MULTIPLE ENDOCRINE NEOPLASIA TYPE 1 Multiple endocrine neoplasia type 1 (MEN 1) is a rare (prevalence ∼two per 100,000) autosomal dominant endocrine disorder that is characterized by neoplasms of the pituitary, parathyroid, and pancreas. In addition, neoplasms may arise in…
CHOLESTEROL SYNTHESIS AND METABOLISM Cholesterol is a 4-ring hydrocarbon structure with an 8-carbon side chain. Cholesterol serves as a key component of cell membranes, and it is the substrate for synthesis of steroid hormones and bile acids. Cholesterol is either…
HISTOLOGY OF THE NORMAL PARATHYROID GLANDS The parathyroid glands are derived from branchial pouches III and IV and number between two to six glands, although four is the usual number. In adults, each of these ovoid (bean-shaped) glands measures 4…
PANCREAS ANATOMY AND HISTOLOGY The pancreas is a retroperitoneal organ that lies in an oblique position, where it slopes upward from the duodenum to the hilum of the spleen. The pancreas is 15 to 20 cm long and weighs 75…
DIFFERENTIATION OF GONADS FACTORS INFLUENCING NORMAL AND ABNORMAL GONADAL DIFFERENTIATION Whether the primordial gonad differentiates as a testis or as an ovary is determined by genetic information coded on the X and Y chromosomes. The differentiation of all the other…
Plate 3-1 Open full size image DEVELOPMENT OF THE ADRENAL GLANDS The detailed anatomy of the adrenal glands was first described by Bartholomeo Eustacius in 1563. Each adrenal gland consists of two parts—the cortex and medulla—that are enveloped in a…
ANATOMY OF THE THYROID AND PARATHYROID GLANDS Located between the larynx and the trachea medially and the carotid sheath and the sternomastoid muscles laterally, the thyroid gland weighs 15 to 25 g. The lateral thyroid lobes are 3 to 4…
DEVELOPMENT OF THE PITUITARY GLAND The pituitary gland, also termed the hypophysis , consists of two major components, the adenohypophysis and the neurohypophysis. The adenohypophysis (anterior lobe) is derived from the oral ectoderm, and the neurohypophysis (posterior lobe) is derived…