Endocrine system

• The endocrine system consists of structures that secrete hormones at the cellular or organ level
• Major glands in the endocrine system include:

  • Hypothalamus, Pineal gland, pituitary gland in the brain
  • Thyroid and parathyroid in the neck area
  • Thymus in the upper chest
  • Adrenal glands above the kidneys
  • Pancreas near the stomach
  • Gonads (ovaries and testes)
• Endocrine gland function releases hormones directly into surroundings without ducts
• Exocrine glands have ducts that carry secretions to body openings or surfaces
• Hormones can be derived from different biomolecules such as amino acids or lipids, influencing their function
• Hormones bind to specific target cells and elicit various responses like increasing mitosis or enzyme activation
• Hypothalamus-pituitary region is crucial in regulating the endocrine system

  • Anterior pituitary secretes hormones like growth hormone, prolactin, TSH, FSH, LH, and ACTH
  • Posterior pituitary secretes oxytocin and antidiuretic hormone
• Pineal gland secretes melatonin to regulate circadian rhythm
• Thyroid produces T4, T3, and calcitonin, impacting metabolic processes and blood calcium levels
• Parathyroid gland releases PTH to raise blood calcium levels
• Thymus produces thymosin to impact immune system function, especially in T cell development
• Adrenal glands secrete epinephrine, norepinephrine, cortisol, and aldosterone, involved in stress response, inflammation, and mineral balance
• Pancreas releases insulin to lower blood glucose levels and glucagon to raise blood glucose levels
• Ovaries produce estrogen and progesterone, while testes produce androgens like testosterone, impacting reproductive functions and secondary sex characteristics
• Estrogen, progesterone, and testosterone serve functions in all individuals but are present in different concentrations based on gender
• Endocrine system signaling involves chemical signals from hormones that act on target cells to induce specific actions
• Hormones can have slow or fast response times and travel short or long distances to reach target cells
• Nervous system signaling uses electrical and chemical signaling with neurotransmitters for short distances and fast response times
• Hypothyroidism is a condition where the thyroid gland is underactive, leading to symptoms like extreme fatigue and slowed heart rate
• Treatment for hypothyroidism may involve replacement thyroid hormone therapy under the care of an endocrinologist