Endocrine System Notes

Endocrine System

• Consists of a group of glands that produce chemicals called hormones.

Hypothalamus

• Activity in the pituitary gland is controlled by the brain, which in turn regulates other glands.

Hormones

• Amino Acid Compounds:
  • These hormones are proteins or related compounds.
• Steroids:
  • These hormones are derived from cholesterol, a type of lipid.

Pituitary Gland

Posterior Pituitary

• ADH and oxytocin are manufactured in the hypothalamus but stored in the posterior pituitary.
• Growth hormone promotes growth in the body.

Anterior Pituitary

• LH (Luteinizing Hormone):
  • This hormone initiates ovulation, corpus luteum formation, and progesterone production in the female; stimulates testosterone secretion in males.
• TSH (Thyroid Stimulating Hormone):
  • This hormone stimulates the thyroid gland, influencing activities required for normal growth.
• T3 and T4:
  • These hormones increase metabolic rate, influencing both physical and mental activities required for normal growth.

Hormonal Therapy

• LHAH Agonists

Adrenal Cortex

• Cortisol:
  • Increases blood glucose concentration in response to stress.
• Aldosterone:
  • Manufactured in the adrenal cortex.
• Insulin: Reduces blood glucose concentration by promoting glucose uptake into cells and promoting fat and protein synthesis
  • Promotes Glucose uptake into cells.
  • Promotes fat and protein synthesis

Pancreas

• Glucagon:
  • Stimulates the liver to release glucose, thereby increasing blood glucose levels.
• Insulin:
  • Reduces blood glucose concentration by promoting glucose uptake into cells and glucose storage; promotes fat and protein synthesis.
  • B-cell dysfunction
  • Glucose Production
  • Lipolysis

Glands

• Mammary Glands
• Pineal: Hormones from this system are released into the blood stream

Target Tissue

• The specific tissue acted on by each hormone.

Hormone Release

• Hormones from this system are not released into ducts but directly into the bloodstream which carries them throughout the body

Negative Feedback

• Keeps the level-regulated variable within a specific range.

ACTH

• ACTH (Adrenocorticotropic Hormone):
  • This hormone stimulates growth and hormonal activity of the adrenal cortex.
• ACTH (Releasing Hormone ormone):
  • This hormone is produced by the hypothalamus renal cortex

PRL

• PRL (Prolactin):
  • Stimulates milk production by the mammary glands.

FSH

• FSH (Follicle Stimulating Hormone):
  • This hormone stimulates growth and hormonal activity of ovarian follicles; stimulates growth of testes; promotes sperm cell development.

PTH

• PTH (Parathyroid Hormone):
  • These glands produce this hormone that regulates the exchange of calcium between blood and bones; increasing the calcium level in the blood.

Adrenal Medulla

• Epinephrine is produced in the Adrenal Medulla

Weak Androgens

• The Role of Androgens in Women
  • Natural Androgens:
    • Testosterone, dihydrotestosterone (DHT), androstenedione (A), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS).
  • Exogenous Natural and Synthetic Androgens:
    • Oxandrolone, Stanozolol, Nandrolona, Trenbolone
  • These contribute to some secondary sex characteristics in women.

Pancreas cell types

• Alpha cells
• Beta cells

Pancreatic Islets of Langerhans

• Insulin is produced in the beta cells of the Pancreatic Islets of Langerhans.