Endocrine System Overview

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Endocrine System Overview

• Anatomy Physiology

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Endocrine System Overview

• Endocrine system works with nervous system to
  coordinate activities of body cells
• Endocrine glands- ductless make hormones
• Hormones influence metabolic activities
• Exocrine glands- external secretions onto surface
  or other organ sweat, mammary, lacrimal,
  salivary glands

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Endocrine System Overview (continued)

• Hormones chemicals released into blood to
  regulate metabolic functions of body cells
• Hormones can be circulating or local

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Main Types of Hormones

• Circulating Hormones
• Amino acid based most common
• Steroids made from cholesterol
• Local Hormones
• Autocrines affect cells that secrete them
• Paracrines affect local and other cells

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Control of Hormone Release

• Typically regulated by negative feedback system
  receptors (upregulated or down)
• 3 Stimuli that Release Hormones
• Neural nerve fibers stimulate hormone release
• Fight-or-flight
• Hormonal release in response to hormones made by
  other endocrine organs
• Chain of command (pg. 271)
• Humoral secrete in response to changing levels
  of nutrients in blood
• glucagon

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Major Endocrine Organs

• Pituitary gland- Vice president secretes 6
  hormones from anterior 2 posterior
• Includes Growth Hormone (GH), PRO, ACTH, TSH,
  FSH, LH posterior ADH and oxytocin
• Thyroid gland- butterfly shaped in neck
• Thyroid hormone (TH)- bodys major metabolic
  hormone
• Calcitonin- regulates blood levels of calcium

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Major Endocrine Organs (continued)

• Parathyroid gland- found behind thyroid
• Secretes parathyroid hormone (PTH)
• Important in controlling blood Ca levels
• Adrenal gland- pyramid shaped top of kidneys
• A. cortex-makes corticosteroids including
  gonadocorticoids (sex hormones)
• Androgens testosterone and estrogens
• A. Medulla epinephrine norepinephrine
• Pancreas- endocrine/exocrine gland
• insulin and glucagon
• Regulate blood sugar

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Major Endocrine Organs (continued)

• Gonads(Ovaries or Testes- sex hormones
• Female estrogens and progesterones
• Male testosterone
• Pineal gland- pine cone-shaped secretes
  melatonin (regulates sleep cycles)
• Thymus- beneath sternum shrinks from child to
  adulthood.
• Makes peptide hormones T lymphocytes

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Other Hormone-Producing Structures

• GI tract, placenta, kidneys, skin, and adipose
  tissue can produce hormones
• Adipose fatty tissue- leptin prostaglandins
• Kidneys- erythropoietin (EPO)