A&P 1 Chapter 5

The Integumentary System
The Integument accounts for ___% of total body weight.
The Integumentary system is known as the "________ _________".
"Frontline Defense"
What are the 2 major components of the integumentary system?
Cutaneous Membrane and Accessory Structures
What are the two components of the Cutaneous Membrane?
Epidermis and Dermis
What is the Epidermis?
Superficial Epithelium
What is the Dermis?
Underlying area of connective tissue
What kind of connective tissue is the Hypodermis?
Loose Connective Tissue
Where is the hypodermis in relation to the dermis?
What are two other names for the Hypodermis?
Superficial Fascia and Subcutaneous Layer
What does the Hypodermis separate the integument from?
Deep fascia from around other organs
What are two general functions of the skin and hypodermis?
Protection of underlying tissues and organs against impact, abrasion, fluid loss, and chemical attack; Excretion of salts, water, and organic wastes by integumentary glands; Maintenance of normal body temperature through either insulation or evaporative cooling; Production of melanin; Production of Keratin, Synthesis of Vitamin D3, Storage of lipids in adipocytes, and detection of touch, pressure, pain, and temperature stimuli.
Epidermis is composed of _______?
The Epidermis contains what kind of epithelium?
Stratified Squamous Epithelium
Epidermis is avascular? True or False?
Epidermis is highly vascular? True or False?
How does the epidermis receive nutrients and oxygen?
Diffusion of nutrients and oxygen from capillaries within the dermis
The Epidermis is dominated by what kind of cells?
Keratinocytes contain large amounts of what protein?
Where is thin skin located?
Covers most of the body's surface
Where is thick skin located?
Palms of hands and soles of feet
How is thick skin different from thin skin?
Contains a fifth layer of keratinocytes or another layer called Stratum Lucidum
Where is the Stratum Basal located?
Innermost epidermal layer
What is the innermost epidermal layer called?
Stratum Basal
What type of cell junction attached the cells of the Stratum Basal to the basement membrane?
What are Hemidsmosomes?
Type of Desmosomes; Attaches a cell to extracellular filaments in the basement membrane
Stratum Basal forms ____________ layers.
Where do the Epidermal layers of the Stratum Basal extend into?
Why are the Epidermal Ridges important for the palms of hands and soles of feet?
Increased the surface area of the skin and increases friction which ensures a secure grip.
What type of cells dominate the Stratum Basal?
Basal Cells
What are Basal Cells and what is their function?
Stem cells whose divisions replace the more superficial keratinocytes that are lost or shed at the epithelial surface.
What is another name for Tactile cells?
Merkel Cells
Where are Tactile cells/ Merkel Cells located?
Scattered among the cells of the Stratum Basal
What is the function of Tactile Cells/ Merkel Cells?
They are sensitive to touch. When compressed, they release chemicals that stimulate sensory nerve endings.
What is the homemade acronym for the layers of the Epidermis?
BSGLC: Bull **** Girls Like Cum
Basal, Spinosum, Granulosum, Lucidum, and Corneum
What are melanocytes?
Pigment cells that give brown tones to the skin
Where are melanocytes located?
Distributed throughout the Stratum Basal
Name two cells that are found in the Stratum Basal.
Tactile/Merkel cells and Basal Cells
What is the layer of Epidermis Superficial to the Stratum Basal?
Stratum Spinosum
The Stratum Spinosum has ___ to ___ layers of Keratinocytes.
8 to 10
How does the Stratum Spinosum receive new cells?
When daughter cells are divided from stem cells in the Stratum Basal layer, it is then pushed up into the Stratum Spinosum
The Stratum Spinosum is known as the "________" layer.
What type of cell is found in the Stratum Spinosum?
Dendritic Cells
What are Dendritic Cells?
Participate in the immune response by stimulating a defense against microorganisms that by stimulating a defense against microorganisms that manage to penetrate the superficial layers of the epidermis and superficial skin cancers.
What layer is superficial to the Stratum Spinosum?
Stratum Granulosum
The Stratum Granulosum is known as the "_________" Layer.
The Stratum Granulosum has ___ to ____ layers of keratinocytes.
3 to 5
What happens to the new cells that reach the Stratum Granulosum?
By the time new cells reach this layer, they have stopped dividing and have started making large amounts of the proteins Keratin and Keratinohyalin.
What is keratin?
A protein that is the basic component of hair and nails in humans
What is the glass, clear layer that covers the Stratum Granulosum?
Stratum Lucidum
Where on the body is Stratum Lucidum found?
Palms of hands and soles of feet
What are the cells of Stratum Lucidum filled with and what are they devoid of?
Filled with Keratin and largely devoid of organelles
What is the most superficial layer of the Epidermal layers?
Stratum Corneum
How many layers of Keratinocytes are found at the Stratum Corneum?
15 to 30 layers
What is Keratinization/Cornification?
The formation of protective, superficial layers of cells filled with keratin
In the Stratum Corneum, are cells dead or alive?
How are the dead cells of the Stratum Corneum interconnected?
Tightly interconnected with Desmosomes
How do the dead cells of the Stratum Corneum shed?
Large groups or sheets rather than individually
How long does it take cells to get from the Stratum Basal to the Stratum Corneum?
Approximately 7 to 10 days
How long do dead cells remain before being washed away or shed?
2 weeks
Can new things grow on the Stratum Corneum?
No, the surface is unsuitable for the growth of many microorganisms
How is the Stratum Corneum maintained?
Coating the surface with lipid secretions from sebaceous glands.
Stratum Corneum is water ________ not water _________.
Water resistant, water proof
What is insensible perspiration?
Water from interstitial fluid slowly penetrates to the surface, to be evaporated into the surrounding air
Can insensible perspiration be seen?
Unable to see or feel the water loss
What is sensible perspiration?
Produced by active sweat glands
How do blisters occur?
Damage that breaks connections with superficial layers and deeper layers of the epidermis and fluid accumulates in pockets.
Damage to the Stratum Corneum reduces its effectiveness as a __________ __________
Water barrier
What does a freshwater bath do to the Stratum Corneum?
Cells of the Stratum Corneum may swell up to four times their normal volume; Causes water to move into the body because the bath is hypotonic
What does swimming in the ocean do to the Stratum Corneum?
Accelerated dehydration slowly; Causes water to rush out of the body because the ocean is hypertonic
What are the two pigments in the epidermal?
Carotene and Melanin
What color pigment is carotene?
Orange-Yellow Pigment
Where is Carotene most apparent?
Cells of the Stratum Corneum of light skinned individuals
What dietary sources can Carotene be found in?
Orange Vegetables such as Carrots and Squash
What is Carotene converted to?
Vitamin A
What is Vitamin A required for?
Normal maintenance of epithelia and the synthesis of photoreceptor pigments in the eye
What color pigment is Melanin?
Brown, Yellow-Brown, and Black Pigment
What is Melanin produced by?
Where is Melanin transported in Melanosomes?
Transferred intact to the Keratinocytes
What are the two things that happen to Melanin when it reaches the Keratinocytes?
Temporarily colors the Keratinocytes and destroyed by fusion with lysosomes
In light colored people, melanosomes travel to what epidermic layers before they are destroyed?
Stratum Basal and Stratum Spinosum
In dark colored people, melanosomes travel to what epidermic layers before they are destroyed?
Stratum Basal, Stratum Spinsum, Stratum Granulosum
Where are there higher concentrations of melanocytes?
Cheeks, Forehead, Nipples, and Genital Region
What are freckles and what kind of borders do they have?
Small pigmented areas on relatively pale skin, irregular border
What are Lentigos and what kind of borders do they have?
Similar to freckles with regular borders
What Senile Lentigos/ Liver spots?
Variably pigmented areas that develop on sun-exposed skin in older individuals with pale skin
What protects your epidermis and dermis from harmful effects of sunlight?
Melanin in Keratinocytes
Small amount of UV Radiation is _______.
Why are small amounts of UV Radiation beneficial?
Stimulates the epidermal productions of a compound required for calcium ion homeostasis.
Too much UV Radiation can damage ______, causing _______ and promoting the development of _________.
DNA, Mutations, Cancer
How do Melanocytes situated themselves in Keratinocytes?
Like an umbrella over the nucleus
When UV Radiation is present what become more present, what happens to the color of the skin?
More melanocytes are activated for protection, More pigment = darker skin = tan
If a burn is severe enough, what does it damage?
Epidermis and Dermis
Why do you get a sun burn the first time you go to the beach in a long time?
Not enough melanocytes are activated in time to protect you
Individuals of _____ ________ can get burned.
any color
People with _____ ______ have more protection from UV Radiation than people with __________ _______.
Dark skin, Light Skin
Cumulative damage to the integument by UV Radiation exposure can harm __________.
What are two harmful things that can happen from too much UV Radiation?
Causing impaired maintenance of the dermis, Leading to permanent wrinkling, and Skin cancer can develop from chromosomal damage (DNA) in basal cells or melanocytes
What is one form of UV Radiation protection?
Combination of protective clothing and sunscreens/sun blocks during outdoor activity
What pigment is found in red blood cells?
What does Hemoglobin attach/bind to?
If vessels are dilated, red tones become more _______.
Why does skin become flushed and red when body temperature rises?
Superficial blood vessels dilate
When blood supply temporarily reduces what happens to skin color?
It turns more pale colored
What is cyanosis?
When the skin takes on a bluish coloration
What causes cyanosis?
Sustained reduction in circulatory conditions, hemoglobin releases oxygen and turns a much darker red
Where is cyanosis most apparent in the body when it takes place?
Thin skin areas like lips and beneath nails
What responses cause cyanosis?
Extreme cold or result of respiratory or cardiovascularity disorders such as heart failure or severe asthma
What is Jaundice?
Liver is unable to excrete bile so a yellowish pigment accumulates in body fluids
How can you tell advanced stages of Jaundice?
Skin and whites of eyes turn yellow
Tumors affecting the Pituitary gland secrete large amounts of...?
Melanocyte-stimulating hormone (MSH)
What does MSH stand for?
Melanocyte- Stimulating Hormone
How can you tell if someone has a tumor affecting the pituitary gland?
Darkening of the skin as if the individual has an extremely deep bronze tan
What is Addison's Disease?
Pituitary gland secretes large quantities of adrenocorticotropic hormone (ACTH)
What is the effect of Addison's Disease similar to?
Individuals with Vitiiligio lose....
Their melanocytes
What percentage of the population has Vitiligo?
About 1%
What causes Vitiligo?
Develops when the immune defenses malfunction and antibodies attack normal melanocytes
Exposure to UV Radiation, epidermal cells in the stratum ______ and stratum ________ convert a _________ ________ _________ into ____________ or Vitamin D3
Stratum Basal, Stratum Spinosum, Cholesterol related steroid, Cholecalciferol
What is another name for Vitamin D3?
________ converts ________________ into an immediatary product used by the __________ to synthesize the hormone __________.
Liver, Cholecalciferol, kidney, calcitriol
What is Calcitriol essential for?
Essential for normal absorption of calcium and phosphorus by the small intestine
What does an inadequate supply of Calcitriol impair?
Impaired bone maintenance and growth
Who is affected by Rickets?
Individuals who live in areas with overcast skies and whose diets lack cholcalciferol can have abnormal bone development
What is Rickets?
Abnormal bone development
Rickets has been largely _______ in the US.
How is the US eliminating Rickets?
Dairy companies are required to add cholecalciferol "Vitamin D" to the milk sold in grocery stores
What does EGF stand for?
Epidermal Growth Factor
Where is EGF produced?
Salivary glands and glands of the duodenum
What are the roles of EGF?
Promoting the division of basal cells in the stratum basal and stratum spinosum; Accelerating the production of Keratin in differentiating Keratinolcytes; Stimulating epidermal development and epidermal repair after injury; Stimulating synthetic activity and secretion by epithelial glands
What is a tissue culture?
Cells are grown under laboratory conditions for experimental or therapeutic use
What does EGF do?
Epidermal Growth Factor stimulates growth and division of epithelial cells
Name the two pigments contained in the epidermis.
Carotene and Melanin
Why does exposure to sunlight or sunlamps darken skin?
When exposed to the ultraviolet radiation in sunlight or sunlamps, melanocytes in the epidermis and dermis synthesize the pigment, melanin, darkening the skin.
Why does the skin of a fair-skinned person appear red during exercise in the hot weather?
When skin gets warm, arriving oxygenated blood is diverted to the superficial dermis for the purpose of eliminating heat. The oxygenated blood imparts a reddish coloration to the skin.
Explain the relationship between sunlight exposure and Vitamin D3 synthesis.
In the presence of Ultraviolet Radiation in sunlight, epidermal cells in the Stratum Spinosum and Stratum Basal, convert a cholesterol related steroid into cholecalciferol, or Vitamin D3.
In some cultures, women must be covered completely, except for their eyes, when they go outside. Explain why these women may develop bone problems later in life.
Cholecalciferol (Vitamin D3) is needed to form strong bones and teeth. When the body surface is covered, UV light cannot penetrate to the Stratum Basal in the skin to begin Vitamin D3 production, resulting in fragile bones.
Name the sources of epidermal growth factor in the body.
Salivary glands and duodenal glands
Identify some roles of epidermal growth factor pertaining to the epidermis.
Epidermal Growth Factor promotes the divisions of basal cells in the Stratum Basal and Stratum Spinosum, Accelerates the production of Keratin in differentiating keratinocytes, stimulates epidermal development and epidermal repair after injury, and stimulates synthetic activity and secretion by epithelial glands.
Describe the location of the dermis.
The dermis (a connective tissue layer) lies between the epidermis and the hypodermis.
Where are the capillaries and sensory neurons that supply the epidermis located?
The capillaries and sensory neurons that supply the epidermis are located in the papillary layer of the dermis.
What accounts for the ability of the dermis to undergo repeated stretching?
The presence of elastic fibers and the resilience of skin turgur allow the dermis to undergo repeated cycles of stretching and recoil.
List the two terms for the tissue that connects the dermis to underlying tissues.
Hypodermis or Subcutaneous layer
Describe the hypodermis.
The hypodermis is the layer of loose connective tissue and adipose tissue below the dermis; it is also call the subcutaneous layer or superficial fascia. It is not considered part of the integument but it is important in stabilizing the position of the skin in relation to underlying tissues.
Identify several functions of subcutaneous fat.
Provides insulation to help reduce heat loss, serves as an energy reserve, and acts as a shock absorber for the body
Describe a typical strand of hair.
A typical strand of hair is a keratinous strand produced by epithelial cells of the hair follicle.
What happens when the arrector pili muscle contracts?
The contraction of the arrector pili muscle pulls the hair follicle erect, depressing the area at the base of the hair and making the surrounding skin appear higher. The result is known as "goose bumps".
Once a burn on the forearm destroys the epidermis and extensive areas of the deep dermis heals, will hair grow again in the affected area?
Even though hair is a derivative of the epidermis, the follicles are in the dermis. Where the epidermis and deep dermis are destroyed, new hair will not grow.
Identify two types of exocrine glands found in the skin.
Sebaceous (oil) glands and Sweat Glands
What are the functions of the sebaceous secretions?
Sebaceous secretions (called sebum) lubricate and protect the keratin of the hair shaft, lubricate and condition the surrounding skin, and inhibit the growth of bacteria.
Deodorants are used to mask the effects of secretions from which type of skin gland?
Deodorants are used to mask the odor of apocrine sweat gland secretions, which contain several kinds of organic compounds; some of these compounds have an odor, and others produce an odor when metabolized by skin bacteria.
Which type of sweat gland is most affected by the hormonal changes that occur during puberty?
Apocrine sweat glands enlarge and increase secretory activity in response to the increase of sex hormones that occurs at puberty.
What substance makes fingernails hard?
Keratin is the substance that gives fingernails their strength
What term is used to describe the thickened stratum corneum underlying the free edge of a nail?
The area of thickened stratum corneum under the free edge of a nail is call the hyponychium.
Where does nail growth occur?
Nail growth occurs at the nail roots, an epidermal fold that is not visible from the surface
What terms describe the combination of fibrin clots, fibroblasts, and the extensive network of capillaries in healing tissue?
Granulation Tissue
Why can skin regenerate effectively even after considerable damage?
Skin can regenerate effectively even after undergoing considerable damage because stem cells persist in both the epithelial and connective tissue components of skin. When injury occurs, cells of the stratum basal replace epithelial cells while mesenchymal cells replace cells lost from the dermis.
Older individuals do not tolerate the summer heat as well as when they were young and they are more prone to heat-related illness. What accounts for these changes?
As a person ages, the blood supply to the dermis decreases and merocrine sweat glands become less active. These changes make it more difficult for the elderly to cool themselves in hot weather.
Why does hair turn white or gray with age?
With advancing age, melanocytes activity decreases, leading to gray or white hair.
Where is the dermis located?
Lies between the epidermis and hypodermis.
What does the papillary layer consist of?
Areolar tissue
What is contained in the dermis?
Capillaries, lymphatics, and sensory neurons
What projects between the epidermal ridges?
Dermal Papillae
Where is the reticular layer in relation to the papillary layer and the hypodermis?
deep, superficial
What kind of tissue is the reticular layer?
Dense irregular connective tissue containing both collagen and elastic fibers.
_______ layer and _______ layer are difficult to tell apart.
Pipillary, Reticular
What two things extend into the dermis?
Hair follicles and sweat glands
What is dermatitis?
An inflammation of the skin that primarily involved the papillary layer
What three things in the dermis help maintain strength and elasticity?
Collagen fibers, Elastic Fibers, and water
How does water help maintain strength and elasticity of the dermis?
Skin turgur
What are three things that permanently reduce the amount of elastin in the dermis?
Aging, Hormones, and the destructive effects of UV-Radiation
What happens to the dermis during pregnancy or substantial weight gain?
Extensive distortion of the dermis that occurs over the abdomen can exceed the elastic limits of the skin
What are stretch marks?
When the dermis is stretched beyond the elastic limits, the skin wrinkles and creates a network of stretch marks
What is Tretinion (Retin-A)?
Vitamin A derivative that can be applied to the skin via cream or gel
What does Tretinion (Retin-A) help with?
Developed to treat acne, increases blood flow to the dermis and stimulates dermis repair, and rate of wrinkle formation decreases and existing wrinkles become small
What are cleavage lines a result of?
Resulting pattern of fiber bundles in the skin
In which direction are collagen and fiber bundles in cleavage lines arranged and why?
Arranged in parallel bundles oriented to resist forces applied to the skin during normal movement.
Why are cleavage lines important for surgery?
A cut parallel to a cleavage line will remain closed and heal without significant scarring
A cut at right angles to a cleavage line will be pulled open as a severed elastic fibers recoil and result in greater scarring.
What is the Cutaneous Plexus?
Artery networks in the hypodermis along its border with the reticular layers of the dermis.
What is a Papillary Plexus?
Small artery branching network in the papillary layer, provides arterial blood to capillary loops that follow the contours of the epidermis-dermis boundary.
What causes a contusion?
Rupture of dermal blood vessels, blood leaks into the dermis, and the areas develops the familiar "black and blue" color
What is another name for a bruise?
What is an ulcer?
Localized shedding of the epithelium
What causes an ulcer?
Circulation that is restricted where superficial vessels are continuously compressed
The Integument is full of __________ receptors.
What do the nerve fibers/sensory receptors in the skin control?
Blood flow, adjust gland secretion rates, and monitor sensory receptors in the dermis and the deeper layers of the epidermis
What are the two specialized receptors in the dermis?
Tactile Corpuscles and Lamellated Corpuscles
What are Tactile Corpuscles sensitive to and where are they located?
Located in the dermal papillae and are sensitive to light touch
What are Lamellates Corpuscles sensitive to and where are they located?
Located in reticular layer and are sensitive to deep pressure and vibration
Why is the hypodermis important?
Important in stabilizing the position of the skin in relation to other tissues
What two tissues make up the hypodermis?
Areolar and adipose tissue
Only superficial region of hypodermis contain _______ _____ and ________.
Large arteries and veins
Subcutaneous membrane = ______________ needle
____________ membrane = hypodermal needle
Children and infants have extensive "______ _______" which helps with...?
"Baby Fat", Provides extra insulation, helps reduce heat loss, energy reserve, and shock absorber
During _______, subcutaneous fat moves to different positions in the body of women and men
During puberty, women's subcutaneous fat moves to.....?
Breasts, Buttocks, Hips and Thighs
During puberty, men's subcutaneous fat moves to...?
Neck, on the arms, along the lower back, and over the buttocks
Adults of either gender, subcutaneous fat leaves _________ and moves to the _________ _______ known as a "_____ _________".
Back of hands and upper surfaces of feet, abdominal region, "pot belly"
Describe the surgery process of liposuction/lipoplasty.
Subcutaneous adipose tissue is removed through a tube inserted deep to the skin
What are some risks from having a procedure like liposuction done?
Risks from anesthesia, bleeding, sensory loss and fluid loss
What is the death rate of liposucton?
1 in 5,000
Why is liposuction a "quick fix"?
Adipose tissue will repair itself and areas of areolar tissue will convert to adipose tissue
What are sebaceous glands?
Oil glands; Holocrine glands that discharge an oil lipid secretion into hair follicles.
How are the secretions of the Sebaceous glands released? (4 Steps)
1. Lipids released from gland cell
2. Enter the lumen (Passageway) of the gland
3. Arrector pili muscles contract, squeezing the sebaceous gland and forcing the lipids into the hair follicle.
4. Secreted onto the surface
What is the secreted lipid from Sebaceous glands called?
What are the functions and effects of Sebum?
Inhibits the growth of bacteria, lubricates and protects the keratin of the hair shaft and conditions the surrounding skin
What is the difference between Sebaceous glands and Sebaceous follicles?
Sebaceous glands release secretions into the hair follicles and Sebaceous follicles are not associated with hair follicles
What are Sebaceous follicles?
Larger sebaceous glands that are not associated with hair follicles; their ducts discharge sebum directly onto the epidermis
What secretion does Sebaceous follicles produce?
Where are Sebaceous follicles located?
Face, Back, Chest, Nipples, and external genitalia
When are the two times in life when Sebaceous follicles are most active?
Last few months of fetal development and puberty
What is Seborrheic dermatitis?
Inflammation around abnormally active sebaceous glands, most often on the scalp
In infants, what is Seborrheic Dermatitis typically called?
Cradle Cap
In adults, what is Seborrheic Dermatitis typically called?
What factors aggrevate Seborrheic Dermatitits?
Anxiety, stress, and fungal or bacterial infections
What are the two types of sweat glands in the body?
Apocrine sweat glands and Merocrine sweat glands
What is another name for sweat glands?
Sudoriferous Glands
Where do apocrine sweat glands secrete their products into?
Hair follicles
Where are apocrine sweat glands found?
Armpits, around the nipples, and in pubic region
What mode of secretion do apocrine sweat glands use?
Merocrine secretion
Which sweat gland is the "stinky" sweat gland?
Apocrine sweat glands
What cells contract and squeeze the Apocrine sweat glands?
Myoepithelial cells
What two things control the secretory activities and contractions of epithelial cells of the Apocrine sweat glands?
Nervous system and circulating hormones
Where do merocrine sweat glands secrete their products?
Directly onto the surface of the skin
What is another name for merocrine sweat glands?
Eccrine sweat glands
Where are the highest number of merocrine sweat glands located?
Palms of hands and soles of feet
Merocrine sweat glands = _____________ perspiration?
Merocrine sweat consists of what and how much?
99% water
What are the functions of merocrine sweat glands?
Cooling the surface of the skin to reduce body temperature, excreting water and electrolytes, and providing protection from environmental hazards
What are ceruminous sweat glands and what do they produce?
Modified sweat glands in the passageway of the external ear which forms a mixture called cerumen also known as earwax
What are earwax functions and why is it important?
Helps trap foreign particles preventing them from reaching the eardrum
What is the Autonomic Nervous System (ANS)?
Controls the activation and deactivation of sebaceous glands and apocrine sweat glands at the subconscious level.
What is thermoregulation and what type of feedback is this?
Process of maintaining temperature homeostasis and negative feedback
What is an incision?
A slender, straight cut may heal very quickly
What is an abrasion?
Deep scrape that involved much greater surface area to be repaired
What is the first stage of regeneration called and what is involved?
Inflammatory Phase: Bleeding occurs at the site of injury immediately after the injury, and mast cells in the region trigger an inflammatory response.
What is the second stage of regeneration called and what is involved?
Migratory Phase: After several hours, a scab (blood clot) has formed and cells of the Stratum Basal are migrating along the edges of the wound. Phagocytic cells are removing debris and more of these cells are arriving via enhanced circulation in the area. Bulk of the clot consists of an insoluble network of fibrin, a fibrous protein.
What is Granulation tissue?
Combination of blood clot, fibroblasts and an extensive capillary network.
What is a combination of blood clot, fibroblasts and an extensive capillary network called?
Granulation Tissue
What is the third stage of regeneration and what is it called?
Proliferation Phase: Deeper portions of the clot dissolve and number of capillaries decline. Fibroblast activity leads to appearance of collagen fibers and typical ground substance. The dermis will not contain an abnormally large number of collagen fibers and a few blood vessels.
What is scar tissue?
Inflexible, fibrous, noncellular tissue completes the repair process but fails to restore the tissue to its original condition.
What is a keloid?
Thick, raised area of scar tissue
What is the fourth stage of regeneration and what is it called?
Maturation Phase: Scab has been shed and the epidermis is complete, a shallow depression marks the injury site but fibroblasts in the dermis to create scar tissue that will gradually elevate the overlying epidermis.
What are burns a result from? Give two.
Exposure of the skin to heat, friction, radiation, electrical shock or strong chemical agents
What are first and second degree burns called and why?
Partial thickness burns because they are restricted to the superficial layers of the skin
First degree burns only effect what part of the skin, symptoms, and what is the most typical first degree burn?
Only the surface of the epidermis is affected, skin reddens and becomes painful, most typically sunburns
What do second degree burns affect?
Entire epidermis and some of the dermis are damaged
What are the symptoms of second degree burns?
Blistering, pain, and swelling occur
How long does it take second degree burns to heal?
one to two weeks
Will scar tissue form for second degree burns?
Some scar tissue may form
Third degree burns are also called... because...?
Full thickness burns because it destroys the epidermis and dermis, extending into the hypodermis
What are the symptoms of the third degree burns?
Swelling but less painful than second degree burns
Why are third degree burns less painful than second degree burns?
Less painful than second degree burns because sensory nerves are destroyed
Why can repair not be made for third degree burns?
The Stratum Granulosum can not produce new cells and it remains open to infection
Burns that cover more than ___% of the skin surface threaten life.
When 20% of the skin surface is covered in burns, why does it threaten life?
Fluid and electrolyte balance, thermoregulation and protection of infection are compromised.
What are three effects of aging?
Epidermis thins as basal cell activity declines, connections between the epidermis and dermis weaken, number of dendritic cells decrease to about 50%, Vitamin D3 production declines about 75%, Melanocyte activity declines, glandular activity declines, blood supply to the dermis is reduced, hair follicles stop functioning, dermis thins and elastic fiber network decrease in size, changes in levels of sex hormones and skin repairs more slowly.