Module 20: The Integumentary System

Lesson 4: Brief Review of Skin Problems

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Mỗi bài học (lesson) bao gồm 4 phần chính: Thuật ngữ, Luyện Đọc, Luyện Nghe, và Bàn Luận.
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Dưới đây là danh sách những thuật ngữ Y khoa của module The Integumentary System.
Khái quát được số lượng thuật ngữ sẽ xuất hiện trong bài đọc và nghe sẽ giúp bạn thoải mái tiêu thụ nội dung hơn. Sau khi hoàn thành nội dung đọc và nghe, bạn hãy quay lại đây và luyện tập (practice) để quen dần các thuật ngữ này. Đừng ép bản thân phải nhớ các thuật ngữ này vội vì bạn sẽ gặp và ôn lại danh sách này trong những bài học (lesson) khác của cùng một module.

Medical Terminology: The Integumentary System

acne
skin condition due to infected sebaceous glands
albinism
genetic disorder that affects the skin, in which there is no melanin production
anagen
active phase of the hair growth cycle
apocrine sweat gland
type of sweat gland that is associated with hair follicles in the armpits and genital regions
arrector pili
smooth muscle that is activated in response to external stimuli that pull on hair follicles and make the hair “stand up”
basal cell
type of stem cell found in the stratum basale and in the hair matrix that continually undergoes cell division, producing the keratinocytes of the epidermis
basal cell carcinoma
cancer that originates from basal cells in the epidermis of the skin
bedsore
sore on the skin that develops when regions of the body start necrotizing due to constant pressure and lack of blood supply; also called decubitis ulcers
callus
thickened area of skin that arises due to constant abrasion
catagen
transitional phase marking the end of the anagen phase of the hair growth cycle
corn
type of callus that is named for its shape and the elliptical motion of the abrasive force
cortex
in hair, the second or middle layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb
cuticle
in hair, the outermost layer of keratinocytes originating from the hair matrix, as seen in a cross-section of the hair bulb
dermal papilla
(plural = dermal papillae) extension of the papillary layer of the dermis that increases surface contact between the epidermis and dermis
dermis
layer of skin between the epidermis and hypodermis, composed mainly of connective tissue and containing blood vessels, hair follicles, sweat glands, and other structures
desmosome
structure that forms an impermeable junction between cells
eccrine sweat gland
type of sweat gland that is common throughout the skin surface; it produces a hypotonic sweat for thermoregulation
eczema
skin condition due to an allergic reaction, which resembles a rash
elastin fibers
fibers made of the protein elastin that increase the elasticity of the dermis
eleiden
clear protein-bound lipid found in the stratum lucidum that is derived from keratohyalin and helps to prevent water loss
epidermis
outermost tissue layer of the skin
eponychium
nail fold that meets the proximal end of the nail body, also called the cuticle
external root sheath
outer layer of the hair follicle that is an extension of the epidermis, which encloses the hair root
first-degree burn
superficial burn that injures only the epidermis
fourth-degree burn
burn in which full thickness of the skin and underlying muscle and bone is damaged
glassy membrane
layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis
hair
keratinous filament growing out of the epidermis
hair bulb
structure at the base of the hair root that surrounds the dermal papilla
hair follicle
cavity or sac from which hair originates
hair matrix
layer of basal cells from which a strand of hair grows
hair papilla
mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle
hair root
part of hair that is below the epidermis anchored to the follicle
hair shaft
part of hair that is above the epidermis but is not anchored to the follicle
hypodermis
connective tissue connecting the integument to the underlying bone and muscle
hyponychium
thickened layer of stratum corneum that lies below the free edge of the nail
integumentary system
skin and its accessory structures
internal root sheath
innermost layer of keratinocytes in the hair follicle that surround the hair root up to the hair shaft
keloid
type of scar that has layers raised above the skin surface
keratin
type of structural protein that gives skin, hair, and nails its hard, water-resistant properties
keratinocyte
cell that produces keratin and is the most predominant type of cell found in the epidermis
keratohyalin
granulated protein found in the stratum granulosum
Langerhans cell
specialized dendritic cell found in the stratum spinosum that functions as a macrophage
lunula
basal part of the nail body that consists of a crescent-shaped layer of thick epithelium
medulla
in hair, the innermost layer of keratinocytes originating from the hair matrix
Meissner corpuscle
(also, tactile corpuscle) receptor in the skin that responds to light touch
melanin
pigment that determines the color of hair and skin
melanocyte
cell found in the stratum basale of the epidermis that produces the pigment melanin
melanoma
type of skin cancer that originates from the melanocytes of the skin
melanosome
intercellular vesicle that transfers melanin from melanocytes into keratinocytes of the epidermis
Merkel cell
receptor cell in the stratum basale of the epidermis that responds to the sense of touch
metastasis
spread of cancer cells from a source to other parts of the body
nail bed
layer of epidermis upon which the nail body forms
nail body
main keratinous plate that forms the nail
nail cuticle
fold of epithelium that extends over the nail bed, also called the eponychium
nail fold
fold of epithelium at that extend over the sides of the nail body, holding it in place
nail root
part of the nail that is lodged deep in the epidermis from which the nail grows
Pacinian corpuscle
(also, lamellated corpuscle) receptor in the skin that responds to vibration
papillary layer
superficial layer of the dermis, made of loose, areolar connective tissue
reticular layer
deeper layer of the dermis; it has a reticulated appearance due to the presence of abundant collagen and elastin fibers
rickets
disease in children caused by vitamin D deficiency, which leads to the weakening of bones
scar
collagen-rich skin formed after the process of wound healing that is different from normal skin
sebaceous gland
type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum
sebum
oily substance that is composed of a mixture of lipids that lubricates the skin and hair
second-degree burn
partial-thickness burn that injures the epidermis and a portion of the dermis
squamous cell carcinoma
type of skin cancer that originates from the stratum spinosum of the epidermis
stratum basale
deepest layer of the epidermis, made of epidermal stem cells
stratum corneum
most superficial layer of the epidermis
stratum granulosum
layer of the epidermis superficial to the stratum spinosum
stratum lucidum
layer of the epidermis between the stratum granulosum and stratum corneum, found only in thick skin covering the palms, soles of the feet, and digits
stratum spinosum
layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes
stretch mark
mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits
sudoriferous gland
sweat gland
telogen
resting phase of the hair growth cycle initiated with catagen and terminated by the beginning of a new anagen phase of hair growth
third-degree burn
burn that penetrates and destroys the full thickness of the skin (epidermis and dermis)
vitamin D
compound that aids absorption of calcium and phosphates in the intestine to improve bone health
vitiligo
skin condition in which melanocytes in certain areas lose the ability to produce melanin, possibly due an autoimmune reaction that leads to loss of color in patches
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Dưới đây là các bài văn nằm ở bên trái. Ở bên phải là các bài luyện tập (practice) để đánh giá khả năng đọc hiểu của bạn. Sẽ khó khăn trong thời gian đầu nếu vốn từ vựng của bạn còn hạn chế, đặc biệt là từ vựng Y khoa. Hãy kiên nhẫn và đọc nhiều nhất có kể, lượng kiến thức tích tụ dần sẽ giúp bạn đọc thoải mái hơn.
The integumentary system is susceptible to a variety of diseases, disorders, and injuries. These range from annoying but relatively benign bacterial or fungal infections that are categorized as disorders, to skin cancer and severe burns, which can be fatal. In this section, you will learn several of the most common skin conditions.
One of the most talked about diseases is skin cancer. Cancer is a broad term that describes diseases caused by abnormal cells in the body dividing uncontrollably. Most cancers are identified by the organ or tissue in which the cancer originates. One common form of cancer is skin cancer. The Skin Cancer Foundation reports that one in five Americans will experience some type of skin cancer in their lifetime. The degradation of the ozone layer in the atmosphere and the resulting increase in exposure to UV radiation has contributed to its rise. Overexposure to UV radiation damages DNA, which can lead to the formation of cancerous lesions. Although melanin offers some protection against DNA damage from the sun, often it is not enough. The fact that cancers can also occur on areas of the body that are normally not exposed to UV radiation suggests that there are additional factors that can lead to cancerous lesions.

In general, cancers result from an accumulation of DNA mutations. These mutations can result in cell populations that do not die when they should and uncontrolled cell proliferation that leads to tumors. Although many tumors are benign (harmless), some produce cells that can mobilize and establish tumors in other organs of the body; this process is referred to as metastasis. Cancers are characterized by their ability to metastasize.

A. Basal Cell Carcinoma

Basal cell carcinoma is a form of cancer that affects the mitotically active stem cells in the stratum basale of the epidermis. It is the most common of all cancers that occur in the United States and is frequently found on the head, neck, arms, and back, which are areas that are most susceptible to long-term sun exposure. Although UV rays are the main culprit, exposure to other agents, such as radiation and arsenic, can also lead to this type of cancer. Wounds on the skin due to open sores, tattoos, burns, etc. may be predisposing factors as well. Basal cell carcinomas start in the stratum basale and usually spread along this boundary. At some point, they begin to grow toward the surface and become an uneven patch, bump, growth, or scar on the skin surface (Figure 1). Like most cancers, basal cell carcinomas respond best to treatment when caught early. Treatment options include surgery, freezing (cryosurgery), and topical ointments (Mayo Clinic 2012).

B. Squamous Cell Carcinoma

Squamous cell carcinoma is a cancer that affects the keratinocytes of the stratum spinosum and presents as lesions commonly found on the scalp, ears, and hands (Figure 2). It is the second most common skin cancer. The American Cancer Society reports that two of 10 skin cancers are squamous cell carcinomas, and it is more aggressive than basal cell carcinoma. If not removed, these carcinomas can metastasize. Surgery and radiation are used to cure squamous cell carcinoma.

C. Melanoma

A melanoma is a cancer characterized by the uncontrolled growth of melanocytes, the pigment-producing cells in the epidermis. Typically, a melanoma develops from a mole. It is the most fatal of all skin cancers, as it is highly metastatic and can be difficult to detect before it has spread to other organs. Melanomas usually appear as asymmetrical brown and black patches with uneven borders and a raised surface (Figure 3). Treatment typically involves surgical excision and immunotherapy.

Doctors often give their patients the following ABCDE mnemonic to help with the diagnosis of early-stage melanoma. If you observe a mole on your body displaying these signs, consult a doctor.

  • Asymmetry – the two sides are not symmetrical.
  • Borders – the edges are irregular in shape.
  • Color – the color is varied shades of brown or black.
  • Diameter – it is larger than 6 mm (0.24 in).
  • Evolving – its shape has changed.

Some specialists cite the following additional signs for the most serious form, nodular melanoma:.

  • Elevated – it is raised on the skin surface.
  • Firm – it feels hard to the touch.
  • Growing – it is getting larger
Two common skin disorders are eczema and acne. Eczema is an inflammatory condition and occurs in individuals of all ages. Acne involves the clogging of pores, which can lead to infection and inflammation, and is often seen in adolescents. Other disorders, not discussed here, include seborrheic dermatitis (on the scalp), psoriasis, cold sores, impetigo, scabies, hives, and warts.

Eczema is an allergic reaction that manifests as dry, itchy patches of skin that resemble rashes (Figure 4). It may be accompanied by swelling of the skin, flaking, and in severe cases, bleeding. Many who suffer from eczema have antibodies against dust mites in their blood, but the link between eczema and allergy to dust mites has not been proven. Symptoms are usually managed with moisturizers, corticosteroid creams, and immunosuppressants.

Acne is a skin disturbance that typically occurs on areas of the skin that are rich in sebaceous glands (face and back). It is most common along with the onset of puberty due to associated hormonal changes, but can also occur in infants and continue into adulthood. Hormones, such as androgens, stimulate the release of sebum. An overproduction and accumulation of sebum along with keratin can block hair follicles. This plug is initially white. The sebum, when oxidized by exposure to air, turns black. Acne results from infection by acne-causing bacteria (Propionibacterium and Staphylococcus), which can lead to redness and potential scarring due to the natural wound healing process (Figure 5).
A burn results when the skin is damaged by intense heat, radiation, electricity, or chemicals. The damage results in the death of skin cells, which can lead to a massive loss of fluid. Dehydration, electrolyte imbalance, and renal and circulatory failure follow, which can be fatal. Burn patients are treated with intravenous fluids to offset dehydration, as well as intravenous nutrients that enable the body to repair tissues and replace lost proteins. Another serious threat to the lives of burn patients is infection. Burned skin is extremely susceptible to bacteria and other pathogens, due to the loss of protection by intact layers of skin.

Burns are sometimes measured in terms of the size of the total surface area affected. This is referred to as the “rule of nines,” which associates specific anatomical areas with a percentage that is a factor of nine (Figure 6). Burns are also classified by the degree of their severity. A first-degree burn is a superficial burn that affects only the epidermis. Although the skin may be painful and swollen, these burns typically heal on their own within a few days. Mild sunburn fits into the category of a first-degree burn. A second-degree burn goes deeper and affects both the epidermis and a portion of the dermis. These burns result in swelling and a painful blistering of the skin. It is important to keep the burn site clean and sterile to prevent infection. If this is done, the burn will heal within several weeks. A third-degree burn fully extends into the epidermis and dermis, destroying the tissue and affecting the nerve endings and sensory function. These are serious burns that may appear white, red, or black; they require medical attention and will heal slowly without it. A fourth-degree burn is even more severe, affecting the underlying muscle and bone. Oddly, third and fourth-degree burns are usually not as painful because the nerve endings themselves are damaged. Full-thickness burns cannot be repaired by the body, because the local tissues used for repair are damaged and require excision (debridement), or amputation in severe cases, followed by grafting of the skin from an unaffected part of the body, or from skin grown in tissue culture for grafting purposes.
Most cuts or wounds, with the exception of ones that only scratch the surface (the epidermis), lead to scar formation. A scar is collagen-rich skin formed after the process of wound healing that differs from normal skin. Scarring occurs in cases in which there is repair of skin damage, but the skin fails to regenerate the original skin structure. Fibroblasts generate scar tissue in the form of collagen, and the bulk of repair is due to the basket-weave pattern generated by collagen fibers and does not result in regeneration of the typical cellular structure of skin. Instead, the tissue is fibrous in nature and does not allow for the regeneration of accessory structures, such as hair follicles, sweat glands, or sebaceous glands.

Sometimes, there is an overproduction of scar tissue, because the process of collagen formation does not stop when the wound is healed; this results in the formation of a raised or hypertrophic scar called a keloid. In contrast, scars that result from acne and chickenpox have a sunken appearance and are called atrophic scars.

Scarring of skin after wound healing is a natural process and does not need to be treated further. Application of mineral oil and lotions may reduce the formation of scar tissue. However, modern cosmetic procedures, such as dermabrasion, laser treatments, and filler injections have been invented as remedies for severe scarring. All of these procedures try to reorganize the structure of the epidermis and underlying collagen tissue to make it look more natural.
Skin and its underlying tissue can be affected by excessive pressure. One example of this is called a bedsore. Bedsores, also called decubitis ulcers, are caused by constant, long-term, unrelieved pressure on certain body parts that are bony, reducing blood flow to the area and leading to necrosis (tissue death). Bedsores are most common in elderly patients who have debilitating conditions that cause them to be immobile. Most hospitals and long-term care facilities have the practice of turning the patients every few hours to prevent the incidence of bedsores. If left untreated by removal of necrotized tissue, bedsores can be fatal if they become infected.

The skin can also be affected by pressure associated with rapid growth. A stretch mark results when the dermis is stretched beyond its limits of elasticity, as the skin stretches to accommodate the excess pressure. Stretch marks usually accompany rapid weight gain during puberty and pregnancy. They initially have a reddish hue, but lighten over time. Other than for cosmetic reasons, treatment of stretch marks is not required. They occur most commonly over the hips and abdomen.
When you wear shoes that do not fit well and are a constant source of abrasion on your toes, you tend to form a callus at the point of contact. This occurs because the basal stem cells in the stratum basale are triggered to divide more often to increase the thickness of the skin at the point of abrasion to protect the rest of the body from further damage. This is an example of a minor or local injury, and the skin manages to react and treat the problem independent of the rest of the body. Calluses can also form on your fingers if they are subject to constant mechanical stress, such as long periods of writing, playing string instruments, or video games. A corn is a specialized form of callus. Corns form from abrasions on the skin that result from an elliptical-type motion.

OpenStax. (2022). Anatomy and Physiology 2e. Rice University. Retrieved June 15, 2023. ISBN-13: 978-1-711494-06-7 (Hardcover) ISBN-13: 978-1-711494-05-0 (Paperback) ISBN-13: 978-1-951693-42-8 (Digital). License: Attribution 4.0 International (CC BY 4.0). Access for free at openstax.org.

Basal cell carcinoma can take several different forms. Similar to other forms of skin cancer, it is readily cured if caught early and treated. (credit: John Hendrix, MD)

Squamous cell carcinoma presents here as a lesion on an individual’s nose. (credit: the National Cancer Institute)

Melanomas typically present as large brown or black patches with uneven borders and a raised surface. (credit: the National Cancer Institute / Centers for Disease Control)

Eczema is a common skin disorder that presents as a red, flaky rash. (credit: “Jambula” Wikimedia Commons / NIAID, Flickr)

Acne is a result of over-productive sebaceous glands, which leads to formation of blackheads and inflammation of the skin.

The size of a burn will guide decisions made about the need for specialized treatment. Specific parts of the body are associated with a percentage of body area.

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Dưới đây là video và các luyện tập (practice) của bài này. Nghe là một kĩ năng khó, đặc biệt là khi chúng ta chưa quen nội dung và chưa có nhạy cảm ngôn ngữ. Nhưng cứ đi thật chậm và đừng bỏ cuộc.
Xem video và cảm nhận nội dung bài. Bạn có thể thả trôi, cảm nhận dòng chảy ngôn ngữ và không nhất thiết phải hiểu toàn bộ bài. Bên dưới là script để bạn khái quát nội dụng và tra từ mới.
Script:
  1. Skin cancer, often caused by DNA damage from excessive exposure to UV radiation, includes highly curable types like basal cell carcinoma (from stratum basale cells) and squamous cell carcinoma (from stratum spinosum cells).
  2. Melanoma, affecting melanocytes, is the most dangerous, with the potential to metastasize.
  3. Burns, resulting from extreme heat, radiation, or chemicals, range from first-degree to fatal third-degree burns, penetrating the full skin thickness.
  4. Scars form during skin damage repair, with fibroblasts generating collagen that appears different from normal skin.
  5. Pressure-induced conditions include bedsores (tissue necrosis due to immobility) and stretch marks (resulting from rapid growth).
  6. Eczema, an allergic reaction, manifests as a rash, while acne arises from clogged sebaceous glands.
  7. Calluses and corns stem from abrasive pressure on the skin.
  8. Successful treatment is possible for mild cases of eczema and acne, but these conditions, along with calluses and corns, can persist as long-term skin issues.
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