Integumentary System Flashcards
General characteristics of the Integumentary System:
- protective covering
- composed of several tissues
- maintains homeostasis
- retards water loss
- regulates body temperature
- houses sensory receptors
- contains immune system cells
- synthesizes chemicals (vitamin D)
- excretes small amounts of waste
- help synthesize vitamin D
- Keratinocytes
produce substances which stimulate the development of white blood cells
keratinocytes
active form
calcitrol
aid in the development of bone and teeth
vitamin D
Layers of skin:
- Epidermis
- Dermis
- Subcutaneous layer
- below the dermis
- not a true layer of skin
subcutaneous layer
*hypodermis
made up of:
- loose connective tissue
- adipose tissue
- contains: some blood vessels
Subcutaneous Layer
What is the function of the subcutaneous layer?
Insulates
-Keritonized
-Lack blood vessels
Basement membrane
Stratified Squamous Epithelium
where is simple squamous the thickest?
on the soles and palms (.8-1.4 mm thick)
produce melanin
melanocytes (simple squamous epithelium)
Layers of the epidermis:
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
What are the two regions of the dermis:
- Papillary
- Reticular
What is the dermis made up of?
Mostly connective tissue with collagen and elastic fibers
- Dermal Papillae
- areolar tissue with elastic fibers
Papillary Region
- deeper portion of the dermis
- has dense irregular connective tissue
Reticular Region
Pigment released so it only covers superficial portion of keritanocytes
melanocytes
General characteristics of dermis:
- bind epidermis to underlying tissue
- is about 1.0-2.0 mm thick
- includes nerve processes and sensory receptors, blood vessels, muscle tissue, hair follicles, and glands
Structural basis of skin color:
melanin, carotene, hemoglobin
What leads to an increase in melanin production?
UV light stimulates enzymatic activity within the melanosome, leading to an increase in melanin production
melanin-forming organelle in malanocytes
melanosome
Yellow-orange pigment and a precursor to Vitamin A
Carotene
When oxygenated it has a bright red color
Hemoglobin
Lack of (functional) melanocytes
Albinism
Melanocytes die off slowly over time
Vitiligo
Not found on soles, palms, lips, nipples, external genetalia
Hair
What accounts for distribution and thickness of hair
genetics and hormones
*males have more hair because of testosterone
Structure of hair:
- Root
- Shaft
Both the root and shaft are composed of:
Epithelial cells that are being keritonized
The hair follicle surrounds the:
root
The hair follicle is composed of:
- tube-like depression of epidermal cells into the dermis
- in here we find the: papilla, root, shaft, dead, epidermis, melanin cells
The hair follicle is attached to the:
arrector pili muscle
A bulb is at the:
base of each follicle
The bulb houses the:
papilla
What does the papilla contain?
areolar tissue, blood vessels, nerves, and a germinal layer of cells
Hair color is primarily due to:
the amount and type of melanin in the keritonized cell
“True” melanin
Eumelanin
*Brown-Black colors
Where are melanocytes found?
in the matrix of the bulb
Dark hair is caused by:
lots of melanin
Blonde hair color is due to the presence of
Sulfur
Red hair color is due to the presence of
Iron
Not the “true” melanin
Phenomelanin
Four major types of glands:
- subaceous
- eccrine
- apocrine
- ceruminous
- simple, branched, acinar gland
- everywhere except palms and soles
- secretes sebum
sebaceous glands
- sweat glands that empty their contents onto the skin surface via pores and hair follicles
- exist as eccrine and appocrine
- originate in dermis or hypodermis
Suderiferous Glands
Two types of suderiferous glands:
- appocrine
- eccrine
- Simple, coiled, tubular glands
- produce swear (mostly water, salts, and urea)
Eccrine Gland
- Simple, coiled, tubular gland
- produces protein and lipid rich secretions
- Found in axillary and groin region
Apocrine Gland
Category 1, type 1:
Sebaceous Glands
Category 2:
Suderiferous
Type 2:
Eccrine
Type 3:
Appocrin
Type 4:
Ceruminus
- modified glands of the external ear
- secrete earwax/cerumen
Ceruminous
- Functional only in women
- Are modified sweat glands in men
Mammary Glands
Tightly packed, hard, keratinized epidermal cells:
nails
Parts of nails:
- Nail body
- Free edge
- Nail root
- Lanula
What type of skin is right underneath the nail?
epidermis (blood vessel)
Homeostatic regulation of body temp:
Thermoregulation
Pessure and temperature
Cutaneous Sensations
sense deep pressure
Pacinian corpulses
sense light touch
Meisner’s corpulses
- in the stratum spinosum
- immunity
Langernans cells
Functions of the skin:
- Protection
- Excretion and absorption
protection from harmful UV rays:
pigments
Skin absorbs what kind of substances
hydrophobic
*Ex: Vitamins A, E, D, and K
Precursors to vitamin D are synthesized when the skin is:
exposed to UV radiation
Active form of Vitamin D
Calcitrol
Aids in the absorption of Ca++ from the small intestines
Calcitrol
Two types of wound healing:
- Epidermal wound healing (superficial)
- Deep wound healing
occurs when a wound extends into the dermis or subcutaneous area
Deep Wound Healing
- epidermis
- superficial partial-thickness
First Degree Burn
- Epidermis and section of dermis
- deep partial-thickness
Second degree burn
-full-thickness
Third Degree Burn
tissue grafted from one area of a patient’s body to another
Autograft
various “skin substitutes”
Allograft
What do scar creams do?
help inhibit the production of collagen fibers
Due to an overproduction of collagen fibers where a wound was healed
Hypertrophic Scar
Kind of scar that does not extend beyond the boundaries of a wound
Hypertrophic Scar
- Over-growth of collagen fibers
- Extends beyond the boundaries of the would
Keloid Scar
The three tissues layers seen in the early embryo
the primary germ layers
8 weeks after fertilization, the cells are
simple, cuboidal (but become flattened)
Fetal cells arise from the ____
ectoderm
11 weeks after fertilization, the dermis is formed form the ____
mesoderm
hair follicles form
9-12 weeks after fertilization
fine hair
lanugo
Lanugo can be seen at:
5 or 6 months after fertilization
sudoriferous glands form ____
20 weeks after fertilization
mix of deep epidermal cell secretions from the sebaceous glands, and dead hair cells
vernix caseous
vernix caseous forms:
6 months
Amniotic Fluid is mostly
urine
As we age, collagen fibers:
stiffen, decrease in number, and break
As we age, elastic fibers:
lose elasticity and clump
As we age:
- sweat production diminishes
- melanocytes begin to dwindle
- subcutaneous fat is lost
- skin is thinner and harder to heal