Part 4: Integumentary system Flashcards
Membranes Composed of
epithelium (epidermis) & connective tissue (dermis)
type of membrane skin
cutaneous membrane(epidermis +dermis)
skin heals ___
easily
accessory structures of skin
Exocrine glands
Hair
Nails (variant of hair)
Major functions of skin
- a barrier
- Thermoregulation
- Sensation
- Metabolic functions (vitamin D, subcutaneous fat)
- Social functions (identity of social animals)
constriction- heat ____, dilation- heat ____
in
out
All 4 tissue types are represented in ____
skin
Skin structure
- Epithelium
- Connective tissue
- Muscle (smooth muscle)
- Nerve
nerve of skin does what?
-Controls the smooth muscle in CT
- Generates sensation (tactile,pressure, temperature, pain)
- Stimulates exocrine glands
Muscle of skin does what>
Controls the diameter of blood vessels /hair position
CT of skin does what?
-Supports epithelial tissue
-Provides strength & elasticity
-Important for thermoregulation
Structure of epidermis (5 layers) -superficial to deep (Come, Let’s Get Sun Burnt)
-Stratum corneum
-Stratum lucidum* (in non-hairy skin only)
-Stratum granulosum
-Stratum spinosum
-Stratum basale (germinativum)
_____cells producing keratin (tough protein that helps epidermis with its protective properties)
Keratonized stratified squamous epithelial
structure of dermis
-dermal papilla
dermis reticular layer (scaffolding)
Stratum germinativum (basal layer) is ____ composed of _____
the deepest layer composed of large cuboidal basal stem cells and 2 other types of cells (Merkel cells & melanocytes)
in stratum germinativum, stem cells constantly divide to give rise to ____
new keratinocytes (most abundant epithelial cells in epidermis)
Keratinocytes synthesize _____ which is a _____
keratin
tough fibrous protein to replace the dead ones that flake off
Stratum germinativum forms ____. makes sure that _____
basal lamina; this makes sure that the epithelium is firmly attached to the basal membrane (with CT – dermis)
Merkel (tactile) cells is ____ cell type but abundant ______. It is important for ____ because it has _____ receptor. It interacts with _____ fibre collectively called ____
-least common
-where skin has no hair (fingertips, lips)
-touch sensation
-sensory touch receptor - tactile
- dermal nerve fibre
-Tactile (Merkel) disc
Melanocytes synthesizes _____ by transferring _____ to ______. They contain ______ between _____.
of melanocyte cells depend by region of the body (ex. palm of hand) but NOT by people
melanin pigment
melanin granules to keratinocytes
long and slender processes
keratinocytes
Melanin granules are _____by keratinocytes – form _____ to protect DNA from _____.
phagocytized
“umbrella” over nucleus
UV radiation
What determines skin tone?
Activity (granules produced) of melanocytes
Stratum spinosum (spiny layer) composed of _____
several layers (8-10) of living keratinocytes & Langerhans cells
Stratum spinosum (spiny layer) have ______ that attach ______ together, providing ______ (gives the _____ appearance of layer)
desmosomes
keratinocytes
strength
spiny
Langerhans (dendritic) cells are a type of ____ that comes from _____ and migrates to _____. Function?
macrophage
bone marrow
epidermis
engulf foreign microbes, immune response
Langerhans (dendritic) cells found in great numbers?
found in great numbers in the oral cavity, esophagus, anal canal, & vaginal canal
Stratum granulosum (granular layer) is _____. They produce ______.
-3-5 layers of mature keratinocytes
-2 types of granules
Types of granules produced by stratum granulosum. Too much of both granules is due to _____
Keratohyalin granules: keratin (protein) producing; important for cornification
Lamellar granules: water-resistant glycolipids, which stick cells together, & responsible for waterproof properties of skin
abrasion = calluses
Keratinization (def.)
accumulation of keratin from deep to superficial layers as cells mature, cells also start to die (away from nutrient source)
Stratum lucidum (clear layer) has large amounts of ______. This layer is only found ___
keratin & thickened plasma membranes
in volar/thick hairless skin (palmar & plantar skin)
Stratum lucidum (clear layer) has no _________. Cells have no _____
nutrients or oxygen at this level
nucleus or organelles (3-5 layers)
Stratum corneum has _____. The cells have no ____. This layer is ____ and provides _____
multiple layers of flattened, dead, interlocking keratinocytes (up to 30 layers), organelles,
keratinized
protection
Cells continuously shed (called _____: dandruff is clumps of _____ from the scalp)
dander
dander stuck together with oil
From basal to corneum = ____days (mitosis active at ____, shedding occurs during the ____). Injury or mechanical stress accelerates division and can result in ____
30-40
night
day
more keratin (therefore calluses)
Interface between dermis & epidermis
1: Epidermal ridge
2: Dermal papilla
layers of dermal papilla
papillary layer (superficial)
reticular layer
Peak-and-valley interface between dermis & epidermis allows for _____ (can resist _____)
a tight bond between different layers of skin
shearing stresses
Sensitive areas (lips, genitals) dermal papillae are _____allowing nerve fibres & capillaries to be ____
tall
near the surface
Papillary layer of dermis supports _____
Connection to the epidermis
Papillary layer of dermis have what type of CT?
Areolar connective tissue (loose CT)
Papillary layer of dermis contains _____
nerve endings (Meissner’s corpuscles: touch & vibrations) & many capillaries (oxygen, nutrients, WBC & other immune defenses)
Reticular layer of dermis type of CT
Dense irregular connective tissue (thicker layer: 80%)
Reticular layer contains _____ (provides ______ to skin). It also contains ____.
collagen bundles & elastic fibres extensibility & elasticity
Blood vessels, nerves, lymphatics, hair follicles, glands, adipocytes between fibre bundles
Skeletal muscles of the face attach here for facial expressions?
Reticular layer
Lines of cleavage
- Collagen fibre bundles in dermis align differently in different regions of body
- Collagen fibre bundles align along these lines of tension to resist stretching) in the reticular layer of the dermis and form lines of cleavage
Lines of cleavage + surgery
surgeons will try to cut parallel to line of cleavage
stretch marks + lines of cleavage
Stretch marks are due to scarring due to internal damage of collagen bundles & stretching of vasculature
red streaks: tearing of vessels
white streaks: lack of vasculature after tearing
hypodermis aka ______.It stabilizes ______
superficial fascia or subcutaneous tissue (layer under the skin)
position of skin relative to underlying tissues
Hypodermis (def.) + function
Loose connective tissue that stores fat (adipose)
-pads the body, serves as energy reservoir, provides thermal insulation (also has blood vessels & sensory receptors)
People with _____ adipose are more sensitive to temperatures (elderly)
less
skin tone varies throughout body due to ____
thickness of skin & dermal papillae
3 pigments are responsible for skin tone
Melanin – yellow/tan/brown/black from melanocytes in stratum basale (protects from UV radiation)
Hemoglobin – red pigment in dermal blood vessels (check nail body, around the lips)
Carotene – yellow/orange in stratum corneum & hypodermis (precursor to vitamin A)
Skin tone can be diagnostic:
cyanosis: _____
erythema _____
jaundice ____
pallor _____
hematoma _____
lack of O2- blue
pooling of RBC -red
bilirubin - yellow
pale - low blood flow
bruising – clotted blood - purple
Skin tissue damage summary
Excessive UV radiation, heat, electricity, chemicals
1st degree of skin tissue damage to ____
epidermis, mild pain, erythema (flaking after 3-6 days)
2nd degree of skin tissue damage to ____
epidermis & some dermis (most structures still function), blister formation, edema, redness, pain (scarring after 3-4 weeks)
3rd degree of skin tissue damage to ____
hypodermis, skin functions lost, numb (no sensory endings), granulation forms, skin grafting may be needed
Merocrine (sweat gland)
Normal exocytosis
Apocrine (mammary gland)
Apical surface pinched off
Holocrine (sebaceous gland)
Entire cell released
4 types of exocrine cutaneous glands
- Sweat glands
- Sebaceous glands
- Ceruminous glands
- Mammary glands
Sweat glands secrete ____ + 2 types
water & electrolytes
2 types: merocrine secretion (most common) & apocrine secretion (puberty)
Sebaceous glands secrete _____
oily lipid (sebum) that coats hair & skin surface (Holocrine secretion)
Ceruminous glands secretes ______
earwax (apocrine secretion)
Mammary glands secretes ______
breast milk (apocrine secretion)
Sweat glands (sudoriferous glands) release _____
secretions onto the skin (directly or via hair follicle)
Merocrine sweat gland secrete______. where? controlled by _____. Can also be released due to ______
-regular sweat (water & electrolytes) directly onto skin surface
-distributed over most of body but more numerous on palms, soles, & forehead
-the sympathetic nervous system (autonomic)
-stress, fear, embarrassment
Apocrine sweat gland secrete _____. where? Strongly influenced by _____
sweat contains _____Secretion of _____. Stimulated during ______
-odiferous sweat (puberty) opens into a hair follicle
-Specific to some body regions (axilla, groin, breast areola, male facial hair)
-(sexual) hormones
-water, electrolytes, lipids, proteins (acted on by bacteria to produce odor)
-emotional stress & arousal
Sebaceous glands produces ____ which inhibits ____. Open mainly onto _____. Onset of puberty causes _____
sebum
bacterial growth
hair follicle
glands to increase in size & sebum secretion to increase
Acne is inflammation of ______
sebaceous glands & follicles
Both hair & nails are composed of _____
dead keratinized cells (with HARD keratin)
Pilus (pili) (def.)
slender filament of keratinized cells that grow from a tube (follicle)
Hair coves _____
all body surfaces, except volar skin (hands & feet), lips, nipples, & parts of genitalia
3 types of hair
1) lanugo (fine hair foetus to birth)
2) vellus (most hair on body surfaces)
3) terminal hair (longer, coarser, & pigmented)
Anatomy of hair follicle (3 parts)
Bulb (1) (deep in dermis cell growth occurs)
Root (2)(deep to shaft, penetrates dermis)
Shaft (3) (above the skin/epidermis)
Hair papilla of hair is _______. Hair follicle has an ______
sole source of nutrition
epithelial root sheath & a CT root sheath
Hair receptors (nerve fibres) are associated with ______
the root sheath
Arrector pili (def.)
smooth muscle from dermal collagen fibres (at the papillary layer of the dermis) to the root sheath (sympathetic nervous system – goose bumps)
Texture of hair is depending on _____
keratin
Colour of hair is determined by ______
pigment in the cells of the cortex from the melanocytes
Root sheath of hair (def.)
epithelial & dermal
Cortex of hair (def.)
densely packed elongated keratinized cells (most of the hair)
Medulla of hair (def.)
2-3 layers of cells or irregular shape with presence of air
Cuticle of hair (def.)
single layer of scaly (hardest keratin) flat cells overlapping one another (exposed edge pointing up)
Hair papilla of hair (def.)
hair matrix (germinal cells around papilla that give rise to all cells, including epithelial root sheath
Hair growth cycle & hair loss
Growth stage: stem cells from hair matrix multiply & push existing cells superficially, these cells become keratinize & die (2-6 years in scalp hair)
Regression stage: cells in hair matrix stop dividing, preventing further growth. Hair follicle atrophies (shrinks: 2-3 weeks)
Resting stage: Metabolic activity is reduced, hair loses its anchorage & falls out after 3 months
85% of hair in growth stage at any given time, influenced by illness, diet, stress, hormones (70-100 hairs lost/day)
Label hair
1) root sheath
2) cortex
3) medulla
4) hair papilla
5) melanocytes
6) cuticle
Nail is a ______
Clear scale-like modification of epidermis on distal, dorsal surface of fingers & toes (hard dead keratinized cells)
nail root (def.)
stratum basale -lunula
nail body (def.)
stratum corneum
cuticle of nail
band of epidemris (stranum corneum)
hyponychium
nail bed ( stratum corneum)
label nail
black: free edge
grey: eponychium
purple: nail body
red:lunula
yellow: distal phalanx
brown: nail root (under skin)
blue: hyponychium
