Endocrine system

• What is the primary function of the endocrine system?

  Transport hormones to target tissues
• How do endocrine glands transport hormones?

  Via the blood
• How do exocrine glands transport hormones?

  Via ducts
• Where are hormones produced in the anterior pituitary?

  In specialized cells in the anterior lobe

  
• What connects the hypothalamus to the anterior pituitary?

  A system of blood vessels

  
• What stimulates the release of hormones from the anterior pituitary?

  Releasing and inhibiting factors

  
• Where are hormones produced for the posterior pituitary?

  In specialized cell bodies in the hypothalamus
• How are hormones transported to the posterior pituitary?

  Down the axons of specialized cells
• What happens when the posterior pituitary receives a nerve impulse?

  Hormones are released into the bloodstream
• What are the key differences between the nervous and endocrine systems?

  • Communication: Electrical and chemical vs. chemical
  • Speed of response: Quick vs. slow
  • Persistence of response: Stops quickly vs. may last weeks
  • Area of effect: Targeted vs. general
  • Adaptation to long-term stimuli: Quick decline vs. persists
• What is the effect of a small amount of hormone in the body?

  Activates thousands of enzyme molecules
• What is enzyme amplification?

  One molecule activates many enzymes
• Where are hormones cleared from the body?

  By the liver
• What is the half-life of a hormone?

  Time to clear 50% from blood
• What factors affect a hormone's half-life?

  Molecular structure, weight, binding status

  
• What are the steps in the mechanism of hormone action?

  1. Hormones influence target cells
  2. Bind to receptors on cell membranes
  3. Alter cell activity by:

  • Changing membrane potential
  • Stimulating protein synthesis
  • Activating or deactivating enzymes
  • Stimulating mitosis

  
• What type of hormones are lipid soluble?

  Steroid hormones

  
• How do steroid hormones enter cells?

  Diffuse through the plasma membrane

  
• What do steroid hormones bind to in the nucleus?

  Chromatin (DNA)

  
• What type of hormones are water soluble?

  Protein/peptide hormones

  
• How do protein/peptide hormones act on target cells?

  Bind to plasma membrane receptors

  
• What do protein/peptide hormones usually activate?

  Existing enzyme systems
• What is Grave's Disease characterized by?

  Overactive thyroid gland
• What are symptoms of Grave's Disease?

  Elevated metabolic rate, nervousness, sweating
• What is a common treatment for Grave's Disease?

  Surgery or radioactive iodine
• Who is more commonly affected by Grave's Disease?

  Women