillary layer (areolar connective tissue)
- Reticular layer (dense irregular connective tissue)
Papillary Layer
- Loose connective tissue with collagen and elastic fibers.
- Dermal papillae extend into the epidermis.
- These papillae contain capillaries, nerve endings, and touch receptors (Meissner's corpuscles).
- In thick skin, dermal papillae rest on dermal ridges, creating epidermal ridges (friction ridges). Ridge patterns form unique fingerprints.
Reticular Layer
- Dense fibrous connective tissue.
- Collagen fibers provide structure and strength, while elastic fibers allow stretch and recoil.
- Cutaneous plexus of blood vessels exists between this layer and hypodermis.
- Cleavage (tension) lines run parallel to collagen fibers, influencing surgical incision healing.
- Flexure lines are dermal folds at or near joints where skin is tightly anchored, and they produce deep creases.
Clinical-Homeostatic Imbalance 5.1
- Striae, or stretch marks, are silvery white scars caused by skin stretching.
- Blistering can occur from acute skin traumas where fluid-filled pockets separate epidermal and dermal layers.
5.4 Skin Color
- Skin color is influenced by melanin, carotene, and hemoglobin:
- Melanin: Produced by melanocytes, ranging from reddish-yellow to brownish-black. It protects against UV damage.
- Carotene: Yellow-orange pigment accumulating in stratum corneum and hypodermis, convertible to vitamin A, essential for vision and epidermal health.
- Hemoglobin: Pinkish hue due to lower melanin levels. Skin color of Caucasians is due to hemoglobin showing through the skin.
Clinical-Homeostatic Imbalance 5.2
- Sun exposure can lead to skin damage, leather-like texture, immune system depression, potentially causing skin cancer.
- UV light can destroy folic acid, crucial for embryonic development.
- Skin hypersensitivity can occur.
Clinical-Homeostatic Imbalance 5.3
- Skin color deviations can signal underlying diseases. Examples include:
- Cyanosis (blue): Low oxygenation
- Pallor (pale): Anemia, low blood pressure
- Erythema (red): Fever, allergies
- Jaundice (yellow): Liver disorders
- Bruises: Blood clots beneath the skin
- Brown or black markings: Could indicate insulin resistance or high blood glucose
5.5 Hair
- Composed of dead keratinized cells.
- Absent from palms, soles, lips, nipples, and external genitalia.
- Functions:
- Detecting insects
- Protecting from physical trauma
- Protecting from heat loss
- Providing protection from sunlight
- Hair structures: -Shaft -Root -Medulla -Cortex -Cuticle
Structure of a Hair Follicle
- Extends down to the dermis.
- Contains a bulb where the hair cells are actively produced and replaced.
- Has a receptor, including nerve endings, to detect touch.
- Wall consists of peripheral connective tissue sheath (from dermis) and epithelial root sheath (from epidermis).
- Matrix: actively dividing cells within the bulb that produce new hair cells.
- Arrector pili muscle attached to follicles.
- Hair papilla: dermal tissue containing capillaries to supply nutrients.
Types and Growth of Hair
- Vellus hair: Fine, pale hair (children and women).
- Terminal hair: Coarse, long hair (scalp, eyebrows, pubic areas).
- Hair growth is affected by nutrition and hormones during specific puberty stages.
Clinical-Homeostatic Imbalance 5.4
- Women with certain endocrine disorders can have significant excessive amounts of hair, called hirsutism, and other symptoms of masculinization.
5.6 Nails
- Scale-like modifications of epidermis with hard keratin.
- Protect distal, dorsal surface of fingers and toes.
- Composed of free edge, nail plate, and root.
- Embedded within the nail bed, the thickened portion of the nail bed, is the nail matrix which is responsible for nail growth.
- Nail folds surround the nail; the cuticle (eponychium) is a nail fold onto the nail body.
- Hyponychium is the area beneath the free edge of the nail plate. Nail matrix is visible as the lunule (thickened portion, typically white).
Clinical-Homeostatic Imbalance 5.6
- Nail appearance can reflect underlying illnesses or deficiencies; color changes or abnormal shapes can indicate issues like iron deficiency, respiratory or thyroid problems. Beau's lines (horizontal lines) can signal severe diseases, like diabetes, heart attacks, or cancer treatment.
5.7 Sweat Glands
- Also called sudoriferous glands.
- Present across skin surfaces except nipples and external genitalia.
- Two major types:
- Eccrine (merocrine): Most numerous, primarily thermoregulation.
- Apocrine: Larger, associated with hair follicles, and involved in secretions that may play a role as a scent gland. Modified apocrine sweat glands exist as ceruminous glands (earwax) and mammary glands (milk).
- Myoepithelial cells in sweat glands help force sweat into ducts when stimulated.
Eccrine Sweat Glands
- Abundant on palms, soles, and forehead.
- Involved in thermoregulation (controlled by sympathetic nervous system).
Apocrine Sweat Glands
- Found in axillary and anogenital areas.
- Secrete viscous sweat with fatty substances and proteins.
- Activated during puberty.
Sebaceous (Oil) Glands
- Found everywhere except thick skin (palms and soles).
- Usually develop from hair follicles.
- Relatively inactive until puberty, stimulated by hormones.
- Secrete sebum, an oily substance composed of holocrine secretions, with antibacterial properties, to lubricate and soften hair and skin.
Clinical-Homeostatic Imbalance 5.7
- Acne is sebaceous gland inflammation.
- Whiteheads and blackheads are blocked sebaceous glands.
- Overactive sebaceous glands in infants manifest as seborrhea (cradle cap).
5.8 Functions of Skin
Skin is a protective barrier with many functions:
- Protection: Multiple levels to physically, chemically, and biologically protect the body from pathogens, chemicals, and damage.
- Body Temperature Regulation: Sweating and vasoconstriction regulate body temperature via heat loss.
- Cutaneous Sensations: Receptors detect temperature, pressure, and pain.
- Metabolic Funtions: Synthesizes vitamin D, converts hormones, and produces collagenase for natural collagen turnover.
- Blood Reservoir: Holds up to 5% of the body's blood volume for other organs.
- Excretion: Secretion of nitrogenous wastes (minimal).
Protection
- Chemical barrier: Sweat contains antimicrobial proteins, sebum contains defensins. Acidic mantle (low pH) retards bacterial multiplication. Melanin protects against UV radiation.
- Physical barrier: Flat, dead keratinocytes of stratum corneum, surrounded by glycolipids, create a barrier. Substances like water and water-soluble materials pass over this barrier with difficulty.
- Biological barrier: Dendritic cells patrol and activate the immune system. Macrophages activate the immune system. DNA absorbs and converts UV radiation into harmless heat.
Clinical-Homeostatic Imbalance 5.8
- Organic solvents or heavy metals which are absorbed through the skin can be harmful to multiple organ systems. This can be lethal as a result of organ failure, as well as neurologic defects.
Body Temperature Regulation
- Insensible perspiration: About 500ml of daily sweat, normally unnoticed.
- Sensible perspiration: Increased sweat production (up to 12L) to help with regulating temperature control. This is noticeable as sweat due to higher sweat volume.
- Dermal vasoconstriction to curtail heat loss.
Cutaneous Sensations
- Cutaneous sensory receptors respond to stimuli outside the body, such as temperature and touch.
- Free nerve endings sense painful stimuli.
Metabolic Functions
- Skin synthesizes vitamin D for calcium absorption in the intestine.
- Skin chemicals neutralize some carcinogens.
- Keratinocytes convert hormones (like cortisone) to other forms.
- Skin makes collagenase to regulate collagen turnover.
Blood Reservoir
- Skin can store up to 5% of the body's total blood volume.
- Blood can be shunted to other areas (e.g., exercise muscles).
Excretion
- Skin secretes limited amounts of nitrogenous wastes (such as ammonia, urea, and uric acid).
- Sweating causes salt and water loss.
5.9 Skin Cancer and Burns
- Skin can develop various conditions including infections and cancers.
- Skin cancer types include Basal cell carcinoma, Squamous cell carcinoma, and Melanoma; Each has varying severity and treatment.
- Burns are categorized by severity (first, second, third-degree) and classified as critical if >25% of the body contains second-degree burns, or if >10% of the body contains third-degree burns (especially involving face, hands, or feet).
Skin Cancer
- Basal cell carcinoma: Least malignant and most common. Involves stratum basale, slow spread. Usually cured by excision.
- Squamous cell carcinoma: Second most common. Involves cells of stratum spinosum. Usually scaly lesions on sun-exposed areas. Good prognosis with treatment.
- Melanoma: Most serious, highly malignant, and often metastasizes. Key to survival is early detection using ABCD rule (asymmetry, border irregularity, color, and diameter).
Burns
- Tissue damage by heat, electricity, radiation, or chemicals. Leading causes of immediate tissue damage and dehydration.
- Classified by degree of severity (first, second, and third degree), which depend on epidermal and dermal damage.
- Critical burns are those where >25% of the body's surface has second-degree burns, or where >10% of the body's surface is third-degree burns (especially on face, hands, or feet). This severity often requires debridement, antibiotics, temporary coverings, and/or skin grafts.
Developmental Aspects of the Integumentary System
- Fetal: Lanugo (fine hairs) and vernix caseosa (sebum) protect the developing fetus in amniotic fluid.
- Infancy to Adulthood: Skin thickens, subcutaneous fat increases, sebaceous and sweat gland activity increases.
- Aging: Epidermal replacement slows, skin becomes drier, less elastic, more susceptible to skin cancers, and can also experience hair thinning.
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Description
Test your knowledge on human skin and hair anatomy with this quiz. Topics include skin conditions, hair structure, and functions of various skin components. Perfect for biology students and anyone interested in human physiology.