Chapter 19: endocrine system

• functions of the endocrine system 


  ductless glands that secrete hormones, hormones will travel to various organs and cause physiological effects
• 3 types of hormonal stimulation

  1. humoral stimuli 2. neural stimuli 3. hormonal stimuli
• what are humoral stimuli?

  too much or lack of specific ions or nutrients in blood stimulate hormone production
• what are neural stimuli


  nerves signals stimulate hormone production
• what are hormonal stimuli

  one hormone induces the productions and release of another hormone
• negative vs. positive feedback

  -negative feedback loop when enough hormone is bloodstream.

  • positive feedback loop when not enough hormone is in bloodstream
• know the names and functions of all the endocrine organs

  pineal, hypothalamus, pituitary, thyroid, parathyroid, thymus, adrenals, pancreas, ovaries/testers
• pineal gland


  secretes melatonin
• hypothalamus 


  hormonal control center
• pituitary gland 


  anterior pituitary gland cell type
• anterior pituitary gland cell types

  1. lactotrophs
  2. thyrotropes
  3. corticotropes
  4. gonadotrops
  5. somatotrope
• lactotrophs


  produce prolactin.
• prolactin


  stimulates milk productions
• thyrotropes

  • produce thyroid-stimulating hormone
  • affects metabolism
  • stimulates the thyroid glands to secrete hormones
• corticotropes


  produces adrenocortoctropes hormone and melanocyte-stimulating hormone

  • stimulates the adrenal cortex to secrete hormones to cope with stress
• gonadotropes 


  follicle-stimulating hormones (FSH) and luteinizing hormone (LH)
• FSH and LH affect

  reproduction
• FSH and LH stimulate

  the production of gametes
• somatotropes 


  produces growth hormone

  affects growth during childbirth and metabolism in adult

  directly it causes growth in children

  indirectly it causes liver to secrete insulin-like growth factors
• posterior pituitary

  1. secretes antidiuretic hormone
  2. secretes oxytocin
• secretes antidiuretic hormone 


  stimulates the resorption of more water from the kidneys to the bloodstream (ie. concentrates urine)
• secrets oxytocin


  stimulates childbirth

  bonding: "happy" hormone
• thyroid

  • located on the trachea
  • 2 lobes
• the thyroid gland produces which hormones?
• the thyroid gland produces which hormones? 


  thyroxine (T4), triiodothyronine (T3) and calcitonin
• T3 and T4 affect?


  basal metabolic rate
• produces is secretes when 


  when blood calcium levels are high
• calcitonin function


  slows the rate of calcium release by bone and increase calcium secretions by kidney
• parathyroid glands produce and secrete 


  parathyroid hormones
• parathyroid hormone 


  increase calcium levels in the blood

  increasing calcium release by bone

  decrease calcium secreation by kidney secretion
• adrenal glands

  1. adrenal medulla
  2. adrenal cortex
• adrenal medulla 


  secretes epinephrine and norepinephrine
• adrenal cortex layer

  1. zona glmerulosa: secretes aldosterone
  2. zona fasciculate: secretes cortisol
  3. zona reticularis: secretes cortisol
• aldosterone 


  stimulates the kidneys to absorb more sodium into the blood to maintain BP
• cortisol is released in response to

  stress
• function of cortisol 


  keeps glucose levels in blood high enough to support brian activity
• endocrine cells of pancreas are located 


  pancreatic islets
• alpha cells secrete 


  glucagon
• beta cells secrete


  insulin
• delta cells secrete 


  somatostain