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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.

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