The Endocrine System

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The Endocrine System
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The Endocrine System

• A system containing many glands that secrete
  hormones that send messages in order to maintain
  homeostasis
• A group of glands that work together with the
  nervous system to coordinate all body functions.

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Glands of the Endocrine System
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• An Overview of the functions of the Endocrine
  Glands

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• Pituitary Gland the master gland. Called this
  b/c it controls all other endocrine glands and
  b/c it produces the highest number of different
  hormones compared to all other endocrine glands.
• Hypothalamus senses the hormone levels in the
  blood, then tells the pituitary what to do with
  either hormones it produces or by direct nerve
  stimulation.

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• Pineal Gland produces a hormone (melatonin)
  that helps you go to sleep.
• Thyroid Gland produces hormones that influence
  metabolic rate, decrease blood calcium and
  increase bone calcium levels.
• Parathyroid Glands produces a hormone that
  increases blood and decreases bone calcium
  levels.
• Thymus Gland produces a hormone that stimulates
  the immune response in children.

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• Adrenal Glands produces hormones help prepare
  the body for stress and control blood pressure.
• Pancreas produces hormones that control BSL
  (blood sugar level).
• Ovaries produces hormones that control female
  characteristics and menstrual cycle.
• Testes produces a hormone that control male
  characteristics and sperm production.

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The Endocrine System

• Endocrine gland
• a group of cells organized into a ductless gland
  (no tubes) that secretes molecular messengers
  (hormones) directly into the bloodstream.
• Examples pituitary, adrenal and thyroid

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Sketch the diagram in your notes

• Basic Structure of an endocrine gland

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• Exocrine gland
• a gland that dumps molecules (ex. enzymes or
  tears - not hormones) into ducts that generally
  lead out of the body or into another organ. It is
  a ducted gland (has tubes).
• Exocrine glands are NOT part of the endocrine
  system
• Examples salivary, milk, and sweat glands

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Sketch the diagram in your notes

• Basic Structure of an exocrine gland

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Endocrine Glands vs. Exocrine Glands

• Endocrine Gland Exocrine Gland

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The Pancreas

• The pancreas is a gland that is part endocrine
  and part exocrine.
• The endocrine part of the pancreas secretes
  hormones.
• The exocrine part of the pancreas secretes
  digestive juices including enzymes.

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Hormone

• A chemical that acts like a messenger a protein
  or steroid that causes a response in a target
  cell or organ
• Produced by endocrine glands, NOT exocrine
  glands.
• Examples ADH (Antidiuretic hormone),
  testosterone, thyroxin

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Target Cell

• A cell that a hormone is specifically directed
  towards.
• Example ADH works on the collecting tube
  in the nephron.
• Target cells contain molecules on their surface
  called receptors, to which hormones can bind.
  Target cells do their job when hormones are
  bound to their receptors.

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Target Cells

• In order for a hormone to cause a response, its
  shape must match the shape of its target cells
  receptors.
• If the hormone and the cells receptors do not
  match, the cell will not be affected and no
  response by the cell will occur.
• Its like the lock and key model

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Target Cells

• Example

http//www.ftmguide.org/images/receptors.gif
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Master Gland

• The hypothalamus and pituitary gland in the brain
  both work together to control all secretions by
  all endocrine glands.
• The pituitary is called the MASTER GLAND
  because it is near the top of the chain of
  command, telling other glands what to do, and
  because it produces a large number of different
  hormones
• The endocrine glands are essential in helping the
  body to maintain Homeostasis.

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Chain of Command
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AssignmentComplete the Compare and Contrast
chart on Endocrine vs. Exocrine Glands
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Master Chart
Gland Hormone Target Site Effect Produced
Hypothalamus A. Various RFs
B. Oxytocin
C.
Pituitary Gland