The Endocrine System

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The Endocrine System

• Anatomy Physiology 2

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Hormones

• The endocrine system is the chemical control of
  your body (aka hormones)
• Endocrine glands are found throughout the body
• Hormones are chemicals that are made in one part
  of the body and affect another part of the body
• Two types amino acid-based molecules or steroids

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Hormones

• Hormones affects target only certain tissues or
  organs called target cells or target tissues
• The target cell or target tissue has a specific
  proteins that allows the hormone to attach to

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Controlling Hormones

• Negative feedback mechanisms in the blood are the
  primary means of controlling hormones
• This occurs three ways
• Hormonal stimulus hormones trigger by other
  hormones most triggers start in the
  hypothalamus in the brain

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Controlling Hormones

• This occurs three ways, continued
• Humoral stimuli fluids in the blood cause the
  release , example is the production of insulin
• Neural stimuli nerve fibers trigger the release,
  example is adrenaline

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Endocrine Organs

• Major organs include
• Pituitary, thyroid, parathyroid, adrenal, pinal,
  thymus, pancreas and gonads
• Hypothalamus is part of the nervous system, but
  also considered part of the endocrine as well

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Endocrine Organs

• Pituitary Gland
• Located in the brain and approximately the size
  of a grape
• Called the master gland because it makes hormones
  that regulate other glands
• Causes people to grow and onset of puberty
• Produces tropic, growth, prolactin,
  adrenocorticotropic, thyroid-stimulating,
  thyrotropic, gonadotropic, follicle-stimulating,
  lueteinizing, and interstitial cell- stimulating
  hormones

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Endocrine Organs

• Thyroid Gland
• Found in your lower neck by the wind pipe
• Regulates your metabolism
• Parathyroid Glands
• Two lobes found near the thyroid gland
• Help control blood calcium levels and calcium
  absorption

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Endocrine Organs

• Adrenal glands
• Found over the top of the kidneys
• Helps to regulate mineral absorption, helps
  regulate blood pressure, helps regulate blood
  sugar and produces some sex hormones

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Endocrine Organs

• Pancreas
• Produces insulin, which regulates blood sugar
• If there is too much sugar in the blood in pushes
  the sugar out of the blood if there is too
  little causes stored sugars to be releases

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Endocrine Organs

• Pinal gland
• Found in the brain
• Not much is known about this gland, but the
  sleep trigger appears to be here
• It also appears to inhibit sexual maturation
  until an adult size body is reached

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Endocrine Organs

• Thymus
• Located in the upper throat
• Large in infants and children, but decreases in
  size as we age
• Helps with growth and immunity

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Endocrine Organs

• Gonads
• Female gonads ovaries
• Almond-sized and located in the pelvic cavity
• Produce estrogen and progesterone
• The rhythmic cycle of these two hormones cause
  the release of the ova and the secondary sex
  characteristics in females

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Endocrine Organs

• Gonads
• Male gonads testes
• Located outside the body in the scrotum
• Produce androgens, which testosterone is the most
  important
• Testosterone cause the production of sperm and
  male sex characterisitics

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Unique Hormone Producing Organ

• Placenta
• A temporary organ found in the uterus only during
  pregnancy
• Provides respiratory, excretory and nutrition
  delivery for the growing fetus, but also produces
  hormones necessary to maintain the pregnancy

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Unique Hormone Producing Organ

• Placenta
• Produces human chorionic gonadotropin (hCG)
  hormone this is what home pregnancy tests
  detect
• Also produces human placental lactogen to prepare
  breasts for lactation
• Also produces relaxin to loosen ligaments for
  childbirth

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Disorders with the Endocrine System

• Diabetes mellitus
• Goiters
• Graves disease
• Tumors