Integumentary system Flashcards
cutaneous membrane
skin
- Regulates body temperature.
- Stores blood.
- Protects body from external environment.
- Detects cutaneous sensations.
- Excretes and absorbs substances.
- Synthesizes vitamin D.
Skin
Two main parts of integumentary system
Epidermis
Dermis
surface epithelial layer
Epidermis
deeper connective tissue layer
Dermis
lies deep to dermis; is not part of the skin
Subcutaneous (subQ) layer or hypodermis
nerve endings that are sensitive to pressure.
pacinian (lamellated) corpuscles
Keratinized stratified squamous epithelium
Epidermis
4 cell types
Keratinocytes
Melanocytes
Langerhans cells
Merkelcells
90% of epidermal cells
4-5 layers
Produce keratin
Protectsskin
Waterproofs skin
Keratinocytes
Make up 8% of epidermal cells
Transfer pigment to keratinocytes
Produce melanin
Melanocytes
a yellow-red or brown-black pigment that contributes to skin color and absorbs damaging ultraviolet (UV) light.
Melanin
aka epidermal dendritic cells
Immune response
Langerhans cells
Consist of tactile disc and neuron
for touch sensation
Merkel cells
Four Layers (strata)
Stratum basale (stratum germinativum)
Stratum spinosum: 8-10 cell layer
Stratum granulosum makes keratin
Stratum corneum: flattened dead cells
Includes stem cells; new cells arise here
Stratum basale (stratum germinativum)
8-10 cell layer
Cells beginning to look flattened
provides both strength and flexibility to the skin
Stratum spinosum
makes keratin
Losing cell organelles and nuclei
lipid-rich secretion acts as water sealant
Stratum granulosum
flattened dead cells
Cells here consist mostly of keratin.
Cells here are shed and replaced from below.
Stratum corneum
-Present only in thick skin areas of fingertips,
palms, and sole
-consists of four to six rows of clear, flat, dead
keratinocytes with large amounts of keratin
-provides an additional level of toughness
Stratum Lucidum
transfer of a patch of healthy skin taken from a donor site to cover a wound.
Skin Grafts
skin taken from the same individual
Autograft
identical twin
Isograft
individual’s epidermis are removed, and the keratinocytes
are cultured in the laboratory to produce thin sheets of skin
Autologous skin transplantation -
- chronic skin disorder in which keratinocytes divide and move more quickly than normal from the s. basale to the s. corneum.
- abnormal keratin, which forms flaky, silvery scales at the skin surface,
Psoriasis
various topical ointments and ultraviolet phototherapy
Tx
-second, deeper part of the skin
-composed of dense irregular connective
tissue containing collagen and elastic fibers
Dermis
thin superficial
papillary region
thick deeper
reticular region
— surfaces of the palms, fingers, soles, and toes have a series of ridges and grooves
- part genetically determined and is unique for each individual
- basis for identification
Epidermal ridge pattern
dark color
Melanin
yellow to red
Pheomelanin
brown to black
Eumelanin
yellow orange
Carotene
pink-red
Hemoglobin
Depends on blood flow
Hemoglobin in blood
- Precursor of vitamin A
- In stratum corneum and adipose layers-
Carotene
- Pheomelanin - yellow to red
- Eumelanin - brown to black
- Darkness depends on amount of melanin produced.
- Provides some protection against UV rays
Melanin
producing cells, synthesize melanin from the amino acid tyrosine in the presence of an enzyme called tyrosinase.
Melanin
Synthesis occurs in an organelle called
Melanosome
increases the enzymatic activity with thus increases melanin production.
Exposure to ultraviolet (UV) light
benign localized overgrowth of melanocytes
nevus or a mole
the inherited inability of an individual to
produce melanin
Albinism
the partial or complete loss of melanocytes from patches of skin produces irregular white spots.
Vitiligo
skin appear bluish, blood is not picking up an adequate amount of oxygen from the lungs
Cyanotic
yellowish appearance of the skin is due to a buildup of bilirubin
Jaundice
redness of the skin, engorgement of capillaries in the dermis with blood due to skin injury
Erythema
paleness of the skin
Pallor
mucous membranes, nail beds, and skin appear bluish
Cyanotic
usually indicates liver disease
Jaundice
exposure to heat, infection, inflammation, or allergic rxn
Erythema
may occur in conditions such as shock and anemia
Pallor
Accessory Structures
- Hair
- Skin glands
- Nails
- Found on most skin surfaces
- Made of fused keratinized cells
- Consists of shaft and root
- Surrounded by hair follicle
Hair
bulb which includes growing matrix producing
cells
Base
muscle that pulls on hair
Arrector pili
- secrete oily sebum
- Connected to hair follicles; keeps hair from drying out
Sebaceous gland
- Eccrine sweat gland - wide distribution- thermoregulation
- Apocrine sweat gland - axilla, groin, areolae, beard
- Contain other cell material
Sudoriferous (sweat) gland
- Wax combines with sebum to produce cerumen or earwax
- waterproofs the canal and prevents bacteria and fungi from entering cells
Ceruminous (wax) gland
wide distribution- thermoregulation
Eccrine sweat gland
axilla, groin, areolae, beard q Contain other cell material
Apocrine sweat gland
Plates of packed hard dead keratinized cells
Nails
part extending past finger or toe
Free edge
major visible portion in nails
Nail body (plate)
portion of the nail that is buried in a fold of skin
root
crescent-shaped area of the proximal end of the nail body
lunula
the homeostatic regulation of body temperature.
Thermoregulation
dermis houses an extensive network of blood vessels that carry 8–10% of the total blood flow in a resting adult.
Blood reservoir
FUNCTIONS OF THE SKIN
Blood reservoir
Protection
Cutaneous sentations
Excretion
Absorption
Vitamin D synthesis
usually is an indication of impending or actual tissue damage
Pain
include tactile sensations—touch, pressure, vibration, and tickling—as
well as thermal sensations such as warmth and coolness
Cutaneous sentations
enables a drug contained within an adhesive skin patch to pass across the epidermis and into the blood vessels of the dermis.
Transdermal (transcutaneous) Drug Administration
angina pectoris (chest pain)
Nitroglycerin
Motion sickness
scopolamine
estrogen-replacement during menopause
estradiol
ethinyl estradiol and norelgestromin
contraceptive
smoking cessation
nicotine
relieve severe pain in cancer patients
fentanyl
a hormone that aids in the absorption of calcium from foods in the GIT into the blood.
Calcitriol
three common forms of skin cancer
Basal cell carcinomas
Squamous cell carcinomas
Malignant melanomas
- 78% of all skin cancers
- tumors arise from cells in the stratum basale and rarely metastasize.
Basal cell carcinomas
- 20% of all skin cancers, arise from the stratum spinosum, and have a variable tendency to metastasize
Squamous cell carcinomas
- arise from melanocytes and account for about 2% of all skin cancers.
- metastasize rapidly and can kill a person within months of diagnosis
Malignant melanomas
Early warning signs of malignant melanoma
A (asymmetry)
B (border)
C (color)
D (diameter) E (evolving)
irregular shapes, two very different looking halves.
A (asymmetry)
irregular notched, indented, scalloped, or indistinct—borders.
B(border)
- uneven coloration, contain several colors
C (color)
about the size of a pencil eraser
D(diameter)
change in size, shape, and color
E (evolving)
can be cured by surgical excision in 99% of the cases
Basal cell carcinoma
Prognosis is good if treated by radiation therapy or removed surgically
Squamous cell CA
- Resistant to chemotherapy
- Treated by wide surgical excision accompanied by
immunotherapy
-Chance of survival is poor if the lesion is over 4 mm thick
Malignant melanoma
tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature (break down) proteins in the skin.
Burns
– only the epidermis is damaged
- Symptoms include localized redness, swelling, and
pain, no blister
First-degree
– epidermis and upper regions of dermis are damaged
- redness, blister formation, edema, and pain result
Second-degree
– entire thickness of the skin is damaged, burned area appears gray-white, mahogany, or black;
- Most skin functions are lost, marked edema, and the burned region is numb because sensory nerve endings have been destroyed.
Third-degree
Burns considered critical if:
- Over 25% of the body has second-degree burns,
— Over 10% of the body has third-degree burns - There are third-degree burns on face, hands, or feet
- When the burn area exceeds 70%, more than half the victims die.
A quick means for estimating the SA affected by a burn
Rule of Nine