integumentary system

subcutaneous layer

deepest layer composed of adipose (fat) tissue, loose connective tissue & large blood vessels

dermis

thick middle layer packed with collagen, nerves, blood vessels, sweat glands, hair follicles

epidermis

thin, outer layer that protects against germs & environmental damage; waterproof barrier

melanocytes

responsible for producing melanin, which protects against UV radiation

keratinocytes (epidermis)

produce keratin protein that form protective barrier against water loss & germs, help heal wounds

langerhans cells (epidermis)

specialized-tissue resistant macrophages; capture, engulf invaders & breakdown antigens

fibroblasts

connective tissue; role in making collagen/elastin that give skin its shape & elasticity; healing wounds

stratum basale

new skin cells (keratinocytes) & pigment cels (melanocytes)

stratum spinosum

“spiny” layer holds cells together & skin flexible/strong

stratum granulosum

“grainy” layer fills with keratin & make waterproofing fats; cell death begins

stratum lucidum

clear thin layer found in thick skin (palms, soles)

stratum corneum

dead skin cells that protect from germs, dirt, water loss

vitamin D synthesis

activation of a precursor molecule into vitamin D when exposed to sunlight (calcium absorption)

muscle tissue

skeletal (move bone), cardiac (heart), smooth (stomach walls); contracts & shortens for physical movement & pumps blood

connective tissue

bone, cartilage, fat (adipose), blood; connects, supports, binds; transports nutrients, gases, and waste

nervous tissue

brain, spinal cord, peripheral nerves; sends quick messages/electrical signals back/forth through body

epithelial tissue

outer layer of skin, lining of mouth, inner lining of gut

excretion

involves the elimination of waste products like urea/salts through sweat

corneocytes (epidermis)

cells dead and filled with keratin protein

sensation

involves detection of touch, temperature, pain

protection

provides a barrier against harmful agents such as bacteria and UV radiation

regulation of body temp

producing sweat to help cool down the body is an example of

skin

regulation of body temp, protection against environmental hazards, sensation

squamous cells

flat, scale-like cells designed for diffusion & filtration; found in alveoli of lungs & lining blood vessels (endothelium)

cuboidal cells

cube-shaped cells with central nuclei specializing secretion & absorption; found in kidney tubules & granular duct

columnar cells

tall, rectangular cells with basal nuclei that excel in absorption & mucus secretion; line digestive tract (stomach & intestines)

cardiac cells

pump blood, generate electrical signals & coordinate heartbeats through involuntary control

cardiac muscle

contract to pump blood through heart

cartilage

though, flexible the of connective tissue that cushions joints, supports body structures & lacks blood vessels; ear canal, nose

erythrocytes

rbc that deliver O₂ from lungs to body tissues; remove CO₂ & form in bone marrow

myocytes

specialized muscle cell designed for contraction & movement

osteocytes

mature bone cells that originate from osteoblasts; detect physical pressure/movement/cracks in bone matrix; remodeling: osteoblast build new bone & breakdown old bone; manage levels of calcium & phosphate in body to keep bones strong & healthy