paracrine regulation - acts on local area 

• cytokines - regulate other immune system cells
• growth factors - promotes growth/cell division
  • neurotrophins - paracrine regulators of nervous system
• prostaglandins - 20-carbon-long fatty acid w/ carbon ring
  • released from phospholipids in membrane
  • promotes inflammation (pain/fever)
  • regulates gamete transport/labor
  • inhibits gastric secretions
  • cause constrictions/dilations of blood vessels
• nonsteroidal anti-inflammatory drugs (NSAIDs) - drugs that inhibit production of prostaglandins
  • aspirin - most commonly used form
  • can also inhibit enzyme that maintains walls of digestive tract

posterior pituitary gland - fibrous part of pituitary gland, derived from brain 

• directly controlled by hypothalamus through the supraopticohypophyseal tract
• consists of axons (cell bodies in hypothalamus)
• antidiuretic hormone (ADH) - aka vasopressin
  • stimulates water retention in kidneys
  • frequent urination occurs if kidneys don’t retain water
  • alcohol suppresses ADH >> more urination to rid body of toxins
• oxytocin - stimulates uterus contractions and mammary glands (milk-letdown reflex) in women
  • responds to sucking on nipples
  • regulates orgasm/arousal in men/women
• neuroendocrine reflex - involves both the neural/endocrine systems

anterior pituitary gland - glandular part of pituitary gland, not derived from brain 

• controlled by hormones secreted by hypothalamus
• releases mostly growth hormones (aka tropic hormones, tropins)
• gonadotropin - hormone that stimulates other reproductive hormones
  • includes FSH, LH
  • positive feedback controls amount of reproductive hormones in females >> cyclic level
  • negative feedback controls amount of reproductive hormones in males >> constant level
• growth hormone (GH, somatotropin) - stimulates muscle/bone growth
  • targets all tissues, bones in particular
  • can’t increase height once cartilage becomes bone
  • too much >> gigantism, acromegaly (bone deformity)
• adrenocorticotropic hormone (ACTH, corticotrophin) - stimulates adrenal cortex
  • responds to chronic stress, excess exercise
  • cortisol from adrenal cortex can suppress immune system
  • produces corticosteroid hormones >> regulates glucose metabolism
• thyroid-stimulating hormone (TSH, thyrotropin) - stimulates thyroid to make thyroxine
  • affects oxidative respiration, thermal regulation
  • underdeveloped thyroid glands >> cretinism (undergrowth, mental retardation)
• luteinizing hormone (LH) - used for ovulation, production of testosterone
  • develops the corpus luteum (makes estrogen/progesterone)
• follicle-stimulating hormone (FSH) - used for development of ovarian follicles and sperm
• prolactin (PRL) - stimulates mammary glands to produce milk
  • also controls electrolyte balance
• melanocyte-stimulating hormone (MSH) - stimulates melanin (dark skin pigment) production
  • released by middle pituitary