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Questions and Answers
What primarily causes loss of skin turgor?
What happens to the epidermis as a person ages?
Which type of sweat glands are primarily responsible for producing body odor?
Which characteristic is NOT associated with aging of the integumentary system?
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What is the primary mode of water loss through the skin during insensible perspiration?
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What is one function of the skin related to temperature management?
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Which pigment is primarily responsible for protecting the skin from UV radiation?
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What condition results from a buildup of bile due to liver issues, affecting skin color?
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What effect does blood flow to the skin have on skin color?
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What is the primary dietary source of carotene that can affect skin color?
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What is the primary role of melanin in the skin?
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How does carotene influence skin color?
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What condition can cause the skin to appear bluish?
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What effect does local dilation of blood vessels have on skin appearance?
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What is the main reason for jaundice affecting skin color?
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What is the role of myoepithelial cells in relation to apocrine sweat glands?
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Which factor contributes to the thinning of the dermis as people age?
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Which of the following statements best describes sensible perspiration?
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What physical changes occur to the skin due to aging?
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What is a primary characteristic of the secretions from eccrine (merocrine) sweat glands?
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Which of the following factors does NOT contribute to the loss of skin turgor?
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What is the primary component of secretions from eccrine (merocrine) sweat glands?
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Which of the following age-related changes in the integumentary system specifically affects blood supply?
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Which type of perspiration is primarily responsible for water loss through evaporation when the stratum corneum is intact?
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Which of the following statements accurately describes a characteristic of apocrine sweat glands?
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Which of the following conditions can lead to an increase in skin pigmentation due to excess hormone production?
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What happens to melanin distribution in individuals with darker skin compared to those with lighter skin?
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Which factor is directly responsible for the bluish appearance of the skin in cases of reduced oxygenation?
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Which of the following is true regarding carotene and its effects on skin appearance?
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What physiological response occurs when blood vessels dilate due to heat, influencing skin color?
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Study Notes
Skin Repair and Aging
- Loss of skin turgor (elasticity) can be caused by dehydration, aging, hormones, and UV radiation.
- Dehydration-induced loss of skin turgor is reversible.
- Excessive skin stretching due to pregnancy or weight gain can cause stretch marks.
- Aging causes the epidermis to thin, a decrease in dendritic cells, reduced vitamin D3 production, decreased melanocyte and gland activity, reduced blood supply to the dermis, declining hair follicles, thinner dermis with a shrinking elastic fiber network, fading of sex-specific hair and body fat distribution, and a slower repair rate.
Perspiration
- Water loss from the skin occurs through insensible and sensible perspiration.
- Insensible perspiration involves water diffusing across the stratum corneum and evaporating, typically losing 500 mL per day.
- Insensible perspiration increases when the stratum corneum is damaged, for example, from burns.
- Sensible perspiration involves water excreted by sweat glands.
Apocrine sweat glands
- Found in areas like the armpits, around nipples, and the pubic region.
- Secrete products into hair follicles by merocrine secretion (not through the pinching off of cytoplasm).
- Produce sticky, cloudy secretions. The secretions become odorous when bacteria metabolize them.
- Surrounded by myoepithelial cells that squeeze secretions out of the glands in response to hormonal or nervous signals.
Eccrine (Merocrine) sweat glands
- Coiled, tubular glands that discharge directly onto the skin surface, producing sensible perspiration.
- Widely distributed on the body, particularly on palms and soles.
- Secretions are predominantly water (99%), with some salts and other components.
- Functions include cooling the skin to regulate body temperature, excreting water and electrolytes, and providing protection from environmental hazards.
- Eccrine sweat gland activity can be precisely controlled, allowing for localized sweating.
Pigmentation
- Melanin, a red-yellow or brown-black pigment, is produced by melanocytes and stored in intracellular vesicles called melanosomes.
- Melanosomes transfer melanin to keratinocytes.
- Dark-skinned individuals have larger and more numerous melanosomes.
- Melanin protects the skin from ultraviolet (UV) radiation.
- Small amounts of UV radiation are beneficial, but excessive exposure can damage DNA and lead to cancer.
Carotene
- An orange-yellow pigment found in orange vegetables.
- Accumulates in epidermal cells, the deep dermis, and the subcutaneous layer.
- Can be converted to vitamin A, which is essential for maintaining epithelia and synthesizing photoreceptor pigments in the eye.
Blood flow and Oxygenation
- Hemoglobin, when bound to oxygen, is bright red.
- Vasodilation (widening of blood vessels) due to heat causes skin reddening.
- Vasoconstriction (narrowing of blood vessels) leads to skin paleness.
- Deoxygenated hemoglobin turns dark red.
- Cyanosis (bluish skin) can occur when oxygen levels in the blood are low, potentially caused by extreme cold, heart failure, or severe asthma.
Illness and Skin Color
- Jaundice is caused by a buildup of bile produced by the liver.
- Jaundice can cause the skin and whites of the eyes to turn yellow.
- Pituitary tumors can lead to excess melanocyte-stimulating hormone (MSH), resulting in increased melanin production.
- Addison’s disease involves the pituitary gland releasing excess adrenocorticotropic hormone (ACTH), which has a similar effect to MSH.
- Vitiligo is a condition characterized by the loss of melanocytes, causing a loss of skin color.
Skin Repair and Aging
- Loss of skin turgor can be caused by dehydration, aging, hormones, and UV radiation.
- Stretch marks can be caused by excessive distortion of skin from pregnancy or weight gain.
Effects of Aging on the Skin
- The epidermis thins as we age.
- The number of dendritic cells decreases.
- Vitamin D3 production declines.
- Melanocyte and glandular activities decline.
- Blood supply to the dermis is reduced.
- The function of hair follicles declines.
- The dermis thins and the elastic fiber network shrinks.
- Sex-specific hair and body fat distribution fades.
- The skin's repair rate slows.
Types of Perspiration
- Water is lost from the skin through insensible perspiration (water diffusing across the stratum corneum) and sensible perspiration (water excreted by sweat glands).
- Insensible perspiration accounts for about 500 mL of water loss per day.
- The rate of insensible perspiration increases if the stratum corneum is damaged.
Apocrine Sweat Glands
- Apocrine sweat glands are located in the armpits, around the nipples, and in the pubic region.
- They secrete products into hair follicles via merocrine secretion.
- They produce sticky, cloudy secretions that can be a nutrient source for bacteria, leading to odors.
- Myoepithelial cells surround the glands and squeeze secretions out in response to hormonal or nervous signals.
Eccrine (Merocrine) Sweat Glands
- Eccrine sweat glands are coiled, tubular glands that discharge directly onto the skin surface.
- They are widely distributed across the body surface, particularly on palms and soles.
- Their secretions are primarily water with small amounts of salt and other substances.
- Functions of eccrine sweat glands include cooling the skin, excreting water and electrolytes, and providing protection from environmental hazards.
- Eccrine sweat gland activity is precisely controlled, and sweating can occur locally.
Pigmentation
-
Melanin is a red-yellow or brown-black pigment produced by melanocytes.
-
Melanin is stored in intracellular vesicles called melanosomes, which are transferred to keratinocytes.
-
Dark-skinned individuals have large, numerous melanosomes.
-
Melanin protects skin from ultraviolet (UV) radiation.
-
Small amounts of UV radiation are beneficial, but excessive exposure can damage DNA and cause cancer.
-
Carotene is an orange-yellow pigment found in orange vegetables.
-
Carotene accumulates in epidermal cells, the deep dermis, and the subcutaneous layer.
-
Carotene can be converted to vitamin A, which is necessary for the maintenance of epithelia and the synthesis of photoreceptor pigments in the eye.
Blood Flow and Oxygenation
- Hemoglobin is bright red when bound to oxygen, causing the skin to redden when blood vessels dilate.
- When blood flow to the skin decreases, the skin pales.
- Hemoglobin turns dark red when oxygen is released, leading to cyanosis (bluish skin) which can be caused by extreme cold, heart failure, severe asthma, and other conditions.
Illness and Skin Color
- Jaundice (a yellowing of the skin and whites of the eyes) is caused by a buildup of bile produced by the liver.
- A pituitary tumor can cause excess MSH, which increases melanin production.
- Addison's disease causes the pituitary gland to release excess ACTH, which also has an effect similar to MSH.
- Vitiligo is a loss of color caused by a loss of melanocytes.
Skin Damage and Aging
- Skin turgor loss can be caused by dehydration, aging, hormones, and UV radiation.
- Stretch marks can occur due to excessive skin distortion from factors like pregnancy or weight gain.
- Aging affects the skin in several ways:
- Epidermis thins.
- Dendritic cell count decreases.
- Vitamin D3 production declines.
- Melanocyte and glandular activities decrease.
- Blood supply to the dermis reduces.
- Hair follicle function declines.
- Dermis thins and elastic fibers shrink.
- Sex-specific hair and body fat distribution fades.
- Repair rate slows down.
Perspiration
- Water is lost through the skin via insensible and sensible perspiration:
- Insensible: Water diffuses through the stratum corneum and evaporates.
- Sensible: Water excreted by sweat glands.
- Apocrine sweat glands:
- Located in the armpits, around nipples, and pubic region.
- Secrete products into hair follicles via merocrine secretion.
- Produce sticky, cloudy secretions that attract bacteria causing odor.
- Surrounded by myoepithelial cells, which squeeze secretions out in response to hormonal or nervous signals.
- Eccrine (merocrine) sweat glands:
- Coiled, tubular glands discharging directly onto the skin surface.
- Widely distributed, particularly on palms and soles.
- Secretions comprise mostly water, salt, and other substances.
- Functions include cooling skin, excreting water and electrolytes, and providing environmental protection.
- Sweating can be controlled precisely and occur locally.
Skin Pigmentation
- Melanin:
- Red-yellow or brown-black pigment produced by melanocytes.
- Stored in melanosomes, which are transferred to keratinocytes.
- Dark-skinned individuals have larger and more numerous melanosomes.
- Protects skin from UV radiation.
- Carotene:
- Orange-yellow pigment found in orange vegetables.
- Accumulates in the epidermis, deep dermis, and subcutaneous layer.
- Can be converted to vitamin A, essential for maintaining epithelia and synthesizing photoreceptor pigments.
- Blood flow and oxygenation influence skin color:
- Hemoglobin is bright red when bound to oxygen, causing redness when blood vessels dilate.
- Hemoglobin turns dark red when oxygen is released, potentially leading to cyanosis (bluish skin) due to factors like cold, heart failure, etc.
- Illness and skin color:
- Jaundice: Buildup of bile leads to yellowing of skin and whites of eyes.
- Pituitary tumor: Excess MSH increases melanin production.
- Addison’s disease: Excess ACTH release causes similar effects to MSH.
- Vitiligo: Loss of melanocytes results in loss of skin color.
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Description
Test your knowledge on skin repair processes and the effects of aging on skin health. This quiz covers topics such as skin turgor, perspiration mechanisms, and the physiological changes that occur as we age. Improve your understanding of dermatological health with this informative quiz.
