Endocrine System

• Describe endocrine system


  The main chemical messenger of the body, where hormones are secreted into bloodstream from glands, and then are transported towards target cells in the blood, with complementary receptors.
• Which gland is the master gland?

  Pituitary gland
• What does the endocrine system work alongside?

  The nervous system
• What is the endocrine system?

  A control system that secretes hormones which are required to regulate many bodily functions
• What does the endocrine system have?

  A series of glands

  • These release hormones throughout the bloodstream
• Briefly describe hormones 


  Chemical messengers
• Where are hormones sent?

  Target organs or cells to elicit responses

  • can target more than 1 organ
• Give one detail of the endocrine system in comparison to nervous transmission?

  Endocrine system is much slower than nervous transmission
• Example of a hormone

  Adrenaline

  • released to increase HR so the target organ would be the heart
• glands i need to know about

  • thyroid gland
  • adrenal glands
  • testis
  • ovaries
  • pancreas
  • pituitary gland
• The fight or flight response is an example of what?

  The nervous system and endocrine system working in parallel (at the same time)
• fight or flight - what is this generated by

  the sympathetic branch of the autonomic nervous system
• What is the fight or flight response

  A physiological reflex response designed to help us manage stressful situations
• What does the fight or flight response mean

  we can react more quickly than useful, and facilitates optimal conditions to enable us to fight or get out of the way
• Fight or flight stages?

  1. hypothalamus recognises a threat and triggers the switch from parasympathetic to sympathetic branch of ANS
  2. this sends a message to adrenal medulla
  3. which releases adrenaline into bloodstream
  4. leading to the effects of adrenaline (covered in other slides)
• what is the adrenal medulla

  centre of the adrenal gland
• general effects of adrenaline?

  Prepares the body for action (ie fight or flight response)

  • increased oxygen supply to the brain for rapid responses planning
• Direct effects of adrenaline

  • Increased HR
  • Blood vessel constriction so RATE of blood flow is greater (blood pressure increases)
  • increased sweat production
  • increased repiration
  • reduced blood flow to digestive system
  • increased blood flow to brain and skeletal muscles
• fight or flight - what happens when threat passes

  The PNS brings bodily functions to a normal rate, it is 'antagonistic' to the sympathetic system

  • this is called 'rest and digest'
• what are the 2 branches of the autonomic NS

  sympathetic and parasympathetic

  • these are antagonistic
• What does the thyroid do?

  Releases the hormone thyroxine , which increases HR = increases rate of growth
• What does the adrenal gland do?

  Releases adrenaline:

  • creates physiological arousal preceding the fight or flight response, through increasing the activity within the sympathetic branch of the nervous system
• Why is the pituitary gland considered to be the 'master' gland?

  Because it controls the release of hormones from all other glands in the body
• what response is adrenaline linked to?

  sympathetic

  fight or flight
• where are adrenal glands

  by the kidneys?
• testes function?


  secrete male sex hormones

  testosterone
• What does pancreas do

  regulates level of sugar in bvlood
• adrenal glands help to do what

  help trigger fight or flight response
• thyroid gland affects what?

  metabolism
• Details about pituitary gland

  • AKA master gland
  • 'most influential gland' in endocrine system
  • in brain
  • secretes oxytocin and growth hormone
• why is hypothalamus important in context of pituitary gland

  brain region controlling pituitary gland
• the nervous system directs the endocrine system which directs the nervous system
• what can the fight or flight response be triggered by?

  • unhealthy food
  • emotional stress
• fight or flight details

  generated by sympathetic branch of ANS