Integumentary System. Cutaneous = skin. Skin Hair Nails and associated glands. Skin is the largest organ of the body 17,000 sq cm –average adult. Function: Protection -prevent vs dehydration,microbes,UV radiation, physical insult Regulate Temperature Vitamin D synthesis
Cutaneous = skin
and associated glands
Subcutaneous tissue anchors skin to the underlying tissue/organs
1/2 of the body’s adipose tissue
‘storage adipose’ = energy adipose
also contributes to cushioning and temperature control
aging/maturation = distribution of fat stores changes
“baby fat” over whole body
male - neck, lower back ‘love handles’
female - breast,hips/thighs
Epidermis – The outer most layer composed of epithelial cells. It is subdivided in to thin layers called strata and contains no blood vessels
stratum basale - one layer of cells
stratum spinosum - 8-10 layers of cells
stratum granulosum - 2-5 layers of cells
stratum lucidum - several layers of cells
stratum corneum - 25 + layers of cells
Melanocytes - produce melanin - pigment--- 25% of basal cells
Keratinocytes - produce a protein mixture of keratin
Langerhans cells - phagocyte
Merkel’s cells - specialized cells associated with nerve endings -detect light touch and pressure
The stratum corneum is the outer most stratum of the epidermis.
It is comprised of flat, tough, keratin containing cells that provide a protective layer for the skin.
Keratin is a protein that strengthens the cells and is also found in other areas of the body.
The cells in this stratum are either dead or dying, as they have no blood vessels to keep them alive.
Also called the “true skin.”
Is a network of elastic connective tissue that contains blood vessels and nerves, as well as the appendages of the skin.
Extensions of the dermis, known as papillae, extend toward the epidermis and form what we know as fingerprints.
Papillary region: top area loose connective tissue with high % of elastin fibers
folds called dermal papillae - ridges for friction/gripping
Reticular region:connective tissue with collagen and elastin fibers stretch -return to original shape
sweat glands [sudoriferous glands]
merocrine - help regulate temperature
eccrine - don’t regulate temperature -odor
arrector pili muscle
Nerve endings – pain, temperature, touch, vibration
other glands: ceruminous glands [modified merocrine]
The technical name for sweat glands is sudoriferous glands.
Sudoriferous glands help regulate body temperature through the evaporation of sweat.
Secretions of the sweat glands in the groin and armpits also contain cellular debris that produce body odor when broken down by bacteria.
Produce sebum, an oily substance that prevents drying of the skin and hair.
Blackheads are blocked sebaceous glands full of dried sebum and keratin.
Pimples are infected blackheads.
Sebaceous cysts may form over time if the glands stays blocked and will continue to increase in size. (until they’re dealt with)
The hair grows from the follicle, a sheath in the dermis.
Most follicles have a small muscle associated with it, which allows it to raise forming “goose bumps.”
Factoid: eye lashes protect eyes, but also sense when something is coming towards the eye. Grow new eyelashes every 5 weeks.
shaft : part above skin surface
root: part below skin surface
Protective & functional
The larger the digit, the faster the nail grows
Nails are made of hard, keratinized cells and provide protection to the fingers and toes.
New cells form continuously in the nail root at the proximal end of the nail.
Pallor – often decreased blood flow or anemia.
Flushing – increased blood flow, often related to exercise,fever, or infection.
Cyanosis – blueing of the skin due to decreased oxygenation of the blood.
Jaundice – yellowing of the skin from increased bilirubin in the blood often associated with liver disease and hemolytic disease.
Carotenemia – excessive intake of carotene containing vegetables, like carrots, leading to an orange cast to the skin.
Bronzing/ gray/ brown discolorations – Addison’s disease, chronic poisonings
Size, shape, height, and/or depth of the lesion are all important aspects in evaluating a skin lesion.
Rash – an area of erythema (redness) of the skin.
Eruption – a raised rash, often erythematous.
Macules – flat spots, such as in measles and freckles.
Papules – firm, raised areas, such as in chickenpox or pimples
Nodules – Large papules
Vesicles – blisters full of fluid, such as in poison ivy
Pustules – infected vesicles filled with pus, such as in folliculitis
Papules from scabies
Excoriation – scratches, often associated with intense itching or a psychological disturbance
Laceration – a rough, jagged wound from tearing, more than cutting
Ulcer – from death of tissue, such as with diabetic and tropical ulcers
Fissure – a crack in the skin, such as in athlete’s foot.
Excoriations from Swimmer’s Itch
Approx. 50%of male population will have some degree of balding with increased age
B D Tyagi of Bhopal in India The hair growing from the middle of his ears measures an astonishing 10.2cm at its longest point, which is probably long enough for small pony tails.