integumentary system + pictures

integumentary system

includes skin, hair and nails

integument system functions

responsible for protection, sensation, temperature regulation, and production of vitamin d

skin

made of epidermis and dermis

epidermis

made of epithelial tissue (stratified squamous keratinized)

cells of epidermis

keratinocytes, melanocytes, dendrites, tactile cells

keratinocytes

the most common cell type, produces keratin which is hard to permeate

melanocytes

produce melanin, responsible for pigmentation (regardless of skin color everyone will have the same amount), uv lights prompt more melanin production as it protects from uv

dendrite cells

immune cells that capture foreign bad things before they get too deep

tactile cells

detect light touch and pressure

layers of epidermis (bottom top)

basement membrane, hemidesmosome, stratum basale, stratum spinosum, stratum granulosome, stratum lucidum, stratum corneum

stratum basale

bottom layer, house highly mitotic cells (19 days approx cycle) cells go up to the superficial layer (45-46 days)

stratum spinosum

2nd bottom

stratum granulosome

house keratohyaline granules, release hydrophobic lipids

stratum lucidum

thin, clear layer where keratohyaline and melanin not burst yet

stratum corneum

squamous cells, where keratin and melanin are released, is cornified meaning dead and full of keratin

thick skin

has all 5 layers of epidermis, found in places with lots of friction, such as soles, palms and fingertips

thin skin

4 layers, with no stratum lucidum

melanin transfer

melanin created by melanocytes are stored in melanosomes, phagocytosized into keratocytes, and brought to superficial layer

skin cancer

usually caused by uv damage to dna, higher melanin means less risk of skin cancer

basal cell carcinoma

most common, happens in basal layer (stratum basale)

squamous cell carcinoma

cancer in the spinosum layer

melanoma

cancer of melanocyte

dermis

layer beneath epidermis, above hypodermis, made of connective tissue

papillary layer

the top layer of dermis made of loose areolar ct, which has touch receptors

reticular layer

the deeper layer of the dermis made of dense irregular ct (to withstand lots of forces)

stratum basale

stratum spinosum

stratum granulosum

stratum corneum

papillary layer of dermis

reticular layer of dermis