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Questions and Answers
What is the primary function of the keratohyaline granules that accumulate in the stratum granulosum?
What is the primary function of the keratohyaline granules that accumulate in the stratum granulosum?
In which layer of the epidermis do cells begin to die due to distance from dermal capillaries?
In which layer of the epidermis do cells begin to die due to distance from dermal capillaries?
What is the primary characteristic of the stratum corneum?
What is the primary characteristic of the stratum corneum?
Which layer of the epidermis is found only in thick skin?
Which layer of the epidermis is found only in thick skin?
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What role do lamellar granules play in the stratum granulosum?
What role do lamellar granules play in the stratum granulosum?
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What feature accounts for the thickness of the stratum corneum?
What feature accounts for the thickness of the stratum corneum?
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How often can humans shed skin cells?
How often can humans shed skin cells?
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What process leads to the death of cells in the epidermis as they move upwards in the layers?
What process leads to the death of cells in the epidermis as they move upwards in the layers?
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Which part of the hair follicle is responsible for the production of hair cells?
Which part of the hair follicle is responsible for the production of hair cells?
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What type of hair is characterized as short and fine, typically found on children and adult females?
What type of hair is characterized as short and fine, typically found on children and adult females?
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What is the primary function of the arrector pili muscle associated with hair follicles?
What is the primary function of the arrector pili muscle associated with hair follicles?
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Which structure provides nutrients to the growing hair?
Which structure provides nutrients to the growing hair?
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What can cause excessive hairiness, also known as hirsutism, in women?
What can cause excessive hairiness, also known as hirsutism, in women?
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How much hair on average do people lose from the scalp daily?
How much hair on average do people lose from the scalp daily?
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What structure is derived from the epidermis in a hair follicle?
What structure is derived from the epidermis in a hair follicle?
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What is the average growth rate of hair follicles per week?
What is the average growth rate of hair follicles per week?
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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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What role do keratinocytes have in the skin?
What role do keratinocytes have in the skin?
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How much of the body’s total blood volume can the skin hold?
How much of the body’s total blood volume can the skin hold?
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Which of the following substances can be excreted through the skin?
Which of the following substances can be excreted through the skin?
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Which type of sensory receptors in the skin respond to painful stimuli?
Which type of sensory receptors in the skin respond to painful stimuli?
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What is one of the metabolic functions of the skin?
What is one of the metabolic functions of the skin?
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Which condition is considered less common but more damaging than infections of the skin?
Which condition is considered less common but more damaging than infections of the skin?
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What role does sweat play in skin protection?
What role does sweat play in skin protection?
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How does the acid mantle contribute to skin protection?
How does the acid mantle contribute to skin protection?
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Which substance can penetrate the skin more easily due to its lipid-soluble nature?
Which substance can penetrate the skin more easily due to its lipid-soluble nature?
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What is the primary function of dendritic cells in the epidermis?
What is the primary function of dendritic cells in the epidermis?
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What potential health risk do organic solvents and heavy metals pose when absorbed through the skin?
What potential health risk do organic solvents and heavy metals pose when absorbed through the skin?
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Which component of the skin provides a barrier against UV radiation damage?
Which component of the skin provides a barrier against UV radiation damage?
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How do macrophages in the dermis contribute to the immune response?
How do macrophages in the dermis contribute to the immune response?
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Which of the following substances is NOT listed as having limited penetration through the skin?
Which of the following substances is NOT listed as having limited penetration through the skin?
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Which of the following components is NOT part of the integumentary system?
Which of the following components is NOT part of the integumentary system?
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What characterizes the epidermis in terms of its vascularity?
What characterizes the epidermis in terms of its vascularity?
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The primary function of keratinocytes is to produce which of the following?
The primary function of keratinocytes is to produce which of the following?
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Which layer of the skin underlies the epidermis?
Which layer of the skin underlies the epidermis?
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Which type of tissue primarily composes the dermis?
Which type of tissue primarily composes the dermis?
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What is the main function of the hypodermis?
What is the main function of the hypodermis?
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What is true about the keratinocytes in the epidermis?
What is true about the keratinocytes in the epidermis?
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How is the hypodermis related to the skin layers?
How is the hypodermis related to the skin layers?
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Study Notes
Integumentary System
- The integumentary system consists of skin, hair, nails, sweat glands, and sebaceous (oil) glands.
Structure of Skin
- The skin has two distinct regions: the epidermis and the dermis.
- The epidermis is the superficial region and is avascular, consisting of epithelial tissue.
- The dermis is the layer beneath the epidermis, composed mostly of fibrous connective tissue and is vascular.
- The hypodermis is the subcutaneous layer deep to the skin, mostly adipose tissue that absorbs shock and insulates.
Epidermis
- The epidermis is mostly composed of keratinized stratified squamous epithelium.
- There are four types of cells in the epidermis: keratinocytes, melanocytes, Langerhans cells, and Merkel cells.
- Keratinocytes produce the protein keratin, which gives skin its protective properties and are the major cells of the epidermis.
- Melanocytes produce the pigment melanin, which protects against UV radiation and provides skin color.
- Langerhans cells are immune cells that help fight infection.
- Merkel cells are sensory cells that detect touch.
Layers of the Epidermis
- The epidermis is composed of five layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.
- The stratum basale is the deepest layer and contains rapidly dividing cells that continually produce new keratinocytes.
- The stratum spinosum is a layer of cells that are held together by desmosomes.
- The stratum granulosum is a layer of cells that begin to keratinize, accumulate keratin, and a water-resistant glycolipid.
- The stratum lucidum is only found in thick skin and is a thin, translucent layer of cells.
- The stratum corneum is the outermost layer of the epidermis and is composed of dead, keratinized cells that provide protection from the environment.
Hair Follicles
- Hair follicles extend from the epidermal surface to the dermis,
- The hair bulb is the expanded area at the deep end of the follicle.
- The hair follicle receptor (or root hair plexus) is a sensory nerve ending that wraps around the bulb and acts as a touch receptor.
- The wall of the follicle has three layers: peripheral connective tissue sheath (or fibrous sheath), glassy membrane, and epithelial root sheath.
- The hair matrix is an actively dividing area of the bulb that produces hair cells.
- The arrector pili is a smooth muscle that attaches to the follicle and causes the hair to stand on end, creating "goose bumps."
- The hair papilla is a protrusion of dermal tissue that contains blood vessels that supply nutrients to the hair.
Types and Growth of Hair
- Vellus hair is a pale, fine body hair found in children and adult females.
- Terminal hair is coarse, long hair found on the scalp and eyebrows.
- Hair growth is affected by nutrition and hormones.
- Hair follicles cycle between active and regressive phases and grow an average of 2.25 mm per week.
Skin Functions
- The skin provides protection against environmental factors.
- The skin functions as a chemical barrier by secreting antimicrobial proteins, lipids, and acids, and an acid mantle with a low pH.
- The skin acts as a physical barrier by blocking water and water-soluble substances, while allowing some chemicals to penetrate, such as lipid-soluble substances.
- The skin provides a biological barrier with dendritic cells and macrophages that activate immune responses.
- The skin regulates body temperature by controlling blood flow and sweat gland activity.
- The skin senses touch, pressure, temperature, and pain through cutaneous sensory receptors.
- The skin synthesizes vitamin D.
- The skin carries out metabolic functions, including converting cortisone into hydrocortisone, and producing collagenase.
- The skin acts as blood reservoir for blood storage.
- The skin excretes a limited amount of nitrogenous wastes, such as ammonia, urea, and uric acid.
Skin Cancer and Burns
- Skin cancer is a serious condition that can occur when cells in the skin begin to grow abnormally.
- Three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma.
- Burns are injuries that can occur when the skin is exposed to heat, chemicals, or radiation.
- Burns are classified by degree: first-degree burns, second-degree burns, and third-degree burns.
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Description
This quiz covers key concepts related to the integumentary system, including the structure and function of skin layers, types of cells in the epidermis, and associated glands. Test your knowledge on the vital roles these components play in protection and regulation.
