Endocrine System PDF

Endocrine System Edie Sperling, PhD(c), DPT, OCS COMP-NW  Pituitary Gland Also called the Hypophysis, it has many elements in it, and even more functions. Its main function is to regulate other endocrine glands.  The pituitary gland is a small gland located...

Endocrine System Edie Sperling, PhD(c), DPT, OCS COMP-NW  Pituitary Gland Also called the Hypophysis, it has many elements in it, and even more functions. Its main function is to regulate other endocrine glands.  The pituitary gland is a small gland located in the hypophyseal fossa of the sphenoid bone. Above it is the hypothalamus. Pituitary stalk (aka infundibulum) connecting to hypothalam  Posterior Pituitary Endocrine secreting cells are located in the hypothalamus Their long axons project down the pituitary stalk (infundibulum) to terminate as “herring bodies” (enlarged nerve endings where the hormones are stored) Their axon terminals end on blood vessels. Hormones secreted: Oxytocin and Vasopressin (AKA Anti-Diuretic Hormone/ADH). 1. Secretory cell bodies in the hypothalamus 2. Axons pass through pituitary stalk 3. Axon terminals end as enlarged Herring Bodies on capillaries in posterior pituitary. Hypophysea l vein 4. Upon depolarization, hormone is released into capillary. Inferior hypophyseal artery  Anterior pituitary The anterior pituitary secretes a large number of hormones—Growth Hormone (GH), prolactin, Follicle Stimulating Hormone (FSH), Luteinizing Hormones (LH), Thyroid Stimulating Hormone (TSH), and Adrenocorticotropic Hormone (ACTH). It is under control of the hypothalamus, which secretes releasing factors or inhibiting factors to control the release of the hormones Thyroid & Parathyroid Glands  Thyroid gland—position in neck Thyroid cartilage of larynx Cricoid cartilage of larynx Right lobe of Left lobe of thyroid gland thyroid gland Isthmus of Trachea thyroid gland F. Netter.  Thyroid Gland Tissues The thyroid gland is an encapsulated gland in the neck; the gland itself covers over the larynx and Xrst tracheal cartilages. The gland mostly consist of follicles, which have a peripheral epithelium and central mass of colloid (thyroglobulin) from which T3 and T4 thyroid hormone are made. A second cell, the Parafollicular cell (C-cell), which makes the hormone Calcitonin, can also be found between follicles.  Thyroid gland follicles. Thyroi d capsul e  Thyroid follicle: Follicular epithelium Colloid Capillary C-Cell (Parafollicular cells) Simple cuboidal epithelium  Functions of Thyroid Hormones T-3 and T-4 Increase basal metabolic rate Rate utilization of food (such as protein synthesis, catabolism) (Will be discussed in detail in Physiology) C-Cells (Parafollicular cells) Arise from ultimobranchial bodies derived from endoderm Migrate into thyroid gland and spread out in the gland; C-cells remain independent of thyroid follicles. Secrete Calcitonin (causes decrease in blood calcium levels by every means possible, including deposition of calcium into bones) See Physiology for details on calcitonin function. It is the counterpoint to Parathyroid hormone.  Parathyroid Glands Four separate encapsulated glands that sit on the posterior surface of the thyroid gland. Manufacture Parathyroid Hormone, necessary for maintaining the normal levels of Calcium ion in the bloodstream. While it is attached to the thyroid gland, it’s not *really* a part of it.  Parathyroi d glands: shown on the posterior surface of Location of parathyroid Superior parathyroid the gland. glands on the posterior surface of the thyroid gland. Inferior Parathyroid http://www.cunninghamforcouncil.com/thyroid-and-parathyroid/stunning-thyroid-and- parathyroid-80-for-anatomy-of-the-human-ear-with-thyroid-and-parathyroid/  Capsule of parathyroid Parthyroid Gland: note small cells, lots of nuclei, and Thyroid Gland its close association nestled next to (but not within) thyroid gland Thyroid capsule Pancreas  Pancreas Endocrine Functions Releases insulin when blood sugar levels are high to help lower them Releases glucagon when blood sugar levels are low to help raise them Other  Pineal Gland Suprachiasmatic nucleus (SCN) Heart as an Endocrine Organ Atrial natriuretic peptide (ANP Brain natriuretic peptide (BNP Kidneys & Adrenals Glands  Adrenals Gland Hormones