**Quiz 1 Integumentary: Epidermis and Dermis Honors know dermis & epidermis layers & characteristics

Skin

Single largest organ in the body

2 layers of skin

Epidermis, dermis

Hypodermis

Lies under the skin, not considered part of skin. Consisting of loose connective tissue/fat and binds skin loosely to subadjacent tissue

Skin functions

Protect the body from injury & infection; regulates body temp/sweats & vessels dilate/constrict; absorbs UV radiation (synthesis of Vitamin D crucial for bone development); contains receptors for touch, temperature, and pain stimuli from the external environment

Epidermis

Superficial, avascular layer of the skin. Composed predominantly of keratinocytes. Regenerates approx every 30 days

Fingerprints

Unique to each person. Dermis makes layers for the epidermis to produce fingerprints

Melanin

Is a pigment that protects against tissue damage caused by UV radiation

Carotene

the orangish pigment of the skin from liver damage or newborn infants

Hemoglobin

gives reddish pink color and carries oxygen

Layers of the epidermis (from deep to superficial)

Startum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Stratum basale

the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells quickly. It receives nutrients and contains keratinocytes, melanocytes, and Merkel cells.

Stratum spinosum

A layer of the epidermis that provides strength and flexibility to the skin. The spiny layer just above the stratum germinativum layer.

Stratum granulosum

a layer of the epidermis that marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata

Stratum lucidum

Clear, homogenous layer, contains dead keratinocytes; found ONLY in PALMAR and PLANTAR skin

stratum corneum

The superficial layer of the epidermis. Cornified layer, thin over body surface Dead keratinocytes, 5->20 layers that slough off continously

2 layers of the dermis

Dermal papillary layer, dermal reticular layer

reticular layer

Deeper layer of the dermis that supplies the skin with blood vessels, glands, lymphatics and nerve cells.

Dermal papillary layer

Membranes of ridges and grooves that attach to the epidermis creates fingerprints. The upper/superficial part of the dermis.

Paccinian corpuscles (honors)

Sensory receptors that respond to heavy pressure.

Bare nerve (honors)

Senses temperature-cold and heat

Ruffini (honors)

stretch receptors

Meissner's corpuscles (honors)

type of nerve ending in the skin that is responsible for sensitivity to light touch.

Apocrine glands (honors)

produce true sweat plus fatty substances and proteins; found in the axillary (armpit) and anogenital areas of the body

Sebaceous gland

small oil-producing gland present in the skin of mammals. Usually attached to hair follicles and release a fatty substance, sebum located throughout the body except the soles of the feet and the palms of the hands.

Arrector pili muscle

smooth musle attaching at an oblique angle to the dermal sheath surrounding a hair follicle; contraction of the smooth muscle elevates the hair--> formation of goose bumps = depression of the skin where the muslce attaches to the papillary layer of the dermis

Jaundice

Yellow coloring due to liver damage and newborns

Pallor

white coloring due lack of blood flow

Cyanosisi

blue color due to lack of oxygen

Erythema

red color due increased blood flow, allergies, inflammation and fever

Bronzing

bronze color caused by Addison disease.

Hematoma

blue/purple color from bruises can be caused by hemophilia

sudoriferous glands/sweat glands functions include...

cooling, cleaning the ear, preventing overheating, indicating sexual readiness, evaporating which is cooling, and prving nourishment to infants.

sebaceous glands (which are throughout the body except the soles of the feet & palms of hands) problems include...

whiteheads(blocked sebum), blackheads (oxidized whiteheads), acne (Inflammation), and seborrhea (flaky scales)

mammary glands

Specialized organs in mammals that produce milk to nourish the young/Exocrine gland