Integumentary System

what is the integumentary system?

skin and accessory structures

what are accessory structures?

hair, nails, and glands

what is the cutaneous membrane?

skin

what is skin made of?

epidermis and dermis

what is the hypodermis?

is underneath the skin but is not part of the integumentary system

what are the layers from superficial to deep?

epidermis, dermis, hypodermis, fascia, muscle, and bone

what are the main functions of the integumentary system?

protection, excretion/secretion, sensation, thermoregulation, vitamin D synthesis, and energy storage

what is the epidermis made of?

keratinized stratified squamous epithelium

what is the vascularity of the epidermis?

avascular, nutrients diffuse from the underlying dermis

where is thick skin found?

palms, fingertips, and soles

what are the major epidermal cells?

keratinocyte, melanocyte, dendritic cell, and tactile cell

what is the role of a keratinocyte?

produces keratin, most abundant epidermal cell

what is the role of a melanocyte?

produces melanin

what is the role of a dendritic cell?

immune defense

what is the role of a tactile cell?

touch sensation

What are the layers of the epidermal strata from deep to superficial

stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum

what are the features of the stratum basale?

deepest, stem cells, metabolically active, melanocytes, and tactile cells

what are the features of the stratum spinosum?

thickest living layer, keratin production, desmosomes give a spiny appearance

what are the features of stratum granulosum?

organelles degenerate, lipids released, contributes to water resistance

what are the features of stratum lucidum?

thin dead-cell layer found only in thick skin

what are the features of stratum corneum?

most superficial, dead keratinized cells, continuously shed

what is the mnemonic for remembering the layers of the epidermal strata?

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how does the epidermis become water resistant?

keratin inside cells and lipids between cells make it kinda impermeable

what effects skin pigment?

melanin, cyanosis, jaundice, and vitiligo

what are facts about basal cell carcinoma?

occurs in the stratum basale and is most common

what are facts about squamous cell carcinoma?

occurs in the stratum spinosum and arises from squamous epidermal cells

what are facts about melanoma?

occurs in melanocytes and is most dangerous

what are features of the dermis?

vascular, innervated, and provides support for the epidermis and accessory structures

what are the layers of the dermis?

papillary layer and the reticular layer

what tissue makes up the papillary layer?

areolar connective tissue

what is the function of the papillary layer?

supports/nourishes epidermis, contains capillaries and nerves

what is the tissue in the reticular layer?

dense irregular connective tissue

what are key characteristics of the reticular layer?

strength and elasticity, rich in collagen and elastic fibers

what does collagen do?

provides strength

what do elastic fibers do?

provide stretch and recoil

what is the function of the dermis?

contains sensory receptors and participates in thermoregulation

how does thermoregulation work?

dermal blood vessels work with the cardiovascular system to regulate body temperature

how does the body regain heat?

warm blood reaches the skin surface

what are damages to the skin?

dermatitis, stretch marks, aging, and burns

what is dermatitis?

inflammation in the papillary layer

what is aging?

reduced collagen, decreased blood supply, dehydration, hormonal changes, slower repair, and UV exposure contributes to wrinkles and sagging

what is the sequence of burns?

tissue damage contributes to water/electrolyte loss which decreases blood pressure and leads to possible circulatory shock

what is the hypodermis made of?

areolar and adipose

what is the function of the hypodermis?

stabilize the skin and allows movement over deeper tissues

what is unique about the hypodermis?

it is not part of the skin

what is the function of hair?

protects, insulates, guards openings, and contributes to light touch sensation

where is hair not found?

palms, soles, lips, and portions of the external genitalia

what are the three types of hair?

lanugo, vellum, and terminal

what is lanugo?

fine hair on a newborn

what is vellus?

soft, fine “peach fuzz” covering much of the body

what is terminal hair?

thick, pigmented hair; scalp/eyebrows and hormonally influenced regions after puberty

what are the components of hair?

root, shaft, hair layers (medulla, cortex, cuticle), arrestor pill, and sebaceous glands

how do remember hair layers?

medulla in the middle, cortex is the core, cuticle is the coat

what are the five integumentary glands?

eccrine sweat, apocrine sweat, sebaceous, ceruminous, and mammary

what is the secretion/role of eccrine sweat?

watery, salty, acidic sweat

where is eccrine sweat found?

widely distributed

what is the secretion/role of apocrine sweat?

thicker secretion with proteins/lipids; bacterial action contributes to odor

what is the secretion/role of sebaceous glands

sebum; oily/waxy; lubricates skin and hair; bactericidal

where are sebaceous glands founds?

usually empties into the hair follicle

what is the secretion/role of ceruminous glands?

cerumen (earwax)

where are ceruminous glands found?

external acoustic meatus

what is the secretion/role of mammary glands?

milk

what are nails made of?

epidermal structures made of dead cells packed with hard keratin

what is the role of nails?

protection

what does epithelium repair?

epithelium

what does connective tissue repair?

connective tissue

what does stress do to the body?

weaken keratinocyte connections, slow rejuvenation, increase inflammation, promote dehydration, and contribute to collagen/elastin breakdown

what can hormones do?

stimulate new cells and production of collagen and keratin