A&P ch. 5

how many layers is the dermis divided into?

2

How many layers are in the epidermis?

5

What areas of the skin consist of 5 layers, and 4 layers o the body?

5 layers- palms of hands, soles of feet 4 layers- rest of the body

What is bigger eccrine or apocrine glands

Apocrine are much larger

specialized glands found only in the external acoustic meatus?

Ceruminous glands

What are the most common sweat glands and are widely distributed over the body?

Eccrine

What are the two types of sweat glands?

Eccrine Apocrine

What else is absorbed through the skin?

O2, CO2, UV light, toxins, (steroids, Vit A, D, E, K) nonpolar

What disease is caused by vitamin D deficiency?

Rickets

What layer is composed of a single layer of cells in contact with the dermis>

Stratum Basal

What are the layers of the epidermis?

Stratum Basal Stratum spinosum Stratum granulosum Stratum lucidum Stratum corneum

What are the 2 layers of the dermis?

Stratum Papillarosum (papillary layer) Stratum Reticulararosum (reticular)

What contains several layers of cells that have a spiny appearance after staining?

Stratum spinosum

What are smooth muscles attached to hair follicles called?

arrector pili which contract involuntarily cause goose bumps

What are Eccrine sweat glands controlled by?

autonomic nervous system and function in evaporative cooling

Where are apocrine glands found?

axillary and pubic regions where they secrete into hair follicles

nerve receptores are further apart on

backside

Why is skin considered an organ?

because it is composed of groups of tissues performing similar functions

what five things does the dermis contain?

blood vessels sweat glands oil secreting glands (sebaceous glands) nerve endings hair follicles

What supplies nutrients to the mitotically active stratum basale of the epidermis?

blood vessels within the dermis

When babies are fed increased amounts of carrots and squash why do they take on an orange color?

carotene deposition

What do motor nerves do?

carry information to various glands ie..sweat glands and muscles (arrector pili and smooth muscle of blood vessels)

What do Ceruminous glands secrete?

cerumen or ear wax

What is keratohyalin?

chemical precursor to keratin

What reinforces the hypodermis

collagenous and elastic fibers

What is the reticular layer primarily composed of?

collagenous fibers are dense and regularly arranged

fever and shock can be detected by?

color and temperature of skin

sensory receptors also

communicate

The skin acts as a dynamic interface between what?

continually changing external environment and the body's internal environment

birth control and nicotene patches are example of what?

cutaneous apsorption through the skin

What are abundant in the dermis and hypodermic of the face, palms and fingers of hands, soles of feet and genitalia?

cutaneous receptors

How is vitamin D synthesized?

dehydrocholesterol in the presence of UV light

What is the layer of the skin under the epidermis?

dermis

Where is the vascular supply found?

dermis

What is the dermis composed of?

elastic and collagenous fibers arranged in a dense irregular fashion

what is the purpose of perspiration

excretion and evaporative cooling

nerve receptors are closer together on

fingers, lips

motor nerves carry info to

glands and muscles

What do theses cells get their granular appearance from?

granules filled with keratohyalin

What are accessory structures of the skin

hair, nails and glands

what binds the dermis to the underlying organs

hypodermis

Where does carotene tend to accumulate?

in the epidermal cells and fatty parts of the dermis

blushing is a result of?

inviluntary vasodilation of dermal blood vessels

What do keratinocytes produce?

keratin

What does the integumentary system synthesize?

keratin---water proofing melanin---protect from UV Vitamin D---synthesized from cholesterol and absorbs Ca+ and K

What 4 cell types is the stratum basal composed of?

keratinocytes melanocytes tactile cells non-pigmented granular dendrocytes

what is the hypodermis composed of?

loose irregular connective tissue adipose cells interlaced with bloods vessels

what are specialized sudoriferous glands that secrete milk during lactation under the influence of pituitary and ovarian hormones

mammary glands

What happens if sebaceous glands become blocked?

may become infected and result in acne (if you pop a zit you are spreading infection across your face

What do melanocytes produce?

melanin

what is brown-black pigment produced in the melanocytes of the stratum basal?

melanin

coloration of skin is due to what 3 pigments?

melanin carotene hemoglobin

Physical protection of skin?

microorganisms water excessive sunlight (UV light)

The skin is innervated by what 2 things?

motor efferent and sensory afferent nerves (this is info coming in)

what type of molecules are readily absorbed by the skin...list examples

nonpolar lipid soluble toxins, pesticides, hexane, benzane

Where are subcutaneous layers sparse?

over the joints

What are non-pigmented granular dendrocytes?

protective macrophagic cells that ingest bacteria and other foreign debris and molecules part of immune system

When are apocrine glands funtional>

puberty

What 3 ways is excess heat lost from the body?

radiation from dilated blood vessels secretion and evaporation of perspiration convection and conduction of heat directly through the skin

What do sex hormones do?

regulate production and secretion of sebum

blood vessels of the dermis play an important role in?

regulating body temperature and blood pressure

Vitamin D is essential for?

regulation of calcium and phosphate levels in the body

sensory nerves

respond to the stimulus

This layer is fairly distenable, but if stretched to far it tears and causes stretch marks or line albicans

reticular layer

What is the layer that corresponds to the hide of an animal used to make leather and suede?

reticular layer

what secretes sebum and are associated with hair follicles?

sebaceous glands

What happens if you have hyperactivity of your sebaceous glands

serious acne problems particularly during teen years

What does excessive heat loss trigger

shivering response in muscles

What is the largest organ of the body?

skin

What is the Integumentary system composed of?

skin hair nails glands

Hydroregulation

skin is virtually waterproof protects from dehydration on land and water absorption when immersed in water

Why are some areas of the body more sensitive to touch?

some areas of the body have a greater concentration of nerve endings ie..palms of hands, lips, external genitalia

What is composed is cornified protective and is composed of 25-30 flattened scale-like cells

stratum corneum

Stratum basale and stratum spinosum are collevtively called?

stratum germinativum

What consists of only 3 or 4 flattened rows of cells?

stratum granulosum

What is clear because the nuclei, organelles and the cell membranes are no longer visible?

stratum lucidem

What is the epidermis composed of?

stratum squamous epithelium

What secretes perspiration onto the surface of the skin?

sudoriferous glands or sweat glands

What is the epidermis?

superficial protective layer of the skin

tactile cells aid in?

tactile reception (touch)

the sensory nerves respond to various stimuli such as?

tactile touch pressure temperature tickle pain

what determines racial variations in skin color?

the amount of melanin produced and the distribution of melanin

Where are cutaneous layers less abundant?

the back and back of the neck

What causes the skin to be more pinkish?

the closer vessels, in the dermis, are to the surface of the skin the more pinkish

Hemoglobin

the oxygen-binding pigment found in red blood cells

thermoregulation

the skin plays a crucial role in the regulation of body temperature

cutaneous receptors respond to?

thermal (heat and cold) mechanical (pressure, touch and vibration) noxious (pain) stimuli

What causes odoriferous secretion>

thought to act as a sexual attractant pharamones

what is the purpose of melanin

to protect the basal layer against damaging effects of UV rays from the sun

What is perspiration composed of?

water salts urea uric acid

cerumen acts as?

water and insect repellant

Carotene

yellowish-orangish pigment that is not produced naturally by the body

Do all individuals of similar size have similar number of melanocytes?

yes