Endocrine System

• Pituitary Gland

  Also known as: HYPOPHYSIS
• Pituitary Gland


  • A small gland about the size of a pea
  • Rests in a depression of the sphenoid bone inferior to the hypothalamus of the brain
• Parts of the Pituitary Gland

  • Anterior Pituitary
  • Posterior Pituitary
• Anterior Pituitary


  • Made up of epithelial cells derived from the embryonic oral cavity
  • Receives signaling molecules from the hypothalamus, and in response, synthesizes and secretes seven important hormones including thyroid stimulating hormone & growth hormone
• Posterior Pituitary


  An extension of the brain and

  is composed of nerve cells

  • Does not produce its own

  hormones. It secretes two

  hormones made in the

  hypothalamus – oxytocin &

  anti – diuretic hormone
• Pituitary Gland Histology

  Pars Nervosa

  • Also known as neural lobe or posterior lobe
  • Storage site of oxytocin & vasopressin

  Pars Intermedia

  • Referred as the neurointermediate lobe
  • Secretes Melanocyte –stimulating hormone (MSH)

  Pars Distalis

  • Also known as the anterior lobe
  • Secretes growth hormone, thyroid – stimulating hormone, adrenocorticotropic hormone, follicle- stimulating hormone, luteinizing hormone & prolactin
• THYROID

  GLAND

  • Made up of two lobes connected by a narrow band called the isthmus
  • One of the largest endocrine glands
  • Appears more red than the surrounding tissues because it is highly vascular

  HORMONE

  • Thyroid Hormones ( Thyroxine, Triiodothyronine)
  • Calcitonin
• ADRENAL

  GLANDS

  • Two small glands located superior to each kidney
  • Each adrenal gland has an inner part known as adrenal medulla and adrenal cortex

  1. Adrenal Medulla: located inside the adrenal cortex in the center of the adrenal gland
  2. Adrenal Cortex: outer region & also the largest part of an adrenal gland. 3 zones: Zona Glomerulosa, Fasciculata &Reticularis
• THYMUS

  • Lies in the upper part of the thoracic cavity
  • Large in infants but decreases in size after puberty
  • Secretes thymosin which aids in the development of white blood cells known as T cells

  HORMONE:

  • Thymosin
• PINEAL GLAND

  • A small, pinecone-shaped structure located superior and posterior to the thalamus of the brain

  HORMONE:

  Melatonin - it is thought to decrease the secretion of LH & FSH by decreasing the release of hypothalamic – releasing

  hormones
• Pancreas

  • BOTH an endocrine & exocrine glandm
  • Two main functions: Digestion & Blood Sugar Regulation
  • Located in the abdomen & surrounded by the stomach, small intestine, liver, spleen & gallbladder

  Hormone:

  • INSULIN
  • GLUCAGON