Integumentary System

functions of the integumentary system

barrier, vitamin d synthesis, thermoregulation, excretion, sensation

skin

cutaneous membrane

epidermis

highly mitotic, cells are pushed up front the bottom layer- superficial, keratinized stratified (layered) squamous (flat and spread out) epithelium

dermis

more permanent- strong flexible connective tissue, made of fibroblasts macrophages white blood cells, high concentration of nerve fibers blood and lymphatic vessels, contains epidermal hair follicles (oil and sweat glands)

hypodermis

superficial fascia- subcutaneous layer deep to skin, not part of skin but shares some functions, mostly adipose tissue, anchors

layers of the epidermis

•Stratum basale

•Stratum spinosum

•Stratum granulosum

•Stratum lucidum 

•Stratum corneum

deepest layer of the epidermis

 stratum basale- single row of stem cells which are actively mitotic, produces daughter cells, melanocytes are found here 

layer above the stratum basale

stratum spinosum- layers thick, prekeratin filaments attacked to desmosomes, abundant melanocytes and langerhans cells

layer above the stratum spinosum

stratum granulosum- cells flatten, nuclei and organelles disintegrate, keratinization begins, cells accumulate keratohyalin granules, water proofing

layer above the stratum granulosum

stratum lucidum- only in thick skin, clear, few rows of flat dead keratinocytes

layer above the stratum lucidum

stratum corneum- 20-30 rows of dead, flat, anucleate keratinized, protect from water loss, abrasion, barrier

keratinocytes

produce fibrous protein keratin, most cells of epidermis, tightly connected desmosomes

melanocytes

cell produces melanin, protect from UV damage

dendritic (lagerhans) cells

 key activators of  immune system

tactile (merkel) cells

sensory touch receptors

layers of the dermis

papillary the reticular

papillary

• superficial wave like projections, dermal papillae contribute to finger prints

• dermal papillae contain capillary loops some contain meissner’s corpuscles (touch receptors) some contain free nerve endings (pain receptors)

• finger prints

reticular

• 80 percent of dermal thickness, dense connective tissue, elastic fibers, collagen fibers to provide strength

• cleavage lines because most collagen fibers parallel to skin surface

flexure lines

dermal folds at or near joints, dermis tightly succeed to deeper structures

striae

silvery white scare, stretch marks

blister

papillary layer and stratum basale is where the blister forms

melanin

pigment

melanosomes

• organelles or collections with in the cell

carotene

• yellow to orange pigment, accumulate in hypodermis, can be conferred to vitamin a for vision and epidermal health

cyanosis

• blue meaning low oxygenation

erythema

• redness sign of fever, hypertension, inflammation

pallor

•  anemia, low blood pressure

jaundice

• liver disorder meaning high bilirubin

contusion

which is clotted blood beneath the skin

machanoreceptor

sense of touch

thermorecptors

temperature

proprioceptors

body position

nociceptors

pain

melanoma

Cancer of melanocytes, Most dangerous form of skin cancer because highly metastatic and resistant to chemotherapy

what does ABCDE stand for

• A (asymmetric) B (border irregular) C (color) D diameter) E (evolution)

fascia

Sheath of CT (mostly collagen) that wraps and separates to divide deep structure of the body

superficial fascia

subcutaneous tissue (hypodermis)

deep fascia

covers most of the body and has no adipose tissue

investing fascia

• extensions from deep fascia and separates compartments

retinaculum

thicker version of fascia located around joints

accessory organs of the skin

hair, nails, glands

functions of hair

warn insects off, decrease heat loss, sunlight shield

hair bulb is composed of

hair follicle receptor, hair matrix (high level of mitosis), and hair papilla

Below the matrix is the _______ where there is blood supply

hair papilla

where there are sensory nerve endings

hair follicle receptor

arrector pili

smooth muscle that makes the hair stand up

lunule

white region at base of nail, thicker region of nail matrix blocking blood vessels from showing through, pinkish color of nails due to rich blood supply in dermis under the nail bed 

sudoriferous

sweat

sebaceous

oil

two types of sudoriferous glands

eccrine and apocrine

sudoriferous

all skin surfaces except nipples and parts of external genitalia, contain myoepithelial cells, contract upon nervous system stimulation to force sweat into ducts

eccrine

most numerous found in palms, soles and forehead, ducts connect to pores

apocrine

confined to axillary and genital areas, the sweat is more milky, ducts empty into hair follicles

modified apocrine glands

ceruminous glands and mammary glands

sebaceous glands

not in thick skin of palms and soles, secrete into hair follicles, secrete sebum