the endocrine system

• Key features

  The endocrine system works alongside the nervous system to control vital functions in the body through the action of hormones. It works more slowly than the nervous system but has widespread and powerful effects.
• Gland

  Glands are organs in the body that produce hormones. The key endocrine gland is the pituitary gland which is located in the brain. IT is called the master gland as it controls the release of hormones from all the other endocrine glands in the body
• Hormones

  Hormones are secreted in the bloodstream and affect any cell in the body that has a receptor for that particular hormone. For example, thyroide produced by the thyroid gland affects cells in the heart and also cells throughout the body which increase metabolic rates. This in turn affects growth rates.
• The endocrine system and the Autonomic nervous system work together

  Often the endocrine system and the autonomic nervous system work in parallel, for instance during a stressful event.
• Fight or flight response - the endocrine system and the autonomic nervous system working together.

  Stressor is percieved by the hypothalamus which activates the pituitary gland. The sympathetic nervous system is now aroused. Adrenaline is released from the adrenal medulla into the blood. This delivers the aroused state causing changes in target organs in the body. Immediate and autonomic responses occur the instance a threat is percieved. Parasympathetic nervous system takes over once the threat has passed. This returns the body to its resting state.
• Symapthetic nervous system

  Increased heart rate

  increases breathing rate

  dilates pupils

  inhibits digestion

  inhibits saliva production

  contracts rectum
• Parasympathetic nervous system

  decreases heart rate

  decreases breathing rate

  constricts pupils

  stimulates digestion

  stimulates saliva production

  relaxes rectum