Chapter 5: The Integumentary System Flashcards
3 parts of the integumentary system
- cutaneous membrane
- Accessory Structures
- subcutaneous layer
2 components of the cutaneous membrane
- epidermis
- Dermins
What is the epidermis made of
epithelial tissue
What is the dermis
underlying area of CT
What are the accessory structures?
originate in the dermis
- extend through the epidermis to the skin surface
Examples of accessory structures
hairs, hair follicles, nails, sweat glands, sebaceous glands
Describe the hypodermis
known as the subcutaneous layer/superficial fascia
- made of loose CT- adipose and areolar tissue
- injections go here
- separates the skin from deep fascia around other organs
5 functions of the integument & description
- protection e.g. from impact, abrasion, chemicals, microorganism, fluid loss, UV rays
- Excretion: salts, water, organic wastes in sweat
- Maintenance of Body Temperature- evaporation of sweat, insulation through subcutaneous layer
- Production of melanin: UVray protection
- Synthesis of Vitamin D3
- Storage: of lipids in adipose tissue in the hypodermis
- Detection of touch, pressure, pain temperature –>Signals to CNS
The epidermis is described as what type of epithelial tissue?
Stratified squamous epithelium
If the epidermis is avascular, where does it get its nutrients from?
nutrients & O2 diffuse from cells and fluids in the dermis (has a blood supply)
Describe the nature of superficial and deep epidermis cells.
superficial- dead
deep- closer to dermis and more active
What are the most abundant cells in the epidermis?
Keratinocytes
Function of keratinocytes
contain a lot of keratin
structural proteins- give strength to hair, skin and nails
provides a little bit of waterproofing
Where do you find thick skin and how many layers of keratinocytes does it have?
covers palms and soles of feet
5 layers of keratinocytes
What does thick skin not have and how thick is thick skin?
No hair follicles, no fingerprints
thick as a paper towel
Where do you find thin skin and how many layers of keratinocytes does it have?
covers most of the body
it has 4 layers of keratinocytes
Describe the thickness of thin skin and what structures it has.
thick as a plastic sandwich bag
has hair follicles no fingerprints
What are the 5 layers of keratinocytes in thick skin? (basement membrane to the free surface)
- Stratum basale
- Stratum Spinosum
- Stratum Granulosom
- Stratum Lucidum
- Statratum Corneum
How many rows of cells does S. Basale have?
single row- others have multiple layers of cells
What is S Basale attached to the membrane by?
Hemidesmosomes: joins cell to basement membrane
What does the S. Basale form?
forms epidermal ridges- fingerprints follow the pattern of these ridges
- interlock with dermal papillae- creates a strong bond b/w the two layers (dermis and epidermis)
What is the S. Basale the location of and what type of cells does it have an abundance of?
Germinative cells- stem cell that divide to replace epidermal cells
Location of melanocytes
What occurs in S. Granulosum?
cells stop diving & starts producing lots of keratin- tough fibrous, protein that gives strength and water resistance to hair, skin and nails
Where is S. Lucidum found in and describe the cells in this strata?
found only in thick skin
cells are flattened, densely packed, and filled with keratin
What is another name of the S. Corneum and what does it do?
What is it composed of
“honr layer”
covers all exposed surfaces except eyeballs and it is water resistant
15-30 layers of dead, keratinized cells tightly interconnected by desmosomes
How long do cells on the S. Corneum stay there for?
2 weeks untl they fall off onto the ground
How long does it take for cells to be come flat, dead and full of keratin?
15-30 days
Describe sensible perspiration
sweating, water excreted by sweat glands
Describe insensible perspiration
water lost by evaporation through s. corneum
includes exhalation of water vapor
S. corneum is water-resistant but you lose up to 500mL water per day by evaporation
Why does skin become wrinkly in water?
osmosis- in hypotonic solutions (fresh water)
water diffuses into the dead flat keratinized cells, swell up to 4x their volume and waviness of skin swells
skin color forms because of
epidermal pigmentation and dermal circulation
What is carotene
orange-yellow pigment found in plants- especially orange vegetables
what can carotene be converted to
vitamin A
Where does carotene accumulate in
epidermal cells and in fatty tissues
Where is melanin produced?
in stratum basale
everyone has same # melanocytes
What are the 3 aspects of melanin?
- comes in different shades of brown
- pigment molecules travel upwards from the s. basale and are transferred into keratinocytes
- melanin travels more toward the surface in darker-skinned individuals - some people’s melanocutes are more productive- freckles
What is tanning the result of?
increased melanin production for UV production
How does melanin protect DNA?
clusters around the cell nuclei to absorb the UV rays
What is the role of dermal circulation?
redness–> more blood flow= red less –> more pale
Blood flow and age correlation?
blood flow decreases with old age- old people look more pale & have decreased melanin production
Describe cyanosis
bluish skin tint
–>reduced oxygenated blood flow
Describe Jaundice
results from liver tissue
How does jaundice form?
if liver can’t excrete bile, a yellowish pigment accumulates in body fluid
so skin & whites of eyes get yellowish color
-not uncommon for babies to be born w/ jaundice –>livers are not fully developed
What is vitiligo?
Autoimmune disorder affects of 1%
results in loss of melanocytes
skin or hair has not pigment in areas w/ no melanocyte
cosmetic issue
What is Rickets caused by
lack of Vitamin D; deficiency disease
and in occurred in poverty conditions and its seen in children
define osteomalacia
results in weak, flexible bones with abnromal bone development e.g. bow legged shape
in adults
What accessory structures does the dermis have?
sweat glands, hair follices
What are the 2 layers of the dermis?
- Papillary Layer
- The Reticular Layer
What is the papillary layer named after?
named for the dermal papillae that project b/w the epidermal ridges
What is the papillary made of and what does it contain?
Made of areolar
contains capillary, small lymphatic vessels & sensory neurons that supply the skin surface
What is consist of the reticular layer?
dense irregular CT
can stretch a bit but prevents it from stretching too much
How is stretch marks caused by?
caused by tearing or rupturing of the dermis due to rapid weight gain, pregnancy, anything that causes the skin to stretch out
What are cleavage lines used for?
used for surgery
What do the lines on the diagram represent?
bundle of collagen and elastic fibers in the dermis
Why is cutting parallel to cleavage line bundles good?
result in minimal scarring
Define contusion and description
bruise
damage to the blood vessels
blood bleeds into the surface
black and blue appearance
Why does a bruise turn green and yellow
green and yellow are actually created when hemoglobin is broken down
What are bed sores and when does it happen
pressure ulcers aka decubitus ulcers
happen when a person is unable to move
How do bed sores form?
gravity pulls bones down, which presses into the dermis and blocks blood flow. Kills epidermal cells
dead tissue allows bacteria to invade the integument
process causing necrosis and it gets more painful and deaddly
how do you prevent bed sores
frequently changing positions
What decides where the baby fat gets redistributed in adulthood
distrubted patterns influenced by hormones
WHat does the hypodermis conatin>
blood resorvoir
Describe liposuction
cosmetic surgery removes tissues (fat) from the hypodermis to change the appearance of limbs
What is the most dangerous fat?
Visceral fat (abdominal)
Define hairs
nonliving structure produced in small organs called hair follicles
What is a hair follicle connected to?
a root hair plexus- nerve endings
What are the functions of hair on the head
UV protection, insulation and some cushioning
What are the hairs on nostrils, ear canals and eyelashes useful for?
guarding against particles, insects, etc.
What can hairs on skin help for?
sense things
What is an arector pili muscle?
smooth muslce that contracts under certain conditions –>causes goosebumps
due to cold temperature, certain emotions (flight or fight)
How is hair produced?
1 . hair follicles produce living cells- deep in dermis
2. Older cells get push up, keratinized and die
How much does hair grow and how much hair does a person lose?
scalp hair grows for 2-5 years at a rate of 0.33 mm per day
person loses 50-100 hairs per day from the head
What can be detected from hair
Nutrients in hair structure
Heavy metals and drugs can be detected
Define vellus hairs
soft fine “peach fuzz” hairs found on much of the body surfaces
Define terminal hairs
heavier and more pigmented, some vellus hairs become terminal at puberty
what is hair color due to?
various in pigments made by melanocytes located at the base of the hair
pigments stop being produced with age
What do sebaceous glands secrete? Define it.
secrete sebum- an oily, lipid product into hair follicles using holocrine secretion
How do arrector pili muscles help with sebaceous glands?
It’s contractions help squeeze the sebum onto the skin surface
What is the function of sebum?
protects the skin, hair and nails from getting too dry and brittle
(integument and stuff can’t do their job if they crack and break)
What does sebum inhibit?
bacteria
What are sebaceous follicles?
not assosciated with hair follicles; have their own pores
Where are sebaceous follicles found?
chest , back, face, nipples and external genetalia
How do sweat glands perform secretions? (2 types)
Apocrine and merocrine
Where is apocrine sweat secretion found on the body?
armpits, nipples and pubic regions
Where is the apocrine secretion product secreted into?
hair follicles
Characteristics of apocrine secretion sweat
cloudy and potentially odorous
When do you begin to sweat apocrine secretions?
at puberty
WHat is body odor the result of?
bacteria not sweat
Where do you find merocrine sweat secretions on the body?
(far more numerous)
palms, forehead, soles of the feet–> thick skin has the highest concentration
What is the merocrine sweat secretions secreted onto?
directly onto the skin surface
When do merocrine sweat secretions occur?
when body temperature rises
What is the merocrine sweat secretions composed of?
99% water plus salt
tiny amounts of organic wastes
What are the 3 functions of merocrine sweat secretions?
- covers the skin surface to reduce body temperature
- washes the skin surface & flushes off microorganisms
acidic nature fights off microorganisms
What molecule does merocrine sweat secretions contain?
Dermicidin- a small peptide that has antimicrobial properties
What are mammary glands similar in structure with?
apocrine sweat glands
What are ceruminous glands?
modified sweat glands in the passageway of the external ear
Define cerumen & how is it made
secretions combine with sebum from nearby sebaceous glands to make it (ear wax)
function of cerumen
traps particles to protect the eardrum
What does nails protect?
fingertips and toes
What is the nail body
the part that you can see and it covers the nail bed
What is the nail bed
skin under the nail body
Where does the nail production occur?
At the nail root deep in the dermis
Define the lanula
crescent where the color of underlying blood vessels don’t show through; pale
What is the nail body made up of?
Dead, tightly packed keratinized cells
What is the appearance of nails useful for?
to diagnose diseases
What are some abnormal signs of nails?
concave, pitted, yellow or distorted; could be a sign of disease or nothing
What are thick yellow toenails caused by?
fungus- a close relative of fungi that cause ringworm and athlete’s foot
what type of regulation carries out repair of skin
regulation or local
When do calluses occur?
when germinative cells in the stratum basale divide more rapidly so depth of the entire epidermis increases; in areas where skin is trying to protect itself
define a scab
a blood clot, a temporary covering to protect the wound
What replaces the lost epidermis?
cells of the s basale divide and migrate along the edges of the wound to replace
what is a scab made of ?
made of fibrin- a sold protein that forms from blood proteins in the clotting process
Define macrophages
come into the area to phagocytize debris and pathogens
define scar tissue
made of lots of collagen fibers produced by fibroblasts
What are some accessory structures that are not repaired?
sweat glands and hair follicles
define what a keloid is
a thickened mass of scar tissue that grows into the surrounding tissue. Raise with a shiny, smooth surface
What activity decreases when aging occurrs and describe each? (6)
Germinative cell activity–> epidermis thins
Vitamin D3 production by 75%–> weak bones and muscle weakness
melanocyte activity–> pale skin, more prone to sun burn
sweat gland & sebaceous activity –> dry skin in danger of overheating
Skin repair more slowly longer it takes to heal
Bloody supply to dermis–> skin is cool, person may feel cold
What happens when the dermis thins?
elastic and collagen fiber netword reduced
What happens to the integument when aging?
weaker sagging and wrinkly especially skin that has a lot of sun exposure
When aging what is there a greater risk of?
recurring infections
What is the first step of repair of injury to the integument?
bleeding
mast cells trigger an inflammatory response
What is the second step fo repair of injury to the integument?
scab has formed
s basale cells migrate to edge of the wound
phagocytic cells- removing debris ; more arriving due to increased circulation
clotting
What is the third step of repair of injury to the integument?
1 week later phagocytic activity almost ended
fibrin clot is breaking up
What is the fourth step fo repair of injury to the integument?
after few weeks scab is shed
shallow depression
fibroblasts continue to create scar tissue
What occurs in stratum spinosum?
Daughter cells from the germinative layer get pushed into this layer.
Cells in this layer continue to divide
What types of cells do stratum spinosum contain?
Langerhan cells- a type of dendritic cells type of WBC, hanging out in the epidermis to destroy bacteria; may start immune response when epidermis is invaded by bacteria
