Muscle In Supra Hyoid Region

Hyoides region are located in depressors of the lower jaw. This region divide into 4 area:

1. Digastric
2. Mylo-hyoid
3. Stylo-hyoid
4. Genio-hyoid

To dissect these muscles a block should be placed beneath the back of the neck and the head drawn backward and retained in that position. On the removal of the deep fascia the muscle are at once exposed.

Digrastric consists of two fleshy bellies united by an intermediate, rounded tendon. It is a small muscle, situated below the side of the body of the lowe jaw, The posterior belly, longer than the anterior, arises from the digastric groove on the inner side of the mastoid process of the temporal bonde, and passes downward and backward.

The stylo-hyoid is a samall, slender muscle, lying in front of, and above, the posterior belly of the Digastric. It arises from the back and outer surface of the styloid process, near the base, and passing downward and forward, is inserted into the body of the hyoid bone, just at its juction with the greater cornu, and immerdiately above the Omo hyoid. This muscle is perforated, near its insertion, by the tendon of the Digastric.

Endocrine System

The endocrine system consists of specialized glands located in different parts of the body. These glands secrete chemical substances called Hormones, which transfer information from one set of cells to another. This enables the organism to adjust various activities of the body to the changing demands of the external and internal environment. The endocrine glands have no ducts connecting them to their target organs or tissues (they are hence often called the ductiles glands), and so they liberate hormones directly into the bloodstream.

Mammalian endocrine glands include the hypothalamus, pituitary, thyroid, parathyroid, thymus, pancreas, adrenal, testis, and ovary. Invertebrates posses few glands, and many of these are simply clusters of nerve cells. Arthropods have neurosecretory structures in the eyestalks, brain and ganglia that regulate reproduction, moiting, development, pigmentation, water balance, blood sugar level, and heart rate. The conventional ductless glands of arthropods include the following: Y organs or prothoracic glands (molting hormones); corpora allata (juvenile hormones); nongonadal adrogenic glands (male hormones): ovaries, and intestinal glands that secrete a developmental factor.