    It also help in the detection of sensations         The adipose tissue has metabolic
     and give strength and flexibility to the             functions: it is responsible for production
     skin.                                                of vitamin D, and triglycerides.
Components of the dermis include:                     DIGESTIVE SYSTEM or Excretory system
Blood vessels - transport oxygen and nutrients           It is a group of organs working together to
to the skin and remove waste products. These              convert food into energy and basic
vessels also transport vitamin D from the skin            nutrients to feed the entire body.
to the body.                                             Food passes through a long tube inside the
                                                          body known as the alimentary canal or the
Lymph vessels - supply lymph (milky fluid
                                                          gastrointestinal tract (GI tract).
containing white blood cells of the immune
                                                         The alimentary canal is made up of the
system) to skin tissue to fight microbes.
                                                          oral cavity, pharynx, esophagus, stomach,
Sweat glands - regulate body temperature by               small intestines, and large intestines.
transporting water to the skin"s surface where           The entire system from mouth to anus is
it can evaporate to cool down the skin.                   about 30 feet (9 meters) long.
                                                         To providing energy and nutrients to the
Sebaceous (oil) glands - secret oil that helps            body, six major functions take place in the
to waterproof the skin and protect against                digestive system: ingestion, secretion,
microbe build-up. They are attached to hair               mixing      and     movement,      digestion,
follicles.                                                absorption, excretion.
Hair follicles - tube-shaped cavities that
enclose the hair root and provide nourishment
to the hair.
Sensory receptors - nerve endings that
transmit sensations such as touch, pain, and
heat intensity to the brain.
Collagen - tough structural protein that holds
muscles and organs in place and gives strength
and form to body tissues.
Elastin - rubbery protein that provides
elasticity and makes the skin stretchable. It is
also found in ligaments, organs, muscles and
artery walls.
Hypodermis (Subcutis)
                                                      Digestive system components
    The innermost layer of the skin is the
     hypodermis.                                      Mouth
    This layer is underneath the dermis, and
                                                         The mouth is the first part of the
     merges with it.
                                                          gastrointestinal tract and is equipped with
    It mainly contains adipose tissue and                several structures that begin the first
     sweat glands.                                        processes of digestion. These include
                                                          salivary glands, teeth and the tongue.
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