Endocrine system part I

Histology 2016-2017
Department of Anatomy &Histology: Dr.Rajaa Ali
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Endocrine System I:
• The endocrine system produces various secretions called hormones [Gr. hormaein, to set in motion] that release for delivery to the bloodstream for transport to target cells and organs, serve as effectors to regulate the activities of various cells, tissues, and organs in the body.
• Its functions are essential in maintaining homeostasis and coordinating body growth and development and are similar to that of the nervous system: Both communicate information to peripheral cells and organs.
• These two systems are functionally interrelated. But endocrine system produces a slower and more prolonged response than the nervous system.
• Both systems may act simultaneously on the same target cells and tissues.
• The endocrine system including the discrete endocrine Glands (pituitary gland & hypothalamus, thyroid gl., adrenal gl. ,pineal gl. ,parathyroid gl.) as well as individual cells within the gonads, liver, pancreas, kidney, and gastrointestinal system.
Pituitary Gland(Hypophisis):
The pituitary gland and the hypothalamus, the portion of the brain to which the pituitary gland is attached, are morphologically and functionally linked in the endocrine and neuroendocrine control of other endocrine glands.
Gross Structure and Development
The pituitary gland is composed of glandular epithelial tissue and neural (secretory) tissue.
The pituitary gland [Lat. Pituta , phlegm—reflecting its nasopharyngeal origin] is a pea-sized, compound endocrine gland .
It is centrally located at the base of the brain, where it lies in a depression of the sphenoid bone called the sella turcica.
A short stalk, the infundibulum, and a vascular network connect the pituitary gland to the hypothalamus.
The pituitary gland has two functional components (Fig. 1,2):