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Questions and Answers
Which layer of the integumentary system houses the germinal matrix?
Which layer of the integumentary system houses the germinal matrix?
What is the function of the hair papilla?
What is the function of the hair papilla?
Which type of hair does not have a medulla?
Which type of hair does not have a medulla?
What is the purpose of the arrector pili muscle?
What is the purpose of the arrector pili muscle?
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Which gland produces sebum?
Which gland produces sebum?
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During which stage of the hair growth cycle do cells divide by mitosis and move upwards to become keratinized?
During which stage of the hair growth cycle do cells divide by mitosis and move upwards to become keratinized?
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What is the average growth rate of scalp hair per month?
What is the average growth rate of scalp hair per month?
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Which stage of the hair growth cycle determines the final length of the hair?
Which stage of the hair growth cycle determines the final length of the hair?
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What percentage of scalp follicles are in the anagen stage?
What percentage of scalp follicles are in the anagen stage?
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How long does scalp hair typically live?
How long does scalp hair typically live?
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Which of the following statements is true?
Which of the following statements is true?
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Where can we find the fifth layer of the epidermis?
Where can we find the fifth layer of the epidermis?
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The most common keratins found in the basal keratinocyte are:
The most common keratins found in the basal keratinocyte are:
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Which of the following is the product of spontaneous decarboxylation of DOPAchrome?
Which of the following is the product of spontaneous decarboxylation of DOPAchrome?
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What are pigmentary demarcation lines?
What are pigmentary demarcation lines?
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What is periorbital pigmentation commonly known as?
What is periorbital pigmentation commonly known as?
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What are melanocytic nevi?
What are melanocytic nevi?
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What is melanoma?
What is melanoma?
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What is albinism?
What is albinism?
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What are striae distensae commonly known as?
What are striae distensae commonly known as?
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Which phase of the hair cycle is characterized by the shedding of hair?
Which phase of the hair cycle is characterized by the shedding of hair?
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What cells release melanin to give hair its color?
What cells release melanin to give hair its color?
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Which type of hair is fine, soft, and non-pigmented?
Which type of hair is fine, soft, and non-pigmented?
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What are the major types of natural skin creases based on tri-radii?
What are the major types of natural skin creases based on tri-radii?
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Which lines are produced by the effect of gravity on loose skin or fatty tissue?
Which lines are produced by the effect of gravity on loose skin or fatty tissue?
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Which lines correspond to the underlying, interlocking pattern of dermal papillae?
Which lines correspond to the underlying, interlocking pattern of dermal papillae?
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Which skin condition is characterized by follicular epidermal hyperproliferation, sebum production, presence of Cutibacterium acnes, and inflammation?
Which skin condition is characterized by follicular epidermal hyperproliferation, sebum production, presence of Cutibacterium acnes, and inflammation?
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What is the rare condition characterized by the lack of ridges on the skin of the fingers, toes, palms, and soles?
What is the rare condition characterized by the lack of ridges on the skin of the fingers, toes, palms, and soles?
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Which lines represent skin tension in rigor mortis and are ideal for skin incisions without scarring?
Which lines represent skin tension in rigor mortis and are ideal for skin incisions without scarring?
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Which skin condition is related to early developmental boundaries or skin cell migration during embryogenesis?
Which skin condition is related to early developmental boundaries or skin cell migration during embryogenesis?
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Study Notes
Integumentary System Overview
- The germinal matrix is located in the hair follicle, specifically in the dermis layer of the integumentary system.
- Hair papilla serves as a dermal structure that supplies nutrients and signals hair growth, facilitating the growth cycle.
- Vellus hair is a type of hair that does not contain a medulla, typically found on the face and body.
- The arrector pili muscle functions to raise hair follicles, causing "goosebumps," and aids in thermoregulation.
- Sebum is produced by sebaceous glands, which are essential for moisturizing and protecting the skin and hair.
Hair Growth Cycle
- Anagen phase is the active growth stage during which hair follicle cells divide through mitosis, moving upward to become keratinized.
- The average growth rate of scalp hair is approximately 1.25 cm (0.5 inches) per month.
- The final length of the hair is determined during the anagen phase, which lasts several years.
- Approximately 85-90% of scalp follicles are in the anagen stage at any given time.
- Scalp hair typically has a lifespan of 2-7 years.
Skin Layers and Epidermis
- The fifth layer of the epidermis, known as the stratum lucidum, can be found in certain areas of thick skin, such as palms and soles.
- The most common keratins in basal keratinocytes are keratin 5 and keratin 14.
Pigmentation and Conditions
- Spontaneous decarboxylation of DOPAchrome produces indole-5,6-quinone, a pivotal intermediate in melanin biosynthesis.
- Pigmentary demarcation lines are visually distinct boundaries of skin tone, often found on limbs and between different areas of pigmentation.
- Periorbital pigmentation is commonly known as dark circles under the eyes.
- Melanocytic nevi, or moles, are benign growths formed from clusters of melanocytes.
- Melanoma is a serious form of skin cancer resulting from the uncontrolled growth of melanocytes.
- Albinism is a genetic condition characterized by a lack of melanin, leading to pale skin, hair, and eyes.
- Striae distensae are commonly known as stretch marks, caused by rapid skin stretching.
Hair Cycle Phases
- The telogen phase is characterized by the shedding of hair, with old hair falling out as new hair begins to grow.
- Melanocytes are the cells responsible for producing melanin, which gives hair its color.
- Vellus hair is fine, soft, and non-pigmented, commonly found on the body.
Skin Creases and Conditions
- Major natural skin creases are based on tri-radii patterns found in areas like palms and soles.
- Gravitational lines are formed due to the effect of gravity on loose skin or adipose tissue over time.
- Langer lines correspond to the orientation of dermal papillae and align with the underlying features of the dermis.
- Acne vulgaris is characterized by follicular hyperproliferation, increased sebum production, colonization by Cutibacterium acnes, and associated inflammation.
- A rare condition with a lack of skin ridges on fingers and toes is known as adermatoglyphia.
- Tension lines from rigor mortis represent skin tension and are ideal for making incisions without causing scarring.
- Certain skin conditions are linked to early developmental boundaries or issues in skin cell migration during embryogenesis.
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Description
Test your knowledge of the integumentary system and its three layers: medulla, cortex, and cuticle. Learn about the germinal matrix, hair papilla, and melanocyte cells that determine hair color. Understand the characteristics of vellus hair and its transformation into terminal follicles during puberty.