The Endocrine System

• Endocrine glands are composed of cells that secrete:

– Hormones

• amino acid derivatives

• peptides and proteins

• steroids

• Hormones act by attaching to receptors of specific target cells

• Function of endocrine system:

– homeostasis

– growth and development

Endocrine Glands

• Hypothalamus

– oxytocin production (sent to posterior pituitary for secretion)

– ADH production (sent to posterior pituitary for secretion)

– production and secretion of regulatory hormones for anterior pituitary

• Pituitary (hypophysis)

– posterior pituitary

• oxytocin secretion

• ADH secretion

– anterior pituitary

• Tropic hormones

– TSH

– ACTH

– Gonadotropins: FSH, LH

• prolactin

• growth hormone

– all anterior pituitary hormones are regulated by hypothalamic hormones

– regulation dependent upon hypophyseal portal system

• Thyroid Gland

– T₄ and T₃: released by thyroid follicles

– calcitonin: released by C cells

• Parathyroid Glands

– PTH

· Adrenal Gland

– Adrenal cortex

• mineralocorticoids

• glucocorticoids

• adrenal androgens

– Adrenal medulla

• E and NE

• Endocrine pancreas

– Islets of Langerhans

• glucagon: from alpha cells

• insulin: from beta cells

• somatostatin: from delta cells

• Pineal gland

– melatonin

• Heart

– ANP

• Kidney

– renin

– EPO

• Thymus Gland

– thymosin

• Testes

– testosterone

– inhibin

• Ovaries

– estrogens

– progesterone

• Small intestine

– Cholecystokinin (CCK)

– Secretin

• Stomach

– Gastrin

Endocrine Disorders

• Acromegaly

• Goiter

• Grave’s disease

• Cretinism

• Cushing’s disease

• Addisons’s disease