ENDOCRINE SYSTEM

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ENDOCRINE SYSTEM

• Series of glands that produce hormones to help
  maintain homeostasis.
• Hormones Chemical regulators that affect other
  parts of the body.
• Insulin
• Growth Hormone
• Gastrin

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Hormones

• Some glands produce one hormone, some produce
  many kinds and even other chemicals.
• Hormones must be produced and travel through the
  blood to a target cell or organ.
• Levels of hormones vary throughout the day.

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Coordination

• The nervous system and the endocrine system work
  together to allow the body to function.
• Nervous System --gt SHORT TERM corrections
• Endocrine System --gt LONG TERM stability

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HORMONES

• Two types of hormones
• Steroid hormones made from cholesterol, complex
  ring structures, fat soluble
• Sex hormones, cortisol
• Protein hormones amino acid chains
• Insulin, growth hormone
• To be susceptible to the effects of a hormone, a
  cell must have a specific receptor.

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Mechanism of Action Steroid Hormones

1. hormones diffuse out of blood stream and into the
   target cells
2. combine with receptor molecules in cytoplasm

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Mechanism of Action Steroid Hormones

• hormone-receptor complex diffuses into nucleus
• attaches to chromosomes and activates a gene,
  initiating transcription and protein synthesis.

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Mechanism of Action Protein Hormones

• hormones diffuse out of blood stream
• attach to receptors on the cell membranes of
  target cells

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Mechanism of Action Protein Hormones

• the receptor-hormone complex activates the
  production of enzyme that converts ATP into
  cyclic AMP (cAMP)
• cAMP is a messenger that activates various
  enzymes inside the cell to begin their normal
  functions.

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PITUITARY GLAND

• This is known as the master gland because it
  controls a lot of other endocrine glands.
• A small sac connected to the hypothalamus.
• Pituitary gland stores hormones while the
  hypothalamus stimulates it to release them.

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PITUITARY GLAND

• The pituitary gland has two lobes
• The posterior lobe stores and releases hormones
  produced by the hypothalamus (ex. ADH, oxytocin)
• The anterior lobe produces and stores its own
  hormones (ex. TSH, prolactin)

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Presentation adapted from Rebecca Martin
http//schools.alcdsb.on.ca/hcss/teacherpages/mart
inreb/default.aspx