Lecture 1 Integument Flashcards
What does the Integumentary System consist of?
Skin and its derivatives
What are some skin derivatives?
Nails, hair, sweat glands and sebacious glands
T/F The integument is a complex organ that contains all four primary tissue classes
TRUE
What tissue class is found in the epidermis?
Epithelium
The dermis and hypodermis both contain which three tissue classes?
CT, muscle, and nerve
The skin functions as a barrier to protect the body from what?
Chemical irritants, water loss, microbes, and other orgnisms
What are some of the skin’s sensory perceptions?
The skin can function to percept heat, cold, touch, itch, pressure and pain
The exposure of which cells to UV light allows them to convert a cholesterol derivative into Vitamin D?
Epidermal keratinocytes
What is the Vitamin D form that is absorbed into blood?
Cholecalciferol
What hormone is cholecalciferol converted to by enzymes in the liver and kidney?
Calcitriol
What does calcitriol do?
It promotes calcium and phosphorus absorption from the intestines?
How does the integument excrete waste?
Thru sweat
What is sweat?
A watery solution of salts and urea (a nitrogenous waste)
Thermoregulation of the integument is regulated by which part of the brain?
Hypothalamus
Nuclei and other organelles break down in which layer of the skin?
stratum corneum
Name the layers of the skin from basement membrane to surface.
basale, spinosum, granulosum, lucidum, corneum
Mnemonic: Buy Some Green Licking Candy
What type of granules are found in stratum corneum that condense into dense plates that greatly strengthen cells?
keratin
Nuclei and other organelles break down in which layer of the skin?
stratum corneum
In which layer do keratinocytes multiply and start to move up and mature as they start to produce keratin precursor proteins?
stratum basale
In stratum granulosum, what type of cell produces numerous intermediate filaments that aggregate keratohyalin proteins into granules?
keratinocytes
What is the name of the intermediate filament that aggregrates keratohyalin proteins into granules?
tonofilaments
How are the lamellar bodies released in stratum granulosum?
By exocytosis
What are the 3 contents of the lamellar body?
phospholipids, glycosphingolipids, ceramides
What is the largest organ of the body? What is its percentage of body weight?
Skin. 15% of body weight
What are the three main divisions of skin?
- Epidermis
- Dermis
- Hypodermis
Hair, nails, and skin glands are modified _______ structures.
Epidermal
What is the nonintermediate filament protein that is the major product of keratinocytes in stratum granulosum which induces the aggregation of keratins?
Filaggrin
How are the lamellar bodies released in stratum granulosum?
By exocytosis
What are the 3 contents of the lamellar body?
phospholipids, glycosphingolipids, ceramides
Which envelope (cell or lipid) helps waterproof the epidermis?
lipid envelope
Why do our fingers and toes wrinkle after soaking?
Prolonged exposure to water triggers the autonomic nervous system to constrict blood vessels in the tissue under the epidermis resulting in a loss of volume in each finger which causes the skin to shrink inward.
What is the autoimmune blistering disease that targets desmosomes and hemidesmosomes?
Pemphigus
What is the thickness of thin skin? How much of the body does it cover?
1-2 mm. Thin skin covers all of the body except palms on hands and soles on feet
What are the three immigrant cells of epidermis?
Melanocytes, Langerhans, Merkel
Which two immigrant cells of epidermis originate from neural crest cells?
Melanocytes and Merkel
Which immigrant cells of epidermis originates from the bone marrow cell?
Langerhans
How can thick skin be thickened?
By repeated pressure or friction
Which skin is more likely to have more layers of skin, thick or thin? What skin layer does thick skin have that thin skin does not (usually)?
Thick skin has more layers that thin skin. Stratum lucidum is present in thick skin but rare or non-existent in thin skin
What is the autoimmune blistering disease that targets hemidesmosomes in the basal layer?
advanced pemphigus vegetans
Which division of the skin has a papillary region of loose CT and irregular lower region that is dense? What is the dense irregular region called?
Dermis. The reticular region of the dermis
Which type of skin and hair has stable and abundant amounts of melanin and melanosomes, light-colored or dark-colored skin and hair?
dark-colored
What do most regions of the hypodermis contain?
Adipocytes
T/F The dermis contains many collagen fibers, hair follicles, sweat glands, blood vessel, lymphatic vessels, sensory receptors, nerves, and CT cells?
True
Which melanin pigment is a mixed polymer of tyrosine and cysteine that ranges in color from yellow to brown to reddish?
phaeomelanin
Which pigment is a yellow pigment found in vegetables and egg yolks that can become concentrated in the stratum corneum and in subcutaneous fat?
carotene
What is the key enzyme in the production of melanin that is used by neurons in the production of neurotransmitter dopamine?
tyrosinase
What are the melanin pigment granules produced by melanocytes called?
melanosomes
What is the process of transferring melanosomes into keratinocytes called? It is also known as melanosome secretion.
cytocrine injection
What is the abnormal skin color disease associated with yellowing of skin and the sclera due to excess of bilirubin in blood, usually caused by liver disease?
Jaundice
What is the abnormal skin color disease associated with bronzing which is caused by excessive ACTH from the pituitary gland that stimulates melanocytes?
Addison’s disease
What appearance do the keratinocytes have in the stratum spinosum?
Spiny or “prickled” in appearance
Which melanin pigment is a pure polymer of tyrosine?
black eumelalnin
What do Langerhans cells do?
They help protect against pathogens by engulfing them and then presenting characteristic parts of the devoured cells to lymphocytes
What are the characteristics of Langerhans cells?
Dendritic cell processes, indented nucleus, Birbeck granules
Do Langerhan’s Cells have desmosomes?
No desmosome junctions since they need to move around the keratinocytes like amoebas
What are the layers of the gross structure of the skin and underlying tissues?
- Epidermis
- Dermis
- Hypodermis
4, Fascia - Muscle
Mnemonic: Every Dog Has [a] Foul Mouth
What three other cells does the epidermis have besides keratinocytes?
Melanocytes, Langerhans, and Merkel Cells
What are layers of the epidermis named for?
They are named for the activity and morphology of the keratinocytes in each distinct zone
What is the deepest layer of the epidermis?
Stratum basale
T/F Lines of incision made parallel to Cleavage Lines tend to have slower healing.
False, lines of incision made parallel to cleavage lines heal more efficiently.
The stratum basale itself is a single layer of ______ cells sitting on the basement membrane
columnar
Melanocytes and Merkel Cells (tactile cells) are both attached to the basement membrane by what junction?
Hemidesmosome
Which epidermal layer has keratinocytes that produce intermediate filaments that are precursors to forming keratin?
Stratum spinosum
Why are spinosum keratinocytes prickled in appearance?
Because they undergo shrinkage during histological preparation while at the same time remaining attached to each other by numerous desmosomes
Where are lamellar bodies discharged into from the keratinocyte?
into the intercellular space to form a lipid envelope around the cell
What is the abnormal skin color disease associated with blueness resulting form deficiency of oxygen in the circulating blood?
cyanosis
What is the abnormal skin color disease associated with redness due to dilated cutaneous vessels which can be cause by anger, sunburn, heat, allergy, and embarrassment?
erythema
T/F Curly hair is flattened oval in cross section. Straight hair is round cross section.
True
What is the abnormal skin color disease associated with a patterned albinism thought to be cause by an autoimmune disorder?
vitiligo
Psoriasis is an example of what kind of abnormal cell growth?
Hyperplasia
What is the skin marking called when is is discolored by benign tumors of dermal blood capillaries?
hemangiomas (birthmarks)
T/F Blond hair contains a mixture of small amounts of black or brown eumelanin and red pheomelanin pigments.
True
T/F Freckles are flat; Moles are elevated
True
What disease is caused by a virus and can be transmitted by touch and are found in people who have weakened immune system?
warts (verruca vulgaris)
What is the skin marking that forms a unique pattern during fetal development?
friction ridges
What is the skin markings that form after birth by repeated closing of the hand or bending of the wrist or elbow?
flexion creases
What is the flexion crease that is a single palmar crease that is frequently associated with conditions such as Down syndrome and fetal alcohol syndrome?
simian crease
What are the lines called that indicate the direction of the collagen fibers in the reticular layer of the dermis?
cleavage lines (also called langer lines or tension lines)
What do you call excessive hair growth usually caused by a hormone imbalance?
hirsutism
What kind of baldness is under genetic and hormonal control?
pattern baldness
What disease is the thinning of hair of baldness that can occur in patches or across the entire body due to the body’s immune system attacking hair follicles causing round patches of hair loss?
alopecia
What are the 3 repeating stages of the growth cycle of hair?
growth (anagen), shrinking (catagen), resting (telogen) stages
How much does hair grow in young adults?
0.3mm/day
How long is growth stage in young adults?
6-8 years
How many inches can hair grow in a year?
4.3 inches
How long does the shrinking stage (catagen) last?
2-3 weeks
How long does the resting stage (telogen) last?
1-3 months
What kind of hair is a mixture of white hairs and some pigmented hairs?
gray hair
What part of the hair shaft degrades into spongy space making white hair brittle?
medulla
What type of hair contains a mixture of eumelanin and pheomelanin?
red hair
What type of hair has proportionally more phaeomelanin?
bright red hair
What type of melanin is found in black and dark brown hair?
eumelanin
What are the 3 layers of dead keratinocytes in hair shafts?
cuticle, cortex, and medulla
T/F Hair color is due to pigment deposited in cells of the cuticle layer.
False, the cortex layer
What cells in the stratum spinosum layer of the epidermis can be involved in delayed-type hypersensitivity reactions?
Langerhan’s Cells
Why does the stratum granulosum stain darkly?
Because of the increasing protein content of the maturing, squamous kertinocytes
Which epidermal layer produces lots of keratin?
Stratum granulosum
What are keratinocytes filled with abundantly in the stratum granulosum?
Granules of keratohyalin
What is keratohyalin?
A precursor to keratin that combines with other proteins to form a tough protein granule
How are vesicles of glycolipid released from keratinocytes?
Via exocytosis
What do the glycolipids do for the skin?
Glycolipids waterproof the skin
What role do glycolipids play in the absorption of nutrients from deeper layers of the skin?
They block the absorption of nutrients
What is the infolding of layers of epidermal keratinocytes on a basement membrane?
epithelial root sheath
What is the dermal connective tissue that contains the neurovascular supply for the hair?
papilla
What is the outermost layer of a hair shaft?
cuticle
What layer is composed of dead, flattened keratinocytes that are compressed against each other to varying degrees?
cuticle
What is a shaft of keratinized cells?
hair
What is composed of 3 layers of keratinocytes (cuticle, cortex, and medulla) that emerge out of the skin?
hair shaft
What is composed of layer of cells below the surface of the skin within the hair follicle?
hair root
What is the swelling in the base of the root where a hair originates?
hair bulb
What is the vascular tissue that provides nutrients to the hair bulb?
dermal papilla
What is the tubular infolding of the skin that a hair grows out of?
hair follicle
In which layer do keratinocytes begin to die and their nuclei break down?
Stratum granulosum
Only a few ______ nuclei are observed in cells entering the next layer above stratum granulosum
Pyknotic
What are the dark staining structures in the cytoplasm of the keratinocytes of the stratum granulosum?
Condensing granules of keratin
How does the cytoplasm of mature keratinocytes become more smooth and homogenous?
By coalescing keratin granules as organelles disintegrate
What muscle can lift up hairs and depress the skin around it (causing goosebumps)?
piloerector muscle (arrector pili)
What muscle is stimulated by sympathetic nerve fibers in response to cold and fear?
piloerector muscle (arrector pili)
What is associated with apocrine sweat glands and sebaceous oil glands?
hair follicles
What are peritrichal sensory nerve endings that wrap around each follicle?
hair receptors
What is the bundle of smooth muscle cells that connects dermal collagen fibers to the epithelial root sheath?
piloerector muscle (arrector pili)
What is the purpose of body hair?
enhances sense of touch
What is the purpose of eyebrows?
reinforce or exaggerate expression of emotions
What is the purpose of scalp hair?
heat retention in cold weather and protection from sunburn
What is the purpose of facial, pubic, axillary hair?
indicates gender and sexual maturity
What is the purpose of nose hairs, ear hairs, eyelashes?
prevent foreign objects from getting into nostrils, ear canals, or eyes
What types of bridges toughen the keratin of hair and nails?
disulfide bridges
What is given off from disulfide bridges when hair is burned?
sulfur
What are the 3 types of body hair types?
lanugo, vellus, terminal
What body hair type is fine fetal hair?
lanugo
What body hair type is fine, unpigmented hair of children and adults?
vellus
What body hair type is coarse, long, pigmented?
terminal
What kind of fat is the thickest in the abdominal wall, hips, and thighs, but is essentially absent from eyelids, dorsal side of hand, scrotum, and penis?
subcutaneous fat
Which layer of the skin is also called the subcutaneous tissue or the superficial fascia?
hypodermis
What is another name for the subcutaneous fat found in the hypodermis?
adipose
What is the function of the hypodermis?
energy reservoir; thermal insulation
What kind of injections deliver substances into the highly vascular tissue of the hypodermis?
hypodermic injections
T/F Tattoo ink is applied to the epidermis
False; to the dermis
The thickness of dermis across the body varies from ___ to ___.
0.6mm to 3mm
What layer of the skin is composed of collagen, elastic fibers, and reticular fibers produced by fibroblasts?
Dermis
What are the layers of the dermis?
papillary layer and reticular layer
Which layer of the dermis is composed of vascular, sensitive, loose connective tissue arranged into dermal papillae?
papillary layer
What kind of corpuscles are found in the papillary layer of the dermis?
Meissner’s corpuscles and Ruffini corpuscles
Which region of the dermis is the deeper part and is composed of dense irregular connective tissue?
reticular layer
Which nerve fibers wrap around hair bulbs and are stimulated by movement of the hair?
peritrichal nerve endings
Which corpuscles sense pressure, stretch, tickle, and vibration?
Pacinian corpuscles
Why does the stratum lucidum appear pale in comparison to other adjacent layers?
The coalescing keratin protein in this layer does not stain well
Up to how many layers of dead, flattened, and keratinized cells is the stratum corneum composed of?
Up to 30 layers
From what epidermal layer do surface cells continuously flake off or exfoliate?
Stratum corneum
How long does it take for keratinocytes to mature from the stratum basale to exfoliation?
15-30 days
Where are Merkel’s cells located?
basal layer of epidermis.
How abnormally fast do cells move from the stratum basale to the corneum in patients with psoriasis?
In seven (7) days
What is the outcome of abnormally fast cell maturation in psoriasis?
A thicker stratum corneum that forms plaques or flakes
Psoriasis is an example of what kind of abnormal cell growth?
Hyperplasia
What are two treatments for psoriasis?
Cortizone cream and coal tar
Where are Pacinian corpuscles located?
Found in the hypodermis of hands, feet, breasts, and genitals
What corpuscles are sensitive to displacement of surrounding collagen fibers due to slow, sustained mechanical stress of skin, ligaments, tendons, and joint capsules?
Ruffini’s corpuscles
What are the bare dendrites that lack Schwann cell covering and are sensitive to pain and temperature?
free nerve endings
What cells are sensitive, high resolution tactile receptors in the epidermis used for sensing textures, edges, and shapes?
Merkel’s cells
Where are Merkel’s cells derived from?
neural crest
Which corpuscles are composed of a fibrous capsule around a nerve ending?
Meissner’s (Tactile) corpuscles
Which corpuscles sense light touch, shapes and texture and are located in dermal papillae in fingers, hand, foot, forearm, tongue, and are particularly abundant in the vermillion zone of lips?
Meissner’s (Tactile) corpuscles
Meissner Corpuscle and the Merkel Cell are both tactile receptors. Are they both found in the same division of skin?
No, the Meissner is found in the dermis, while Merkel is found in the epidermis
What are the four tactile cells found in the Integument?
- Merkel cell
- Meissner corpuscle
- Ruffini corpuscle
- Pacinian corpuscle
Though the Ruffini and Pacinian corpuscles are structurally similar, they are located in different divisions of the skin. Which one is located in the Dermis? Which one in the hypodermis and deep fascia?
- Ruffini.
- Pacinian.
Memory tool: RIP (R before P)
Which one of the four tactile cells of the integument is a derivative of Neural Crest Cells?
Merkel
Which of the following six sensory receptors of the skin extend into the epidermis?
- Merkel cell
- Meissner corpuscle
- Ruffini corpuscle
- Pacinian corpuscle
- Peritrichial nerve endings
- Free Nerve endings
- Merkel cell
- Peritrichial nerve endings
- Free Nerve endings
The nail plate is a derivative of which epidermal layer?
Corneum
What do nails cover?
Fleshy, sensitive fingertips
What is the cuticle of the nail called?
Eponychium
Where is the eponychium located?
Where the skin and nail meet on the dorsal surface?
What is the epithelium of the nail bed called?
Hyponychium
Where does the nail root grow out of? What stratum is this location equivalent to in the epidermis?
Nail matrix. Basale
What does the nail plate rest on?
The nail bed
T/F New cells are added by mitosis in the nail matrix.
True
What are the four cutaneous glands?
Sweat, sebacious, ceruminous, and mammary
Mnemonic: some say carry money
Where is sweat derived from?
Blood plasma
What are the two types of sweat glands?
Eccrine and Apocrine
Which sweat gland type exists in millions all over the body and functions to cool skin?
Eccrine
Which sweat gland type responds to stress and excitement?
Apocrine
Which sweat glands opens into hair follicles? Which one directly on to skin surface?
Apocrine. Eccrine
Apocrine glands open their ducts to hair follicles of what areas of the body?
Axilla, anus, and genitals
Sweat from which glands contains fatty acids?
Apocrine
What do you call body odor produced by bacterial action on the fatty acids in the apocrine sweat?
Bromhidrosis
T/F Both eccrine and apocrine glands release their secrection by merocrine process.
True
What is the benefit of a coiled duct of a sweat gland?
Allows duct to stretch with skin
Sebaceous glands ducts open into what area of the epidermis? Which type of sweat gland also has ducts to this area?
Hair follicle. Apocrine sweat gland.
By what process is sebum released from the sebaceous gland?
Holocrine
What does sebum do to the keratinocytes at the outer layer of the hair shaft?
It softens them
What is the name of sebum collected from lamb wool and used in some skin creams to soften the corneum?
Lanolin
Which glands are found only in the external auditory meatus (EAM)?
Ceruminous
What do ceruminous secretions combine with to produce earwax?
sebum
What does earwax do?
Repels water, keeps eardrum flexible, and repels mites and other pests
Lots of accumulated and deeply lodged earwax can cause which hearing impairment that is accompanied by ringing in the ears?
Tennitus
What kind of sun rays can induce skin cancer?
UV rays
T/F Skin cancer is most common in fair-skinned and elderly.
True
What are three major skin cancers? Which one is the most deadly?
Basal cell carcinoma, squamous cell carcinoma, and melanoma. Melanoma is the most deadly skin cancer
Which stratum of the epidermis does basal cell carcinoma arise from? What layer does it invade?
Basale. Invades the underlying dermis.
How is basal cell carcinoma treated?
By surgical removal and radiation
In which stratum of the epidermis does squamous cell carcinoma (SCC) arise?
Spinosum
SCC is lethal if affected cells metastasize to what part of the body?
Lymph nodes
From what basal immigrant cell does melanoma arise?
Melanocytes
What is the ABCDE of identifying melanoma?
Assymetry, Border irregular, Color mixed, Diameter over 6 mm, Elevation above skin surface
Which melanomas are hard to spot? Why?
Amelanotic melanoma. The affected melanocytes do not produce melanin so it is difficult to spot.
What are the major causes of burns?
Extreme heat, sunlight, radiation, electric shock, and chemicals
Causes of death from burns are due to what subsequent effects?
Fluid loss and/or infection
What do degrees of burns correspond to?
The depth of the burn, ie, a first degree burn only goes down to the epidermis. Second degree to dermis, Third to hypodermis
Which degree of a burn often requires skin grafts, or may result in disfigurement and fibrosis scarring?
3rd degree
What are some treatments for a burn?
Fluid replacement, infection control, debridement, and intravenous replacement of proteins and nutrients
UVA is often called the “tanning rays.” What is UVB called? Which one can cause burns?
Burning rays. Both can cause burning depending upon exposure conditions
T/F Only UVB is thought to initiate cancer?
FALSE. Both UVA and UVB wavelengths of UV rays are thought to initiate cancer.
T/F The rate of skin cancer has risen with use of sunscreens.
True. There is a statistical correlation
Sunscreen chemicals can be altered by UV rays into compounds that damage DNA by generating harmful ______ radicals
Free
What affect does natural melanin have on free radicals?
It can bind to free radicals and neutralize their effects.
T/F Melanin is the body’s natural sun screen?
FALSE. Melanocytes are basal layer cells that mostly add melanin to cells in the basal layer and therefore would not protect nucleated cells in overlying epidermal layers
How do melanocytes protect skin cells from free radicals?
By cytocrine injection that neutralizes the inner chemistry of the affected cells
T/F Melanin is present in skin, iris, hair follicles, and inner ear.
True
What does melanin do in the inner ear?
Absorbs free radicals from hair cells (mechanoreceptors, not actually made of hair) that are firing action potentials all day. This heavy physiology cranks out a lot of free radicals,
What does cutaneous wound healing involve?
It involves the release of numerous growth factors from a variety of cells including fibroblasts, macrophages, platelets, and keratinocytes
What do the growth factors do during wound healing?
Some attract cells into the wound and others stimulate growth of the cells in the epidermis and dermis
Where can epidermal keratinocytes come from to heal injuries to the skin?
Stratum basale, hair follicles, or sweat glands
What kind of wounds require skin grafts?
Wounds that leave insufficient sources of keratinocytes to repopulate the area
