The Endocrine System

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The Endocrine System
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Section 35.3
Control of the Body

• Internal control of the body is directed by two
  systems
• The Nervous System
• The Endocrine System

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Systems that chemically coordinate the body

• NERVOUS
• ENDOCRINE

• Stimuli-response
• Rapid response
• Short time
• Stimuli-response
• Slow response
• Lasts long time
• BothHOMEOSTASIS

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Section 35.3
The Endocrine System

• Made up of endocrine glands
• Release chemicals (hormones) directly into the
  bloodstream - act as messengers in the body

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Hormones

• Chemicals secreted by endocrine glands
• Conveys information to cells in the body
• Bind to receptors of target cells

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The Endocrine Glands

• Located throughout the body
• Most are controlled by the pituitary gland
• Master endocrine gland

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Pituitary The Master Gland that controls other
endocrine glands

• Bean-size, at base of skull
• Secretes 9 hormones that Regulate Many body
  functions

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Section 35.3
Hypothalamus

• Portion of the brain
• Controls the pituitary gland
• Connected by nerves and blood vessels
• Sends messages to the pituitary gland
• Pituitary glands then releases its chemicals

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Section 35.3
Negative Feedback Control

• I.e. thermostat.
• Temperature drops
• Thermostat stimulates heater to increase output
• Temperature rises, thermostat stops stimulating
  the heater, so it shuts off.
• Cycle continues
• Most endocrine glands operate under negative
  feedback systems

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Section 35.3
Control of blood water levels

• Lets say you are working out in the gym.
• Water level in your blood goes down.
• Hypothalamus stimulates the pituitary gland to
  release antidiuretic hormone (ADH).
• ADH reduces amount of water in urine by causing
  the absorption of water in the kidneys.
• If the body gets over-hydrated, hypothalamus
  stops stimulating the release of ADH

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Section 35.3
Control of blood glucose levels

• When you eat, blood glucose levels rise.
• Pancreas releases insulin.
• Insulin causes liver and muscle cells to take in
  glucose.
• Lowers blood glucose levels.
• When levels go down, pancreas releases glucagon.
• Glucagon causes the release of glucose from the
  liver

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I am STRESSED OUT!!

• The Adrenal Gland is involved in preparing your
  body for stressful situations
• Located on top of the kidneys

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The Adrenal Gland

• Releases steroids
• Increases available glucose and raises blood
  pressure
• Secretes adrenaline and norepinephrine
• Increases heart rate, BP and rate of respiration

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Thyroid and Parathyroid glands

• Thyroid gland
• Regulates metabolism, growth and development
• Releases calcium
• Parathyroid gland
• causes kidney to absorb calcium and magnesium

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Thymus

• The thymus is a specialized organ of the immune
  system.
• T cells attacks foreign substances

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Testes

• Testes are part of the reproductive system and
  part of the endocrine system
• Produce the male sex hormone testosterone and
  sperm