Transcript Integumentary System

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
• Information about environment – extension
of the nervous system
Skin has 3 distinct sections
• Epidermis = layers of
stratified squamous
epithelial tissue
• Dermis = loose
connective tissue
• Hypodermis
[subcutaneous] adipose tissue
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
abdomen
Epidermis
Epidermis – The outer most layer composed of epithelial cells.
It is subdivided in to thin layers called strata and contains no
blood vessels
Epidermis has 5 distinct layers of cells
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
Specialized cells in epidermis
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
melanocyte
Stratum Corneum
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.
Stratum lucidum
Stratum granulosum
Stratum corneum
Highly pigmented skin
keratinocytes
Dermis
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.
Dermis has two distinct regions
Papillary region: top area loose connective tissue with
high % of elastin fibers
folds called dermal papillae - ridges for friction/gripping
fingerprints
Reticular region:connective tissue with collagen and
elastin fibers stretch -return to original shape
Papillary region
Structures in Dermis
Blood vessels
hair follicles
sebaceous glands
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]
Sweat Glands
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.
Sebaceous Glands
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)
Hair is composed primarily of keratin and
covers most of the body.
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.
HAIR
shaft : part above skin surface
root: part below skin surface
Nails – extensions of the epidermis
Protective & functional
The larger the digit, the faster the nail grows
Nails
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.
Pigment
The color of the skin is controlled by the amount of
melanin in the skin.
As melanin helps protect the skin from UV rays, the
amount of melanin increases with sun exposure.
Discolorations
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
Lesions are essentially any damage to tissue.
Size, shape, height, and/or depth of the lesion
are all important aspects in evaluating a skin
lesion.
Surface Lesions
Rash – an area of erythema (redness) of the skin.
Eruption – a raised rash, often erythematous.
Macules – flat spots, such as in measles and freckles.
Surface Lesions
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
Nodule from Basal Cell Carcinoma of Scalp
Herpes simplex induced vesicles
Pustules induced by a
Group A beta-hemolytic
streptococcal infection
Deeper Lesions
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
Fissure
Effects of Aging on the Integumentary
System
•Thinning of the dermis
•Decreased elasticity
•Wrinkling due to decreased collagen and fat
•Thinning, drying, whitening of the hair – by
50 yrs of age, most people will start ‘graying’
•Decreased perspiration
•Nail growth slows
•Decreased blood flow will upset temperature
regulation
Common Terms to be familiar with
• Dermatosis and Dermatitis
• Dermatosis is any skin disorder.
• Dermatitis is an inflammation of the skin
which can have a large variety of causes.
Contact Dermatitis from metal
Contact Dermatitis from Adhesive
Alopecia is the
technical term for
baldness
Aside from hereditary
male pattern baldness,
alopecia can be caused
by:
Malnutrition
Chemotherapy
Systemic disease
It can also be
idiopathic
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.