integumentary

what does epithelium cover

Surface

largest organ in the body? what % of body weight

skin 7%

connective tissue function

provides underlying stability

what’s abundant in connective tissue

blood vessels

where is smooth muscle found

in the walls of blood vessels and attached to hairs

nervous tissues controls what and provides what

blood vessels and sensation

fucntino of integumentary 6

physical protection

Regulation of body temp

excretion (secretion)

nutrition (synthesis)

sensation

immune defense

oil glands are called

sebaceous glands

sweat glands are called

sudoriferous glands

what is the most abundant cell type

keratinocytes

function of keratinocytes

produce keratin (tough protein) that gives epidermis protection

where are keratinocytes found

arise from deepest layer of epidermis from cells undergoing mitosis

what does keratinocytes produce

(besides keratin)

anibioitecs and enzymes to detoxify the body

melanocytes function

produce melanin

Merkle cells

sensory nerve endings can serve as receptors to touch

Langerhans cells function

macrophage using receptor mediated endocytosis

5 layers of epidermis

stratum carenum
stratum lucidum

stratum granulosum

stratum spinosum

stratum basale

stratum carenum

mostly dead keratinocytes, water-proofing glycolipids, 15-30 cells thick, is keratinized

stratum lucidum

transition zone of keratin, only found in thick skin

stratum granulosum

3-5 layers of keratinocytes contains keratohyaline and lamellated granules

cytoplasm of keratinocytes contain

keratohyaline and lamellated granules

keratohyaline

helps form karatin

lamellated granules

contain water proofing glycolipids

stratum spinosum

thick bundles of pre-keratin, Langerhans cells, keratinocytes look spiky here

stratum Basale (stratum germinativum)

single row of basal cells, contains Merkel cells and melanocytes, continuous mitosis happens here

what makes keratinocytes look spiky

production of interconnection proteins called tonofibrils

tonofibrils function

increase stability

cells found in the dermis

fibroblasts, macrophages, mast cells, and scattered white blood cells

what fibers are in the dermis

gcollagen, elastic, and retiuclar

funcitno of the dermis

nourishment and tempature regulation

papilary layer

20% of dermis: loose areolar connective tissue

what structures are in the papillary layer

dermal papillae and epidermal ridges

dermal papillae function

finger like pegs which project into the epidermis and make fingerprints

reticular layer

under the papillary layer: 80% dense irregular connective tissue

what fibers are common in reticular layer

collagen fibers which extend into the layers under and above it which binds everything together

layer below reticular layer

hypodermis or subcutaneous layer

what does the reticular layer provide for the skin

strength and resilience

what structures are found in the reticular layer

blood vessels, glands, muscles, hair follicles, and nerve endings

cutaneous plexus

network of blood vessels at border of reticular layer rand hypodermis

papillary plexus

network of blood vessels just deep to the epidermis wha

what do the cutaneous plexus and papillary plexus functions

thermoregulation and overall blood flow

What form the union of a Merkel cell with a sensory nerve ending

tactile discs

what are the receptors in the skin

tactile corpuscles
root hair plexus
Ruffini Corpuscles

lamellated corpuscles

3 main factors of skin color

Thickness of stratum corneum
amount of pigment in epidermis (melanin)

blood supply in the dermis

hypodermis function

store fat, anchors skin to underlying structure (muscle), insulates us

where do most of our injections happen

hypodermis

main function of hair

sense things

minor functions of hair

protection (UV rays), trapping particles (nasal), movement (goosebumps)

where is soft keratin typically foun

in epidermal cells

hair root

part of hair attached to follicle under the skin

hair follicle

a sheath around the hair root

medulla

central core containing large cells and air spaces

3 concentric layer of keratinized hair

medulla, cortex, cuticle co

cortex

several layers of flattened cells

cuticle

single outer layer of cells, that overlap mostly heavily keratinized for strength

mammary glands

milk producing glands in breasts

ceruminous glands

modified sweat glands in external auditory canal

Cerumen

earwax formed from secretion of these glands