Skin cancer is a result of damage to the DNA of skin cells, often due to excessive exposure to UV radiation. Basal cell carcinoma and squamous cell carcinoma are highly curable, and arise from cells in the stratum basale and stratum spinosum, respectively. Melanoma is the most dangerous form of skin cancer, affecting melanocytes, which can spread/metastasize to other organs. Burns are an injury to the skin that occur as a result of exposure to extreme heat, radiation, or chemicals. First-degree and second-degree burns usually heal quickly, but third-degree burns can be fatal because they penetrate the full thickness of the skin. Scars occur when there is repair of skin damage. Fibroblasts generate scar tissue in the form of collagen, which forms a basket-weave pattern that looks different from normal skin.
Bedsores and stretch marks are the result of excessive pressure on the skin and underlying tissue. Bedsores are characterized by necrosis of tissue due to immobility, whereas stretch marks result from rapid growth. Eczema is an allergic reaction that manifests as a rash, and acne results from clogged sebaceous glands. Eczema and acne are usually long-term skin conditions that may be treated successfully in mild cases. Calluses and corns are the result of abrasive pressure on the skin.
acne
skin condition due to infected sebaceous glands
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
corn
type of callus that is named for its shape and the elliptical motion of the abrasive force
eczema
skin condition due to an allergic reaction, which resembles a rash
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
keloid
type of scar that has layers raised above the skin surface
melanoma
type of skin cancer that originates from the melanocytes of the skin
metastasis
spread of cancer cells from a source to other parts of the body
scar
collagen-rich skin formed after the process of wound healing that is different from normal skin
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
stretch mark
mark formed on the skin due to a sudden growth spurt and expansion of the dermis beyond its elastic limits
third-degree burn
burn that penetrates and destroys the full thickness of the skin (epidermis and dermis)
1. In general, skin cancers ________.
A) are easily treatable and not a major health concern
B) occur due to poor hygiene
C) can be reduced by limiting exposure to the sun
D) affect only the epidermis
C
2. Bedsores ________.
A) can be treated with topical moisturizers
B) can result from deep massages
C) are preventable by eliminating pressure points
D) are caused by dry skin
C
3. An individual has spent too much time sun bathing. Not only is his skin painful to touch, but small blisters have appeared in the affected area. This indicates that he has damaged which layers of his skin?
A) epidermis only
B) hypodermis only
C) epidermis and hypodermis
D) epidermis and dermis
D
4. After a skin injury, the body initiates a wound-healing response. The first step of this response is the formation of a blood clot to stop bleeding. Which of the following would be the next response?
A) increased production of melanin by melanocytes
B) increased production of connective tissue
C) an increase in Pacinian corpuscles around the wound
D) an increased activity in the stratum lucidum
B
5. Squamous cell carcinomas are the second most common of the skin cancers and are capable of metastasizing if not treated. This cancer affects which cells?
A) basal cells of the stratum basale
B) melanocytes of the stratum basale
C) keratinocytes of the stratum spinosum
D) Langerhans cells of the stratum lucidum
C
1. Why do teenagers often experience acne?
Acne results from a blockage of sebaceous glands by sebum. The blockage causes blackheads to form, which are susceptible to infection. The infected tissue then becomes red and inflamed. Teenagers experience this at high rates because the sebaceous glands become active during puberty. Hormones that are especially active during puberty stimulate the release of sebum, leading in many cases to blockages.
2. Why do scars look different from surrounding skin?
Scars are made of collagen and do not have the cellular structure of normal skin. The tissue is fibrous and does not allow for the regeneration of accessory structures, such as hair follicles, and sweat or sebaceous glands.