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