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What is the primary function of the integumentary system?
What is the primary function of the integumentary system?
The epidermis is vascularized and contains many blood vessels.
The epidermis is vascularized and contains many blood vessels.
False
What is the name of the layer of skin located deep to the epidermis?
What is the name of the layer of skin located deep to the epidermis?
dermis
The outermost layer of skin is called the _________.
The outermost layer of skin is called the _________.
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Match the following cell types with their functions:
Match the following cell types with their functions:
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What is the primary function of hair on the scalp?
What is the primary function of hair on the scalp?
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Basal cell carcinomas are the most common type of skin cancer and are generally malignant.
Basal cell carcinomas are the most common type of skin cancer and are generally malignant.
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What are the three layers that make up a hair?
What are the three layers that make up a hair?
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The hair follicle surrounds the outside of hair _________.
The hair follicle surrounds the outside of hair _________.
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Which type of skin cancer represents 20% of cases?
Which type of skin cancer represents 20% of cases?
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Hair traps air to minimize heat loss.
Hair traps air to minimize heat loss.
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What type of muscle interacts with hair follicles to make the hair stand up?
What type of muscle interacts with hair follicles to make the hair stand up?
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Match the following terms with their definitions:
Match the following terms with their definitions:
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What type of cells are responsible for sensing light touch in the skin?
What type of cells are responsible for sensing light touch in the skin?
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The epidermis consists of three strata in most areas of the body.
The epidermis consists of three strata in most areas of the body.
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What are the two primary regions of the dermis?
What are the two primary regions of the dermis?
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The stratum ________ is the deepest layer of the epidermis that contains stem cells.
The stratum ________ is the deepest layer of the epidermis that contains stem cells.
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Which stratum is only found in thick skin?
Which stratum is only found in thick skin?
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Apoptosis occurs in the stratum granulosum layer.
Apoptosis occurs in the stratum granulosum layer.
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What is the primary function of keratin in the stratum corneum?
What is the primary function of keratin in the stratum corneum?
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Fingerprints are formed due to the interlocking of ________ and the dermal papillae.
Fingerprints are formed due to the interlocking of ________ and the dermal papillae.
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Melanocytes secrete different amounts of which pigment that affects skin color?
Melanocytes secrete different amounts of which pigment that affects skin color?
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Match the strata of the epidermis with their key characteristics:
Match the strata of the epidermis with their key characteristics:
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Tattoo ink is deposited only in the epidermis of the skin.
Tattoo ink is deposited only in the epidermis of the skin.
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What is the primary role of lamellar granules in the stratum granulosum?
What is the primary role of lamellar granules in the stratum granulosum?
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The reticular region of the dermis is made up of ________ connective tissue.
The reticular region of the dermis is made up of ________ connective tissue.
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What happens to melanin production when the skin is exposed to UV light?
What happens to melanin production when the skin is exposed to UV light?
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Which of the following statements correctly describes the epidermis?
Which of the following statements correctly describes the epidermis?
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The dermis is the outermost layer of the skin.
The dermis is the outermost layer of the skin.
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What is the primary pigment produced by melanocytes?
What is the primary pigment produced by melanocytes?
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The skin serves several functions, including __________ body temperature and __________ energy.
The skin serves several functions, including __________ body temperature and __________ energy.
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What is the primary role of hair in the body?
What is the primary role of hair in the body?
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The cuticle is the innermost layer of hair.
The cuticle is the innermost layer of hair.
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What are the three layers that make up the hair structure?
What are the three layers that make up the hair structure?
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Hair protects the scalp from UV radiation, the eyes, and nasal cavity from __________.
Hair protects the scalp from UV radiation, the eyes, and nasal cavity from __________.
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Basal cell carcinomas involve cells in which layer of the skin?
Basal cell carcinomas involve cells in which layer of the skin?
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Match the following types of skin cancer with their characteristics:
Match the following types of skin cancer with their characteristics:
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Hair follicles are composed solely of epithelial tissue.
Hair follicles are composed solely of epithelial tissue.
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What role do arrector pili muscles have in relation to hair?
What role do arrector pili muscles have in relation to hair?
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Which layer of skin contains primarily connective tissue and is vascularized?
Which layer of skin contains primarily connective tissue and is vascularized?
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The epidermis is a vascularized layer of skin containing blood vessels.
The epidermis is a vascularized layer of skin containing blood vessels.
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What is the primary pigment produced by melanocytes?
What is the primary pigment produced by melanocytes?
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The ________ layer of skin anchors all structures to the fascia and contains pressure receptors.
The ________ layer of skin anchors all structures to the fascia and contains pressure receptors.
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Match the following cell types with their respective functions:
Match the following cell types with their respective functions:
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Which type of tissue makes up the reticular region of the dermis?
Which type of tissue makes up the reticular region of the dermis?
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The epidermis consists of only three strata in most areas of the body.
The epidermis consists of only three strata in most areas of the body.
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What is the primary role of the stratum granulosum?
What is the primary role of the stratum granulosum?
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The stratum ________ is the outermost layer of the skin composed of dead cells.
The stratum ________ is the outermost layer of the skin composed of dead cells.
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Match the epidermal strata with their key features:
Match the epidermal strata with their key features:
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What is the function of keratin intermediate filaments in the stratum basale?
What is the function of keratin intermediate filaments in the stratum basale?
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Melanocytes are responsible for the production of keratin in the skin.
Melanocytes are responsible for the production of keratin in the skin.
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What distinguishes thick skin from thin skin?
What distinguishes thick skin from thin skin?
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Cells of the stratum granulosum undergo ________ to die and release keratin.
Cells of the stratum granulosum undergo ________ to die and release keratin.
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Match the following structures with their descriptions:
Match the following structures with their descriptions:
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What substance assists in melanin synthesis and increases upon UV exposure?
What substance assists in melanin synthesis and increases upon UV exposure?
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Fingerprints are unique to each individual because they are formed by epidermal ridges.
Fingerprints are unique to each individual because they are formed by epidermal ridges.
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How long does it take for new cells at the stratum basale to reach the stratum corneum?
How long does it take for new cells at the stratum basale to reach the stratum corneum?
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Accumulation of melanin in the skin can appear as _________, age spots, or nevuses.
Accumulation of melanin in the skin can appear as _________, age spots, or nevuses.
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Study Notes
Integumentary System
- The integumentary system includes the skin, hair, nails, oil glands, sweat glands, and sensory receptors.
- Skin is the largest organ in the body, making up 7% of body weight.
- Skin thickness is variable, ranging from 0.5 mm on the eyelids to 4 mm on the heels.
- The epidermis is the outermost layer of skin, composed of stratified squamous epithelium and avascular.
- The dermis lies beneath the epidermis, made of vascularized connective tissue.
- The subcutaneous layer (hypodermis) anchors the skin to the fascia and houses pressure receptors.
- Key functions of the integumentary system:
- Regulates body temperature.
- Protects the body from external insults.
- Senses signals.
- Excretes and absorbs chemicals.
- Stores blood and energy.
- Synthesizes vitamin D.
Epidermis
- Composed of keratinized stratified squamous epithelium.
- Contains various cell types:
- Keratinocytes: Layered cells that produce keratin and lamellar granules for waterproofing and sealing.
- Melanocytes: Contain melanin granules, which absorb UV light and protect DNA.
- Intraepidermal macrophages (Langerhans cells): UV-sensitive phagocytes that engulf and destroy invaders through phagocytosis.
- Tactile epithelial cells: Sense touch in direct contact with tactile discs (nervous tissue).
- The epidermis is further subdivided into strata:
- Stratum basale (deepest layer): Contains stem cells that replenish overlying strata, rich in keratin intermediate filaments (IFs) for strength and reinforcement of cell junctions.
- Stratum spinosum: Provides strength to the skin with thicker keratin IFs and reinforced desmosomes.
- Stratum granulosum: Seals the epidermis, contains cells undergoing apoptosis, produces keratohyalin for keratin IF assembly and lipids for sealing against invasion and fluid loss.
- Stratum corneum (most superficial): Consists of dead, flattened keratinocytes that slough off with abrasion, replenished by cell division from the stratum basale.
- Stratum lucidum (found only in thick skin): Located between the stratum granulosum and corneum, made of dead, flat keratinocytes with thick keratin filaments.
- Most of the body is covered with four-layered skin; five layers are found in high abrasion areas (palms and soles).
- Takes 4-6 weeks for new cells to migrate from stratum basale to the stratum corneum.
- Keratinization reinforces skin through the accumulation of keratin in cells that die by apoptosis.
- Cells farther from the stratum basale have decreased access to nutrients.
Dermis
- Made of connective tissue, providing great tensile strength.
- Divided into two regions:
- Papillary region (top 20%): Consists of areolar connective tissue with collagen and elastic fibers, contains dermal papillae (extensions from dermis into epidermis) with capillaries and touch and pain sensing nervous tissue.
- Reticular region (bottom 80%): Composed of dense irregular connective tissue, a mesh-like network of thick collagen fibers with fibroblasts, resists stretching and shear, anchors the dermis to the subcutaneous layer.
- Fingerprints are unique to each individual, formed by epidermal ridges (shape of dermal papillae) enhancing friction for grip and increasing surface area for touch sensing.
Skin Colour
- Variations in human skin colour are caused by differences in melanin secretion, not the number of melanocytes.
- Accumulation of melanin can manifest as freckles, age spots, or nevuses (moles).
- Tanning: UV light exposure increases tyrosinase activity, which assists melanin synthesis; the tan fades as the skin dies and gets replaced by cells with less melanin production.
- Depth of skin colour is determined by the amount of melanin in the epidermis.
- The stratum corneum stores carotene, which gives an orange tinge to skin.
Hair
- Hair protects and insulates the body and helps sense stimuli.
- Found on the scalp, eyebrows, eyelashes, nasal cavity, axillae, and external genitalia.
- Functions:
- Traps air close to the skin for minimizing heat loss.
- Touch receptors connect to hair movement.
- Hair consists of:
- Root: Embedded in the dermis or subcutaneous layer of scalp.
- Shaft: Superficial portion of the hair.
- Both the root and shaft have three layers:
- Medulla (deepest): Contains pigmented cells.
- Cortex (middle): Makes up the bulk of hair.
- Cuticle (most superficial): Made of flattened keratinized epithelial cells arranged like roof shingles.
- The hair follicle surrounds the hair root:
- External layer: Made of epithelial tissue.
- Internal layer: Makes up the hair matrix, which divides continuously for hair growth.
- Hair interacts with smooth muscle (arrector pili) that contracts during cold or fear, causing hair to stand on end.
Nails
- Provide protection for finger tips, support for fingertips.
Wound Healing
- An essential part of maintaining integumentary homeostasis.
Burns
- Specific injuries that can lead to life-threatening complications like edema and sepsis.
Skin Cancer
- Can result from excessive UV exposure, involves uncontrolled proliferation of epithelial cells.
- Three types of skin cancer:
- Basal cell carcinomas: Involve cells in the stratum basale, most common type of skin cancer (78%), generally benign.
- Squamous cell carcinomas: Involve cells in the stratum spinosum, represent 20% of skin cancers.
- Malignant melanomas: Cancers of melanocytes.
Integumentary System
- The integumentary system includes skin, hair, nails, sweat glands, oil glands, and sensory receptors.
- The skin is the largest organ in the body, making up 7% of body weight.
- The epidermis is the outer layer of the skin and is avascular.
- The dermis is the inner layer of skin and is vascularized.
- The subcutaneous layer, or hypodermis, anchors the skin to the underlying fascia and contains pressure receptors.
Functions of the Integumentary System
- Regulates body temperature.
- Protects the body from external insults.
- Senses signals.
- Excretes and absorbs chemicals.
- Stores blood and energy.
- Synthesizes vitamin D.
The Epidermis
- The epidermis is composed of keratinized stratified squamous epithelium, containing multiple cell types.
Keratinocytes
- Keratinocytes form layers and produce keratin, a protein that strengthens the skin.
- Keratinocytes produce lamellar granules, which contribute to the skin's waterproof barrier.
Melanocytes
- Melanocytes contain melanin granules, a brown-black pigment that absorbs UV light to protect DNA from damage.
- UV light damage to DNA causes mutations.
Intraepidermal Macrophages (Langerhans Cells)
- These cells are UV-sensitive phagocytes that engulf and destroy invaders through phagocytosis.
Tactile Epithelial Cells
- These cells sense touch and are in direct contact with tactile discs, which are part of the nervous system.
Epidermal Strata
- The epidermis is divided into layers, called strata, composed of keratinocytes at different stages of maturity.
- Most of the body is covered in skin containing four strata.
- Thick skin, found on palms and soles, has five strata.
Layers of the Epidermis (deepest to most superficial)
- Stratum basale: Contains stem cells that divide to replace the overlying layers, rich in keratin intermediate filaments (IFs) that provide strength and reinforce cell junctions (desmosomes and hemidesmosomes).
- Stratum spinosum: 8-10 layers of flattened keratinocytes that contain thicker, tougher keratin IFs that reinforce desmosomes and have fewer cells capable of cell division.
- Stratum granulosum: Consists of 3-5 layers of dying cells undergoing apoptosis, with keratin filaments persisting. These cells produce keratohyalin, a dark staining substance that aids in keratin IF assembly, and lamellar granules that contain lipids, contributing to the skin's barrier function.
- Stratum corneum: Most superficial layer, composed of dead, flat, overlapping cells that slough off via abrasion.
-
Stratum lucidum: Found only in thick skin, located between the stratum granulosum and stratum corneum.
- Clear and made of dead, flat keratinocytes with thick keratin filaments and plasma membranes, providing additional mechanical support.
Epidermal Growth
- It takes 4-6 weeks for new cells from the stratum basale to reach the stratum corneum.
- Cells farther from the stratum basale have decreased access to nutrients.
The Dermis
- A connective tissue layer that provides tensile strength and has two regions.
Papillary Region
- Made of areolar connective tissue containing collagen and elastic fibres.
- Dermal papillae are tissue extensions from the dermis into the epidermis, containing capillaries.
- Contains nervous tissue for touch and pain sensation.
- Represents the top 20% of the dermis.
Reticular Region
- Made of dense irregular connective tissue, with a mesh-like network of thick collagen fibers interspersed with fibroblasts and other cells.
- Provides resistance to stretching and shear forces.
- Contains glands, nerves, and blood vessels.
- Anchors the dermis to the subcutaneous layer.
- Represents the bottom 80% of the dermis.
Fingerprints
- Epidermal ridges dig into the dermal papillae to create fingerprints.
- Fingerprints are unique to each individual and differ even between identical twins.
- They increase friction for grip and surface area for touch sensing.
- Sweat pores open on the surface.
Human Skin Color
- Differences in skin color are due to the amount of melanin produced by melanocytes.
- Everyone has the same number of melanocytes, but the cells secrete different amounts of melanin.
- Excess melanin accumulation can lead to freckles, age spots, or nevi (moles).
Tanning
- Melanocytes contain tyrosinase, an enzyme that assists in melanin synthesis.
- Tyrosinase activity increases upon exposure to UV light.
- Tanning fades as the skin cells die and are replaced by cells with less melanin production.
Carotene
- The stratum corneum stores carotene, a pigment that contributes to an orange tinge.
Tattoos
- Tattoos use specialized needles to deposit ink into the dermis.
- Laser treatment for tattoo removal destroys pigmented cells, leading to phagocytosis of cell debris.
Accessory Structures of the Skin
Hair
- Hair protects and insulates the body and aids in sensing stimuli.
- Found on the scalp, eyebrows, eyelashes, nasal cavity, axillae (armpits), and external genitalia.
- Protects: scalp from UV radiation, eyes and nasal cavity from invasion.
Hair Functions
- Traps air to minimize heat loss.
- Touch receptors are attached to hair for sensing movement.
Hair Anatomy
- Hair consists of a root embedded in the dermis or subcutaneous layer, and a shaft that is the superficial portion of the hair.
- Both the root and shaft have three layers:
- Medulla: the deepest layer containing pigmented cells.
- Cortex: makes up the bulk of the hair.
- Cuticle: the most superficial layer made of flat keratinized epithelial cells arranged like shingles.
- Both the root and shaft have three layers:
- The hair follicle surrounds the root of the hair.
- An external layer made of epithelial tissue.
- An internal layer, the hair matrix, that divides continually to enable hair growth.
Hair and Associated Structures
- Hair is associated with smooth muscle (arrector pili) that pulls hair upright in response to cold or fear.
Glands
- Sweat and oil glands are associated with the integumentary system.
Nails
- Made of hardened keratin and protect the ends of fingers and toes.
Skin Cancer
- Can result from excessive UV exposure and involves uncontrolled proliferation of epithelial cells.
Types of Skin Cancer
- Basal cell carcinomas: involve cells in the stratum basale, the most common type (78%), usually benign.
- Squamous cell carcinomas: involve cells in the stratum spinosum, make up 20% of skin cancers.
- Malignant melanomas: cancers of melanocytes, which are the most dangerous type.
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Description
Explore the fascinating components and functions of the integumentary system, which includes the largest organ in the human body—skin. This quiz will cover skin layers, their structures, and the essential roles they play in maintaining body health. Test your knowledge on the various elements and functions of this vital system.
