Anatomy & Physiology Chapter 7 Skin revised

154 terms by gr8ize 

Create a new folder

Advertisement Upgrade to remove ads

Skin

1. body's largest organ, 22 square feet,cutaneous membrane

Integumentary system

describes the skin and its appendages-the hair, nails and skin glands.

2 primary layers of skin

1. epidermis -superfical
2. dermis- true skin joined by dermal-epidermal junction.

Hypodermis

is not part of the skin. AKA subcutaneous layer or superficial fascia.

Structures of the skin- EPIDERMIS

consists of stratified squamous epithelium. There are 4 types present.

Keratinocytes

produces keratin, a protein that hardens and waterproofs the skin. Mature keratinocytes at the skins surface are dead and filled almost entirely with keratin. It protects body from microbes, abrasions, chemicals. Most superficial and constitutes 90% of cells present.

Melanocytes

produce melanin, a pigement that protects cells from ultraviolet radiation. Melanin from the melanocytes is transferred to the keratinocytes.

Langerhans cells

aka epidermal dendritic cells that interact with WBCs during an immune response

Merkel cells

Tactile epithelial cells that attach to sensory nerve endings to form "light touch" receptors. Serves as a sensory function.

5 layers of EPIDERMIS

1. Stratum granuloseum
2. Stratum lucidum
3. Stratum corneum
4. Stratum basale
5. Stratum spinosum

Stratum basale

base layer, single layer of columnar cells; ONLY cells that undergo MITOSIS then migrate through other layers until they are shed.

Stratum spinosum

Spiny layer. cells arranged in 8-10 layers connected by demosomes that pull cells into spiny shapes;rich in RNA.

Stratum germinativum

Fingernail growth is the result of the mitosis of the cells in the stratum __________

Stratum corneum

horny layer. Most superfical layer outer layer of the epidermis
ie dandruff

Epidermal growth and repair/Turnover or regeneration

most important function of skin is protection. Largely depends on epidermis and its ability to create and repair itself after injury or disease. turnover or regeneration time in the stratum basale and migrate to skin surface. TIME: 35 days.

Calluses

shortened turnover time will increase the thickness of the stratum corneum and results in callus formation; a thickened stratum corneum

Epidermal Proliferating Unit- EPU

each group of 8-10 basal cells in mitosis with their vertical columns of migrating keratinocytes is called an EPU.

Meissner Corpuscle

capable of detecting light touch-slight pressure.

Lamellar Corpuscle aka Pacinian Corpuscle

detects sensations of deep touch.

DEJ-dermopidermal junction

basement membrane with unique fibrous elements and a polysacchride gel to serve as the "glue" the epidermis and dermis below.

Dermis

True skin. Much thicker than the epidermis and lies beneath it.
-gives strenght to skin
-serves as a reservior area for storage of water and electrolytes.
-rich vascular supply plays critical role in TEMPERATURE REGULATION.

Dermis structures

1. Arrector pilli muscles and hair follicles
2. Sensory receptors
3. Sweat and sebaceous glands
4. Blood vessels.

2 layers of dermis

1. papillary layer
2. reticular layer

Papillary layer

Composed of dermal papillae that project into the epidermis; forms a unique that gives individual fingerprints

Reticular layer

contains dense, interlacing white collagenous fibers and elastic fibers to make the skin tough yet stretchable; when processed from animal skin, produces leather

dermis

does not continually shed and regenerate itself as does the epidermis/

fibroblasts

During wound healing, _______ begin forming an unusually dense mass of new connective fibers; if not replaced by normal tissue, this mass remains a scar

During wound healing, fibroblasts begin forming an unusually dense mass of new connective fibers; if not replaced by normal tissue, this mass remains a
______.

Scar.

Melanin

;basic determinant of skin color

2 Types of melanin

1. Eumelanin: group of dark brown almost black melanins
2. Pheomelanin: group of reddish and organge melanins.

Albinism

congenital absence of melanin

hemoglobin

a hemoprotein composed of globin and heme that gives red blood cells their characteristic color, color changes as a result of incresed blood flow.

cyanosis

Bluish color caused by darkening of hemoglobin when it loses oxygen and gains carbon dioxide.

bruising

can cause a rainbow of different colors to appear in the skin

jaundice

yellow discoloration of the skin and other tissues such as the sclera of eyes can be caused by bile pigments.

Surface film

Emulsified protective barrier formed by mixing of residue and secretions of sweat and sebaceous glands with sloughed epithelial cells from skin surface.

Desquamation

shedding of epithelial elements;loss of bits of outer skin by peeling or shedding or coming off in scales

7 Functions of the Skin

1. protection
2. sensation
3. flexability
4. metabolism/endocrine
5. excretion
6. immunity
7. Temperature regulation

Protection/surface film functions

against microorganisms;dehydration;UV light:mechanical trauma

surface film

mechanical barrier of skin;Emulsified protective barrier formed by mixing of residue and secretions of sweat and sebaceous glands with sloughed epithelial cells from skin surface

Sensation

skin acts as a sophicated sense organ

Flexability

skin is supple and elactic;permits movement and changes in body contour without injury.

excretion

Water, Urea/ammonia/uric acid

How does skin excrete

sweat glands

a fat-soluble vitamin that prevents rickets

vitamin d

The skin keeps the body immune by

having epidermal dendritic cells trigger helpful immune reaction working with helper T cells

Heat production/homeostasis of body temperature

by metabolism of foods in skeletal muscles and liver

Chief determinant of heat production is?

the amount of muscular work being performed. Example exercise.

homeostasis of body temperatures

to maintain homeostasis of body temperature heat production must be equal to heat loss;skin plays a crtical role in the process.

homeostatic of regulation of heat loss

the heat loss by the skin is controlled by a negative feedback loop;receptors in the hypothalmus monitor the bodys internal temperature. If the bodys temp is increased, the hypothalmus continues to act until the bodys temperature returns to normal

Radiation

transfer of heat from one object to another without actual contact; important method of heat loss in cool environmental temperature.

evaporation/insensible loss

to evaporate any fluid, heat energy must be expended;this method of heat loss is especially important at high environmental temps when the only method by which heat can be lost from the skin.

appendages

hair, nails, skin glands-sweat and sebaceous and arrector pilli muscle

Lanugo

the fine downy hair covering a human fetus

terminal hair

Course hair on the head and other places after puberty

hair papillae

at bottom of bulb; blood-rich connective tissue, hair growth begins here

arrector pili muscle

Each hair follicle has a small bundle of involuntary muscles attached to it called the arrector pili muscles.Part of the sebaceous gland, follicle and hair to a standing position, goose bumps.

growth of hair

5 inches per year

sebaceous glands

attach to and secrete sebum or skin oil into follicle

androgenic alopecia

male baldness pattern, is genetic

nails

epidermal cells converted to hard keratin

nailbody

visible part

lunula

moon shaped white area nearest root

nail bed

layer of epithielum under nail body;contains blood vessels

what are 2 types of sweat glands?

eccrine and apocrine

eccrine glands

most numerous and quite small;distributed throughout body

Function of eccrine glands?

Secrete perspiration or sweat; eliminate wastes and help maintain a constant core temperature

where are apocrine glands located?

deep in sub q layer, limited in axilla, areola, breast and anus.

what is function of apocrine gland?

begins at puberty and secretes cyclic changes such as menstral cycle

Sebaceous glands

secrete sebum keeping hair soft and pliant and prevents water loss

When does sebaceous glands increase production?

puberty

What does the increase of sebaceous glands in teens lead to?

acne

Ceruminous glands

are simple tubular glands, they are apocrine glands.

What does ceruminous glands secrete?

cerumen or wax

What is cerumen made of?

mixed secretions of sebaceous and ceruminous glands

Where is cerumen usually excreted?

ears

How does cerumen protect ears?

protects area from dehydration

What does excess secretion of cerumen cause?

blockage of ear canal and loss of hearing

what are characteristics of skin in children?

smooth, elastic, few sweat glands, rapid healing

What occurs in skin cycle in adults?

development and activation of sebaceous and sweat glands, increase sweat production, can cause body odor and acne.

What happens to skin in old age?

decrease in secaeous and sweat gland activity, wrinkles, decrease in ability of body to cool itself.

What is a major component of skin

it is bodys structural framework

what does skin define?

the internal environment of the body

What are 2 primary functions of skin?

support and protection

Melanin

basic deteminant of color

2 main layers that compose the skin

epidermis and dermis

keratin

tough fibrous protein found in epidermis,made up of keratinocytes

3 microscopic glands of skin are

sweat,eccrine and sebacous glands

hypodermis

Forms a connection between skin and underlying body structure; deep to dermis, mostly fat.hypodermis connects the dermis to the underlying tissues.

An area of the body you would expect to find an especially thick stratum corneum is in the

sole of the foot

The epidermis is composed of several types of __________

epithelial cells

Evaporation

is the cause of the conversion of water from a liquid state into a gaseous state due to the bodyheat loss

Contraction

is not a function of the skin

The skin glands include three kinds of microscopic glands. What are they?

. They are the sweat, sebaceous, and ceruminous glands.

cerumen

are mixed secretions of sebaceous and ceruminous glands that form a brown waxy substance

what 3 vitamins are absorbed through the skin?

Vitamin A, vitamin D and Vitamin K

Synthesis of vitamin E

is not a function of the skin

Basal cell carcinoma

is the most common type of skin cancer

Kaposi sarcoma

is the type of cancer associated with immune deficiencies

Prolonged exposure to the sun causes melanocytes which

increases melanin production.

The hair follicle is found?

in the dermis.

Fingernail growth is the result of the mitosis of the cells?

in the stratum germinativum

Apocrine sweat glands

can't be found in the soles of the feet.

Apocrine sweat glands can be found?

in the armpits, the areolae of the breasts and the pigmented skin areas around the anus.

Sebaceous glands are the type of gland associated with_______?

blackheads

Shaft, the root and the medulla are part of ?

hair

Hair facts -

alternates between periods of growth and rest.
-consists of keratinized cells.
-is formed from cells of the germinal matrix.

The hair papilla consists of:

dermal tissue

The most numerous, important, and widespread sweat glands in the body are:

the eccrine glands

what does sebum do?

lubricates hair and skin.

what are the functions of surface film found on the skin?

including:
-lubrication.
- buffering of caustic irritants.
- antibacterial and antifungal activity

Although body temperature normally changes very little during the course of a day, it is generally the lowest during_______?

the early morning.

Evaporation

is the cause of the conversion of water from a liquid state into a gaseous state due to the body heat loss

Radiation

is the type of body heat loss that characterized by heat transfer from the surface of one object to the surface of another object without actual contact

How does the body compensates for the increase in the core body temperature caused by exercise ?

by increasing the blood flow to the skin.

The same degree of environmental temperature seems hotter in humid climates than it does in dry ones, why?

because evaporation is retarded in humid climates

A person leaning against a cold cement block wall would lose heat by the process of ____________

conduction

The body's temperature control center is located in?

the hypothalamus

A second-degree burn is characterized by?

severe pain, generalized swelling, and edema.

A major distinction between second- and third-degree burns is that ?

third-degree burns are characterized by insensitivity to pain immediately after injury.

First degree burn

s damage the outer layer of skin (epidermis) and cause pain, redness and swelling (erythema)

Second degree burns

damage the epidermis and the inner layer, the dermis, causing erythema and blistering

third degree burns

extend into the hypodermis, causing destruction of the full thickness of skin with its nerve supply (numbness). Third degree burns leave scars and may cause loss of function and/or sensation.

the dermis is a

connective tissue

epidermis

is an epithelial tissue

Dendritic cells

Dendritic cells originate in the bone marrow and are important in the immune function

Stratum corneum is the skin layer called

the barrier area.

Stratum lucidum

cell layers are filled with a protein called eleidin

What % of the cells in the stratum basale enter mitosis each day

10%-12%

The following is true of the dermal-epidermal junction:

It is composed chiefly of basement membrane.
Its function is to "glue" the two layers of skin together.

The following is true of the dermis:

It contains a papillary layer.
It contains a reticular layer.
It plays an important role in body temperature regulation.

"Burns" can be caused by:

ultraviolet light.
corrosive chemicals.
electrical current.

The cell layers of skin from the most superficial to the deepest appear in this order

The cell layers of skin from the most superficial to the deepest appear in this order: Stratum corneum, lucidum, granulosum, spinosum, and basale CLGSB

The time required for the completion of mitosis, differentiation, and the movement of new cells from the stratum basale to the surface of the skin is

about 35 days

Stratum spinosum

are cells in which the epidermal layer are rich in RNA to increase the efficiency of protein synthesis

Stratum granulosum

cells layers have a high level of lysosomal enzymes in their cytoplasm

When the skin looks cyanotic, it is because

oxygen-poor blood can be seen through the skin

Fever

increases in body temperature would be caused by pyrogens

Malignant hyperthermia

increase in body temperature can be caused by anesthetics or muscle relaxants

Hair can become brittle and dry due to

the improper function of the sebaceous glands.

Many liquid medicines, such as insulin, are administered using a subcutaneous injection

The subcutaneous layer has a rich blood supply and loose spongy texture which makes it an ideal site for the administration of such medication

Onycholysis

is usually caused by trauma to long fingernails.

After several hours of landscaping the yard, Jennifer experienced a body temperature of 105° F; a rapid heart rate; headache; and hot, dry skin. She is taken to a medical facility and treated for

heat stroke

Matt is admitted to the hospital with burns to the deep epidermal layers and injury to the upper layers of the dermis. The physician tre ats Matt's condition as

a second-degree burn.

After several months of extensive weight training, Nick has noticed pinkish, depressed furrows with jagged edges in his axillary region. These markings are a result of

healing due to tiny tears in the dermis.

Somatic sensory receptors

are a special network of nerves deep in the dermis that is capable of detecting pressure on the skin surface

This is a true statement that best explains the importance of the dendritic cells:

They find markers on bacteria and other invaders and present them to other immune system cells for recognition and destruction

The regeneration time required for completion of mitosis, differentiation, and movement of new keratinocytes from the stratum basale to the surface of the epidermis be accelerated by

the epidermal proliferating unit

The fibers in which layer make it possible for skin to stretch and be elastic is the

reticular

See More

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set