The Integumentary System
Nervous System
●● Receptor sites for temperature and pressure changes in
the skin provide information to the nervous system so
that we can cope with our external environment.^
●● Nerves activate sweat glands.
Endoc rine System
●● Hormones control the secretion of sebum from the
sebaceous glands.^
●● Hormones increase blood flow to the skin.
●● Hormones control the amount of fat in subcutaneous
tissue.
Cardiovascular System
●● Blood vessels in the dermis help regulate body
-temperature by dilating or constricting.^
●● Dilation of blood vessels in light skin produces
-blushing during embarrassing moments.
Lymphatic System
●● Skin is an effective barrier against invasion by
-microorganisms, providing a first defense for the
immune system.^
●● Sebum has antifungal and antibacterial properties.
●● The acid mantle of the skin helps prevent most
bacterial infections.
Digestive System
●● Vitamin D produced by the skin causes calcium and
phosphorus to be absorbed in the intestine.^
●● Excess calories can be stored as fat in subcutaneous
tissue.
Respiratory System
●● Receptor sites in the skin can bring about changes in
breathing rates.
Urinary System
●● Kidneys can restore water and electrolytes lost during
sweating.
Reproductive System
●● Stimulation of receptor sites in the skin can bring
about sexual interest.^
●● Sucking on the nipple causes the postnatal female to
produce milk from her mammary glands.
131
Summary Outline
Introduction- The integumentary system is made up of the skin,
hair, nails, sebaceous glands, ceruminous or wax
glands in the ear canal, and sweat glands.^ - The skin is waterproof, it protects us from ultraviolet
radiation, and through sweating it dissipates water and
helps regulate body temperature.
The Layers Of The Skin- The skin is composed of two layers: the upper
epidermis- and the lower dermis or corium.
The Epidermis- The epidermis is composed of stratified, squamous,
keratinized epithelium.^ - As cells move up to the surface of the epidermis they
lose water, and their nuclei change chemically, a
process called keratinization.^ - The five layers of the epidermis are from outermost to
deep:^
stratum corneum or horny layer
stratum lucidum or clear layer stratum
granulosum or granular layer stratum
spinosum or spiny layer^
stratum germinativum or regenerative layer.
The Stratum Corneum - It consists of dead cells converted to protein or kera-
tinized cells that constantly are being shed.^ - It is a barrier to light and heat waves, most chemi-
cals, and microorganisms.
The Stratum Lucidum - This layer is only one or two flat and transparent
layers- of cells thick. It is difficult to see.
The Stratum Granulosum - This layer is two or three layers of cells thick and is
very active in keratinization.
The Stratum Spinosum - This layer consists of several layers of spiny-shaped
polyhedron-like cells.^ - The interlocking cellular bridges or desmosomes
are found in this layer.