Healing of Wounds and Burns
& the Aging of Skin
Chapter 6 Sections 5 & 6
Objectives
• Describe wound healing
• Distinguish among the types of burns, including a
description of healing with each type
• Summarize life-span changes in the integumentary
system
The Healing Process
• Inflammation is a normal response to injury or stress
• Blood vessels in affected tissues dilate and become more
permeable, allowing fluids to leak into damaged tissues
• Inflamed skin may become reddened, swollen, warm and painful
to touch
• However, the dilate vessels provide more nutrients and oxygen
to the injured site, which aids in healing
• The specific events of the healing process depend on the
nature and extent of the injury
Shallow Cuts
• If a cut in the skin is shallow, epithelial cells along its margin are
stimulated to divide more rapidly than usual
• The newly formed cells fill the gap
4 Stages of Healing for Deep Wounds
• Hemostasis
• Inflammation
• Proliferation
• Remodeling
Deeper Cuts
• If the cut extends into the dermis or subcutaneous fat layer, blood vessels
break and the released blood forms a clot in the wound (hemostasis)
• A clot consists of mainly the fibrous protein fibrin, blood cells and platelets
trapped in the protein fibers
• Tissue fluids seep into the area and dry
• The blood clot and the dried tissue fluids form a scab that covers and
protects the underlying tissues
• Epithelial cells proliferate beneath the scab, bridging the wound
• Fibroblasts migrate into the injured area and secrete collagenous fibers to
the bind the edges of the wound (proliferation)
• Cells are stimulated to divide and regenerate the damaged tissue (remodeling)
Healing Continued
• Blood vessels extend beneath the scab
• Macrophages remove dead cells and other debris
• Eventually all the damaged tissue is replaced and the scab falls
off
• If the wound is deep, extensive production of collagenous
fibers may form an elevation above the normal epidermal
surface, called a scar
Burns
• Three types of burns:
• 1st degree
• 2nd degree
• 3rd degree
1st Degree Burns
• Also known as superficial partial-thickness
burns
• Occur when the epidermis only is injured
• Skin becomes dry, warm and reddened
(erythema)
• Mild edema may occur
• Surface layer of the skin may peel off a few
days later
• Healing takes a few days to weeks but no
scaring occurs
• Examples: minor sunburn
2nd Degree Burns
• Also known as deep partial-thickness burns
• Occur when some of the epidermis and some
of the underlying dermis is destroyed
• Fluid escapes from the damaged dermal
capillaries, forming blisters
• The injured area becomes moist and firm
• It can vary in color from dark red to waxy
white
• Examples: exposure to hot objects, hot
liquids, flames or burning clothing
2nd Degree Burn Healing
• Healing depends on the stem cells that are
associated with accessory structures of the
skin
• Hair follicles, sweat glands and sebaceous
glands survive this injury because they
extend into the dermis
• During healing, the stem cells divide and
their daughter cells grow out onto the
surface of the dermis, spread over it, and
differentiate as new epidermis
• Scar tissue doesn’t develop unless infection
occurs
3rd Degree Burns
• Also known as full-thickness burns
• Occur when epidermis, dermis and the
accessory structures of the skin are
destroyed
• The injured skin becomes dry and leathery
• It can vary in color from red to black to
white
• Examples: immersion in hot liquids or
prolonged exposure to hot objects, flames, or
corrosive chemicals
Burn Treatments
• 1st degree
• Soak in cool water for a few minutes
• Apply antibiotic cream
• Take ibuprofen or acetaminophen
• 2nd degree
• Soak in cool water for several minutes
• Apply antibiotic cream
• Cover with non-stick bandage and change daily
• Take ibuprofen or acetaminophen
Burn Treatments
• 3rd degree
• Seek medical attention in an emergency room
• Try to elevate burn above the heart
• Once in the ER the following steps may be taken:
• Securing your airway
• Sedation
• Removing necrotic skin
• Blood transfusions
• IV fluids
• IV antibiotics
• Surgery
• Skin grafts
How Skin Ages
• Aging skin affects appearance, temperature regulation, and vitamin D
formation
• Aging effects to the skin:
• Epidermis thins and appears scaly
• Age spots or liver spots appear, which are patches of pigment formed
•
•
•
•
•
•
from the oxidation of fats and the production of oxygen free radicals
Dermis is reduced as creation of collagen and elastin slows
The combination of a shrinking dermis and the loss of fat in the
subcutaneous layer results in wrinkling and sagging of the skin
Reduction of fibroblasts delay wound healing
Decrease in oil from sebaceous glands dries the skin
Slowed melanin production whitens hair
Hair growth slow, hairs thin and the number of follicles decreases