Integumentary System

Integumentary - hair, skin, nails & glands

integumentary system functions include

protection

sweat excretion

sensory

thermoregulation

vitamin D synthesis

integument

aka the skin, body’s largest organ

integument’s 2 layers are:

epidermis and dermis

cutaneous membrane made of keratinized stratified squamous epithelium, located on top of the dermis, avascular, made of 4-5 layers

epidermis

how many layers does thin skin have?

4 layers

how many layers does thick skin have?

5 layers

what part of the body contain “thick skin”

palms of hands & soles of the feet

what are the epidermis layers

stratum corneum (most superficial)

stratum lucidum

stratum granulosum

stratum spinosum

stratum basale (deepest)

which epidermis layer is NOT composed of keratinocytes (cells that produce keratin)?

stratum corneum

stratum lucidum

stratum granulosum

stratum spinosum

stratum basale

stratum basale

made up of areolar and dense irregular connective tissues

dermis

underneath the skin (deep to the dermis), well vascularized and composed of loose areolar & adipose tissue, NOT part of the skin

hypodermis

undergo mitosis to produce keratinocytes

basal cells

receptors responsible for stimulating sensory nerve that the brain perceives as touch

merkel cells

melanin production, pigment responsible for color of the hair & skin

melanocytes

small, finger-like projections of the dermis that extend upward into the epidermis, increasing the surface area between the skin layers

dermal papillae

"glue-like connections" between neighboring cells; hold cells tightly together so they don't pull apart when the tissue is stretched, scraped, or rubbed

desmosomes

a clear protein rich in lipids, derived from keratohyalin, giving keratinocytes their transparent appearance

eleiden

immune cells, help fight infections

langerhans cell

tiny, oil producing glands are called

sebaceous glands

two layers of the dermis

papillary layer and reticular layer

papillary layer

composed of loose areolar connective tissue

reticular layer

can see lots of fibers, composed of dense irregular connective tissue (NOT made by reticular fibers and NOT reticular connective tissue !!!)

hypodermis functions include

insulation, fat storage, & cushioning

functions of the hair

protection (from sunburn, injury, bugs)

heat retention

sensory reception

visual identification

chemical signal dispersal

Which layer of the epidermis is deepest, attached to the dermis, and characterized by actively mitotic stem cells responsible for continually replenishing the upper epidermal layers?

stratum corneum

stratum basale

stratum spinosum

stratum lucidum

stratum basale

What is the primary characteristic and functional importance of the outermost layer of the epidermis, the stratum corneum?

a. it contains actively dividing melanocytes that determine baseline skin tone

b. it is rich in blood vessels that nourish the deeper layers of the epidermis

c. it consists of dead keratinized cells that form a durable, water-resistant protective barrier

d. its the thickest layer of the dermis containing dense collagen bundles

c. it consists of dead keratinized cells that form a durable, water-resistant protective barrier

.

As keratinocytes migrate from the stratum basale toward the skin surface, they accumulate a tough, fibrous intracellular protein that hardens and protects the cells. What is this protein called?

melanin

keratin

elastin

collagen

keratin

Where are melanocytes primarily located within the skin, and what is their primary physiological function?

a. dermal reticular layer; synthesizing collagen to maintain skin elasticity and tension lines

b. stratum corneum; secreting aqueous sweat to regulate core body temperature

c. hypodermis; storing triglycerides for long-term metabolic insulation

d. stratum basale; producing pigment granules that shield nuclear DNA fro UV radiation

d. stratum basale; producing pigment granules that shield nuclear DNA fro UV radiation

Which epidermal layer gets its name from the microscopic appearance of its cells shrinking during slide preparation while remaining tightly bound by desmosomes?

stratum basale

stratum spinosum

stratum lucidum

stratum granulosum

stratum spinosum

The deeper 80% of the dermis is composed of dense irregular connective tissue and provides structural strength and elasticity. What is the name of this specific layer?

papillary layer

hypodermal layer

reticular layer

basal layer

reticular layer

Which tissue layer lies deep to the dermis, serving as an energy reservoir, shock absorber, and thermal insulator, and what primary cell type does it contain?

hypodermis; composed predominantly of adipocytes

papillary dermis; composed of loose areolar connective tissue with fibroblasts

stratum basale; composed of simple columnar keratinocytes

reticular dermis; composed of dense regular fibrous tissue

hypodermis; composed predominantly of adipocytes

Sebaceous glands are typically associated with hair follicles and secrete an oily, lipid-rich substance that lubricates hair and skin. What is this secretion called and what type of release mechanism is used?

sweat; eccrine secretion via active transport channels

cerumen; apocrine secretion involving pinching off of the apical cell membrane

sebum; merocrine secretion involving direct exocytosis of vesicles

sebum; holocrine secretion where entire cells rupture to release their product

sebum; holocrine secretion where entire cells rupture to release their product

When exposed to cold temperatures or emotional stimuli, what specific muscle type contracts to pull hair follicles upright, producing "goosebumps"?

skeletal muscle attached to the hypodermal fascia

smooth muscle known as the arrector pili

cardiac muscle fibers embedded within the deep dermis

smooth muscle forming the endothelial walls of dermal arterioles

smooth muscle known as the arrector pili

The stratum lucidum is a clear, flat, dead layer of keratinocytes found exclusively in which specific anatomical regions of the human body?

areas with dense hair follicles such as the scalp and eyebrows

high friction areas of the face and neck

thick skin regions, such as the palms of hands and soles of feet

thin skin areas covering the abdomen and back

thick skin regions, such as the palms of hands and soles of feet