Integumentary System Flashcards
What are the 3 types of Epithelial membranes in the body?
- Cutaneous membrane: The skin, the primary organ of the integumentary system. Made up of the epidermis and dermis.
- Serous membranes: Simple squamous epithelium on a connective tissue basement membrane. Examples include the pleura (lungs), peritoneum (abdominal cavity), and pericardium (heart). These membranes secrete a lubricating fluid to reduce friction.
- Mucous membranes: Line cavities and tubes that open to the body’s exterior, such as the digestive, respiratory, urinary, and reproductive tracts. They secrete mucus, which traps pathogens and debris.
What are the 2 primary layers of the skin?
-Epidermis: Outermost layer, composed of (a relatively thin sheet) stratified squamous epithelium. Protects against water loss, injury, and pathogens. Has 5 layers (strata) in thick skin (e.g., palms/soles).
-Dermis: Deeper and thicker of the two primary skin layers and mainly composed of connective tissue. Contains collagen and elastin fibers, giving skin strength and elasticity. It also houses sensory receptors, hair follicles, blood vessels, and glands.
What do Connective tissue membranes consist of?
Synovial membranes: Line the cavities of movable joints (e.g., knee, elbow) and secrete synovial fluid, which lubricates the joints and nourishes cartilage.
HAIR
-Soft hair of a fetus and newborn is called lanugo
-Hair growth requires an epidermal tubelike structure called hair follicle
-Hair growth begins from hair papilla
-Hair root lies hidden in the follicle and visible part of hair called shaft
-Arrector pili is a specialized smooth muscle that produces “goose bumps” and causes hair to stand up straight
NAILS
-Produced by epidermal cells, filled with keratin, become hard and cover the terminal ends of fingers and toes
-Visible part is called nail body
-The root lies in a groove and is hidden by cuticle
-Crescent-shaped area nearest root is called lunula
-Nail bed may change color with change in blood flow
SKIN RECEPTORS
-Specialized nerve endings: Make it possible for skin to act as a sense organ
-Lamellarcorpuscle (Pacini corpuscle): Capable of detecting pressure
-Tactile corpuscle (Meissner corpuscle): Capable of detecting light touch
-Skin receptors relay messages to the brain concerning sensations like touch, pain, and pressure.
-Burn injuries destroy skin receptors.
What are the 2 types of SKIN GLANDS? (Sweat (sudoriferous) glands)
ECCRINE GLANDS
* More numerous,
important and widespread
* Elimination of waste
* Function throughout life
and assist in body heat
regulation
* Produce perspiration or
sweat, which flows out
through pores on skin
surface
APOCRINE GLANDS
* Found primarily in the skin
in the axilla (armpit)
* Larger than eccrine
glands
* Thicker secretion
* Odor from apocrine gland
secretion is caused by the
contamination/decomposit
ion of the secretion by
skin bacteria
SEBACEOUS GLANDS
-Secrete oil for the hair and skin
-Grow where hairs grow
-Tiny ducts open into hair follicles
-Sebum secretion increases during adolescence
List each ACCESSORY ORGAN of the Skin-
HAIR
NAILS
SKIN RECEPTORS
What are the 5 MOST IMPORTANT FUNCTIONS OF THE SKIN?
-PROTECTION: the first line of defense against:
Infection by microbes
Ultraviolet rays from sun
Harmful chemicals
Cuts and tears
-TEMPERATURE REGULATION
*Skin can release almost 3000 calories of body heat per day
*Mechanisms of temperature regulation
*Regulation of sweat secretion
*Regulation of flow of blood close to the body surface
-SENSE ORGAN ACTIVITY
*Skin functions as an enormous sense organ, millions of nerve endings
*Receptors serve as receivers for the body, keeping it informed of changes in its environment
-EXCRETION
*Body rids itself of wastes
*Excess vitamins, drugs, and hormones can be excreted onto the skin by sweat
-SYNTHESIS OF VITAMIN D
*Occurs when skin is exposed to ultraviolet light, dietary intake
*Vitamin D is critically important to good health
Epidermal layers (from deep to superficial)
- Stratum germinativum: Deepest layer, where keratinocytes divide and begin their migration to the surface. This layer also contains melanocytes, which produce melanin to protect from UV damage.
- Stratum spinosum: Contains spiny-shaped keratinocytes and Langerhans cells (involved in immune response).
- Stratum granulosum: Keratinocytes begin to die, and keratinization (formation of keratin) occurs, giving cells a granular appearance.
- Stratum lucidum: Found only in thick skin (palms, soles). It appears translucent under a microscope due to the presence of dead keratinocytes.
- Stratum corneum: Outermost layer, consisting of flat, dead, keratinized cells that form a tough, protective barrier. Cells are constantly shed and replaced.
Skin color determinants
Melanin: Brown-black pigment produced by melanocytes. Protects skin from UV radiation. The amount and type of melanin determine skin color (eumelanin vs. pheomelanin).
Burns and classifications
First-Degree Burn:
-Minor discomfort, skin reddening (e.g., sunburn).
-The epidermis may peel in 1-3 days.
-No blistering; minimal tissue destruction.
Second-Degree Burn:
-Affects deep epidermis and upper dermis.
-Blisters, severe pain, swelling, and fluid loss.
-Damages sweat glands, hair follicles, and sebaceous glands.
-Common scarring; classified as partial-thickness burn.
Third-Degree Burn:
-Destruction of epidermis and dermis; extends to subcutaneous tissue.
-It may involve muscle/bone, full-thickness burn.
-Initially painless due to nerve-ending destruction, intense pain follows.
-Fluid severe loss and increased infection risk.
Fourth-Degree Burn:
-Full-thickness burn extending into muscle or bone.
-Often, it results from high-voltage electrical burns or prolonged intense heat.
-Treatment may require extensive skin grafting or limb amputation.
