Podcast
Questions and Answers
What is the approximate weight percentage of the skin compared to total body weight?
What is the approximate weight percentage of the skin compared to total body weight?
Which layer of the skin is primarily responsible for temperature regulation?
Which layer of the skin is primarily responsible for temperature regulation?
What role does skin pigmentation play in protecting the body?
What role does skin pigmentation play in protecting the body?
Which structure primarily forms the barrier against dehydration in the skin?
Which structure primarily forms the barrier against dehydration in the skin?
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What is the primary method through which skin absorbs substances?
What is the primary method through which skin absorbs substances?
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What physiological effect does elevated body temperature have on the skin's blood vessels?
What physiological effect does elevated body temperature have on the skin's blood vessels?
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Which statement is true about the epidermis?
Which statement is true about the epidermis?
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How does aging affect the skin?
How does aging affect the skin?
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Which layer of the skin is primarily composed of loose connective tissue and fat?
Which layer of the skin is primarily composed of loose connective tissue and fat?
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What is the main function of sebaceous glands in the skin?
What is the main function of sebaceous glands in the skin?
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What is the primary component of collagen in the skin's structure?
What is the primary component of collagen in the skin's structure?
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Which layer of the skin primarily synthesizes keratin?
Which layer of the skin primarily synthesizes keratin?
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What percentage of the dermis consists of collagen?
What percentage of the dermis consists of collagen?
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What role do fibroblasts play in the skin?
What role do fibroblasts play in the skin?
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What substance is primarily responsible for the moisture retention in the dermis?
What substance is primarily responsible for the moisture retention in the dermis?
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Which layer of the epidermis is involved in the keratinization process?
Which layer of the epidermis is involved in the keratinization process?
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What happens to the collagen fibers as skin ages?
What happens to the collagen fibers as skin ages?
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What type of cells are primarily responsible for the immune response in the skin?
What type of cells are primarily responsible for the immune response in the skin?
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In which layer does the conversion to mature keratin occur?
In which layer does the conversion to mature keratin occur?
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What is the primary function of the dermal papillae?
What is the primary function of the dermal papillae?
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What is the primary function of keratinocytes in the epidermis?
What is the primary function of keratinocytes in the epidermis?
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Which layer of the epidermis is primarily responsible for the skin's strength and flexibility?
Which layer of the epidermis is primarily responsible for the skin's strength and flexibility?
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What occurs in the stratum granulosum?
What occurs in the stratum granulosum?
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Which cells in the epidermis help absorb harmful UV radiation?
Which cells in the epidermis help absorb harmful UV radiation?
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What are the characteristics of the stratum lucidum?
What are the characteristics of the stratum lucidum?
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What happens when the basal layer of the epidermis is damaged?
What happens when the basal layer of the epidermis is damaged?
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How does the stratum corneum contribute to skin protection?
How does the stratum corneum contribute to skin protection?
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What is the primary characteristic of malignant melanoma?
What is the primary characteristic of malignant melanoma?
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Which of the following UV rays is mostly absorbed by the ozone layer?
Which of the following UV rays is mostly absorbed by the ozone layer?
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What is the function of lamellar granules found in the stratum granulosum?
What is the function of lamellar granules found in the stratum granulosum?
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What role do tactile cells play in the skin?
What role do tactile cells play in the skin?
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What typically causes pressure ulcers?
What typically causes pressure ulcers?
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In which skin area would you most likely find the stratum lucidum?
In which skin area would you most likely find the stratum lucidum?
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What is a significant risk of burns covering more than 70% of the body surface area?
What is a significant risk of burns covering more than 70% of the body surface area?
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What is the role of matrix metalloproteinase (MMP) in skin damage?
What is the role of matrix metalloproteinase (MMP) in skin damage?
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Which sign is NOT used to detect malignant melanoma?
Which sign is NOT used to detect malignant melanoma?
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How does sunlight primarily affect the skin?
How does sunlight primarily affect the skin?
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What type of burn affects only the skin's surface and does not penetrate deeper layers?
What type of burn affects only the skin's surface and does not penetrate deeper layers?
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What type of sweat glands are responsible for body odor and begin to function during puberty?
What type of sweat glands are responsible for body odor and begin to function during puberty?
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What is the primary function of ceruminous glands found in the ear canal?
What is the primary function of ceruminous glands found in the ear canal?
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Which of the following changes is associated with skin aging?
Which of the following changes is associated with skin aging?
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How does nicotine in cigarette smoke affect the skin?
How does nicotine in cigarette smoke affect the skin?
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What is the growth rate of nails typically measured at?
What is the growth rate of nails typically measured at?
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What skin condition is primarily linked to the UV exposure and type of skin?
What skin condition is primarily linked to the UV exposure and type of skin?
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What consequence may arise due to a decrease in sebaceous gland activity with age?
What consequence may arise due to a decrease in sebaceous gland activity with age?
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Which of the following is NOT a component in the secretion of apocrine sweat glands?
Which of the following is NOT a component in the secretion of apocrine sweat glands?
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What typically happens to collagen fibers in the skin as a person ages?
What typically happens to collagen fibers in the skin as a person ages?
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Which vitamin is significantly affected by smoking and is important for skin health?
Which vitamin is significantly affected by smoking and is important for skin health?
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What is the primary factor that determines skin color?
What is the primary factor that determines skin color?
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Which layer of the dermis constitutes approximately 80% of its thickness?
Which layer of the dermis constitutes approximately 80% of its thickness?
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What is the role of elastin fibers in the skin?
What is the role of elastin fibers in the skin?
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Which pigment can accumulate excessively and cause skin spots?
Which pigment can accumulate excessively and cause skin spots?
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What type of administration involves the delivery of substances through the dermis?
What type of administration involves the delivery of substances through the dermis?
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What condition is characterized by the absence of melanin production?
What condition is characterized by the absence of melanin production?
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Which receptor is responsible for touch sensation in the skin?
Which receptor is responsible for touch sensation in the skin?
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What percentage of hair follicles is in the resting phase at any given time?
What percentage of hair follicles is in the resting phase at any given time?
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What are the main components of hair?
What are the main components of hair?
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The papillary dermis increases surface area for which purpose?
The papillary dermis increases surface area for which purpose?
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Study Notes
Dermatological Physiology
- The subject matter involves the physiology of the skin.
- Skin weight accounts for roughly 7% of total body weight.
- Skin thickness varies between 1.5mm and 4.4mm.
- The skin consists of the epidermis and dermis layers.
- The epidermis (outer layer) is approximately 0.1mm thick in the palms and soles, 0.8–1.4mm on the palms and soles.
- The epidermis contains around 20-30% water.
- The dermis (inner layer) lies below the epidermis.
- Subcutaneous tissue (hypodermis) is below the dermis.
- Skin is composed of areolar connective tissue and adipose tissue.
- Subcutaneous tissue functions to connect skin to muscles, contain white blood cells, mast cells, and chemicals that facilitate inflammation, contain stored energy in fats, cushions bony areas, insulates from cold, and influences appetite. Also produces cytokines to activate white blood cells.
Lecture Objectives
- Introduction to the structure and functions of the skin
- Function of epidermal cells and stratum corneum
- Impact of ultraviolet radiation and environmental factors
- Influence of age and pathological changes on skin
Outline
- Introduction to skin function
- Stratum corneum layers
- Dermal layers
- Skin coloration
- Appendages of the skin
- Aging and skin disorders
- Common skin abnormalities
Skin- Body's Largest Organ
- Skin comprises 7% of total body weight
- Skin thickness is 1.5 to 4.4 mm
- Skin is divided into two layers: Epidermis and Dermis
- Epidermis (epidermal layer): approx. 0.1mm (palms and soles 0.8-1.4 mm) and contains 20-30% water.
- Dermis (dermal layer): lies beneath epidermis
Subcutaneous Tissue/Hypodermis
- Located below the dermis
- Composed of loose connective tissue and adipose tissue
- Connect skin to underlying muscles
Body Temperature Regulation
- Blood vessels (and sweat glands) regulate temperature
- Blood flow changes with temperature changes
- Sweating is a primary cooling mechanism
Protection
- Physical barrier against pathogens,
- Prevention of water loss
- UV radiation protection
- Barrier to pathogens and harmful substances
- Barrier against microbes
- Prevention from dehydration
Sensation
- Sensory nerve endings for pressure, touch, temperature, and pain are located in the dermis
- Sensory receptors detect stimuli and transmit signals to the brain
- Skin aids in preventing external harm via detecting stimuli
Excretion and Absorption
- Sweat and sebum release (secretion)
- Limited transdermal absorption, but limited clinical use
Vitamin D Production
- Skin produces vitamin D3 when exposed to UV radiation
- Crucial for calcium and phosphorus regulation
Skin Structure - microscopic view
- Keratinocytes (approx 90%)
- Melanocytes (approx. 8%)
- Langerhans cells
- Tactile cells (Merkel cells)
Stratum Basale
- Deepest layer of epidermis
- Contains stem cells for new keratinocytes
- Contains melanocytes (produce melanin)
- Contains Merkel cells
Stratum Spinosum
- Several layers of cells
- Contains intermediate filaments (resisting mechanical stress)
- Cells are interconnected via desmosomes (cell junctions)
Stratum Granulosum
- 3-5 layers of flattened cells
- Cells are dying and becoming keratinized
- Contain keratohyalin granules (help form the stratum corneum)
- Containing lamellar granules
Stratum Lucidum
- Only present in thick skin
- Clear layer of flattened, dead cells
Stratum Corneum
- Outermost layer of epidermis
- Many layers of flattened, dead cells
- Forms a waterproof barrier
- Lipids (ceramides, cholesterol, fatty acids) fill the spaces between the cells, contributing to the skin's barrier function
- Water content generally ranges from 20–35%. 50-60% in granular layer, 65% in spinous, and 70 % in basal
Skin Coloration
- Melanin production by melanocytes is primary factor for skin color
- Carotenoids and hemoglobin contribute
- Melanin protects against UV radiation
Skin Appendages
- Hair follicles
- Sebaceous glands
- Sweat glands
- Eccrine
- Apocrine
- Nails
Aging and Skin Disorders
- Loss of collagen and elastin, reduced blood supply, and decreased cell turnover lead to wrinkles, sagging and a decrease in skin thickness
- Skin's immune defenses lessen
- Increased risk for age-related skin cancers
Pressure Ulcers
- Also known as bedsores
- Tissue damage due to prolonged pressure
- Occur frequently in patients who are bedridden or immobile.
- Develop frequently on bony areas (such as the heels, buttocks, or over the tailbone).
Burns
- Thermal injuries to the skin.
- Vary in severity depending on duration of exposure, temperature, and depth of tissue damage.
- Degree of injury divided into categories: 1st, 2nd, and 3rd.
- Healing times vary based on severity.
Skin Cancer
- Basal cell carcinoma (most common)
- Squamous cell carcinoma
- Malignant melanoma (most serious type)
- Diagnosed by asymmetry, irregular borders, color variation, diameter, evolution (ABCDE)
General Skin Function
- Protection
- Temperature regulation
- Sensation
- Excretion
- Vitamin D synthesis
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Description
Test your knowledge on the anatomy and physiology of the skin. This quiz covers various aspects such as skin layers, functions, and the effects of aging. Perfect for students in biology classes or anyone interested in learning more about skin health.
