6.1 – Skin and subcutaneous tissue Flashcards
integumentary system consists of…
skin, hair, nails, glands
skin (integument) is the body’s ___ and ___ organ
largest
heaviest
integument consists of ___ layers:
the layers are the ___ and the ___
epidermis and dermis
the epidermis is made of…
stratified squamous epithelium
the dermis is…
a deeper connective tissue layer
below the dermis is another layer called the ___, which is not part of the skin but is customarily studied in conduction with it.
hypodermis
the hypodermis is…
another connective tissue layer
thick skin covers…
palms, soles, and corresponding surfaces of the fingers and toes
thick skin has a very thick surface layer of dead cells called the ___
stratum corneum
thick skin has (1) but no (2) or (3)
sweat glands but
no hair follicles or sebaceous (oil) glands
epidermis of thick skin is ___ mm thick
0.5 mm
epidermis of thin skin is ___ mm thick
0.1 mm
thin skin has a thin ___
stratum corneum
thin skin possess (1), (2) , and (3)
sweat glands
hair follicles
sebaceous glands
functions of the skin:
(0) – container for body
(1) – resistance to trauma and infection
(2) – other barrier functions
(3) – vitamin D synthesis
(4) – sensation
(5) –thermoregulation
(6) – nonverbal communication
functions of the skin
(1) resistance to trauma and infection (describe)
epidermal cells are packed w/ tough protein keratin and linked by strong desmosomes
resists infection from bacteria and fungi by skin’s dryness and slight acidity
cells of the epidermis
there are ___ types
5
cells of the epidermis:
the 5 types of cells:
(1) keratinocytes
(2) stem cells
(3) melanocytes
(4) tactile cells
(5) dendritic cells
cells of the epidermis:
(1) keratinocytes
great majority of epidermal cells
synthesize keratin
cells of the epidermis:
(2) stem cells
undifferentiated cells that
stratification of the skin and hypodermis:
epidermis (description)
keratinized stratified squamous epithelium
clear,
stratum corneum (description)
dead, keratinized cells of the skin surface
stratification of the skin and hypodermis:
epidermis:
stratum lucid (description)
clear, featureless, narrow zone seen only in thick skin
stratification of the skin and hypodermis:
epidermis:
stratum graunulosum (description)
2 to 5 layers of cells w/ dark-staining keratohyalin granules; scanty in thin skin
stratification of the skin and hypodermis:
epidermis:
stratum spinosum (description)
many shrunken layers –> keratinocytes attached to each other by desmosomes –> spiny look
stratification of the skin and hypodermis:
epidermis:
stratum basale (description)
single layer of cuboidal to columnar cells resting on basement membrane
site of most mitosis – consists of stem cells, keratinocytes, melanocytes, and tactile cells
stratification of the skin and hypodermis:
dermis (description)
fibrous connective tissue, richly endowed w/ blood vessels and nerve endings
sweat glands and hair follicles originate here and in hypodermis
stratification of the skin and hypodermis:
dermis:
papillary layer (description)
superficial 1/5th of dermis
composed of areolar tissue
often extends upward as dermal papillae
stratification of the skin and hypodermis:
dermis:
reticular layer (description)
deeper 4/5th of dermis
dense irregular connective tissue
stratification of the skin and hypodermis:
hypodermis (description)
areolar or adipose tissue b/n skin and muscle
melanin (def)
most significant factor in skin color
produced by melanocytes but accumulates in keratinocytes of the of the stratum basal and stratum spinoisum
2 forms of melanin
eumelanin (brownish black)
pheomelanin (reddish yellow)
people of different skin colors have essentially the same number of ___, but in dark skin, the melanocytes produce greater quantities of ___, the ___ granules in the keratinocytes are more spread out than tightly clumped, and the ___ breaks down more slowly
melanocytes
melanin
melanin
melanin
friction ridges (def)
markings on the fingertips
flexion lines (flexion creases)
lines on the flexor surfaces of the digits, palms, wrists, elbows, and other places
mark sites where the skin folds during flexion of the joints –> skin is tightly bound to deeper connective tissues along these lines
freckles (def)
flat patches that vary w/ heredity and exposure to the sun
mole/nevus (def)
elevated patch of melanized skin, often w/ hair
hemangioma aka birthmarks (def)
patches of skin discolored by benign tumors of blood capillaries
what are accessory organs of the integumentary system?
hair, nails, and cutaneous glands
identify the components of the integumentary system
epidermis
dermis
hair
nails
cutaneous glands
which 2 distinct layers make up the skin?
epidermis and dermis
the layer that is located deep to the dermis and is not part of the skin is the ___
hypodermis
some functions of the integumentary system:
thermoregulation
sensory reception
vitamin D production
protection
the system that consists of the skin and its accessory organs is the ___ system
integumentary
the superficial layer of the skin contains abundant ___
keratin
the epidermis is a barrier to ultraviolet rays, blocking much of the cancer-causing radiation from reaching the nuclei of cells called ___
keratinocytes
the skin is composed of what?
epidermis and dermis only
what is the connective tissue layer that lies b/n the skin and the deeper muscle or other tissue?
hypodermis
the skin is essential in sensing which of the following?
sensing external stimuli:
injury, touch, temp
what are functions of the skin?
vitamin D synthesis
sensory reception
thermoregulation
resistance to trauma and infection
other barrier functions
nonverbal communication
which cools the skin?
evaporation of sweat
a protein that is produced in the cells of the epidermis that improves its durability and resistance to infection is called ___
keratin
the skin functions as an important barrier to what?
water
UV radiation
microorganisms
cells in the epidermis are nourished by blood vessels located in which of the following?
dermis
dermis is directly deep to the epidermis and contains blood vessels
skin plays an important role in the synthesis of what?
vitamin D production
sensory reception
thermoregulation
resistance to trauma and infection
other barrier functions
nonverbal communication
5 types of cells found in the epidermis are…
stem cells
keratinocytes
tactile cells
dendritic cells
melanocytes
5 types of cells found in the epidermis are stem cells, keratinocytes, tactile cells, dendritic cells, and ___
melanocytes
sensory receptors in the dermis and epidermis contribute to which function of the skin?
detecting changes in the environment
keratinocytes are the most numerous type fo skin cells. Where are they located?
epidermis
during the process of thermoregulation, the body surface temperature is monitored by which of the following types of receptors?
thermoreceptors
various shades of brown pigmentation in the skin result from which of the following?
the production of melanin (brown to black pigments) by melanocytes
what is true about the most superficial layer of the skin?
it contains abundant keratin
place the epidermal layers in order:
superficial at top
deepest layer at bottom
stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum
straum basale
true or false:
the epidermis is highly vascular
false
epidermis is highly avascaular and must be supplied w/ nutrients by blood vessels in the underlying dermis
actively mitotic cells are found in which layer of the epidermis?
stratum basale
the stratum corneum is the most ___ layer of the epidermis. This layer is full of ___
superficial
keratin
the epidermis is composed of ___ cell types
cell types:
5
stem cells
keratinocytes
melanocytes
tactile cells
dendritic cells
stem cells (def)
undifferentiated cells that divide and give rise to keratinocytes
keratinocytes (def)
epidermal cells that produce keratin
melanocytes (def)
cells that produce the dark pigments that act as a UV shield
tactile cells (def)
sensory receptors for touch
dendritic cells (def)
immune cells that guards against pathogens that penetrate into the skin
which epidermal stratum is the thickest layer in thick skin?
stratum corneum
which epidermal stratum is the thickest layer in thin skin?
stratum spinosum
keratinocytes synthesize ___
keratin
the stratum granulosum can be best described as what?
thin, non-mitotic cell layer w/ clusters of keratohyalin
the stratum basale can be described as what?
a mitotic zone of keratinocytes deep to the stratum spinosum
the stratum corneum can be described as what?
the thickest layer of the epidermis containing mitotic cells
which feature of the skin protects the body from UV damage?
melanin deposited in keratinocytes
the stratum lucidum contains what?
the clear protein eleiden
the stratum basale contains what?
melanocytes
dendritic cells
actively mitotic stem cells
the most superficial layer of the epidermis is the ___
stratum corneum
which epidermal layer is structure to resist abrasion, penetration, and water loss?
stratum corneum
the stratum basale contains what?
actively dividing cells
the colored pigment melanin
true or false:
the stratum corneum is the thickest epidermal layer in thin skin
false
in thin skin: stratum spinosum is thickest layer of the epidermis
in thick skin: stratum corneum is usually the thickest layer
name the course dark-staining granules found in the stratum granulosum
keratohyalin granules
keratinocyte life history
(1) stem cells divide to produce new keratinocytes
(2) mitosis ceases as epidermal cells are pushed upward
(3) keratinocytes flatten and produce waterproof bundles of keratin filaments
(4) dead keratinocytes flake off surface of the skin as dander
(5) keratinocytes die
cells in which epidermal layer contain the protein eleidin?
stratum lucidum
the presence of a layer of lipids b/n the stratum spinosum and stratum granulosum facilitates which of the following?
water retention
why are the cells in the stratum corneum dead?
epidermal cells die as they move away from their nutrient supply in the dermis
what is found in the dermis?
nerve endings
fibers
blood vessels
glands
other types of fibrous connective tissue
hair follicles
nail roots
where are melanocytes found?
epidermis
which of the following layers of the epidermis contains cuboidal stem cells, keratinocytes, and melanocytes?
stratum basale
hair follicles and nail roots are embedded in which of the following layers of the skin?
dermis
(epidermis has no connective tissues, so it’s difficult to embed structures w/in it)
which epidermal stratum is the thickest layer in thin skin?
stratum spinosum
which epidermal stratum is the thickest layer in thick skin?
stratum corneum
the deepest layer of the dermis is called the ___ layer
reticular
how does the structure of the skin play a role in minimizing water loss from the body?
tight junctions b/n keratinocytes impeded water loss
oxygen and nutrients needed by the epidermal cells undergoing mitosis are acquired from blood vessels in which one of the following layers?
dermis
subcutaneous injections are administered into which highly vascular tissue layers?
hypodermis
subcutaneous tissue is highly vascular and absorbs drugs quickly
the skin layer that has the hair follicles and nail roots embedded in it is the ___
dermis
the hypodermis primarily consists of which type of tissue?
adipose tissue
what are the 2 zones of the dermis?
papillary and reticular layer
T or F:
darker skinned people have more melanocytes per square centimeter than lighter skinned people
false
(skin color is not determined by the number of melanocytes present, but by the amount of melanin produced, by how tightly clumped the granules are, and by how quickly the melanin breaks down)
why are injections frequently administered into the hypodermis?
the subcutaneous tissue is highly vascular
what is the function of the subcutaneous layer?
an energy reservoir and thermal insulation
w/in a hair follicle, the ___ root sheath is an extension of the epidermis, and lies adjacent to the hair root.
epithelial
which compound is the primary determinant of skin color?
melanin
