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Chapter 5

Chapter 5 Textbook Notes

Health Studies
Course Code
Ingrid L.Stefanovic

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Chapter 5: Aging of the Skin and Musculoskeletal System
¾ The skin provides the covering for the body and is the first line of defense against bacteria, viruses, and other
type of environmental damage.
¾ The bones, ligaments, tendons, and muscles that make up the musculoskeletal system provide shape and support
for the body, make movement and adjustments in position possible, and protect the internal vital organs from
external trauma.
¾ The skin and musculoskeletal system provides the most obvious signs of aging, with both normal changes and
disease processes.
Basic Anatomy and Physiology
¾ The skin, or integumentary, has several major functions. It is our front line of defense against harmful
environmental influences and is an important part of our immunological and endocrine systems.
¾ The skin is critical in temperature maintenance and, in general, aids in homeostasis.
¾ Sensory nerves in the skin allow us to monitor the environment but also warn us of danger through pain.
¾ Finally, the integumentary system has important symbolic functions in that it is a key component of our
appearance and is a critical source of cues that affect social interaction.
¾ The skin is the largest visible organ of the body.
¾ The outermost layer of skin is called the epidermis, and the second layer is the dermis.
¾ Beneath the epidermis and dermis is a layer of subcutaneous fat.
¾ The epidermis consists mostly of keratinocytes (more than 90% of all epidermis cells) cells that protect the skin
from the outside harm and help it heal if it is injured.
¾ Keratinocytes slowly move to the surface of the epidermis as they age, a process that takes about 30 days.
¾ If the skin is injured, they will reproduce and turn over at a more rapid rate, allowing the damage to be repaired.
¾ Melanocytes make up 2% of the cells in the epidermis; it gives colour to the skin.
¾ Although only about 1% of the cells in the epidermis, they are an important part of the immune system as they
respond to toxic allergic stimuli.
¾ The dermis consists largely of collagen and elastin tissue, which provides strength and elasticity to the skin.
¾ Under the epidermis and the dermis is a layer of subcutaneous fat, which consists mostly of adipocytes (fat
¾ Subcutaneous fat fives shape and form to the body and provides protection and insulation.
Age Related Changes
¾ Changes in hair follicles result in the graying and loss of hair.
¾ Wrinkles are partially due to a decrease in the subcutaneous fat layer and in the collagen and elastin found in the
dermal layer.
¾ The skin over the nose almost always stays smooth, whereas there is usually some wrinkling around the eyes
and deepening of the lines around the mouth.
¾ The turnover rate of keratinocytes is reducHGDVPXFKDVOLPLWLQJWKHVNLQVDELOLW\WRKHDO
¾ The dermis is almost about 20% thinner in an older person, and fewer fibroblasts in the layer make the skin less
elastic and not as strong as that of younger people.
¾ There is a flattening of the junction between the epidermis and dermis, which decreases the adhesion between
two layers.
¾ Because of these changes, the skin is much more likely to bruise and tear if an injury occurs and less likely to
¾ Decrease in number of sensory nerves also results in decreased sensitivity to touch, injury, and to heat and cold.
¾ Thinning of the subcutaneous fat layer also affects the ability of the body to maintain homeostasis with age.
¾ This thinning not only makes the skin less fragile, but the loss of insulation also increases the risk of an older
¾ One of the most common dermatological problems of the older person is xerosis, or dry skin.
¾ Xerosis is characterized by red, scaly, and itchy skin on the legs, back and arms.
¾ The cause of xerosis is not known, although it may be associated with the slowing of keratinocyte turnover rate.
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¾ Xerosis is particularly troublesome during the winter months.
¾ Treatment is generally the application of skin creams (topical emollients) after bathing to slow the loss of water
from the epidermis.
Seborrheic Keratoses
¾ Seborrheic keratoses, or old-age spots, are benign (nonmalignant) lesions commonly found in older people.
¾ They are usually brown to black in colour and have irregular edges.
¾ They appear more frequently with age.
¾ Because they are slightly raised, people frequently remark that they appear to be stuck on top of the skin.
¾ Although sun exposure is a risk factor for seborrheic keratoses, some people probably have a hereditary
predisposition to develop them.
¾ It is important that they be evaluated, and possibly removed, to differentiate them from malignant growths.
Skin Cancer
¾ Two of the most common forms of skin cancer are basal-cell and squamous-cell carcinomas.
¾ A basal-cell carcinoma appears as a small, fleshy bump or nodule (pearly in appearance), usually on the head or
¾ The greatest risk factor for the development of this type of cancer is exposure to the sun.
¾ Although basal-cell carcinoma is very slow growing and metastases are rare, the lesions are generally removed
in an early stage of growth to minimize further damage to the skin.
¾ Squamous-cell carcinomas as usually found on the face of the back of the hand.
¾ They have the appearance of a red, scaly, and hard patch, although they may become ulcerated and crusty with
¾ Exposure to the sun is a significant factor but other risks unclose chronic irritation.
¾ Squamous-cell carcinomas are always removed and follow-up is very important.
¾ These types of skin cancers can be very unattractive, and many older people wish to have it removed for this
¾ Malignant melanomas are the most dangerous of the skin cancers.
¾ They are cancers of melanocytes, cells normally found in the epidermis of the skin.
¾ Typically, a melanocyte is a red, white, blue, or black growth with an irregular border.
¾ These growths are painless although they may ulcerate and bleed in later stages of development.
¾ Risk factors for this type of cancer include very light skin and blond or red hair, a family history of melanoma,
and a history of severe intermittent sunburns, especially when young.
¾ A malignancy can develop as a primary site in the eye, digestive tract, of the liver because melanocytes are also
found in these parts of the body.
¾ Men are more likely to have malignant melanomas on the trunk of the body or the head and neck, and women
on the lower legs or the soles of their feet.
¾ People with dark or black skin are less likely to develop melanoma (although when they do it normally appears
under the fingernails, toenails, or on the soles of feet).
¾ This disease happens at all ages, but older people are more likely to die of the disease.
¾ It is essential that malignant melanoma be detected early and treated aggressively.
¾ Treatment options for melanomas include surgery, chemotherapy, and radiation.
Pressure Ulcers
¾ Pressure ulcers are conditions of the skin that most likely occur in those who spend long periods of time in
wheelchairs or beds.
¾ They are frequently called bedsores or decubitus, but the preferred name is pressure ulcer because they are
caused by pressure over a susceptible tissue.
¾ It usually begins because an area of skin has been damaged or there is a breakdown of tissue over a bony
¾ There are numerous risk factors for pressure ulcers in later years. The aging skin has fewer blood vessels and
nerves, collagen tissue in the skin loses elasticity, and all layers of the skin are thinner, including the layer of
subcutaneous fat.
¾ The ability to sense cutaneous pain decreases in later years and with the disease, making people unaware that
they have injured tissue.
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