Endocrine System Structure and Function

• System orchestrates body changes throughout lifetime: growth, puberty, reproduction
• Regulates sleep, heart rhythm, cellular processes
• Three key components:
  • Glands (hormone-producing): 3 in brain, 7 in rest of body
  • Hormones: manufactured from blood vessel ingredients, pumped in tiny amounts
  • Trillions of cell receptors: special proteins inside/on cell surfaces

Hormone-Receptor Mechanism

• Hormones locate target cells via bloodstream
• Receptors recognize specific hormones, bind when they pass by
• Hormone-receptor combination triggers cellular effects
• Effects increase/decrease specific cell processes
• System exposes millions of cells simultaneously to regulated hormone quantities

Thyroid Hormone Examples

• Thyroid produces: triiodothyronine and thyroxine
• Travel to most body cells
• Influence cellular energy use speed and work rate
• Regulate: breathing rate, heartbeat, body temperature, digestion

Puberty and Sexual Development

• Men: Testes secrete testosterone
  • Triggers sexual organ development
  • Causes facial hair growth, voice deepening, height increase
• Women: Ovaries secrete estrogen
  • Signals adulthood start
  • Causes hip widening, womb lining thickening
  • Prepares for menstruation/pregnancy

Hormone Misconceptions and Facts

• Common misconception: exclusively male/female hormones
• Reality: Both men and women have estrogen and testosterone in different amounts
• Pregnancy involves both hormones plus 10+ others
• Functions: fetus growth, birth enablement, maternal feeding support

Mood and Behavioral Influence

• Hormonal changes associated with mood fluctuations
• Hormones influence brain chemical production (e.g., serotonin)
• Chemical level shifts cause mood changes
• Behavior shaped by multiple factors:
  • Brain neurotransmitters
  • Hormones
  • Social factors
• Primary function: regulate bodily processes, not control behavior

Hormonal Disorders

• Diabetes: Pancreas secretes insufficient insulin (blood sugar management hormone)
• Hypothyroidism: Too little thyroid hormone
  • Symptoms: slowed heart rate, fatigue, depression
• Hyperthyroidism: Too much thyroid hormone
  • Symptoms: weight loss, sleeplessness, irritability
• Disruption causes: disease, stress, diet
• Effects: altered hormone secretion quantities, changed cellular responses

System Balance

• Endocrine system maintains body balance most of the time
• Constant regulation drives developmental changes
• Helps individuals become who they are